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Influences of supplemental fat, differing in fatty-acid composition, on performance, lactation, and reproduction of beef cows
The Professional Animal Scientist 29 (2013):587–594
©2013 American Registry of Professional Animal Scientists
Influences of supplemental fat, differing in fatty-acid
composition, on performance, lactation, and reproduction of beef cows D. W. Shike,1 F. A. Ireland, PAS, and D. B. Faulkner,2 PAS Department of Animal Sciences, University of Illinois, 1207 W. Gregory Drive, Urbana 61801
ABSTRACT Angus × Simmental, fall-calving cows (n = 480) were allotted to 1 of 4 supplements containing whole raw soybeans (SY), OmegaFlax (FLX), Energy Booster 100 (EB), or corn–soybean meal (CON). The SY, FLX, and EB supplements were formulated to have the same concentration of crude fat. The FLX, EB, and CON supplements were formulated to be isonitrogenous. Cows were blocked by age (2 groups) and randomly assigned to treatments before calving (36 ± 0.6 d prepartum). The cows were fed 1.81 kg of DM/d of respective supplement for 108 d. There were no differences in BW or BCS change in any contrasts. There were no differences in percentage of cows cycling before the breeding season or first-service AI conception for any of the contrasts. The SY-supplemented cows had lower (P = 0.01) overall pregnancy rate compared with FLX-supplemented cows and tended (P = 0.06) to have lower overall pregnancy rates compared Corresponding author: [email protected] Present address: Department of Animal Sciences, University of Arizona, Shantz 205, PO Box 210038, Tucson, AZ 85721-0038. 1 2
with EB-supplemented cows. There was no difference in overall pregnancy for SY, FLX, and EB versus CON (P = 0.81). The SY-supplemented cows tended (P = 0.06) to have greater AI embryonic loss than did EB-supplemented cows. Fat supplementation during the pre- and postpartum period did not affect cow BW or reproductive performance compared with cows fed control supplement. Cows fed supplement containing soybeans as the fat source had poorer reproductive performance than did cows fed supplements containing OmegaFlax (flaxseed) or Energy Booster 100 (hydrolyzed animal fat) as the fat source. Key words: beef cow, fat supplementation, polyunsaturated fat, reproduction, soybean
INTRODUCTION The economic success of a beef cow–calf operation is dependent upon the cow having a short postpartum interval to first estrus and high firstservice conception rates. Inadequacies in either of these areas will result in lower pregnancy rates, higher culling rates, and lower weaned calf/
cow numbers. Nutrition plays a key role in reproductive success in cattle, and one of the most studied nutrition relationships is the effect of dietary energy and body energy reserves on postpartum breeding performance (Kinder et al., 1987; Randel, 1990). In a review, Hess et al. (2005) concluded that prepartum nutrition is critical in determining the length of postpartum anestrus; a BCS ≥5 will ensure body energy reserves sufficient for postpartum reproduction, and beef cows in a negative energy balance will have lower reproductive performance. Fat supplementation is one method of addressing these concerns. Fat sources vary widely and differ in their fattyacid content. In general, most of the seed-derived oils contain higher levels of linoleic acid, forages and flaxseed contain higher levels of α-linolenic acid, and rendered fats such as tallow contain a large proportion of saturated fats and the monounsaturated oleic acid (Coppock and Wilks, 1991; Staples et al., 1998). However, once the fats enter the rumen, they are hydrolyzed, and the FFA undergo biohydrogenation (Mattos et al., 2000). Staples et al. (1998) estimated
588 that polyunsaturated fatty acids such as linoleic acid are biohydrogenated at a range of 60 to 90% efficiency. Polyunsaturated fatty acids, such as linoleic and linolenic acid, may inhibit prostaglandin F2α (PGF2α; Mattos et al., 2000). Conversely, Grant et al. (2003) reported that high-linoleate safflower seeds increased PGF2α metabolite. Uterine production of PGF2α is critical during the early postpartum period for proper uterine involution (Madej et al., 1984; Filley et al., 2000). However, elevated levels of PGF2α later in the postpartum interval could result in early embryonic mortality (Troxel and Kesler, 1984; Funston, 2004). Funston (2004), in a summary of work on fat supplementation, concluded that the duration and time of supplemental fat necessary to elicit a response is not precisely known. Much of the benefit of supplemental fat has been proposed to be attributed to polyunsaturated fatty acids (Funston, 2004). Graham et al. (2001) showed soybeans (high in linoleic acid) improved conception rates; Petit et al. (2001) reported improved conception rates for flaxseed (high in linolenic acid). Although saturated fat sources seem to have less effect, Son et al. (1996) found improved reproductive function for tallow. There is no published data available comparing the effects of soybeans, flaxseed, and animal fat on beef-cow reproduction. These 3 fat sources represent differing fatty-acid profiles. The objectives of this experiment were to evaluate the effects of supplemental fat, differing in fatty-acid profile, on cow performance, milk production, and reproduction.
MATERIALS AND METHODS Experimental Animals Angus × Simmental, fall-calving cows (n = 480) from the University of Illinois beef herd at the Dixon Springs Agriculture Center were used in this experiment. Animals used in this experiment were managed according to the guidelines recommended in the Guide for the Care and Use of Agricul-
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tural Animals in Agriculture Research and Teaching (FASS, 1988). Experimental protocols were submitted and approved by the Institutional Animal Care and Use Committee.
