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Abstracts American Dairy Science Association Southern Branch
ABSTRACTS AMERICAN DAIRY SCIENCE ASSOCIATION SOUTHERN BRANCH!
February, 1-4, 1998 Little Rock, AR
Sol Luteinizing hormone, growth hormone and prolactin response to the dopamine antagonist, pimozide, during the luteal phase of the estrous cycle in lactating Holstein cows. A. Ahmadzadeh*, M. A. Barnes, D. M. Denbow, A. W. Pryor, and S. M. jobst, Virginia Polytechnic Institute and State University, Blacksburg.
502 Effects of stage of lactation on follicular dynamics and recovered oocytes in Holstein cows. A. W. Pryor*, T .L. Bailey, S. Nadir, M. H. Irby, R. E. Bethard, and F. C. Gwazdauskas, Virginia Tech, Blacksburg. Lactating Holstein cows were used to evaluate effects of stage of lactation on follicular dynamics and quality of recovered oocytes. Cows in early lactation (EL;n=8) and mid-lactation (ML:n=7) were subjected to twice weekly ultrasonic ovarian evaluation and ovum pick-up beginning at d 28 and 118 postpartum, respectively, for 10 wk. Follicles were categorized as small (2 to 5 mm), medium (6 to 9 mm), large (10 to 12 mm) and very large (>12 mm). Recovered oocytes were graded from 1 to 4 based on cumulus density and ooplasm homogeneity. Milk yield averaged 39.9± .3 kg/d (mean ±SE) for EL and 37.4±.3 for ML. There was a significant interaction of treatment with the cubic effect of aspiration session for milk yield with a peak of 45 kg/d for EL at 6 wk postpartum, while ML milk yield declined from 41 kg/d at d 90 to 36 kg/d at d 190 postpartum. BW decreased significantly from 660 kg at 4 wk prepartum to 565 kg at 8 wk postpartum for EL compared an increase from 575 kg at wk 13 to about 590 kg at wk 23 postpartum. There were significant interactions of treatment by linear effects of aspiration session for total number of follicles, number of small follicles and follicular growth index. Total number of follicles increased from 13.5 to 18 for ML compared to 14.2 to 14.9 for EL; number of small follicles increased from 8.5 to 13 for ML compared to 9.8 to 10.6 for EL; and follicular growth index increased from 20.8 to 28 in ML compared to 22 to 23 for EL. There was a trend for the interaction of treatment with the cubic effect of aspiration session for total number of oocytes recovered and number of poor oocytes. Later stages of lactation were associated with increased follicle numbers, follicular growth index, oocytes recovered and poor quality oocytes compared to earlier stages of lactation.
Pimozide, a non-selective dopamine receptor antagonist, was used to investigate the role of endogenous dopamine on serum LH, GH, and prolactin secretion in lactating Holstein cows. Estrous cycles were synchronized using prostaglandin (25 mg) in 5 cows. On d 10 or 11 postestrus (mid-luteal phase), cows received 0.1 mg/kg BW pimozide Lv. Blood samples were collected at 15-min intervals for 4 h before and 4 h after pimozide. Immediately thereafter all cows received 25 ug of GnRH Lv. and blood collection was continued for 1 h. Mean serum progesterone concentration was 3.0 ± 0.5. Pimozide significantly increased mean serum prolactin concentrations. Mean LH concentrations, pulse frequencies and pulse amplitudes were not altered by pimozide treatment. Exogenous GnRH caused a significant increase in mean LH concentrations. Mean GH concimtrations were not affected by pimozide. These results suggest that endogenous dopamine plays an inhibitory role in prolactin secretion in lactating Holstein cows. However, a dopaminemediated mechanism for modulation of LH and GH secretion is absent during the mid-luteal phase of the estrous cycle. Hormone pre-pimozide post-pimozide prolactin conc. (ng/ml) 4.1 ± 6.7" LH conc. (pg/ml) 252 ± 23 LH pulse frequency (pulses/4h) 1.4 ± 0.2 LH pulse amplitude(pg/ml) 306 ± 177 GH conc. (ng/ml) 7.8 ± 1.6 ",bMeans within a row differ (P < .01).
81.9 ± 298 ± 1.8 ± 672 ± 10.1 ±
8.5 b 24 0.2 177 1.6
1Asterisk indicate:s author who presented paper.
1998 j Dairy Sci 81:1186-1193
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503 Effects of dry period supplementation of parenteral vitamin E and selenium in Jersey and Holstein cows. R. T. Bass, 11*, W. S. Swecker, Jr., and C. C. Stallings, Virginia Polytechnic Institute and State University, Blacksburg. The effects of late gestation parenteral supplementation of vitamin E and Se on parturient and post-parturient blood concentrations of these micronutrients were determined in 16 Jersey and 36 Holstein cows. Cows were allotted to blocks by breed and expected calving date; cows within blocks were randomly assigned vitamin E or Se treatment in a 2X2 factorial design. Treatments were administered as subcutaneous injections at the time of mid-dry period sampling. Dosages were empirically based on body weight differences between breeds. Holsteins were given 3000 IU and 32.5 mg of vitamin E and Se, respectively, while Jerseys were given 2400 IU of vitamin E and 22.5 mg of Se. All groups were similarly managed and fed through the study period. Blood samples were taken at dry off, 3-4 weeks prior to predicted calving date (the time of treatment), within 24 hours after calving, and 2-3 weeks post-calving for assessment of "serum vitamin E and blood Se concentrations. Both Se and vitamin E concentrations differed between breeds at dry off. The breed effect for Se persisted, with Jerseys exhibiting higher blood concentrations than Holsteins at the pre-calving and calving samplings. Selenium supplementation resulted in higher blood Se concentrations at calving. Treatment did not affect serum vitamin E concentrations at calving or post-calving, nor blood Se concentrations post-calving. A periparturient decline in serum vitamin E concentrations was observed in both breeds and all treatment groups.
504 Grazing behavior and rumen fermentation patterns in lactating cows supplemented with different forms of corn. F. D. Soriano* and C. E. Polan, Virginia Polytechnic Institute &. State University, Blacksburg. The objectives were to determine time patterns of grazing and rumination in lactating cows, and to measure rumen pH, ammonia nitrogen, and volatile fatty acids (VFA). An intensive rotational grazing system was used. Cows grazed from 0400 to 1000 and from 1500 to 2200 h daily. In experiment 1, 38 Holstein and 2 Jersey cows were supplemented daily either with (kg/d) 7.8 high moisture corn (HMC), 6.7 coarsely ground corn (CGC), 6.7 finely ground corn (FGC), or 5.2 of high moisture corn (HMCL)- in two equal feedings. For two consecutive days, while grazing, the number of cows grazing, lying, or standing were recorded every half hour. Individual behavior was recorded for 4 cows each with the most and least daily milk yield. Cows grazed an average of 6.4 hid, 4.1 h in the afternoon and 2.3 h in the morning. No difference was observed in grazing patterns between those cows with the most or least daily milk yield. In experiment 2, four rumen cannulated cows in mid-lactation, 1 Jersey and"Y-Holstiiin each, were supplemented twice daily with either CGC of HMC as above. After milking (1400 h) ruminal pH was measured and rumen fluid samples were collected. After supplementation with corn (0 h) and at 1, 2, 3,... 8 h post-corn feeding while grazing, ruminal pH was measured and rumen fluid was collected to determine ammonia nitrogen and VFA. Ruminal fluid pH was similar for both corn supplements and was lowest (5.9 and 5.8) at 5 and 8 h respectively. Rumen ammonia nitrogen concentrations started to increase approximately 2 h after cows began grazing, and was 15.5% lower in cows supplemented with HMC vs. CGC (26 vs. 31 mg/dl), although differences were not significant. In experiment 1, results indicated that cows spent more time grazing in the afternoon than in the morning. High moisture corn may improve microbial incorporation of dietary nitrogen compared to CGC.
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505 Evaluation of whole cottonseed (fuzzy, mechanically delinted and starch coated) as an ingredient in the diet of high producing dairy cows. D. N. Moore*, J. E. Tomlinson, B. L. Clark, R. B. Moore, M. E. Boyd, and W. J. Ricks, Mississippi State University. Forty-eight lactating Holstein cows (mean = 143 Days in milk) were randomly assigned to 1 of 4 diets based on energy corrected milk (ECM), lactation and days postpartum to evaluate sources of dietary lipid in a 96 day trial. All diets contained corn silage, chopped grass hay, corn, soybean meal, minerals, vitamins and were fed as total mixed ration (TMR). The 4 dietary lipid sources were: animal fat (fat); fuzzy whole cottonseed (FCS); delinted whole cottonseed (DCS); and starch coated cottonseed (SCS). Lipid was added at a rate of .57 kg/cow/day and all diets were isonitrogenous and isocaloric. Diets were fed twice daily in amounts to allow 5-10% refusal. Body weights and body condition scores were taken at 28 day intervals. Individual cow pooled milk samples (AM & PM milkings) were taken 1 day weekly for fat, protein, milk urea nitrogen (MUN) and somatic cell count (SCC) analyses. Individual cow milk yield was recorded at each milking daily. Mean dry matter intake (DMI) (kg/cow/d), actual milk (kg/cow/d) and ECM (kg/cow/d) respectively, were 20.6, 29.2, 27.8 for Fat; 21.0, 25.6, 26.6 for FCS; 22.1, 26.1, 26.8 for DCS; and 22.1,26.7,27.3 for SCS. Milk % fat, % protein, urea-N (mg/dl), and SCC, respectively were 3.21, 3.37, 18.2, 298 for Fat; 3.87, 3.39, 18.1, 448 for FCS; 3.70, 3.37, 18.6, 385 for DCS; and 3.74, 3.4, 17.4, 566 for SCS. Milk % fat was lower (p<.05) for Fat than the 3 cottonseed diets. Body weight and BCS data were not significantly different between treatments. The data from this trial indicate that Fat, FCS, DCS and SCS are acceptable dietary lipid sources for lactating dairy cows.
506 Supplemental dietary protein effects on the energy status of grazing dairy cows: Year II. A. M. Chapa*, J. M. Fernandez, M. E. McCormick, and J. F. Beatty, Louisiana State University Agricultural Center, Baton Rouge and Southeast Research Station, Franklinton. An experiment conducted to investigate the influence of dietary protein on the energy status of dairy cattle was continued during November 1996 - April 1997(Year II) at the Southeast Research Station. Holstein cows (n = 60) were blocked on the basis of milk equivalents and calving group (pre-partum group: dietary treatments imposed at calving [avg days in milk = 0] and post-partum: dietary treatments imposed after calving [avg days in milk = 41]). Cows were randomly assigned to one of three treatment groups and rotationally grazed on immature ryegrass pastures. Treatment groups included: 1) control-corn/SBM (22.2% CP, 10.2% VIP); 2) corn/SBM (15.6% CP, 7.9% VIP); and 3) corn/corn gluten meal/ blood meal (15.6% CP, 9.0% UIP). Blood samples were collected on d 50, 100, and 150 post-partum and on breeding days. Day 50, 100, and 150 plasma was analyzed for glucose, ,6-hydroxybutyrate, NEFA, urea N, and ammonia N; whereas breeding day samples were analyzed for glucose, NEFA, and urea N. ,6-hydroxybutyrate values were highest (P < .02) during d 100 compared with d 50 and 150 (0.61 vs 0.47 and 0.50 mM). NEFA, urea N and ammonia N were higher (P < .005) on d 50 compared to d 100 and 150 (220 vs 127 and 121 JLEq/L; 14.9 vs 13.9 and 13.1 mM: 87 vs 76 and 76 JLM, respectively). Cows in the post-partum calving group had higher (P < .05) NEFA and urea N values compared with the pre-partum group (177 vs 136 JLEq/L; 14.4 vs 13.3 mM, respectively). At the time of breeding, glucose was lower (P < .06) in TRT 3 compared with TRT 2 and 1 (3.38 vs 3.51 and 3.46 mM) and urea N levels were higher (P < .02) in TRT 1 compared with TRT 2 and 3 (17.2 vs 13.9 and 13.8 mM). Cows in the post-partum calving group had higher (P < .05) NEFA values compared with the pre-partum group (256 vs 209 JLEq/L) at breeding. Calving group and days postpartum excerted a greater influence on energy status than the level of supplemental dietary protein.
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507 Comparison of Arkansas dairy herds whose owners sell to different cooperatives. T. R. Bedingfield, C. F. Rosenkrans, J. A. Pennington, Z. B. Johnson, and C. V: Tarn, The University of Arkansas Department of Animal Science, Fayetteville.
509 Effect of adding levels of molasses on amino acid composition of bermudagrass (Cynodon dactylon) silage. V. Nayigihugu*, D. W. Kellogg, E. K. Vaught, Z. B. Johnson, and K. S. Anschutz, University of Arkansas, Fayetteville.
Arkansas dairy producers (n=749) were surveyed about herd characteristics and management techniques. Herds differed in size location in state, and total income. Furthermore, as shown in the table above, these data indicate that dairy producers that use progressive management techniques vary by marketing strategy. Cooperatives or Processor Item Prob. A B C D
Four levels (0, 4, 8, and 12%) of molasses (M) were ensiled with bermudagrass, and amino acid composition of silage was determined. Dried M (97% DM) was applied to chopped forage that had been treated with 1174 Pioneer® Silage Inoculant (1.54 lit of forage). Forage was packed in 19-1 plastic containers that were double-lined with .025 mm thick polyethylene bags, and approximately -1.03 x 10- 5 Pa of vacuum was applied. Silages were sampled after ensiling for d 5, 15, and 33. There was an interaction between sampling day and level of M for phenylalanine (P<.05). Means of phenylalanine decreased (P<.05) on d 5 from .64% with OM to .50, .44, and .45% with 4M, 8M, and 12M, respectively. On d 15 and 33, there were no differences (P>.05) of phenylalanine due to M levels. Means of alanine decreased (P<.05) from .97% with OM to .90% when 12M was applied. Means of glutamic acid increased (P<.05) from .70% to .80%, respectively when forage was treated with OM and 12M. Threonine decreased (P<.05) from .40% to .38% at OM and 12M. All other amino acids percentages were not affected by M. While means of alanine, histidine and valine increased (P<.05) froI\1l .91 to .98%, from .54 to .69% and from .52 to .56%, means of glutamic acid decreased (P<.05) from .79 to .73%, respectively, on d 5 and d 33. Increasing M in bermudagrass silage lowered phenylalanine (only on d 5), alanine, and threonine but increased glutamic acid.
Milking· Cows Use DHIA,% ET Conducted,% Synchronize Heifers,% Grain to Dry Cows, % Dry Treat Cows,% Disinfect Hands, % Own Antibiotic Test,% ID Calves by 30 d, % Store Feed in Silo,% FFA as Youth,% Employee and Family,%
.01 .01 .01 .03 .01 .01 .01 .01 .05 .01 .01 .01
63.8 22.6 5.5 6.0 86.9 73.5 29.9 60.9 50.9 17.7 65.1 61.9
87.0 57.1 16.7 15.1 93.3 97.4 30.4 75.3 56.0 40.5 80.3 38.9
53.7 23.4 7.7 11.5 82.3 83.1 36.4 70.3 62.3 10.9 57.8 64.9
55.2 11.9 2.5 2.6 54.8 57.1 20.0 21.9 73.0 12.5 53.7 79.4
5010 Effect of treating Tifton 85 bermudagrass hay or cottonseed hulls with a forage oxidant on nutrient composition, and in situ and in vitro digestion. P. Mandebvu* and J. West, University of Georgia, Tifton.
508 Ensiling characteristics of tall growing soybean cultivars used for silage. V. Nayigihugu*, D. W. Kellogg, D. E. Longer, Z. B. Johnson, K. A. Anschutz, and T. E. Devine, University of Arkansas, Fayetteville. Seven cultivars of soybean (Glycine max [L.] Merr.)['PA 5-2-1' (T1), 'PA Bu-2-2' (T2), 'OR 5-12-1T' (T3), 'OR 5-12-1G' (T4), 'OR 14-12-2' (T5), 'OR 13-12-3' (T6), 'OR 19-12-2' (T7), 'Hutchinson' (C1)J and a sorghum (Sorghum bicolor [L.] Moench ['Pioneer 838F' (C2)]) variety were ensiled and tested for nutritive quality to evaluate potential of cultivars as silage crops. Cultivars were grown in four replicate plots near Fayetteville and Rohwer in 1995 and 1996. Forages were harvested at full seed (R6 growth stage) and ensiled for 33 d. Silages from all the cultivars were well preserved as indicated by low pH (4.6, 4.7, 4.5, 4.3, 4.5, 4.3, 4.4, and 4.9) and high lactic acid content (1.0, 1.3, 1.3, 1.1, 1.2, .9, 1.3, and 1.8%, respectively for T1, T2, T3, T4, T5, T6, T7, and C1). The IVDMD was 70.2, 72.9, 65.4, 73.2, 71.7, 72.5, 68.9, and 75.7%, respectively for T1, T2, T3, T4, T5, T6, T7, and C1. Any of the soybean cultivars would dramatically improve the CP of silage if grown with sorghum, and the tall-growing cultivars should be more competitive for light than typical soybean varieties if planted with sorghum.
Journal of Dairy Science Vol. 81, No.4, 1998
The objectives of this study were to determine the effects of treating Tifton 85 bermudagrass hay (BGH) or cottonseed hulls (CSH) with a hypochlorite forage oxidant or sodium hypochlorite solution (commercial liquid bleach) on nutrient composition and in situ and in vitro disappearances of DM, NDF and ADF. The initial nutrient composition (% DM) for BGH and CSH respectively, were OM: 94.9 and 96.8; CPo 6.5 and 6.2; ash-free NDF: 79.7 and 79.8; ash-free ADF: 40.6 and 60.7; hemicellulose: 39.2 and 19.0; cellulose: 34.4 and 31.6; and acid detergent lignin (ADL): 6.0 and 28.0. The forage oxidant decreased (P < 0.05) concentration of ADF and had no effect on the concentrations of NDF or ADL, in situ DM or NDF disappearance, or in vitro DM disappearance. Disappearance of NDF in vitro declined slightly with increasing oxidant levels. Increasing the water content of the treatment solution at application of the forage oxidant from 10 to 50% of the forage weight (as fed basis) decreased the concentrations of ADF (P < 0.01) and cellulose (P < 0.05), increased (P < 0.01) the concentration of ADL, but had no effect on in situ DM, NDF or ADF disappearance. When compared with sodium hypochlorite, the forage oxidant decreased the concentrations of ADF (P < 0.10) and cellulose (P < 0.01). Sodium hypochlorite decreased (P < 0.01) the concentration of ADL when compared with the forage oxidant. It is concluded that the forage oxidant or sodium hypochlorite failed to significantly improve the nutritive value or digestibility of BGH orCSH. .,
ASSOCIATION AFFAIRS
5011 Production response of Jersey cows to whole fuzzy cottonseed coated with starch or a combination of starch and sugar. J. K. Bernard*, H. H. Dowlen, D. L. Johnson, and H. Moorehead, The University of Tennessee, Jackson and Lewisburg. Thirty-six Jersey cows averaging 170 days in milk were used in a randomized block experiment to determine the effect of coating whole fuzzy cottonseed on dry matter intake and milk production and composition. After a 2-wk pretrial period, cows were assigned randomly to one of three experimental diets. Whole fuzzy cottonseed provided 15% of the ration DM and was coated with: 1) control, 2) 5% gelatinized corn starch, "or 3) 5% gelatinized corn starch and 10% multidextrin sugar. Experimental rations were fed twice daily for six weeks. Cows fed the coated cottonseed tended to consumed more DM and produced more milk than the control ration. Concentrations of milk fat and protein were lower but yield was not different when the coated cottonseed were fed compared to whole fuzzy cottonseed. Energy-corrected milk yield (ECM) was not different among treatments. Starch Contrast ' Control Starch + Sugar SE 1 2 DMI, kg/d 19.4 20.5 20.2 0.4 0.06 0.61 Milk, kg/d 22,2 23.9 24.3 0.8 0.08 0.76 Fat, % 4.99 4.70 4.49 0.15 0.04 0.34 Fat, kg/d 1.09 1.11 1.09 0.04 0.88 0.80 Protein, % 3.90 3.75 3.67 0.08 0.06 0.48 Protein, kg/d 0.86 0.89 0.89 0.03 0.34 0.99 ECM, kg/d 27.3 28.3 28.2 0.9 0.39 0.96 1 Contrast included: 1 = whole fuzzy cottonseed versus coated cottonseed and 2 = starch coating versus starch plus sugar coating.
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5013 Mycotoxin occurrence in farmer submitted samples of North Carolina feedstuffs: 1989-1997. L. W. Whitlow*, W. M. Hagler, Jr., and B. A. Hopkins, North Carolina State University, Raleigh. From 1989 through 1997, >2400 feed samples were submitted by North Carolina producers for mycotoxin analyses to laboratories operated by either the North Carolina Department of Agriculture or by North Carolina State University. Mycotoxin analyses were conducted by various methods such as gas-liquid chromatography, HPLC, thin layer chromatography and ELISA, however, the majority of results were by ELISA. Feeds were frequently analyzed for aflatoxin (AF), deoxynivalenol (DON), zearalenone (ZEN), and T-2 Toxin (T-2), and infrequently for fumonisin (FBI). A greater (P < .05) percentage of samples were contaminated with either ZEN (38%) or T-2 (19%) in 1994 than in other years, however, there was no effect of year (P > .05) on mean concentrations of either ZEN or T-2. Incidence of DON was greater (P < .05) during 1990 (73%) and 1993 (70%) than during other years but there was no year effect on DON concentrations. The yearly incidence of AF was greatest (P < .05) for 1989 (32%) and 1990 (23%) than during other years, however, yearly mean AF concentration (358 ppb) was greater (P < .05) only during 1990. When feeds were grouped as forages, concentrates, or total diets over the total period, there were no significant differences (P > .05) in mean mycotoxin concentrations or in mean frequency of occurrence except for DON. Occurrence of DON was greatest for total diets and least for forages (P < .05). Mycotoxin Detection Limit n Positive Mean ± s.d. Aflatoxin Deoxynivalenol Zearalenone T-2 Toxin
20 50 70 50
ppb ppb ppb ppb
1617 2472 1769 2243
7.4 57.8 17.5 7.3
% 91 ± 320 ppb % 1739 ± 10880 ppb % 445 ± 669 ppb % 482 ± 898 ppb
5014 Effects of harvest management on yield and quality of two sorghum types. M. E. McCormick* and G. J. Cuomo, Louisiana State University Agricultural Center, Franklinton and University of Minnesota, West Central Experiment Station, Morris. 5012 Effects of processing of pre-ensiled corn silage by rolling and feeding in diets with and without cottonseed hulls on milk yield and milk composition. L. W. Whitlow and B. A. Hopkins*, North Carolina State University, Raleigh. Twenty-four early lactation Holstein cows (12 primiparous and 12 multiparous) averaging 48 days in milk were assigned to treatments in a randomized block design. The objective was to determine the effects of processing temperate corn silage (CS), by rolling with a forage roller mill before ensiling in an upright silo and feeding in diets with and without cottonseed hulls (CSH), on milk yield and milk composition. The CS was Dekalb 743, harvested at 142 days of maturity, and averaged 28.9 % starch as a percentage of the DM. Cows were randomly assigned to one of four trea:t"me;;ts as follows: 1). non-rolled CS without CSH; 2). non-rolled CS with CSH; 3). rolled CS without CSH; and 4). rolled CS with CSH. Cows remained on a treatment period for 28 d, then were changed to a different treatment. Cows received rations twice daily using Calan@ feeding stations; feed refusals were measured once daily; DM and CP intakes were calculated. Rolled CS had no significant effect on DM intake, CP intake, milk yield, milk fat percentage, milk fat yield, milk CP percentage, milk CP yield, or 4 % FCM yield. Cows fed CSH had significant increases in kg DM intake (21.05 vs. 19.83), (P < .024), kg CP intake (1.98 vs. 1.68), (P < .0001), kg milk yield (32.46 vs. 30.33), (P < .005), and kg milk CP yield (.98 vs..91), (P < .002). Milk fat percentage tended to be lower in cows fed CSH (3.11 vs. 3.33), (P < .08).
High forage yield, drought tolerance, and ratooning capabilities of sorghum indicate potential for this crop in balage production systems in the southeastern U.S. The objectives of the present study were to compare harvest management effects on whole-plant yield and quality of a moderate yielding forage sorghum (NK-300 FS) and a high yielding, "delayed maturing" sweet sorghum x sorghum sudan type (4-Evergreen SS). Nine plots of each sorghum type were planted on May 29, 1996 from which three reps of each sorghum were harvested on days 68, 88, and 108 post-planting. Regrowth from d-68 plots was harvested 44 days after initial harvest. FS harvests were in the vegetative, bloom, and hard dough stages of maturity for d-68, d-88 and d-108, respectively. SS remained in the vegetative state at all harvests. Both FS and SS experienced linear increases (P<.05) in forage yield and declines in crude protein and IVTD with advancing age. Magnitude of IVTD decline was greater for SS than FS resulting in lower overall IVTD for SS compared to FS (68.7 and 66.1% IVTD for FS and SS, respectively). Lower IVTD of SS was associated with higher concentrations of ADF, lignin and NDF in d-88 and d-108 samples. Plant height was greater for SS than FS at all harvest dates (2.62 vs 1.68M), but reduced tiller production for SS (314 vs 444 X 103 tillers ha- l ) resulted in similar forage yields over cuttings (mean=15.1 Mg DM Ha- l ). Regrowth yield was also similar between sorghum types (mean=7.9 Mg DM Ha- l ), but IVTD was lower for SS than FS (69.7 vs 73.3%). Both sorghum types contained high concentrations of water soluble carbohydrates (mean=25.3% of DM). These data indicate that, for the two sorghum types evaluated in this study, over-season and regrowth quality favor the moderate yielding type.