Management and Diets Cows were blocked by age (2 age groups) and randomly assigned to treatments before calving (36 ± 0.6 d prepartum). There were 8 groups with 2 replications per treatment. The cows were fed 1 of 4 supplements: whole raw soybeans (SY); corn, soybean meal, and OmegaFlax (ground flaxseed; ADM Alliance Nutrition Inc., Quincy, IL; FLX); corn, soybean meal, and Energy Booster 100 (hydrolyzed animal fat; Milk Specialties Company, Dundee, IL; EB); or corn– soybean meal (CON). The fat sources were selected based on their fatty-acid composition (Table 1). The FLX and EB supplements were formulated to have the same level of crude fat as the SY supplement. The FLX and EB supplements were formulated to be isonitrogenous with the CON (80% corn/20% soybean meal). Corn and soybean meal made up the balance of the FLX and EB supplements. Ingredient and nutrient compositions of supplements are presented in Table 2. Cows grazed endophyte-infected tall fescue (Festuca arundinacea), red clover (Trifolium pratense), and white clover (Trifolium repens) pastures. The cows were fed 1.81 kg of DM/d of respective supplement for 108 ± 0.6 d from trial initiation (36 ± 0.6 d prepartum) until trial completion (72 ± 0.6 d postpartum).
Performance, Lactation, and Reproduction Data Collection Initial shrunk cow BW and BCS were measured at the start of the experiment (36 ± 0.6 d prepartum). Calf birth weights were measured within 24 h of being born and used as initial calf BW. Final shrunk BW and BCS, as well as calf BW, were measured at experiment completion (72 ± 0.6 d postpartum). Cow BW change
and BCS change, as well as calf ADG, were calculated for the 108-d period. Milk production estimates (n = 150) were attained using the weighsuckle-weigh technique at d 55 ± 0.6 of lactation. Twenty-four-hour milk production estimates were determined using a 12-h weigh-suckle-weigh technique (Beal et al., 1990). Six hours following the weigh-suckle-weigh, a subsample of 6 cows per treatment were milked using a commercial portable milk machine (Porta Milker, The Coburn Company Inc., Whitewater, WI). Cows were administered 20 USP units of oxytocin (Phoenix Scientific, St. Joseph, MO) intravenously within 2 min of milking to initiate milk letdown. Milk was sampled and sent to Dairy Lab Services (Dubuque, IA) for compositional analysis. The cows were estrus synchronized using either the CoSynch+CIDR or 7–11 estrus synchronization protocols (Bremer et al., 2004) and artificially inseminated on d 76 ± 0.6. Synchronization protocols were applied evenly across treatments. After AI, cows were exposed to bulls for a 45-d breeding season. First-service conception rates were determined via transrectal ultrasonography at 32 d after AI. Overall pregnancy rate was determined via rectal palpation 64 d after bulls were removed. Cows that were not pregnant at the time of ultrasound and pregnant at the time of palpation were considered pregnant to the clean-up bulls. Cows that were pregnant at the time of ultrasound and not pregnant at the time of palpation were considered to have embryonic loss.
Blood and Feed Data Collection Two blood samples (10 mL) were taken via jugular venipuncture 10 d apart before the breeding season to determine the percentage of cows cyclic. After collection, blood was stored on ice to prevent progesterone metabolism (Wiseman et al., 1982) before centrifugation at 1,000 × g for 20 min at 5°C within 6 h of collection. Serum was stored at −20°C until assaysis for progesterone concentration. Serum
Evaluation of differing fat sources in beef cows
Table 1. Fatty-acid composition of supplemental fat sources Supplemental fat source1
Fatty acid, % of total fat
Soybeans
OmegaFlax
Energy Booster 100
10:0 11:0 12:0 13:0 14:0 14:1 15:0 16:0 trans 16:1 16:1 17:0 18:0 trans 18:1 18:1n-9 cis 18:1n-11 cis 18:1 isomers 18:2n-6 cis 20:0 20:1 18:3n-3 20:2 22:0 20:3n-3 23:0 20:5n-3
0.00 0.02 0.00 0.34 0.08 0.00 0.00 11.47 0.00 0.09 0.36 4.15 0.03 21.55 1.49 0.00 52.92 0.34 0.00 6.47 0.00 0.38 0.00 0.06 0.24
0.00 0.04 0.03 0.06 0.05 0.00 0.01 5.29 0.04 0.06 0.08 3.33 0.02 19.29 0.69 0.00 15.48 0.17 0.00 54.93 0.04 0.15 0.07 0.02 0.13
0.08 0.00 0.42 0.00 1.82 0.25 0.00 30.44 0.22 0.58 1.11 0.00 0.00 53.33 1.04 7.99 1.06 1.02 0.13 0.00 0.00 0.32 0.00 0.05 0.13
OmegaFlax from ADM Alliance Nutrition Inc., Quincy, Illinois, and Energy Booster 100 from Milk Specialties Company, Dundee, Illinois.
1
samples were analyzed for concentrations of progesterone in duplicate using the commercially available RIA procedure of Coat-A-Count (Diagnostic Products Corp., Los Angeles, CA). In brief, 100 μL of serum was added to polypropylene tubes coated with rabbit antibodies to progesterone followed by the addition of 1 mL of iodinated progesterone. Tubes were incubated at room temperature for 3 h and then decanted, allowed to dry overnight, and counted for 1 min in a gamma counter. Standards of 0 to 40 ng/mL were used to develop a calibration curve, and pooled samples were used for intra- and interassay CV calculations. Cows were considered estrous cyclic when progesterone concentrations of either sample exceeded 1.0 ng/mL. Samples of corn, soybean meal, soybeans, OmegaFlax, and Energy Booster 100 were taken from each
load and stored at −20°C until they could be analyzed. Feed samples were dried at 55°C, ground in a Wiley mill (2-mm screen; Arthur H. Thomas, Philadelphia, PA), and composited for analysis. Total fatty acids were determined by gas chromatography (Shimadzu GC-17A, Shimadzu Scientific Instruments Inc., Columbia, MD) of fatty methyl esters formed by acidcatalyzed transesterification (Sukhija and Palmquist, 1988). Chemical composition of all dietary ingredients was ascertained by Rock River Laboratory Inc. (Watertown, WI).
Statistical Analysis Cow and calf performance were analyzed using the GLM procedure of SAS (SAS Institute Inc., Cary, NC) using single degree of freedom orthogonal contrasts [SY vs. FLX; SY vs. EB; and CON vs. SY, FLX, and EB
589 (FT)], with pen serving as the experimental unit. Reproductive parameters were analyzed using the GLIMMIX procedure of SAS using single degree of freedom orthogonal contrasts (SY vs. FLX, SY vs. EB, and CON vs. FT). Block was fitted as a fixed effect and pen(block) and cow(pen) were random effects. Milk production, milk composition, and milk component production were also analyzed using the GLM procedure of SAS using single degree of freedom orthogonal contrasts (SY vs. FLX, SY vs. EB, and CON vs. FT), with individual animal serving as the experimental unit. Treatment effects were considered significant at an α level of 0.05.
RESULTS AND DISCUSSION The performance and milk production data are presented in Table 3. There were no differences in initial BW in any of the contrasts. There were also no differences in initial BCS for SY versus FLX (P = 0.31) or for SY versus EB (P = 0.31). However, cows supplemented with FT had a 0.1 higher (P = 0.02) initial BCS than did the cows fed CON supplement. The SEM for initial BCS was very low (0.03), which may have allowed for very small numerical differences to be detected. This difference in initial BCS (0.1) is not likely to have any significant biological effect. There were no differences in BW or BCS change in any of the contrasts. There were also no differences in final BW or BCS in any of the contrasts. Fat supplementation has resulted in no effect on BW or BCS (Webb et al., 2001; Alexander et al., 2002). In contrast, fat supplementation has increased either BW or BCS (Espinoza et al., 1995, 1997; De Fries et al., 1998). The response of BW and BCS to fat supplementation may be dependent on initial BCS. Webb et al. (2001) hypothesized that cows with >5 BCS may not respond to fat supplementation the same as cows in poorer body condition. The cows in this experiment were above a BCS of 5 at the start and completion of the experimental period. Although there
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Table 2. Supplement composition Item Ingredient, % DM Corn Soybean meal Soybeans5 OmegaFlax6 Energy Booster 1007 Chemical composition, % DM CP NDF ADF Ether extract Ca P NEm,8 Mcal/kg NEg,8 Mcal/kg
SY1
FLX2
0 0 100 0 0 41.05 16.17 7.13 20.36 0.41 0.70 2.35 1.65
50 7 0 43 0 18.89 13.42 6.46 18.76 0.17 0.58 2.44 1.71
EB3
58 25 0 0 17 18.89 10.02 3.23 21.52 0.14 0.46 2.61 1.83
CON4
80 20 0 0 0 18.34 6.70 3.24 5.69 0.13 0.51 2.17 1.49
Supplement containing whole raw soybeans. Supplement containing OmegaFlax (ADM Alliance Nutrition Inc., Quincy, IL). 3 Supplement containing Energy Booster 100 (Milk Specialties Company, Dundee, IL). 4 Supplement containing corn and soybean meal. 5 Whole, unprocessed soybeans. 6 Ground flaxseed (ADM Alliance Nutrition Inc., Quincy, IL). 7 Hydrolized animal fat (Milk Specialties Company, Dundee, IL). 8 NEm and NEg values are from NRC (2000) except for flaxseed (“Alternative Feeds for Ruminants,” Lardy and Anderson, 1999). 1 2
were numerical trends in milk production, there were no differences in milk production in any of the contrasts. There were also numerical trends in calf ADG, but again there were no
differences in any of the contrasts. Calf ADG corresponded to numerical differences in milk production. Higher calf ADG from cows supplemented with fat has been observed (Espinoza
et al., 1997; De Fries et al., 1998; Bellows et al., 2001). Fat supplementation has resulted in increased milk production (Espinoza et al., 1997; Johnson et al., 2002). The milk composition and component production data are exhibited in Table 4. The cows supplemented with SY had 0.57 percentage units lower (P = 0.05) milk protein percent than did the cows supplemented with FLX. There were no differences for SY versus EB (P = 0.28) or for FT versus CON (P = 0.15) in protein percentage. In contrast, fat supplementation often decreases the protein percentage of the milk (Coppock and Wilks, 1991). There were no differences in protein production for SY versus FLX (P = 0.61) or for SY versus EB (P = 0.99). However, the FT-supplemented cows did have 0.03 kg/d more (P = 0.03) protein production than did the cows fed the CON supplement. The SY-supplemented cows had a 1.5 percentage units higher (P = 0.03) milk fat percent than did the FLX-supplemented cows, and this resulted in 0.13 kg/d more (P = 0.001) fat yield. The SY-supplemented cows had 2.17 percentage units higher (P = 0.002) milk fat percent than did the EB-supplemented cows, and this resulted in 0.16 kg/d more (P < 0.001) fat yield. The FT-supplemented cows had 1.23
Table 3. Effects of fat sources on cow performance and milk production Treatment Item Initial BW, kg Final BW, kg BW change, kg Initial BCS Final BCS BCS change Milk production, kg/d Calf ADG, kg/d
Contrast
SY1
FLX2
EB3
CON4
SEM
SY vs. FLX
SY vs. EB
FT5 vs. CON
572 532 −40 6.0 5.7 −0.3 5.8 0.89
570 525 −45 5.9 5.1 −0.8 5.0 0.84
569 532 −37 5.9 5.9 −0.1 5.1 0.93
566 536 −30 5.8 5.4 −0.4 4.7 0.80
9 16 10 0.03 0.3 0.3 0.5 0.06
0.90 0.77 0.73 0.31 0.26 0.29 0.29 0.53
0.87 1.00 0.88 0.31 0.73 0.73 0.37 0.64
0.72 0.75 0.43 0.02 0.74 0.96 0.23 0.27
Supplement containing whole raw soybeans. Supplement containing OmegaFlax (ADM Alliance Nutrition Inc., Quincy, IL). 3 Supplement containing Energy Booster 100 (Milk Specialties Company, Dundee, IL). 4 Supplement containing corn and soybean meal. 5 FT = SY + FLX + EB. 1 2
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Table 4. Effects of fat sources on cow milk composition and component production Treatment
Contrast
Item
SY1
FLX2
EB3
CON4
SEM
SY vs. FLX
SY vs. EB
FT5 vs. CON
Protein, % Protein, kg/d Fat, % Fat, kg/d Lactose, % Lactose, kg/d Other solids, % Other solids, kg/d MUN,6 mg/dL
2.72 0.16 7.47 0.43 4.80 0.28 5.69 0.33 35.18
3.29 0.16 5.97 0.30 4.93 0.25 5.86 0.29 25.14
3.02 0.15 5.30 0.27 4.62 0.24 5.53 0.28 24.47
2.68 0.13 5.02 0.24 4.98 0.24 5.87 0.28 23.50
0.19 0.01 0.44 0.03 0.13 0.02 0.12 0.03 1.70
0.05 0.61 0.03 0.001 0.48 0.39 0.35 0.41 <0.001
0.28 0.99 0.002 <0.001 0.34 0.24 0.36 0.27 <0.001
0.15 0.03 0.02 0.001 0.20 0.42 0.22 0.37 0.03