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5015 Ammoniated and non-ammoniated corn silage supplemented with different amounts of rumen undegradable protein did not alter milk yield of Holstein cows. C. E. Polan* and Z. Wu, Virginia Polytechnic Institute and State University, Blacksburg. Two experiments, each 2x2 factorial, compared ammoniated and 000ammoniated corn silage, and two amounts of rumen-undegradable protein
(RUP) in the diet. Diets in Experiment 1 contained (DM%) 19 alfalfa haylage, 30 to 41 corn silage, 30 to 41 corn, 9.8 soybean meal (SBM) or one-half the SBM replaced with 1.0 corn gluten meal, 1.2 blood meal, and 1.2 fish meal. Urea (O.4%) were included in diets with non-ammoniated silage to equalize to
15.8% crude protein (CP). RUP (%of CP) was 30 and 34 for the lower and 37 and 41 for the higher RUP diets Acid detergent fiber (ADF, 17%), neutral detergent fiber (NDF, 28%) and net energy lactation (NEL, 1.65 Meal/kg) were equal in all diets. After 4 wk, cows were reallocated and the 4 wk interval was
repeated. Neither milk yield (34 kg), dry matter intake (DMI, 22.4 kg), nor milk composition were affected by ammoniation or RUP of the diet. Neither were changes in body condition scores Of body weight (BW) affected. Plasma urea nitrogen was greater in cows fed ammoniated silage (19.5 mg/dl) than
those fed non-ammoniated (15.8 mg/dl). Diets in Experiment 2 compared corn silage with or without ammonia and supplements with zero FM or with
FM substituted for SBM. Diets contained (DM%) 28.5 corn silage, 29.1 alfalfa haylage and 5.8 whole cottonseed. SBM was 6.5 or 2.7 plus 2.9% FM in the non-ammoniated silage diets. In the ammoniated diets, SBM was 3.8 or zero and 2.9% FM. Corn varied to account for difference in CP content of supple-
ments. Diets were (%) 15.0 CP, 18.3 ADF, 30.5 NDF and 30.4 or 36.7 RUP for SBM or FM diets, respectively. Cows remained on the same diet for 10
wk. Neither milk yield (35.5 kg) nor milk composition differed by diet. Milk
5017 Nutritional analyses of a humate soil conditioner. D. W. Kellogg* and K. A. Anschutz, University of Arkansas, Fayetteville. Chemical content and in vitro digestive characteristics were determined for a humate soil conditioner product that was mined in New Mexico. The product contains 83.5% ash (89.5% dry basis) with 1.58% CP (1.69% dry basis). The specific mineral content was 1.43% Ca, 0.13% P, 1.56% K, 1.51% Mg, 3.10% S, 0.20% Na, 3.39% Fe, 2153 mg/kg Mn, 575 mg/kg of Zn, and 143 mg/kg Cu. Based on these samples, and assuming intake by a dairy cow of 10 kg of grain mixture daily containing 1% humate, it would supply the following percentage of daily mineral requirements: 0.8% of Ca (1.43 of 180 g Ca needed), 0.2% P (0.13 of 75 g P needed), 0.5% of K (1.56 of 300 g of K needed), 2.0% of Mg (1.51 of 75 g of Mg needed), 5.2% S (3.1 of 60 g of S needed), 0.4% of Na (0.2 of 54 g of Na needed), 225% of Fe (3.39 g compared to 1.5 g of Fe needed), 2.9% of Zn (57.5 mg of 1,200 mg of Zn needed), and 4.8% of Cu (14.3 mg of 300 mg of Cu needed). The IVDMD of humate was 29.5% when determined separately. There was decreased (P<0.05) IVDMD when 1% humate was added to alfalfa hay (A; 76.2 and 69.6%) or to A mixed with corn grain (C; 85.2 and 83.3). However, IVDMD was higher (P<.05) when 1% humate was added to C alone (84.1 and 87.4), to bermuda'grass hay (B; 60.0% and 63.8%), and to a mixture of C + B (72.4 and 74.6). With more than 1% humate, IVDMD declined, or tended to decline, due to the increasing amounts of indigestible mineral matter in the supplement. This type of supplement may find a niche when cows are consuming young, lush grass, and especially during the dry period of late pregnancy; although it will be necessary to monitor other mineral levels such as calcium and iron.
urea nitrogen differed in ammoniated (20.2 mg/dl) vs non-ammoniated (15.3
mg/dl) silage treatments. Cows fed diets with FM vs no FM gained more BW (47.6 vs 33.1 kg). In these experiments, sources of RUP substituted for SBM did not enhance milk yield regardless of ammonia in silage. In Experiment 2, ammoniated diets were more economical than non-ammoniated.
5016 Effect of hormone therapy on postpartum recovery in lactating Holsteins during the summer. G. Ullah*, B. L. Clark, S. C. Wilkinson, and J. W. Fuquay, Mississippi State University, Mississippi State. The stress of the early postpartum period can be exacerbated by heat stress for those cows calving in late summer with potential negative effects on postpartum recovery. The objective of this research was to determine if early postpartum treatment with gonadotropin-releasing hormone and prostaglandin F2o< would speed postpartum recovery in lactating Holsteins calving in late summer. Thirty-four Holsteins calving during August, either were injected with gonadotropin-releasing hormone 13 to 15 d postpartum followed by prostaglandin f 2o< 12 d later or maintained as control with no injections. Between 13 to 15 d and 44 to 46 d postpartum, all were observed for estrus twice daily using androgenized heifers. Blood samples were drawn twice weekly for determination of progesterone concentrations. On d 25, 36 and 45, uteri were palpated to assess degree of involution and ovaries we~e scanned ultrasonically to determine size and number of antral follicles as well as presence and size of corpora lutea. Average daytime rectal temperatures were 39.9°C for both treated and control cows. Days to first observations of estrus were 27.0 and 36.1 for tested and control cows, respectively (P<0.05). Progesterone concentrations were higher in treated cows than controls between d 37 to 45 postpartum (P<.05), but did not differ for d 15 to 25 or d 26 to 36. More treated cows had observable corpora lutea on d 36 and 45 than did controls (P<.05). Treated cows had more complete uterine involution (P<.Ol) on d 36 and 45 but were not different from controls on d 25. Therefore, early postpartum treatment of cows with gonadotropin-releasing hormone followed by prostaglandin F 2o< resulted in more rapid postpartum recovery as indicated by expression of estrus, observable corpora lutea, and uterine involution, thus providing potential for higher fertility.
Journal of Dairy Science Vol. 81, No.4, 1998
5018 Production and reproductive performance as measured by PCDART herds not enrolled in DHIA. D. W. Webb, University of Florida, Gainesville. PCDART software is being used by over a thousand herds as an onfarm database and herd information management system. While most herds using PCDART are enrolled in DHIA and have data forwarded to the centralized database, some larger herds use PCDART-Independent where no data is uploaded to the DRPC. Computer files from 28 PCDART-I herds are being analyzed to characterize the production and reproductive performance. These herds will be compared to DHIA herds in Florida, Georgia, South Carolina and Alabama using the following parameters: herd size, yearly milk per cow, daily milk per cow, percent days in milk, standardized 150-day milk, peak milk days open, days from calving to first breeding, services per conception, calving interval, percent sire identity, and PTA of service sires.
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5019 Effect of water sprinkling of varying time periods and water misting over the feed area on milk production. J. C. Lin*, B. R. Moss, J. L. Koon, C. A. Flood, B. Brady, and R. C. Smith, Auburn University. Auburn, Alabama.
5021 Impacts of changing regulations and financial assistance on Arkansas dairy waste management. K. W. VanDevender* and J. A. Pennington, University of Arkansas Cooperative Extension Service, Little Rock.
Fifty-two lactating Holstein cows (163±43 DIM) were randomly assigned to one of four treatment areas within an open free-stall barn from June 3 to September 15, 1997. All areas had four fans (on at 23.8°C; air flow = 5570 cu.ft./min) mounted over both the feed alleys and the freestalls. Treatments were [A] sprinklers (7) run for 3 min every 15 minutes; [Bj sprinklers (7) run for 2 min every 15 minutes; [Cj misters (16) run continuously when temperatures above 27.8°C.; [D] no water cooling; "A11 cows were housed inside other than 2 hours outside exercise daily. Sprinklers (10 psi) were on at 27.8°C for four 3-minute or 2-minute cycles per hour. Mist was provided at 27.8°C through nozzles (0.32 LPH at 60 psi) mounted on circular tubing around the two fans (4 each) and on straight pipe (4 each) in the direction of the air stream over the feed alley. Each treatment area contained 22-24 free stalls; 1/2 bedded with mortar sand, 1/2 with rubber containing mattresses. Cattle were all fed the same diets of corn silage, cottonseed, soybean hulls, protein/minerals pellet and corn formulated to contain 59.8% DM, 16.0% CP, 1.66 Mcal NEt/kg and 19.0% ADF. Least squares means for A,B,C,D respectively, were: barn pm temperature (OC) 26.7bc , 27.2\ 25.9", 29.3 a ; barn pm humidity (%) 82.9 ab , 78.8 b , 87.2 a , 68.8 c ; respiration rate 56 b , 52 b , 50 b , 69 a ; body temperature (OC) 38.7a , 38.5 b , 38.4b , 38.8 a ; DMI (kg/d) 23.7 a , 22.1 b , 21.6 bc , 20.8"; milk production (kg/d) 29.8 a , 29.5 a , 27.7 b , 26.3"; milk fat (%) 3.26 ab , 3.14\ 3.32 ab , 3.50 a ; milk protein (%) 3.14", 3.19b ", 3.31 a , 3.23 ab ; and body weight change (kg/d) _0.04 ab , 0.14\ -0.07b , -O.lI b . Water usage per group was 2802, 3260 and 426 liter/d for sprinklers A, B and misters, respectively. Except for cows on treatment A, a higher percentage of the cows preferred lying in stalls bedded with sand rather than on mattresses. Although the first three methods provided a positive effect, cows sprinkled for 3 min every 15 minute had the highest milk production, with lower water usage than for treatment B.
In 1992, Arkansas Department of Pollution Control and Ecology (ADPC&E) enacted Regulation No. 5 requiring confined animal operations using water in managing their manure to be permitted. As a result, every dairy was technically required to be permitted. The permitting process required implementing a waste management plan based on a liquid manure handling system. To address water quality concerns while minimizing the economic impact on dairies, ADPC&E requested assistance of Cooperative Extension Service (CES) and Natural Resource Conservation Service (NRCS) to develop guidelines that addressed environmental concerns while avoiding the permitting of all dairies. After reviewing demonstration dairies, ADPC&E implemented a waiver system. Now, dairies can install dry or liquid systems regardless of their size. However, dairies milking 100 cows or less are exempt from permitting, if they implement separate systems for dry manure management and milk center wash water management. Otherwise a permit is required. For both dry and liquid systems ADPC&E expects dairies to develop waste management plans. The waiver is conditional on significant industry compliance with the permitting or wavier requirements. There were concerns that the number of dairies implementing plans would not meet the goal of 100 per year. Therefore dairies were given a priority in 1997 Environmental Quality Incentives Program (EQIP). Over 100 dairies will implement in excess of $1,260,000 in waste management practices. At least 50% of the funds will be provided by EQIP. The average cost-share allocation is $6800. In addition to the EQIP funds, Arkansas Soil and Water Conservation Commission (ASWCC) made available up to $7500 per dairy for a combined total of 75% cost-share. ASWCC funds are available to more than 90 dairies. The combined regulatory requirements, financial assistance, and cooperative agency and industry efforts will help over 100 dairies implement improved waste management practices in '97-'98. This successful joint effort is expected to continue.
5020 Losses of Nand P from a dairy manure management system. H. H. Van Horn, University of Florida, Gainesville. The University of Florida Dairy Research Farm renovated its manure collection and holding system and installed two 12.1-ha center pivots to distribute wastewater to those sprayfields where forage crops were grown to recycle nutrients. Data collection started in 1992, most of which was utilized in quarterly reports submitted to the Florida Department of Environmental Protection to monitor Nand P as required in the Industrial Wastewater Facility Permit under which the dairy operated. In this system, 275 to 380 milking cows were confined in freestall barns, adjacent concrete covered holding areas, or the milking parlor 100% of the time. In the manure management system: 1) manure was flushed from all areas, 2) sand traps were used to settle out much of the sand which was reused for bedding, 3) a stationary Screen removed fibrous solids, 4) sediment basins removed additional solids, 5) effluent from sediment basins flowed to a small (.25 ha) lagoon, 6) effluent from lagoon was pumped to a 2-ha holding pond, 7) holding pond wastewater was pumped to the two, 12.1-ha sprayfields about every 2 wk. Excretion estimates per cow of Nand P were estimated at 410 and 59 bid for this herd. Recoveries of N· and P were determined from sample analyses, metered volumes of wastewater..''oPplied, number of loads and estimated load weights of solids hauled. Recoveries as a percentage of estimated Nand P excretions were: 28% of N in wastewater irrigated on sprayfields, 12% of N in solids which were land spread, 61% of P in wastewater irrigated on sprayfield, 15% of P in solids. Most of the nonrecovered N was volatized except for a small nondetermined amount in sludge accumulating in the lagoon and holding pond. Data generated from excretion estimated and ratios of N concentrations in sprayfield wastewater to that in concurrent samples taken from effluent from the lagoon suggested that 28% of N (in addition to the 12% recovered in solids) was lost before effluent left the lagoon leaving 32% as the estimated loss in holding pond. Most of the P excretion was recovered (76%) with the remaining, unaccounted 24% not an unusual amount to expect to be retained in lagoon and holding pond sludges.
5022 1996 financial survey of Georgia dairies. L. O. Ely, University of Georgia, Athens. A survey for cash costs and returns for 1996 was distributed to Georgia dairy farmers. This was the fourth year of the survey. Thirty one forms were returned with 25 having usable data. Net balance for feed inventory was hay, 201 tons; silage, -828 tons; grain, -383 tons; concentrate, -3 tons; and by-products, -5 tons. Farms averaged 251 cows per farm and 17400 pounds of milk per cow. Milk income was $15.82/cwt or $709,481/farm. Total income was $834,122/ farm or $18.59/ cwt. Total expenses were $777,909/ farm or $16.55/ cwt. The largest expense item was feed purchased, $319.298/ farm or $7.01/ cwt. The next expense items were other, $1.54/ cwt; cow purchase, $1.43/ cwt; depreciation; $1.38/ cwt and labor, $1.24/ cwt. Net operating income was $132,190/ farm or $3.56/ cwt. This was higher than 1993, 1994 or 1995.
Journal of Dairy Science Vol. 81, No.4, 1998
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5023 Comparison of Arkansas dairy herds whose owners were or were not in 4-H or FFA. J. A. Pennington*, C. Rosenkrans, Jr., Z. Johnson, C. Y. Tarn, and M. L. Scott, University of Arkansas Cooperative Extension Service, Little Rock, and Department of Animal Science: Fayetteville. A survey of 749 dairy farms in Arkansas was conducted to compare herd characteristics and management practices for herds whose owners were in 4-H or FFA to herds whose owners were not in these youth organizations. Of 434 surveys used, 161 were from former 4-H'ers (262 not +11 missing data) and 281 were from former FFA'ers (144 not +9 missing data). Owners in 4-H or FFA had more (P<.05) part-time employees and more (P<.05) frequent visits from veterinarians and milking equipment inspection. Most parameters did not differ (P>.10) for groups but owners in 4-H or FFA as youth (greater with FFA) conducted more preferred practices than owners not in 4-H or FFA (see table). Parameter DHIA Records ID Calves by 30 Days Balance Milk Cow Ration Synchronize Heifers ET Conducted Use KaMaRs Pregnancy Check Dry Treat Cows Grain to Dry Cows Employ Family Member Children in 4-H Children in FFA 4-H/FFA as Youth
Prob. 0.11 0.09 0.08 0.59 0.01 0.10 0.24 0.89 0.62 0.05 0.01 0.03 0.01
5025 How we work with our dairy farm managers - a panel discussion. L. O. Ely, University of Georgia, Athens. Interaction with dairy producers is usually initiated in two ways. The first is a request to solve a particular problem or for specific information. This request is fulfilled as best as possible and often leads to further discussion. The second method of interaction is review sessions with the producer. These are scheduled through our dairy management analysis program - Dairy MAP. This program involves an evaluation of his production records. A comparison to regional averages, a summary of the last three test dates and 19 graphs prepared from the last 18 test days is prepared. Potential problem areas are identified and recommendations are made. Cash flow budgets are often developed to evaluate production changes. Obtaining accurate and complete information is difficult. The starting point for these evaluations is the cash flow budgets that we develop every year from the Georgia dairy farm financial survey.
Not FFAas Not 4-H as Youth 4-H Prob. Youth FFA % Yes % Yes 32.7 25.4 0.03 31.8 21.7 53.0 0.01 61.3 45.4 61.6 0.59 66.7 58.0 60.2 63.0 9.1 7.6 0.05 10.0 4.3 4.2 11.5 4.7 0.06 9.3 48.5 0.60 69.8 59.5 66.5 68.8 58.6 0.01 71.9 47.5 0.09 79.8 72.3 77.4 76.7 82.8 84.6 0.03 87.1 78.7 0.01 63.2 52.5 53.7 70.6 44.7 25.2 0.04 37.2 25.2 0.01 53.4 38.7 54.4 26.6 81.1 55.9 0.01 45.9 20.1
5026 Evaluating milk urea nitrogen data. M. A. Faust* and L. H. Kilmer, Iowa State University, Ames.
5024 Critical factors in successful management. G. A. Benson, North Carolina State University, Raleigh. Individual dairy farm families have different goals and face different problems and opportunities. Individual farm data show a wide variation in financial health and financial performance among dairy farms of any given type or in any particular region of the country. For this reason, it is not possible to manage a business successfully by following general guidelines or thumb rules. Also, the financial health of a particular farm helps set priorities and affects the feasibility of alternative solutions. Approaching farm problems from a purely production perspective without knowledge of, or regard for, the financial status of that business may lead to erroneous recommendations being made. Each farm must be approached as a unique case. Successful management begins with a complete and accurate assessment of the current financial status and recent performance trends of a business. Furthermore, this cannot be inferred from production related data; financial data are required. There are three steps to the process, each of which is explained in detail. The first step describes the business by means of a balance sheet, an earnings statement calculated on an accrual basis, and a summary of cash flows. Second, financial performance measures are calculated from these three statements, to assess strengths and weaknesses. An analysis of production records for livestock and crops helps explain financial performance but only in part. Financial and production records used in combination with benchmark performance measures provide a sound basis for the development of a plan of action that can better accomplish family goals. The record keeping necessary to accomplish this is described.
Journal of Dairy Science Vol. 81, No.4, 1998
Goal was to study non-nutritional sources of variability for milk urea nitrogen results; effects studied were measurement error, milking time, collection day, parity, DIM, percent of group sampled, time relative to feeding change, levels for other milk comp';nents, and laboratory. Stage of lactation (8-380 DIM) did not influence urea nitrogen. Coefficients of variation for measurement error in different laboratories were: lactose % .20-.46%, protein % .24-7.5%, fat % .8-2.5%, urea nitrogen 3.3-7.3%, and sec 6.9-99.4%. Urea nitrogen was highest for milk from cows in parities 3 and 4 and lowest for oldest cows. No important relationships were identified between milk urea nitrogen and percentages of fat, protein, lactose, SNF, and total solids, however, urea nitrogen values were highest for samples with the smallest SCC (b-value = .0026 ± .0009). When milk urea nitrogen was reported for different proportions of cows in the group, variability of replicates for measurement error was smallest for subsets that included 75% of cows, and increased exponentially when sets included fewer cows; for 10, 25, 50, and 75% subsets, coefficients of variation for error were 7.9, 4.7, 3.6, and 1.8%, respectively. Variability for milking time was extremely large; pooled means of urea nitrogen for samples from 2:00 AM, 10:00 AM, and 6:00 PM milkings were 13.4, 15.4, and 15.2 mg/dl, respectively. When soluble nitrogen and readily fermentable carbohydrate levels in diets were increased abruptly, differences for milk urea nitrogen were detected during the first 2 subsequent milkings, and differences were not sustained for milkings during day 2 following treatment. Least significant difference (95% confidence interval) for detecting differences of two means for milk urea nitrogen were: No. values in means Samples evaluated 1,1 5,5 20,20 50,50 --------LSD, mg/dl-----.:Same sample source, milking, and day 14.7 1.20 .52 .32 Different milking, same source and day 32.0 2.60 1.14 .71 Different day, same source and milking 36.3 2.95 1.29 .80
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5027 Role of consultants in evaluating production and management records-a case study. D. M. Amaral-Phillips, University of Kentucky, Lexington.
5029 Two to eight months of age: A critical time in the growth of heifers. R. E. James, Virginia Polytechnic Institute and State University, Blacksburg.
The second and third days of this year's Southern ADSA program includes a workshop for industry and extension consultants entitled "Putting the Concepts into Practice". This program has been designed to integrate invited presentations with how to effectively utilize this information when evaluating actual, on-farm situations. Specifically, the case study will use a Holstein herd producing over 23,000 lb RHA and will evaluate the farm's strengths and areas for possible improvement in the nutritional, reproductive and mastitis programs. This evaluati6fi will utilize the herd's PCDART management records, milk urea nitrogen data, body condition scores and an analysis of the current feeding program. In addition, the panel of a nutritionist, veterinarian, and extension consultants will discuss specific observations and questions which need to be addressed during the follow-up farm visit.
This segment of the life cycle is critical because it sets the stage for early calving and has a strong, permanent influence on mammary development. Most research indicates that moderate rates of gain (.68 .9kg/day) are desirable. Key factors influencing successful rearing during this period are the transition period, control of coccidiosis, and the rate of gain attained. Weaned calves should be housed individually for several weeks while adjusting to the absence of liquid feeds. Next, they should be housed in small groups of 4 - 6 to adjust to competition for feed. Early in this period problems with coccidiosis are most likely to be observed. Including proven coccidiostats or coccidiocides in the diet along with strict sanitation of housing and feeding devices is recommended. There is a substantial risk of impaired mammary development when heifers are fed for accelerated rates of gain during the prepubertal period. At rapid rates of gain, growth hormone secretion and ductal growth into the mammary fat pad is reduced. The rate of gain or the age at which development is impaired is uncertain. Breed differences in the influence of gain on mammary development exist. Daily gains in excess of .9 kg for Holsteins and .6 kg for Jerseys are not recommended. Substandard gains delay onset of puberty and subsequent breeding. Success is likely when housing and management systems exist to control coccidiosis and infectious disease and permit monitoring of body weight gains.
5028 A case study - evaluating dairy nutritional programs using PCDART and feed analyses. J. W. West, University of Georgia, Tifton. The challenge to thorough evaluation of a nutritional program is to have an accurate bench mark against which to compare herd performance, and to be able to capture and interpret data which reveals the response to nutritional and management changes at key points in the lactation. The case study herd is Holstein with a rolling herd average (RHA) of 23,229 lbs. At the most recent test day, average days in milk (DIM) were 207 d, peak and summit test day milk for first, second, and third+ lactation cows was 89, 80;, 104, 98; 107, 101 lbs. These data are consistent with means for 706 herds with RHA exceeding 23000 lbs., where DIM were 184 d, RHA was 24,623 lbs., and peak milk was 85, 105, and 113 lbs. for first, second, and third lactation cows. Body condition scores for the case study herd were 3.5 (dry), 3.3 (calving), 3.0 (early lactation), 3.1 (at pregnancy diagnosis), 3.3 (late lactation), reflecting good nutriti()J:\,.):"!eifers were large at breeding (931 lbs.) and at calving (1412Ibs.), averaged 25 months of age, and apparently were of excellent body size. Somatic cell counts (x1000) currently average 167, 309, and 826 for first, second, and third+ lactation cows and have risen sharply for 3+ lactation cows for the most recent test day. The overall SCC of 427 indicates room for improvement. During the most recent year 67 cows (34.7%) left the herd. Reasons for culling were low production (10.4%), reproduction (19.4%), disease-injury-other (22.4%), died (14.9%), mastitis-udder (20.9%), and feet-legs (11.9%), presenting some target areas for improvement. Comparatively, the case study herd was higher for losses due to deaths, mastitis-udder, and feet-legs than the means for the herds >23000 lbs. milk. Improved performance should be sustainable under current management conditions. Further evaluation of rations and forages will occur during the case study.
5030 On-farm evaluation of heifer management. D. R. Winston, Virginia Polytechnic Institute and State University, Blacksburg. The heifer enterprise represents 15-20 percent of total milk production costs. The goal of the heifer enterprise should be to economically raise heifers to reach their genetic potential at the earliest age possible. Management is about making decisions based on available information. A complete, accurate record keeping system is essential to track growth, reproductive, health, and financial information. Basic information should include animal identification, date of birth, and sire and dam identification. Growth, as measured through body weight and wither or hip height, is the best indicator of performance of the dairy heifer. On many dairy farms a lack of safe, labor efficient handling facilities limits the ability of dairy managers to routinely collect heifer growth data. Reproductive data should include estrus dates, service dates, service sire identification, and pregnancy examination results. Reproductive performance may then be evaluated through average age at first breeding and services per conception. Health events such as dehorning, removal of extra teats, vaccinations, coccidiostat/coccidiocide usage, deworming, and treatment for diseases and injuries as well as death losses should be recorded. Financial data allows the producer to calculate rearing costs. With this information weak link analysis identifies strengths and weaknesses enabling improvement of the enterprise. If the heifer enterprise is not meeting its objectives, one option is to have heifers grown by professional heifer growers. Another alternative is to sell calves at birth and purchase replacements as springers. A heifer management survey was conducted in five states through the NC-119 Regional Research Project. Practices reported in the survey will be presented.