Supplement containing whole raw soybeans. Supplement containing OmegaFlax (ADM Alliance Nutrition Inc., Quincy, IL). 3 Supplement containing Energy Booster 100 (Milk Specialties Company, Dundee, IL). 4 Supplement containing corn and soybean meal. 5 FT = SY + FLX + EB. 6 MUN = milk urea nitrogen. 1 2
percentage units higher (P = 0.02) milk fat percent than did the cows fed the CON supplement, and this resulted in 0.09 kg/d more (P = 0.001) fat yield. Fat supplementation can have negative effects on fiber digestion, which can result in lower milkfat percentages (Coppock and Wilks, 1991). Johnson et al. (2002) reported that supplementing oilseeds resulted in higher fat production. Negative effects of fat supplementation are more common with oil than with oilseeds. Feeding oilseeds results in a slower release of the oil and less negative effects on digestion (Coppock and Wilks, 1991). There were no differences in percentage of lactose or lactose production for any of the contrasts. There were also no differences in percentage of other solids or other solids production for any of the contrasts. The SY-supplemented cows had 10.04 mg/dL higher (P = 0.001) milk urea nitrogen (MUN) concentration than did the FLX-supplemented cows and 10.71 mg/dL higher (P = 0.001) MUN concentration than did the EBsupplemented cows. The differences in MUN between the SY-supplemented cows and the FLX- and EB-supplemented cows are likely because of the differences in protein content of the
supplements; the SY supplement had greater protein concentration than did the other supplements. The focus of the experiment was to evaluate different fat sources, and thus the FLX and EB supplements were formulated to have the same concentration of crude fat as SY and were not formulated to be isonitrogenous with SY. The FTsupplemented cows had 4.76 mg/dL higher (P = 0.03) MUN concentration than did the cows fed the CON supplement. This difference is primarily due to the elevated MUN of the SY-supplemented cows. The reproductive performance data are shown in Table 5. There were no differences (P ≥ 0.22) in the percentage of cows cycling before the breeding season for any of the contrasts. However, fat supplementation previously has increased the percentage of cows cycling (Espinoza et al., 1995; Bader et al., 2000). There were no differences (P ≥ 0.31) in first-service AI conception for any of the contrasts. Previous work has found that fat supplementation has increased firstservice conception rates (Bader et al., 2000; Graham et al., 2001). However, Hess et al. (2007) concluded that feeding high-linoleate supplements postpartum may have deleterious ef-
fects on reproduction. Funston (2004) reported in a review that in some research, fat supplementation had limited benefit when supplementation began prepartum and continued through the postpartum period. There was no difference in overall pregnancy rates for FT versus CON (P = 0.81). Fat supplementation has resulted in improved pregnancy rates (Espinoza et al., 1995; Lammoglia et al., 1997; Bellows et al., 2001) and no effect on pregnancy rates (Alexander et al., 2002; Bottger et al., 2002). Several mechanisms have been proposed for beneficial effects of supplemental fat. Elevated levels of PGF2α later in the postpartum interval could result in early embryonic mortality (Troxel and Kesler, 1984; Funston, 2004). Polyunsaturated fatty acids, such as linoleic and linolenic acid, may inhibit PGF2α (Mattos et al., 2000). Thomas et al. (1997) reported that polyunsaturated fat (soy oil) supplementation resulted in a greater rate of ovarian follicular growth than did supplementation with saturated fat (tallow). Although potential mechanisms exist for improved reproductive performance in fat-supplemented cows, this experiment found no improvement for fat supplementation compared with
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Table 5. Effects of fat sources on cow reproductive performance Treatment Item Cyclicity,6 % AI conception,7 % Bull conception,8 % Overall pregnancy,9 % Embryonic loss,10 %
Contrast
SY1
FLX2
EB3
CON4
83 (100/120) 59 (71/120) 67 (32/48) 82 (97/119) 8 (6/71)
91 (106/117) 64 (75/117) 88 (36/41) 92 (107/116) 5 (4/75)
81 (95/117) 59 (69/117) 76 (35/46) 89 (102/114) 1 (1/69)
81 (93/115) 66 (76/115) 77 (30/39) 89 (101/114) 5 (4/76)
SEM SY vs. FLX SY vs. EB FT5 vs. CON 3 5 8 3 3
0.22 0.45 0.22 0.01 0.38
0.92 0.93 0.45 0.06 0.06
0.57 0.31 0.92 0.81 0.94
Supplement containing whole raw soybeans. Supplement containing OmegaFlax (ADM Alliance Nutrition Inc., Quincy, IL). 3 Supplement containing Energy Booster 100 (Milk Specialties Company, Dundee, IL). 4 Supplement containing corn and soybean meal. 5 FT = SY + FLX + EB. 6 Percentage of cows that were estrous cyclic before breeding. 7 Cows determined pregnant to first-service AI via rectal ultrasonography at 32 d after AI. 8 Cows that were open at time of ultrasound but were pregnant at time of palpation. 9 Cows determined pregnant via rectal palpation 64 d after bulls were removed (45 d of exposure). 10 Cows that were pregnant at time of ultrasound but were open at time of palpation. 1 2
the control supplement. The SYsupplemented cows had 10 percentage units lower (P = 0.01) overall pregnancy rate compared with the FLX-supplemented cows and tended (P = 0.06) to have lower pregnancy rates than the EB-supplemented cows. The cows supplemented with SY had numerically poorer conception rates to the clean-up bulls (67 vs. 88%; P = 0.22) compared with the cows supplemented with FLX. There were no differences in conception to the bulls for SY versus EB (P = 0.45) or for FT versus CON (P = 0.92). The numerically poorer conception to the bulls for the cows fed SY was unexpected. One potential reason is the phytoestrogen content of soybeans. Phytoestrogens that are present in some legumes have been shown to have negative effects on reproduction (Adams, 1995). Lightfoot et al. (1967) reported a failure of sperm transport through the cervix in ewes that had prolonged grazing of estrogenic pastures. The numerically lower conception to bulls for the SY-supplemented cows in this experiment could possibly be due to impaired sperm transport. The phytoestrogen content of the soybeans was not measured.