Journal of Dairy Science Vol. 81, No.4, 1998
February, 1-4, 1998 Little Rock, AR
Sol Luteinizing hormone, growth hormone and prolactin response to the dopamine antagonist, pimozide, during the luteal phase of the estrous cycle in lactating Holstein cows. A. Ahmadzadeh*, M. A. Barnes, D. M. Denbow, A. W. Pryor, and S. M. jobst, Virginia Polytechnic Institute and State University, Blacksburg.
502 Effects of stage of lactation on follicular dynamics and recovered oocytes in Holstein cows. A. W. Pryor*, T .L. Bailey, S. Nadir, M. H. Irby, R. E. Bethard, and F. C. Gwazdauskas, Virginia Tech, Blacksburg. Lactating Holstein cows were used to evaluate effects of stage of lactation on follicular dynamics and quality of recovered oocytes. Cows in early lactation (EL;n=8) and mid-lactation (ML:n=7) were subjected to twice weekly ultrasonic ovarian evaluation and ovum pick-up beginning at d 28 and 118 postpartum, respectively, for 10 wk. Follicles were categorized as small (2 to 5 mm), medium (6 to 9 mm), large (10 to 12 mm) and very large (>12 mm). Recovered oocytes were graded from 1 to 4 based on cumulus density and ooplasm homogeneity. Milk yield averaged 39.9± .3 kg/d (mean ±SE) for EL and 37.4±.3 for ML. There was a significant interaction of treatment with the cubic effect of aspiration session for milk yield with a peak of 45 kg/d for EL at 6 wk postpartum, while ML milk yield declined from 41 kg/d at d 90 to 36 kg/d at d 190 postpartum. BW decreased significantly from 660 kg at 4 wk prepartum to 565 kg at 8 wk postpartum for EL compared an increase from 575 kg at wk 13 to about 590 kg at wk 23 postpartum. There were significant interactions of treatment by linear effects of aspiration session for total number of follicles, number of small follicles and follicular growth index. Total number of follicles increased from 13.5 to 18 for ML compared to 14.2 to 14.9 for EL; number of small follicles increased from 8.5 to 13 for ML compared to 9.8 to 10.6 for EL; and follicular growth index increased from 20.8 to 28 in ML compared to 22 to 23 for EL. There was a trend for the interaction of treatment with the cubic effect of aspiration session for total number of oocytes recovered and number of poor oocytes. Later stages of lactation were associated with increased follicle numbers, follicular growth index, oocytes recovered and poor quality oocytes compared to earlier stages of lactation.
Pimozide, a non-selective dopamine receptor antagonist, was used to investigate the role of endogenous dopamine on serum LH, GH, and prolactin secretion in lactating Holstein cows. Estrous cycles were synchronized using prostaglandin (25 mg) in 5 cows. On d 10 or 11 postestrus (mid-luteal phase), cows received 0.1 mg/kg BW pimozide Lv. Blood samples were collected at 15-min intervals for 4 h before and 4 h after pimozide. Immediately thereafter all cows received 25 ug of GnRH Lv. and blood collection was continued for 1 h. Mean serum progesterone concentration was 3.0 ± 0.5. Pimozide significantly increased mean serum prolactin concentrations. Mean LH concentrations, pulse frequencies and pulse amplitudes were not altered by pimozide treatment. Exogenous GnRH caused a significant increase in mean LH concentrations. Mean GH concimtrations were not affected by pimozide. These results suggest that endogenous dopamine plays an inhibitory role in prolactin secretion in lactating Holstein cows. However, a dopaminemediated mechanism for modulation of LH and GH secretion is absent during the mid-luteal phase of the estrous cycle. Hormone pre-pimozide post-pimozide prolactin conc. (ng/ml) 4.1 ± 6.7" LH conc. (pg/ml) 252 ± 23 LH pulse frequency (pulses/4h) 1.4 ± 0.2 LH pulse amplitude(pg/ml) 306 ± 177 GH conc. (ng/ml) 7.8 ± 1.6 ",bMeans within a row differ (P < .01).
81.9 ± 298 ± 1.8 ± 672 ± 10.1 ±
8.5 b 24 0.2 177 1.6
1Asterisk indicate:s author who presented paper.
1998 j Dairy Sci 81:1186-1193
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503 Effects of dry period supplementation of parenteral vitamin E and selenium in Jersey and Holstein cows. R. T. Bass, 11*, W. S. Swecker, Jr., and C. C. Stallings, Virginia Polytechnic Institute and State University, Blacksburg. The effects of late gestation parenteral supplementation of vitamin E and Se on parturient and post-parturient blood concentrations of these micronutrients were determined in 16 Jersey and 36 Holstein cows. Cows were allotted to blocks by breed and expected calving date; cows within blocks were randomly assigned vitamin E or Se treatment in a 2X2 factorial design. Treatments were administered as subcutaneous injections at the time of mid-dry period sampling. Dosages were empirically based on body weight differences between breeds. Holsteins were given 3000 IU and 32.5 mg of vitamin E and Se, respectively, while Jerseys were given 2400 IU of vitamin E and 22.5 mg of Se. All groups were similarly managed and fed through the study period. Blood samples were taken at dry off, 3-4 weeks prior to predicted calving date (the time of treatment), within 24 hours after calving, and 2-3 weeks post-calving for assessment of "serum vitamin E and blood Se concentrations. Both Se and vitamin E concentrations differed between breeds at dry off. The breed effect for Se persisted, with Jerseys exhibiting higher blood concentrations than Holsteins at the pre-calving and calving samplings. Selenium supplementation resulted in higher blood Se concentrations at calving. Treatment did not affect serum vitamin E concentrations at calving or post-calving, nor blood Se concentrations post-calving. A periparturient decline in serum vitamin E concentrations was observed in both breeds and all treatment groups.
504 Grazing behavior and rumen fermentation patterns in lactating cows supplemented with different forms of corn. F. D. Soriano* and C. E. Polan, Virginia Polytechnic Institute &. State University, Blacksburg. The objectives were to determine time patterns of grazing and rumination in lactating cows, and to measure rumen pH, ammonia nitrogen, and volatile fatty acids (VFA). An intensive rotational grazing system was used. Cows grazed from 0400 to 1000 and from 1500 to 2200 h daily. In experiment 1, 38 Holstein and 2 Jersey cows were supplemented daily either with (kg/d) 7.8 high moisture corn (HMC), 6.7 coarsely ground corn (CGC), 6.7 finely ground corn (FGC), or 5.2 of high moisture corn (HMCL)- in two equal feedings. For two consecutive days, while grazing, the number of cows grazing, lying, or standing were recorded every half hour. Individual behavior was recorded for 4 cows each with the most and least daily milk yield. Cows grazed an average of 6.4 hid, 4.1 h in the afternoon and 2.3 h in the morning. No difference was observed in grazing patterns between those cows with the most or least daily milk yield. In experiment 2, four rumen cannulated cows in mid-lactation, 1 Jersey and"Y-Holstiiin each, were supplemented twice daily with either CGC of HMC as above. After milking (1400 h) ruminal pH was measured and rumen fluid samples were collected. After supplementation with corn (0 h) and at 1, 2, 3,... 8 h post-corn feeding while grazing, ruminal pH was measured and rumen fluid was collected to determine ammonia nitrogen and VFA. Ruminal fluid pH was similar for both corn supplements and was lowest (5.9 and 5.8) at 5 and 8 h respectively. Rumen ammonia nitrogen concentrations started to increase approximately 2 h after cows began grazing, and was 15.5% lower in cows supplemented with HMC vs. CGC (26 vs. 31 mg/dl), although differences were not significant. In experiment 1, results indicated that cows spent more time grazing in the afternoon than in the morning. High moisture corn may improve microbial incorporation of dietary nitrogen compared to CGC.
1187
505 Evaluation of whole cottonseed (fuzzy, mechanically delinted and starch coated) as an ingredient in the diet of high producing dairy cows. D. N. Moore*, J. E. Tomlinson, B. L. Clark, R. B. Moore, M. E. Boyd, and W. J. Ricks, Mississippi State University. Forty-eight lactating Holstein cows (mean = 143 Days in milk) were randomly assigned to 1 of 4 diets based on energy corrected milk (ECM), lactation and days postpartum to evaluate sources of dietary lipid in a 96 day trial. All diets contained corn silage, chopped grass hay, corn, soybean meal, minerals, vitamins and were fed as total mixed ration (TMR). The 4 dietary lipid sources were: animal fat (fat); fuzzy whole cottonseed (FCS); delinted whole cottonseed (DCS); and starch coated cottonseed (SCS). Lipid was added at a rate of .57 kg/cow/day and all diets were isonitrogenous and isocaloric. Diets were fed twice daily in amounts to allow 5-10% refusal. Body weights and body condition scores were taken at 28 day intervals. Individual cow pooled milk samples (AM & PM milkings) were taken 1 day weekly for fat, protein, milk urea nitrogen (MUN) and somatic cell count (SCC) analyses. Individual cow milk yield was recorded at each milking daily. Mean dry matter intake (DMI) (kg/cow/d), actual milk (kg/cow/d) and ECM (kg/cow/d) respectively, were 20.6, 29.2, 27.8 for Fat; 21.0, 25.6, 26.6 for FCS; 22.1, 26.1, 26.8 for DCS; and 22.1,26.7,27.3 for SCS. Milk % fat, % protein, urea-N (mg/dl), and SCC, respectively were 3.21, 3.37, 18.2, 298 for Fat; 3.87, 3.39, 18.1, 448 for FCS; 3.70, 3.37, 18.6, 385 for DCS; and 3.74, 3.4, 17.4, 566 for SCS. Milk % fat was lower (p<.05) for Fat than the 3 cottonseed diets. Body weight and BCS data were not significantly different between treatments. The data from this trial indicate that Fat, FCS, DCS and SCS are acceptable dietary lipid sources for lactating dairy cows.
506 Supplemental dietary protein effects on the energy status of grazing dairy cows: Year II. A. M. Chapa*, J. M. Fernandez, M. E. McCormick, and J. F. Beatty, Louisiana State University Agricultural Center, Baton Rouge and Southeast Research Station, Franklinton. An experiment conducted to investigate the influence of dietary protein on the energy status of dairy cattle was continued during November 1996 - April 1997(Year II) at the Southeast Research Station. Holstein cows (n = 60) were blocked on the basis of milk equivalents and calving group (pre-partum group: dietary treatments imposed at calving [avg days in milk = 0] and post-partum: dietary treatments imposed after calving [avg days in milk = 41]). Cows were randomly assigned to one of three treatment groups and rotationally grazed on immature ryegrass pastures. Treatment groups included: 1) control-corn/SBM (22.2% CP, 10.2% VIP); 2) corn/SBM (15.6% CP, 7.9% VIP); and 3) corn/corn gluten meal/ blood meal (15.6% CP, 9.0% UIP). Blood samples were collected on d 50, 100, and 150 post-partum and on breeding days. Day 50, 100, and 150 plasma was analyzed for glucose, ,6-hydroxybutyrate, NEFA, urea N, and ammonia N; whereas breeding day samples were analyzed for glucose, NEFA, and urea N. ,6-hydroxybutyrate values were highest (P < .02) during d 100 compared with d 50 and 150 (0.61 vs 0.47 and 0.50 mM). NEFA, urea N and ammonia N were higher (P < .005) on d 50 compared to d 100 and 150 (220 vs 127 and 121 JLEq/L; 14.9 vs 13.9 and 13.1 mM: 87 vs 76 and 76 JLM, respectively). Cows in the post-partum calving group had higher (P < .05) NEFA and urea N values compared with the pre-partum group (177 vs 136 JLEq/L; 14.4 vs 13.3 mM, respectively). At the time of breeding, glucose was lower (P < .06) in TRT 3 compared with TRT 2 and 1 (3.38 vs 3.51 and 3.46 mM) and urea N levels were higher (P < .02) in TRT 1 compared with TRT 2 and 3 (17.2 vs 13.9 and 13.8 mM). Cows in the post-partum calving group had higher (P < .05) NEFA values compared with the pre-partum group (256 vs 209 JLEq/L) at breeding. Calving group and days postpartum excerted a greater influence on energy status than the level of supplemental dietary protein.
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507 Comparison of Arkansas dairy herds whose owners sell to different cooperatives. T. R. Bedingfield, C. F. Rosenkrans, J. A. Pennington, Z. B. Johnson, and C. V: Tarn, The University of Arkansas Department of Animal Science, Fayetteville.
509 Effect of adding levels of molasses on amino acid composition of bermudagrass (Cynodon dactylon) silage. V. Nayigihugu*, D. W. Kellogg, E. K. Vaught, Z. B. Johnson, and K. S. Anschutz, University of Arkansas, Fayetteville.