Another possible explanation of the poorer overall pregnancy rates of the SY-supplemented cows could be their elevated MUN concentrations. The SY-supplemented cows had a MUN concentration of ~35 mg/dL, and the other treatment groups had MUN concentrations of ~23 to 25 mg/dL. Butler et al. (1996) reported that dairy cows that had MUN >19 mg/ dL had 21 percentage units poorer pregnancy rates than did cows with MUN concentrations <19 mg/dL. Beck et al. (2005) reported that firstcalf heifers that were grazing tended to have greater MUN concentrations and poorer pregnancy rates compared with heifers that were developed in drylots. Although there are data supporting the relationship of elevated MUN concentrations and poorer pregnancy rates, Shike et al. (2009) reported cows fed corn coproducts and hay had MUN concentrations of >30 mg/dL and still had first-service AI conception rates of >67%. There was no difference in AI embryonic loss between SY and FLX (P = 0.38), but the SY-supplemented cows tended (P = 0.06) to have greater AI embryonic loss than did the EB-supplemented cows. There was no difference in AI
embryonic loss between FT and CON (P = 0.94). One proposed mechanism for improved reproductive performance from supplemental fat is that polyunsaturated fatty acids, such as linoleic and linolenic acid, may inhibit prostaglandin F2α, which could reduce early embryo mortality (Mattos et al., 2000). This study only detected embryonic loss after ultrasound (32 d after AI), and thus early embryonic losses (before d 32) would not have been detected.
IMPLICATIONS Supplementing fat to cows grazing endophyte-infected tall fescue, red clover, and white clover pastures did not affect cow BW or BCS compared with cows fed the control supplement (corn–soybean meal). Fat supplementation also did not affect milk production or calf ADG, although there were some numerical trends. Fat supplementation increased percentage of fat in the milk. Fat supplementation did not affect first-service AI conception rate, overall pregnancy, or embryonic loss compared with cows supplemented with the control supplement. However, there were a few differences
Evaluation of differing fat sources in beef cows
between the different fat sources. The cows fed soybeans had higher fat and MUN concentrations in their milk than did the cows fed OmegaFlax (flaxseed) or Energy Booster 100 (hydrolyzed animal fat). The cows fed soybeans had lower overall pregnancy rates than did the cows fed OmegaFlax (flaxseed), which was due to lower conception rates to the cleanup bulls. The cows fed soybeans also had more embryonic loss than did the cows fed Energy Booster 100 (hydrolyzed animal fat). Fat supplementation during the pre- and postpartum period to cows that are in good condition (BCS >5) may not be beneficial compared with a control supplement; thus, supplement decisions should be based on supplement cost.
LITERATURE CITED Adams, N. R. 1995. Detection of the effects of phytoestrogens on sheep and cattle. J. Anim. Sci. 73:1509–1515. Alexander, B. M., B. W. Hess, D. L. Hixon, B. L. Garrett, D. C. Rule, M. McFarland, J. D. Bottger, D. D. Simms, and G. E. Moss. 2002. Influence of prepartum fat supplementation on subsequent beef cow reproduction and calf performance. Prof. Anim. Sci. 18:351–357. Bader, J. F., E. E. D. Felton, M. S. Kerley, D. D. Simms, and D. J. Patterson. 2000. Effects of postpartum fat supplementation on reproduction in primiparous 2-year-old and mature cows. J. Anim. Sci. 83(Suppl. 1):224. (Abstr.) Beal, W. E., D. R. Notter, and R. M. Akers. 1990. Techniques for estimation of milk yield in beef cows and relationships of milk yield to calf weight gain and postpartum reproduction. J. Anim. Sci. 68:937–943. Beck, P. A., S. A. Gunter, M. Phillips, and D. L. Kreider. 2005. Development of replacement heifers using programmed feeding. Prof. Anim. Sci. 21:365–370. Bellows, R. A., E. E. Grings, D. D. Simms, T. W. Geary, and J. W. Bergman. 2001. Effects of feeding supplemental fat during gestation to first-calf beef heifers. Prof. Anim. Sci. 17:81–89. Bottger, J. D., B. W. Hess, B. M. Alexander, D. L. Hixon, L. F. Woodardt, R. N. Funston, D. M. Hallford, and G. E. Moss. 2002. Effects of supplementation with high linoleic or oleic cracked safflower seeds on postpartum reproduction and calf performance of primiparous beef heifers. J. Anim. Sci. 80:2023–2030.