Arkansas dairy producers (n=749) were surveyed about herd characteristics and management techniques. Herds differed in size location in state, and total income. Furthermore, as shown in the table above, these data indicate that dairy producers that use progressive management techniques vary by marketing strategy. Cooperatives or Processor Item Prob. A B C D
Four levels (0, 4, 8, and 12%) of molasses (M) were ensiled with bermudagrass, and amino acid composition of silage was determined. Dried M (97% DM) was applied to chopped forage that had been treated with 1174 Pioneer® Silage Inoculant (1.54 lit of forage). Forage was packed in 19-1 plastic containers that were double-lined with .025 mm thick polyethylene bags, and approximately -1.03 x 10- 5 Pa of vacuum was applied. Silages were sampled after ensiling for d 5, 15, and 33. There was an interaction between sampling day and level of M for phenylalanine (P<.05). Means of phenylalanine decreased (P<.05) on d 5 from .64% with OM to .50, .44, and .45% with 4M, 8M, and 12M, respectively. On d 15 and 33, there were no differences (P>.05) of phenylalanine due to M levels. Means of alanine decreased (P<.05) from .97% with OM to .90% when 12M was applied. Means of glutamic acid increased (P<.05) from .70% to .80%, respectively when forage was treated with OM and 12M. Threonine decreased (P<.05) from .40% to .38% at OM and 12M. All other amino acids percentages were not affected by M. While means of alanine, histidine and valine increased (P<.05) froI\1l .91 to .98%, from .54 to .69% and from .52 to .56%, means of glutamic acid decreased (P<.05) from .79 to .73%, respectively, on d 5 and d 33. Increasing M in bermudagrass silage lowered phenylalanine (only on d 5), alanine, and threonine but increased glutamic acid.
Milking· Cows Use DHIA,% ET Conducted,% Synchronize Heifers,% Grain to Dry Cows, % Dry Treat Cows,% Disinfect Hands, % Own Antibiotic Test,% ID Calves by 30 d, % Store Feed in Silo,% FFA as Youth,% Employee and Family,%
.01 .01 .01 .03 .01 .01 .01 .01 .05 .01 .01 .01
63.8 22.6 5.5 6.0 86.9 73.5 29.9 60.9 50.9 17.7 65.1 61.9
87.0 57.1 16.7 15.1 93.3 97.4 30.4 75.3 56.0 40.5 80.3 38.9
53.7 23.4 7.7 11.5 82.3 83.1 36.4 70.3 62.3 10.9 57.8 64.9
55.2 11.9 2.5 2.6 54.8 57.1 20.0 21.9 73.0 12.5 53.7 79.4
5010 Effect of treating Tifton 85 bermudagrass hay or cottonseed hulls with a forage oxidant on nutrient composition, and in situ and in vitro digestion. P. Mandebvu* and J. West, University of Georgia, Tifton.
508 Ensiling characteristics of tall growing soybean cultivars used for silage. V. Nayigihugu*, D. W. Kellogg, D. E. Longer, Z. B. Johnson, K. A. Anschutz, and T. E. Devine, University of Arkansas, Fayetteville. Seven cultivars of soybean (Glycine max [L.] Merr.)['PA 5-2-1' (T1), 'PA Bu-2-2' (T2), 'OR 5-12-1T' (T3), 'OR 5-12-1G' (T4), 'OR 14-12-2' (T5), 'OR 13-12-3' (T6), 'OR 19-12-2' (T7), 'Hutchinson' (C1)J and a sorghum (Sorghum bicolor [L.] Moench ['Pioneer 838F' (C2)]) variety were ensiled and tested for nutritive quality to evaluate potential of cultivars as silage crops. Cultivars were grown in four replicate plots near Fayetteville and Rohwer in 1995 and 1996. Forages were harvested at full seed (R6 growth stage) and ensiled for 33 d. Silages from all the cultivars were well preserved as indicated by low pH (4.6, 4.7, 4.5, 4.3, 4.5, 4.3, 4.4, and 4.9) and high lactic acid content (1.0, 1.3, 1.3, 1.1, 1.2, .9, 1.3, and 1.8%, respectively for T1, T2, T3, T4, T5, T6, T7, and C1). The IVDMD was 70.2, 72.9, 65.4, 73.2, 71.7, 72.5, 68.9, and 75.7%, respectively for T1, T2, T3, T4, T5, T6, T7, and C1. Any of the soybean cultivars would dramatically improve the CP of silage if grown with sorghum, and the tall-growing cultivars should be more competitive for light than typical soybean varieties if planted with sorghum.
Journal of Dairy Science Vol. 81, No.4, 1998
The objectives of this study were to determine the effects of treating Tifton 85 bermudagrass hay (BGH) or cottonseed hulls (CSH) with a hypochlorite forage oxidant or sodium hypochlorite solution (commercial liquid bleach) on nutrient composition and in situ and in vitro disappearances of DM, NDF and ADF. The initial nutrient composition (% DM) for BGH and CSH respectively, were OM: 94.9 and 96.8; CPo 6.5 and 6.2; ash-free NDF: 79.7 and 79.8; ash-free ADF: 40.6 and 60.7; hemicellulose: 39.2 and 19.0; cellulose: 34.4 and 31.6; and acid detergent lignin (ADL): 6.0 and 28.0. The forage oxidant decreased (P < 0.05) concentration of ADF and had no effect on the concentrations of NDF or ADL, in situ DM or NDF disappearance, or in vitro DM disappearance. Disappearance of NDF in vitro declined slightly with increasing oxidant levels. Increasing the water content of the treatment solution at application of the forage oxidant from 10 to 50% of the forage weight (as fed basis) decreased the concentrations of ADF (P < 0.01) and cellulose (P < 0.05), increased (P < 0.01) the concentration of ADL, but had no effect on in situ DM, NDF or ADF disappearance. When compared with sodium hypochlorite, the forage oxidant decreased the concentrations of ADF (P < 0.10) and cellulose (P < 0.01). Sodium hypochlorite decreased (P < 0.01) the concentration of ADL when compared with the forage oxidant. It is concluded that the forage oxidant or sodium hypochlorite failed to significantly improve the nutritive value or digestibility of BGH orCSH. .,
ASSOCIATION AFFAIRS
5011 Production response of Jersey cows to whole fuzzy cottonseed coated with starch or a combination of starch and sugar. J. K. Bernard*, H. H. Dowlen, D. L. Johnson, and H. Moorehead, The University of Tennessee, Jackson and Lewisburg. Thirty-six Jersey cows averaging 170 days in milk were used in a randomized block experiment to determine the effect of coating whole fuzzy cottonseed on dry matter intake and milk production and composition. After a 2-wk pretrial period, cows were assigned randomly to one of three experimental diets. Whole fuzzy cottonseed provided 15% of the ration DM and was coated with: 1) control, 2) 5% gelatinized corn starch, "or 3) 5% gelatinized corn starch and 10% multidextrin sugar. Experimental rations were fed twice daily for six weeks. Cows fed the coated cottonseed tended to consumed more DM and produced more milk than the control ration. Concentrations of milk fat and protein were lower but yield was not different when the coated cottonseed were fed compared to whole fuzzy cottonseed. Energy-corrected milk yield (ECM) was not different among treatments. Starch Contrast ' Control Starch + Sugar SE 1 2 DMI, kg/d 19.4 20.5 20.2 0.4 0.06 0.61 Milk, kg/d 22,2 23.9 24.3 0.8 0.08 0.76 Fat, % 4.99 4.70 4.49 0.15 0.04 0.34 Fat, kg/d 1.09 1.11 1.09 0.04 0.88 0.80 Protein, % 3.90 3.75 3.67 0.08 0.06 0.48 Protein, kg/d 0.86 0.89 0.89 0.03 0.34 0.99 ECM, kg/d 27.3 28.3 28.2 0.9 0.39 0.96 1 Contrast included: 1 = whole fuzzy cottonseed versus coated cottonseed and 2 = starch coating versus starch plus sugar coating.
1189
5013 Mycotoxin occurrence in farmer submitted samples of North Carolina feedstuffs: 1989-1997. L. W. Whitlow*, W. M. Hagler, Jr., and B. A. Hopkins, North Carolina State University, Raleigh. From 1989 through 1997, >2400 feed samples were submitted by North Carolina producers for mycotoxin analyses to laboratories operated by either the North Carolina Department of Agriculture or by North Carolina State University. Mycotoxin analyses were conducted by various methods such as gas-liquid chromatography, HPLC, thin layer chromatography and ELISA, however, the majority of results were by ELISA. Feeds were frequently analyzed for aflatoxin (AF), deoxynivalenol (DON), zearalenone (ZEN), and T-2 Toxin (T-2), and infrequently for fumonisin (FBI). A greater (P < .05) percentage of samples were contaminated with either ZEN (38%) or T-2 (19%) in 1994 than in other years, however, there was no effect of year (P > .05) on mean concentrations of either ZEN or T-2. Incidence of DON was greater (P < .05) during 1990 (73%) and 1993 (70%) than during other years but there was no year effect on DON concentrations. The yearly incidence of AF was greatest (P < .05) for 1989 (32%) and 1990 (23%) than during other years, however, yearly mean AF concentration (358 ppb) was greater (P < .05) only during 1990. When feeds were grouped as forages, concentrates, or total diets over the total period, there were no significant differences (P > .05) in mean mycotoxin concentrations or in mean frequency of occurrence except for DON. Occurrence of DON was greatest for total diets and least for forages (P < .05). Mycotoxin Detection Limit n Positive Mean ± s.d. Aflatoxin Deoxynivalenol Zearalenone T-2 Toxin
20 50 70 50
ppb ppb ppb ppb
1617 2472 1769 2243
7.4 57.8 17.5 7.3
% 91 ± 320 ppb % 1739 ± 10880 ppb % 445 ± 669 ppb % 482 ± 898 ppb
5014 Effects of harvest management on yield and quality of two sorghum types. M. E. McCormick* and G. J. Cuomo, Louisiana State University Agricultural Center, Franklinton and University of Minnesota, West Central Experiment Station, Morris. 5012 Effects of processing of pre-ensiled corn silage by rolling and feeding in diets with and without cottonseed hulls on milk yield and milk composition. L. W. Whitlow and B. A. Hopkins*, North Carolina State University, Raleigh. Twenty-four early lactation Holstein cows (12 primiparous and 12 multiparous) averaging 48 days in milk were assigned to treatments in a randomized block design. The objective was to determine the effects of processing temperate corn silage (CS), by rolling with a forage roller mill before ensiling in an upright silo and feeding in diets with and without cottonseed hulls (CSH), on milk yield and milk composition. The CS was Dekalb 743, harvested at 142 days of maturity, and averaged 28.9 % starch as a percentage of the DM. Cows were randomly assigned to one of four trea:t"me;;ts as follows: 1). non-rolled CS without CSH; 2). non-rolled CS with CSH; 3). rolled CS without CSH; and 4). rolled CS with CSH. Cows remained on a treatment period for 28 d, then were changed to a different treatment. Cows received rations twice daily using Calan@ feeding stations; feed refusals were measured once daily; DM and CP intakes were calculated. Rolled CS had no significant effect on DM intake, CP intake, milk yield, milk fat percentage, milk fat yield, milk CP percentage, milk CP yield, or 4 % FCM yield. Cows fed CSH had significant increases in kg DM intake (21.05 vs. 19.83), (P < .024), kg CP intake (1.98 vs. 1.68), (P < .0001), kg milk yield (32.46 vs. 30.33), (P < .005), and kg milk CP yield (.98 vs..91), (P < .002). Milk fat percentage tended to be lower in cows fed CSH (3.11 vs. 3.33), (P < .08).
High forage yield, drought tolerance, and ratooning capabilities of sorghum indicate potential for this crop in balage production systems in the southeastern U.S. The objectives of the present study were to compare harvest management effects on whole-plant yield and quality of a moderate yielding forage sorghum (NK-300 FS) and a high yielding, "delayed maturing" sweet sorghum x sorghum sudan type (4-Evergreen SS). Nine plots of each sorghum type were planted on May 29, 1996 from which three reps of each sorghum were harvested on days 68, 88, and 108 post-planting. Regrowth from d-68 plots was harvested 44 days after initial harvest. FS harvests were in the vegetative, bloom, and hard dough stages of maturity for d-68, d-88 and d-108, respectively. SS remained in the vegetative state at all harvests. Both FS and SS experienced linear increases (P<.05) in forage yield and declines in crude protein and IVTD with advancing age. Magnitude of IVTD decline was greater for SS than FS resulting in lower overall IVTD for SS compared to FS (68.7 and 66.1% IVTD for FS and SS, respectively). Lower IVTD of SS was associated with higher concentrations of ADF, lignin and NDF in d-88 and d-108 samples. Plant height was greater for SS than FS at all harvest dates (2.62 vs 1.68M), but reduced tiller production for SS (314 vs 444 X 103 tillers ha- l ) resulted in similar forage yields over cuttings (mean=15.1 Mg DM Ha- l ). Regrowth yield was also similar between sorghum types (mean=7.9 Mg DM Ha- l ), but IVTD was lower for SS than FS (69.7 vs 73.3%). Both sorghum types contained high concentrations of water soluble carbohydrates (mean=25.3% of DM). These data indicate that, for the two sorghum types evaluated in this study, over-season and regrowth quality favor the moderate yielding type.
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5015 Ammoniated and non-ammoniated corn silage supplemented with different amounts of rumen undegradable protein did not alter milk yield of Holstein cows. C. E. Polan* and Z. Wu, Virginia Polytechnic Institute and State University, Blacksburg. Two experiments, each 2x2 factorial, compared ammoniated and 000ammoniated corn silage, and two amounts of rumen-undegradable protein
(RUP) in the diet. Diets in Experiment 1 contained (DM%) 19 alfalfa haylage, 30 to 41 corn silage, 30 to 41 corn, 9.8 soybean meal (SBM) or one-half the SBM replaced with 1.0 corn gluten meal, 1.2 blood meal, and 1.2 fish meal. Urea (O.4%) were included in diets with non-ammoniated silage to equalize to
15.8% crude protein (CP). RUP (%of CP) was 30 and 34 for the lower and 37 and 41 for the higher RUP diets Acid detergent fiber (ADF, 17%), neutral detergent fiber (NDF, 28%) and net energy lactation (NEL, 1.65 Meal/kg) were equal in all diets. After 4 wk, cows were reallocated and the 4 wk interval was
repeated. Neither milk yield (34 kg), dry matter intake (DMI, 22.4 kg), nor milk composition were affected by ammoniation or RUP of the diet. Neither were changes in body condition scores Of body weight (BW) affected. Plasma urea nitrogen was greater in cows fed ammoniated silage (19.5 mg/dl) than
those fed non-ammoniated (15.8 mg/dl). Diets in Experiment 2 compared corn silage with or without ammonia and supplements with zero FM or with
FM substituted for SBM. Diets contained (DM%) 28.5 corn silage, 29.1 alfalfa haylage and 5.8 whole cottonseed. SBM was 6.5 or 2.7 plus 2.9% FM in the non-ammoniated silage diets. In the ammoniated diets, SBM was 3.8 or zero and 2.9% FM. Corn varied to account for difference in CP content of supple-
ments. Diets were (%) 15.0 CP, 18.3 ADF, 30.5 NDF and 30.4 or 36.7 RUP for SBM or FM diets, respectively. Cows remained on the same diet for 10
wk. Neither milk yield (35.5 kg) nor milk composition differed by diet. Milk
5017 Nutritional analyses of a humate soil conditioner. D. W. Kellogg* and K. A. Anschutz, University of Arkansas, Fayetteville. Chemical content and in vitro digestive characteristics were determined for a humate soil conditioner product that was mined in New Mexico. The product contains 83.5% ash (89.5% dry basis) with 1.58% CP (1.69% dry basis). The specific mineral content was 1.43% Ca, 0.13% P, 1.56% K, 1.51% Mg, 3.10% S, 0.20% Na, 3.39% Fe, 2153 mg/kg Mn, 575 mg/kg of Zn, and 143 mg/kg Cu. Based on these samples, and assuming intake by a dairy cow of 10 kg of grain mixture daily containing 1% humate, it would supply the following percentage of daily mineral requirements: 0.8% of Ca (1.43 of 180 g Ca needed), 0.2% P (0.13 of 75 g P needed), 0.5% of K (1.56 of 300 g of K needed), 2.0% of Mg (1.51 of 75 g of Mg needed), 5.2% S (3.1 of 60 g of S needed), 0.4% of Na (0.2 of 54 g of Na needed), 225% of Fe (3.39 g compared to 1.5 g of Fe needed), 2.9% of Zn (57.5 mg of 1,200 mg of Zn needed), and 4.8% of Cu (14.3 mg of 300 mg of Cu needed). The IVDMD of humate was 29.5% when determined separately. There was decreased (P<0.05) IVDMD when 1% humate was added to alfalfa hay (A; 76.2 and 69.6%) or to A mixed with corn grain (C; 85.2 and 83.3). However, IVDMD was higher (P<.05) when 1% humate was added to C alone (84.1 and 87.4), to bermuda'grass hay (B; 60.0% and 63.8%), and to a mixture of C + B (72.4 and 74.6). With more than 1% humate, IVDMD declined, or tended to decline, due to the increasing amounts of indigestible mineral matter in the supplement. This type of supplement may find a niche when cows are consuming young, lush grass, and especially during the dry period of late pregnancy; although it will be necessary to monitor other mineral levels such as calcium and iron.
urea nitrogen differed in ammoniated (20.2 mg/dl) vs non-ammoniated (15.3
mg/dl) silage treatments. Cows fed diets with FM vs no FM gained more BW (47.6 vs 33.1 kg). In these experiments, sources of RUP substituted for SBM did not enhance milk yield regardless of ammonia in silage. In Experiment 2, ammoniated diets were more economical than non-ammoniated.
5016 Effect of hormone therapy on postpartum recovery in lactating Holsteins during the summer. G. Ullah*, B. L. Clark, S. C. Wilkinson, and J. W. Fuquay, Mississippi State University, Mississippi State. The stress of the early postpartum period can be exacerbated by heat stress for those cows calving in late summer with potential negative effects on postpartum recovery. The objective of this research was to determine if early postpartum treatment with gonadotropin-releasing hormone and prostaglandin F2o< would speed postpartum recovery in lactating Holsteins calving in late summer. Thirty-four Holsteins calving during August, either were injected with gonadotropin-releasing hormone 13 to 15 d postpartum followed by prostaglandin f 2o< 12 d later or maintained as control with no injections. Between 13 to 15 d and 44 to 46 d postpartum, all were observed for estrus twice daily using androgenized heifers. Blood samples were drawn twice weekly for determination of progesterone concentrations. On d 25, 36 and 45, uteri were palpated to assess degree of involution and ovaries we~e scanned ultrasonically to determine size and number of antral follicles as well as presence and size of corpora lutea. Average daytime rectal temperatures were 39.9°C for both treated and control cows. Days to first observations of estrus were 27.0 and 36.1 for tested and control cows, respectively (P<0.05). Progesterone concentrations were higher in treated cows than controls between d 37 to 45 postpartum (P<.05), but did not differ for d 15 to 25 or d 26 to 36. More treated cows had observable corpora lutea on d 36 and 45 than did controls (P<.05). Treated cows had more complete uterine involution (P<.Ol) on d 36 and 45 but were not different from controls on d 25. Therefore, early postpartum treatment of cows with gonadotropin-releasing hormone followed by prostaglandin F 2o< resulted in more rapid postpartum recovery as indicated by expression of estrus, observable corpora lutea, and uterine involution, thus providing potential for higher fertility.
Journal of Dairy Science Vol. 81, No.4, 1998
5018 Production and reproductive performance as measured by PCDART herds not enrolled in DHIA. D. W. Webb, University of Florida, Gainesville. PCDART software is being used by over a thousand herds as an onfarm database and herd information management system. While most herds using PCDART are enrolled in DHIA and have data forwarded to the centralized database, some larger herds use PCDART-Independent where no data is uploaded to the DRPC. Computer files from 28 PCDART-I herds are being analyzed to characterize the production and reproductive performance. These herds will be compared to DHIA herds in Florida, Georgia, South Carolina and Alabama using the following parameters: herd size, yearly milk per cow, daily milk per cow, percent days in milk, standardized 150-day milk, peak milk days open, days from calving to first breeding, services per conception, calving interval, percent sire identity, and PTA of service sires.
ASSOCIATION AFFAIRS
1191
5019 Effect of water sprinkling of varying time periods and water misting over the feed area on milk production. J. C. Lin*, B. R. Moss, J. L. Koon, C. A. Flood, B. Brady, and R. C. Smith, Auburn University. Auburn, Alabama.
5021 Impacts of changing regulations and financial assistance on Arkansas dairy waste management. K. W. VanDevender* and J. A. Pennington, University of Arkansas Cooperative Extension Service, Little Rock.
Fifty-two lactating Holstein cows (163±43 DIM) were randomly assigned to one of four treatment areas within an open free-stall barn from June 3 to September 15, 1997. All areas had four fans (on at 23.8°C; air flow = 5570 cu.ft./min) mounted over both the feed alleys and the freestalls. Treatments were [A] sprinklers (7) run for 3 min every 15 minutes; [Bj sprinklers (7) run for 2 min every 15 minutes; [Cj misters (16) run continuously when temperatures above 27.8°C.; [D] no water cooling; "A11 cows were housed inside other than 2 hours outside exercise daily. Sprinklers (10 psi) were on at 27.8°C for four 3-minute or 2-minute cycles per hour. Mist was provided at 27.8°C through nozzles (0.32 LPH at 60 psi) mounted on circular tubing around the two fans (4 each) and on straight pipe (4 each) in the direction of the air stream over the feed alley. Each treatment area contained 22-24 free stalls; 1/2 bedded with mortar sand, 1/2 with rubber containing mattresses. Cattle were all fed the same diets of corn silage, cottonseed, soybean hulls, protein/minerals pellet and corn formulated to contain 59.8% DM, 16.0% CP, 1.66 Mcal NEt/kg and 19.0% ADF. Least squares means for A,B,C,D respectively, were: barn pm temperature (OC) 26.7bc , 27.2\ 25.9", 29.3 a ; barn pm humidity (%) 82.9 ab , 78.8 b , 87.2 a , 68.8 c ; respiration rate 56 b , 52 b , 50 b , 69 a ; body temperature (OC) 38.7a , 38.5 b , 38.4b , 38.8 a ; DMI (kg/d) 23.7 a , 22.1 b , 21.6 bc , 20.8"; milk production (kg/d) 29.8 a , 29.5 a , 27.7 b , 26.3"; milk fat (%) 3.26 ab , 3.14\ 3.32 ab , 3.50 a ; milk protein (%) 3.14", 3.19b ", 3.31 a , 3.23 ab ; and body weight change (kg/d) _0.04 ab , 0.14\ -0.07b , -O.lI b . Water usage per group was 2802, 3260 and 426 liter/d for sprinklers A, B and misters, respectively. Except for cows on treatment A, a higher percentage of the cows preferred lying in stalls bedded with sand rather than on mattresses. Although the first three methods provided a positive effect, cows sprinkled for 3 min every 15 minute had the highest milk production, with lower water usage than for treatment B.
In 1992, Arkansas Department of Pollution Control and Ecology (ADPC&E) enacted Regulation No. 5 requiring confined animal operations using water in managing their manure to be permitted. As a result, every dairy was technically required to be permitted. The permitting process required implementing a waste management plan based on a liquid manure handling system. To address water quality concerns while minimizing the economic impact on dairies, ADPC&E requested assistance of Cooperative Extension Service (CES) and Natural Resource Conservation Service (NRCS) to develop guidelines that addressed environmental concerns while avoiding the permitting of all dairies. After reviewing demonstration dairies, ADPC&E implemented a waiver system. Now, dairies can install dry or liquid systems regardless of their size. However, dairies milking 100 cows or less are exempt from permitting, if they implement separate systems for dry manure management and milk center wash water management. Otherwise a permit is required. For both dry and liquid systems ADPC&E expects dairies to develop waste management plans. The waiver is conditional on significant industry compliance with the permitting or wavier requirements. There were concerns that the number of dairies implementing plans would not meet the goal of 100 per year. Therefore dairies were given a priority in 1997 Environmental Quality Incentives Program (EQIP). Over 100 dairies will implement in excess of $1,260,000 in waste management practices. At least 50% of the funds will be provided by EQIP. The average cost-share allocation is $6800. In addition to the EQIP funds, Arkansas Soil and Water Conservation Commission (ASWCC) made available up to $7500 per dairy for a combined total of 75% cost-share. ASWCC funds are available to more than 90 dairies. The combined regulatory requirements, financial assistance, and cooperative agency and industry efforts will help over 100 dairies implement improved waste management practices in '97-'98. This successful joint effort is expected to continue.
5020 Losses of Nand P from a dairy manure management system. H. H. Van Horn, University of Florida, Gainesville. The University of Florida Dairy Research Farm renovated its manure collection and holding system and installed two 12.1-ha center pivots to distribute wastewater to those sprayfields where forage crops were grown to recycle nutrients. Data collection started in 1992, most of which was utilized in quarterly reports submitted to the Florida Department of Environmental Protection to monitor Nand P as required in the Industrial Wastewater Facility Permit under which the dairy operated. In this system, 275 to 380 milking cows were confined in freestall barns, adjacent concrete covered holding areas, or the milking parlor 100% of the time. In the manure management system: 1) manure was flushed from all areas, 2) sand traps were used to settle out much of the sand which was reused for bedding, 3) a stationary Screen removed fibrous solids, 4) sediment basins removed additional solids, 5) effluent from sediment basins flowed to a small (.25 ha) lagoon, 6) effluent from lagoon was pumped to a 2-ha holding pond, 7) holding pond wastewater was pumped to the two, 12.1-ha sprayfields about every 2 wk. Excretion estimates per cow of Nand P were estimated at 410 and 59 bid for this herd. Recoveries of N· and P were determined from sample analyses, metered volumes of wastewater..''oPplied, number of loads and estimated load weights of solids hauled. Recoveries as a percentage of estimated Nand P excretions were: 28% of N in wastewater irrigated on sprayfields, 12% of N in solids which were land spread, 61% of P in wastewater irrigated on sprayfield, 15% of P in solids. Most of the nonrecovered N was volatized except for a small nondetermined amount in sludge accumulating in the lagoon and holding pond. Data generated from excretion estimated and ratios of N concentrations in sprayfield wastewater to that in concurrent samples taken from effluent from the lagoon suggested that 28% of N (in addition to the 12% recovered in solids) was lost before effluent left the lagoon leaving 32% as the estimated loss in holding pond. Most of the P excretion was recovered (76%) with the remaining, unaccounted 24% not an unusual amount to expect to be retained in lagoon and holding pond sludges.