Bremer, V. R., S. M. Damiana, F. A. Ireland, D. B. Faulkner, and D. J. Kesler. 2004. Optimizing the interval from PGF to timed AI in the CoSynch+CIDR and 7–11 estrus synchronization protocols for postpartum beef cows. J. Anim. Sci. 82(Suppl. 2):106. (Abstr.) Butler, W. R., J. J. Calaman, and S. W. Beam. 1996. Plasma and milk urea nitrogen in relation to pregnancy rate in lactating dairy cattle. J. Anim. Sci. 74:858–865. Coppock, C. E., and D. L. Wilks. 1991. Supplemental fat in high-energy rations for lactating cows: Effects on intake, digestion, milk yield, and composition. J. Anim. Sci. 69:3826–3837. De Fries, C. A., D. A. Neuendorff, and R. D. Randel. 1998. Fat supplementation influences postpartum reproductive performance in Brahman cows. J. Anim. Sci. 76:864–870. Espinoza, J. L., R. Ortega, S. S. Simmental, and A. Palacios. 1997. Influence of dietary fat inclusion on milk production, growth of calves, and pregnancy of beef cows on range. J. Anim. Sci. 75(Suppl. 1):107. (Abstr.) Espinoza, J. L., J. A. Ramirez-Godinez, J. A. Jimenez, and A. Flores. 1995. Effects of calcium soaps of fatty acids on postpartum reproductive activity in beef cows and growth of calves. J. Anim. Sci. 73:2888–2892. FASS. 1988. Guide for the Care and Use of Agricultural Animals in Agriculture Research and Teaching. Fed. Anim. Sci. Soc., Champaign, IL. Filley, S. J., H. A. Turner, and F. Stormshak. 2000. Plasma fatty acids, prostaglandin F2alpha metabolite, and reproductive response in postpartum heifers fed rumen bypass fat. J. Anim. Sci. 78:139–144. Funston, R. N. 2004. Fat supplementation and reproduction in beef females. J. Anim. Sci. 82(E. Suppl.):E154–E161. Graham, K. K., J. F. Bader, D. J. Patterson, M. S. Kerley, and C. N. Zumbrunnen. 2001. Supplementing whole soybeans prepartum increases first service conception rate in postpartum suckled beef cows. J. Anim. Sci. 79(Suppl. 2):106. (Abstr.) Grant, M. H. J., B. W. Hess, D. L. Hixon, E. A. V. Kirk, B. M. Alexander, T. M. Nett, and G. E. Moss. 2003. Effect of feeding high-linoleate safflower seeds on reproductive endocrine dynamics in postpartum beef females. Proc. West. Sec. Am. Soc. Anim. Sci. 54:36–39. Hess, B. W., S. L. Lake, E. J. Scholljedgerdes, T. R. Weston, V. Nayigihugu, J. D. C. Molle, and G. E. Moss. 2005. Nutrition controls of beef cow reproduction. J. Anim. Sci. 83(E. Suppl.):E154–E161. Hess, B. W., G. E. Moss, and D. C. Rule. 2007. A decade of developments in the area of fat supplementation research with
593 beef cattle and sheep. J. Anim. Sci. 86(E. Suppl.):E188–E204. Johnson, K. A., R. L. Kincaid, H. H. Westberg, C. T. Gaskins, B. K. Lamb, and J. D. Cronrath. 2002. The effect of oilseeds in diets of lactating cows on milk production and methane emissions. J. Dairy Sci. 85:1509– 1515. Kinder, J. E., M. L. Day, and R. J. Kittok. 1987. Endocrine regulation of puberty in cows and ewes. J. Reprod. Fertil. Suppl. 34:167–186. Lammoglia, M. A., R. A. Bellows, E. E. Grings, J. W. Bergman, R. E. Short, and M. D. MacNeil. 1997. Effects of dietary fat composition and content, breed and calf sex on birth weight, dystocia, calf vigor and postpartum reproduction in first calf beef heifers. J. Anim. Sci. 75(Suppl. 1):117. (Abstr.) Lardy, G. P., and V. L. Anderson. 1999. Alternative feeds for ruminants. North Dakota State Univ. Ext. Ser. Bull. AS-1182. North Dakota State Univ., Fargo. Lightfoot, R. J., K. P. Croker, and H. G. Neil. 1967. Failure of sperm transport in relation to ewe infertility following prolonged grazing in oestrogenic pastures. Aust. J. Agric. Res. 18:755–765. Madej, A., H. Kindahl, W. Woyno, L. E. Edqvist, and R. Stupnicki. 1984. Blood levels of 15-keto-13, 14-dihydro-prostaglandin F2α during the postpartum period in primiparous cows. Theriogenology 21:279–287. Mattos, R., C. R. Staples, and W. W. Thatcher. 2000. Effects of dietary fatty acids on reproduction in ruminants. Rev. Reprod. 5:38–45. NRC. 2000. Nutrient Requirements of Beef Cattle 7th rev. ed. Natl. Acad. Press, Washington, DC. Petit, H. V., R. J. Dewhurst, J. G. Proulx, M. Khalid, W. Haresign, and H. Twagiramungu. 2001. Milk production, milk composition, and reproductive function of dairy cows fed different fats. Can. J. Anim. Sci. 81:263–271. Randel, R. D. 1990. Nutrition and postpartum rebreeding in cattle. J. Anim. Sci. 68:853–862. Shike, D. W., D. B. Faulkner, D. F. Parrett, and W. J. Sexten. 2009. Influences of corn co-products in limit-fed rations on cow performance, lactation, nutrient output, and subsequent reproduction. Prof. Anim. Sci. 25:132–138. Son, J., R. J. Grant, and L. L. Larson. 1996. Effects of tallow and escape protein on lactational and reproductive performance of dairy cows. J. Dairy Sci. 79:822–830. Staples, C. R., J. M. Burke, and W. W. Thatcher. 1998. Influence of supplemental
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growth in cows fed isoenergetic diets. J. Anim. Sci. 75:2512–2519.