5022 1996 financial survey of Georgia dairies. L. O. Ely, University of Georgia, Athens. A survey for cash costs and returns for 1996 was distributed to Georgia dairy farmers. This was the fourth year of the survey. Thirty one forms were returned with 25 having usable data. Net balance for feed inventory was hay, 201 tons; silage, -828 tons; grain, -383 tons; concentrate, -3 tons; and by-products, -5 tons. Farms averaged 251 cows per farm and 17400 pounds of milk per cow. Milk income was $15.82/cwt or $709,481/farm. Total income was $834,122/ farm or $18.59/ cwt. Total expenses were $777,909/ farm or $16.55/ cwt. The largest expense item was feed purchased, $319.298/ farm or $7.01/ cwt. The next expense items were other, $1.54/ cwt; cow purchase, $1.43/ cwt; depreciation; $1.38/ cwt and labor, $1.24/ cwt. Net operating income was $132,190/ farm or $3.56/ cwt. This was higher than 1993, 1994 or 1995.
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5023 Comparison of Arkansas dairy herds whose owners were or were not in 4-H or FFA. J. A. Pennington*, C. Rosenkrans, Jr., Z. Johnson, C. Y. Tarn, and M. L. Scott, University of Arkansas Cooperative Extension Service, Little Rock, and Department of Animal Science: Fayetteville. A survey of 749 dairy farms in Arkansas was conducted to compare herd characteristics and management practices for herds whose owners were in 4-H or FFA to herds whose owners were not in these youth organizations. Of 434 surveys used, 161 were from former 4-H'ers (262 not +11 missing data) and 281 were from former FFA'ers (144 not +9 missing data). Owners in 4-H or FFA had more (P<.05) part-time employees and more (P<.05) frequent visits from veterinarians and milking equipment inspection. Most parameters did not differ (P>.10) for groups but owners in 4-H or FFA as youth (greater with FFA) conducted more preferred practices than owners not in 4-H or FFA (see table). Parameter DHIA Records ID Calves by 30 Days Balance Milk Cow Ration Synchronize Heifers ET Conducted Use KaMaRs Pregnancy Check Dry Treat Cows Grain to Dry Cows Employ Family Member Children in 4-H Children in FFA 4-H/FFA as Youth
Prob. 0.11 0.09 0.08 0.59 0.01 0.10 0.24 0.89 0.62 0.05 0.01 0.03 0.01
5025 How we work with our dairy farm managers - a panel discussion. L. O. Ely, University of Georgia, Athens. Interaction with dairy producers is usually initiated in two ways. The first is a request to solve a particular problem or for specific information. This request is fulfilled as best as possible and often leads to further discussion. The second method of interaction is review sessions with the producer. These are scheduled through our dairy management analysis program - Dairy MAP. This program involves an evaluation of his production records. A comparison to regional averages, a summary of the last three test dates and 19 graphs prepared from the last 18 test days is prepared. Potential problem areas are identified and recommendations are made. Cash flow budgets are often developed to evaluate production changes. Obtaining accurate and complete information is difficult. The starting point for these evaluations is the cash flow budgets that we develop every year from the Georgia dairy farm financial survey.
Not FFAas Not 4-H as Youth 4-H Prob. Youth FFA % Yes % Yes 32.7 25.4 0.03 31.8 21.7 53.0 0.01 61.3 45.4 61.6 0.59 66.7 58.0 60.2 63.0 9.1 7.6 0.05 10.0 4.3 4.2 11.5 4.7 0.06 9.3 48.5 0.60 69.8 59.5 66.5 68.8 58.6 0.01 71.9 47.5 0.09 79.8 72.3 77.4 76.7 82.8 84.6 0.03 87.1 78.7 0.01 63.2 52.5 53.7 70.6 44.7 25.2 0.04 37.2 25.2 0.01 53.4 38.7 54.4 26.6 81.1 55.9 0.01 45.9 20.1
5026 Evaluating milk urea nitrogen data. M. A. Faust* and L. H. Kilmer, Iowa State University, Ames.
5024 Critical factors in successful management. G. A. Benson, North Carolina State University, Raleigh. Individual dairy farm families have different goals and face different problems and opportunities. Individual farm data show a wide variation in financial health and financial performance among dairy farms of any given type or in any particular region of the country. For this reason, it is not possible to manage a business successfully by following general guidelines or thumb rules. Also, the financial health of a particular farm helps set priorities and affects the feasibility of alternative solutions. Approaching farm problems from a purely production perspective without knowledge of, or regard for, the financial status of that business may lead to erroneous recommendations being made. Each farm must be approached as a unique case. Successful management begins with a complete and accurate assessment of the current financial status and recent performance trends of a business. Furthermore, this cannot be inferred from production related data; financial data are required. There are three steps to the process, each of which is explained in detail. The first step describes the business by means of a balance sheet, an earnings statement calculated on an accrual basis, and a summary of cash flows. Second, financial performance measures are calculated from these three statements, to assess strengths and weaknesses. An analysis of production records for livestock and crops helps explain financial performance but only in part. Financial and production records used in combination with benchmark performance measures provide a sound basis for the development of a plan of action that can better accomplish family goals. The record keeping necessary to accomplish this is described.
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Goal was to study non-nutritional sources of variability for milk urea nitrogen results; effects studied were measurement error, milking time, collection day, parity, DIM, percent of group sampled, time relative to feeding change, levels for other milk comp';nents, and laboratory. Stage of lactation (8-380 DIM) did not influence urea nitrogen. Coefficients of variation for measurement error in different laboratories were: lactose % .20-.46%, protein % .24-7.5%, fat % .8-2.5%, urea nitrogen 3.3-7.3%, and sec 6.9-99.4%. Urea nitrogen was highest for milk from cows in parities 3 and 4 and lowest for oldest cows. No important relationships were identified between milk urea nitrogen and percentages of fat, protein, lactose, SNF, and total solids, however, urea nitrogen values were highest for samples with the smallest SCC (b-value = .0026 ± .0009). When milk urea nitrogen was reported for different proportions of cows in the group, variability of replicates for measurement error was smallest for subsets that included 75% of cows, and increased exponentially when sets included fewer cows; for 10, 25, 50, and 75% subsets, coefficients of variation for error were 7.9, 4.7, 3.6, and 1.8%, respectively. Variability for milking time was extremely large; pooled means of urea nitrogen for samples from 2:00 AM, 10:00 AM, and 6:00 PM milkings were 13.4, 15.4, and 15.2 mg/dl, respectively. When soluble nitrogen and readily fermentable carbohydrate levels in diets were increased abruptly, differences for milk urea nitrogen were detected during the first 2 subsequent milkings, and differences were not sustained for milkings during day 2 following treatment. Least significant difference (95% confidence interval) for detecting differences of two means for milk urea nitrogen were: No. values in means Samples evaluated 1,1 5,5 20,20 50,50 --------LSD, mg/dl-----.:Same sample source, milking, and day 14.7 1.20 .52 .32 Different milking, same source and day 32.0 2.60 1.14 .71 Different day, same source and milking 36.3 2.95 1.29 .80
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5027 Role of consultants in evaluating production and management records-a case study. D. M. Amaral-Phillips, University of Kentucky, Lexington.
5029 Two to eight months of age: A critical time in the growth of heifers. R. E. James, Virginia Polytechnic Institute and State University, Blacksburg.
The second and third days of this year's Southern ADSA program includes a workshop for industry and extension consultants entitled "Putting the Concepts into Practice". This program has been designed to integrate invited presentations with how to effectively utilize this information when evaluating actual, on-farm situations. Specifically, the case study will use a Holstein herd producing over 23,000 lb RHA and will evaluate the farm's strengths and areas for possible improvement in the nutritional, reproductive and mastitis programs. This evaluati6fi will utilize the herd's PCDART management records, milk urea nitrogen data, body condition scores and an analysis of the current feeding program. In addition, the panel of a nutritionist, veterinarian, and extension consultants will discuss specific observations and questions which need to be addressed during the follow-up farm visit.
This segment of the life cycle is critical because it sets the stage for early calving and has a strong, permanent influence on mammary development. Most research indicates that moderate rates of gain (.68 .9kg/day) are desirable. Key factors influencing successful rearing during this period are the transition period, control of coccidiosis, and the rate of gain attained. Weaned calves should be housed individually for several weeks while adjusting to the absence of liquid feeds. Next, they should be housed in small groups of 4 - 6 to adjust to competition for feed. Early in this period problems with coccidiosis are most likely to be observed. Including proven coccidiostats or coccidiocides in the diet along with strict sanitation of housing and feeding devices is recommended. There is a substantial risk of impaired mammary development when heifers are fed for accelerated rates of gain during the prepubertal period. At rapid rates of gain, growth hormone secretion and ductal growth into the mammary fat pad is reduced. The rate of gain or the age at which development is impaired is uncertain. Breed differences in the influence of gain on mammary development exist. Daily gains in excess of .9 kg for Holsteins and .6 kg for Jerseys are not recommended. Substandard gains delay onset of puberty and subsequent breeding. Success is likely when housing and management systems exist to control coccidiosis and infectious disease and permit monitoring of body weight gains.
5028 A case study - evaluating dairy nutritional programs using PCDART and feed analyses. J. W. West, University of Georgia, Tifton. The challenge to thorough evaluation of a nutritional program is to have an accurate bench mark against which to compare herd performance, and to be able to capture and interpret data which reveals the response to nutritional and management changes at key points in the lactation. The case study herd is Holstein with a rolling herd average (RHA) of 23,229 lbs. At the most recent test day, average days in milk (DIM) were 207 d, peak and summit test day milk for first, second, and third+ lactation cows was 89, 80;, 104, 98; 107, 101 lbs. These data are consistent with means for 706 herds with RHA exceeding 23000 lbs., where DIM were 184 d, RHA was 24,623 lbs., and peak milk was 85, 105, and 113 lbs. for first, second, and third lactation cows. Body condition scores for the case study herd were 3.5 (dry), 3.3 (calving), 3.0 (early lactation), 3.1 (at pregnancy diagnosis), 3.3 (late lactation), reflecting good nutriti()J:\,.):"!eifers were large at breeding (931 lbs.) and at calving (1412Ibs.), averaged 25 months of age, and apparently were of excellent body size. Somatic cell counts (x1000) currently average 167, 309, and 826 for first, second, and third+ lactation cows and have risen sharply for 3+ lactation cows for the most recent test day. The overall SCC of 427 indicates room for improvement. During the most recent year 67 cows (34.7%) left the herd. Reasons for culling were low production (10.4%), reproduction (19.4%), disease-injury-other (22.4%), died (14.9%), mastitis-udder (20.9%), and feet-legs (11.9%), presenting some target areas for improvement. Comparatively, the case study herd was higher for losses due to deaths, mastitis-udder, and feet-legs than the means for the herds >23000 lbs. milk. Improved performance should be sustainable under current management conditions. Further evaluation of rations and forages will occur during the case study.
5030 On-farm evaluation of heifer management. D. R. Winston, Virginia Polytechnic Institute and State University, Blacksburg. The heifer enterprise represents 15-20 percent of total milk production costs. The goal of the heifer enterprise should be to economically raise heifers to reach their genetic potential at the earliest age possible. Management is about making decisions based on available information. A complete, accurate record keeping system is essential to track growth, reproductive, health, and financial information. Basic information should include animal identification, date of birth, and sire and dam identification. Growth, as measured through body weight and wither or hip height, is the best indicator of performance of the dairy heifer. On many dairy farms a lack of safe, labor efficient handling facilities limits the ability of dairy managers to routinely collect heifer growth data. Reproductive data should include estrus dates, service dates, service sire identification, and pregnancy examination results. Reproductive performance may then be evaluated through average age at first breeding and services per conception. Health events such as dehorning, removal of extra teats, vaccinations, coccidiostat/coccidiocide usage, deworming, and treatment for diseases and injuries as well as death losses should be recorded. Financial data allows the producer to calculate rearing costs. With this information weak link analysis identifies strengths and weaknesses enabling improvement of the enterprise. If the heifer enterprise is not meeting its objectives, one option is to have heifers grown by professional heifer growers. Another alternative is to sell calves at birth and purchase replacements as springers. A heifer management survey was conducted in five states through the NC-119 Regional Research Project. Practices reported in the survey will be presented.
Journal of Dairy Science Vol. 81, No.4, 1998