Sukhija, P. S., and D. L. Palmquist. 1988. Rapid method for determination of total fatty acid content and composition of feedstuffs and feces. J. Agric. Food Chem. 36:1202– 1206.
Troxel, T. R., and D. J. Kesler. 1984. Ability of indomethacin to alter prostaglandin metabolite concentrations and to enhance the function of corpora lutea induced in postpartum suckled beef cows. J. Anim. Sci. 59:177–181.
Thomas, M. G., B. Bao, and G. L. Williams. 1997. Dietary fats varying in their fatty acid composition differentially influence follicular
Webb, S. M., A. W. Lewis, D. A. Neuendorff, and R. D. Randel. 2001. Effects of dietary
rice bran, lasalocid, and sex of calf on postpartum reproduction in Brahman cows. J. Anim. Sci. 79:2968–2974. Wiseman, B. S., D. L. Vincent, P. J. Thomford, N. S. Scheffrahn, G. S. Sargent, and D. J. Kesler. 1982. Changes in porcine, ovine, bovine, and equine blood progesterone concentrations between collection and centrifugation. Anim. Reprod. Sci. 5:157–165.
©2013 American Registry of Professional Animal Scientists
Influences of supplemental fat, differing in fatty-acid
composition, on performance, lactation, and reproduction of beef cows D. W. Shike,1 F. A. Ireland, PAS, and D. B. Faulkner,2 PAS Department of Animal Sciences, University of Illinois, 1207 W. Gregory Drive, Urbana 61801
ABSTRACT Angus × Simmental, fall-calving cows (n = 480) were allotted to 1 of 4 supplements containing whole raw soybeans (SY), OmegaFlax (FLX), Energy Booster 100 (EB), or corn–soybean meal (CON). The SY, FLX, and EB supplements were formulated to have the same concentration of crude fat. The FLX, EB, and CON supplements were formulated to be isonitrogenous. Cows were blocked by age (2 groups) and randomly assigned to treatments before calving (36 ± 0.6 d prepartum). The cows were fed 1.81 kg of DM/d of respective supplement for 108 d. There were no differences in BW or BCS change in any contrasts. There were no differences in percentage of cows cycling before the breeding season or first-service AI conception for any of the contrasts. The SY-supplemented cows had lower (P = 0.01) overall pregnancy rate compared with FLX-supplemented cows and tended (P = 0.06) to have lower overall pregnancy rates compared Corresponding author: [email protected] Present address: Department of Animal Sciences, University of Arizona, Shantz 205, PO Box 210038, Tucson, AZ 85721-0038. 1 2
with EB-supplemented cows. There was no difference in overall pregnancy for SY, FLX, and EB versus CON (P = 0.81). The SY-supplemented cows tended (P = 0.06) to have greater AI embryonic loss than did EB-supplemented cows. Fat supplementation during the pre- and postpartum period did not affect cow BW or reproductive performance compared with cows fed control supplement. Cows fed supplement containing soybeans as the fat source had poorer reproductive performance than did cows fed supplements containing OmegaFlax (flaxseed) or Energy Booster 100 (hydrolyzed animal fat) as the fat source. Key words: beef cow, fat supplementation, polyunsaturated fat, reproduction, soybean
INTRODUCTION The economic success of a beef cow–calf operation is dependent upon the cow having a short postpartum interval to first estrus and high firstservice conception rates. Inadequacies in either of these areas will result in lower pregnancy rates, higher culling rates, and lower weaned calf/
cow numbers. Nutrition plays a key role in reproductive success in cattle, and one of the most studied nutrition relationships is the effect of dietary energy and body energy reserves on postpartum breeding performance (Kinder et al., 1987; Randel, 1990). In a review, Hess et al. (2005) concluded that prepartum nutrition is critical in determining the length of postpartum anestrus; a BCS ≥5 will ensure body energy reserves sufficient for postpartum reproduction, and beef cows in a negative energy balance will have lower reproductive performance. Fat supplementation is one method of addressing these concerns. Fat sources vary widely and differ in their fattyacid content. In general, most of the seed-derived oils contain higher levels of linoleic acid, forages and flaxseed contain higher levels of α-linolenic acid, and rendered fats such as tallow contain a large proportion of saturated fats and the monounsaturated oleic acid (Coppock and Wilks, 1991; Staples et al., 1998). However, once the fats enter the rumen, they are hydrolyzed, and the FFA undergo biohydrogenation (Mattos et al., 2000). Staples et al. (1998) estimated
588 that polyunsaturated fatty acids such as linoleic acid are biohydrogenated at a range of 60 to 90% efficiency. Polyunsaturated fatty acids, such as linoleic and linolenic acid, may inhibit prostaglandin F2α (PGF2α; Mattos et al., 2000). Conversely, Grant et al. (2003) reported that high-linoleate safflower seeds increased PGF2α metabolite. Uterine production of PGF2α is critical during the early postpartum period for proper uterine involution (Madej et al., 1984; Filley et al., 2000). However, elevated levels of PGF2α later in the postpartum interval could result in early embryonic mortality (Troxel and Kesler, 1984; Funston, 2004). Funston (2004), in a summary of work on fat supplementation, concluded that the duration and time of supplemental fat necessary to elicit a response is not precisely known. Much of the benefit of supplemental fat has been proposed to be attributed to polyunsaturated fatty acids (Funston, 2004). Graham et al. (2001) showed soybeans (high in linoleic acid) improved conception rates; Petit et al. (2001) reported improved conception rates for flaxseed (high in linolenic acid). Although saturated fat sources seem to have less effect, Son et al. (1996) found improved reproductive function for tallow. There is no published data available comparing the effects of soybeans, flaxseed, and animal fat on beef-cow reproduction. These 3 fat sources represent differing fatty-acid profiles. The objectives of this experiment were to evaluate the effects of supplemental fat, differing in fatty-acid profile, on cow performance, milk production, and reproduction.
MATERIALS AND METHODS Experimental Animals Angus × Simmental, fall-calving cows (n = 480) from the University of Illinois beef herd at the Dixon Springs Agriculture Center were used in this experiment. Animals used in this experiment were managed according to the guidelines recommended in the Guide for the Care and Use of Agricul-
Shike et al.
tural Animals in Agriculture Research and Teaching (FASS, 1988). Experimental protocols were submitted and approved by the Institutional Animal Care and Use Committee.
Management and Diets Cows were blocked by age (2 age groups) and randomly assigned to treatments before calving (36 ± 0.6 d prepartum). There were 8 groups with 2 replications per treatment. The cows were fed 1 of 4 supplements: whole raw soybeans (SY); corn, soybean meal, and OmegaFlax (ground flaxseed; ADM Alliance Nutrition Inc., Quincy, IL; FLX); corn, soybean meal, and Energy Booster 100 (hydrolyzed animal fat; Milk Specialties Company, Dundee, IL; EB); or corn– soybean meal (CON). The fat sources were selected based on their fatty-acid composition (Table 1). The FLX and EB supplements were formulated to have the same level of crude fat as the SY supplement. The FLX and EB supplements were formulated to be isonitrogenous with the CON (80% corn/20% soybean meal). Corn and soybean meal made up the balance of the FLX and EB supplements. Ingredient and nutrient compositions of supplements are presented in Table 2. Cows grazed endophyte-infected tall fescue (Festuca arundinacea), red clover (Trifolium pratense), and white clover (Trifolium repens) pastures. The cows were fed 1.81 kg of DM/d of respective supplement for 108 ± 0.6 d from trial initiation (36 ± 0.6 d prepartum) until trial completion (72 ± 0.6 d postpartum).
Performance, Lactation, and Reproduction Data Collection Initial shrunk cow BW and BCS were measured at the start of the experiment (36 ± 0.6 d prepartum). Calf birth weights were measured within 24 h of being born and used as initial calf BW. Final shrunk BW and BCS, as well as calf BW, were measured at experiment completion (72 ± 0.6 d postpartum). Cow BW change
and BCS change, as well as calf ADG, were calculated for the 108-d period. Milk production estimates (n = 150) were attained using the weighsuckle-weigh technique at d 55 ± 0.6 of lactation. Twenty-four-hour milk production estimates were determined using a 12-h weigh-suckle-weigh technique (Beal et al., 1990). Six hours following the weigh-suckle-weigh, a subsample of 6 cows per treatment were milked using a commercial portable milk machine (Porta Milker, The Coburn Company Inc., Whitewater, WI). Cows were administered 20 USP units of oxytocin (Phoenix Scientific, St. Joseph, MO) intravenously within 2 min of milking to initiate milk letdown. Milk was sampled and sent to Dairy Lab Services (Dubuque, IA) for compositional analysis. The cows were estrus synchronized using either the CoSynch+CIDR or 7–11 estrus synchronization protocols (Bremer et al., 2004) and artificially inseminated on d 76 ± 0.6. Synchronization protocols were applied evenly across treatments. After AI, cows were exposed to bulls for a 45-d breeding season. First-service conception rates were determined via transrectal ultrasonography at 32 d after AI. Overall pregnancy rate was determined via rectal palpation 64 d after bulls were removed. Cows that were not pregnant at the time of ultrasound and pregnant at the time of palpation were considered pregnant to the clean-up bulls. Cows that were pregnant at the time of ultrasound and not pregnant at the time of palpation were considered to have embryonic loss.
Blood and Feed Data Collection Two blood samples (10 mL) were taken via jugular venipuncture 10 d apart before the breeding season to determine the percentage of cows cyclic. After collection, blood was stored on ice to prevent progesterone metabolism (Wiseman et al., 1982) before centrifugation at 1,000 × g for 20 min at 5°C within 6 h of collection. Serum was stored at −20°C until assaysis for progesterone concentration. Serum
Evaluation of differing fat sources in beef cows
Table 1. Fatty-acid composition of supplemental fat sources Supplemental fat source1
Fatty acid, % of total fat
Soybeans
OmegaFlax
Energy Booster 100
10:0 11:0 12:0 13:0 14:0 14:1 15:0 16:0 trans 16:1 16:1 17:0 18:0 trans 18:1 18:1n-9 cis 18:1n-11 cis 18:1 isomers 18:2n-6 cis 20:0 20:1 18:3n-3 20:2 22:0 20:3n-3 23:0 20:5n-3
0.00 0.02 0.00 0.34 0.08 0.00 0.00 11.47 0.00 0.09 0.36 4.15 0.03 21.55 1.49 0.00 52.92 0.34 0.00 6.47 0.00 0.38 0.00 0.06 0.24
0.00 0.04 0.03 0.06 0.05 0.00 0.01 5.29 0.04 0.06 0.08 3.33 0.02 19.29 0.69 0.00 15.48 0.17 0.00 54.93 0.04 0.15 0.07 0.02 0.13
0.08 0.00 0.42 0.00 1.82 0.25 0.00 30.44 0.22 0.58 1.11 0.00 0.00 53.33 1.04 7.99 1.06 1.02 0.13 0.00 0.00 0.32 0.00 0.05 0.13
OmegaFlax from ADM Alliance Nutrition Inc., Quincy, Illinois, and Energy Booster 100 from Milk Specialties Company, Dundee, Illinois.
1
samples were analyzed for concentrations of progesterone in duplicate using the commercially available RIA procedure of Coat-A-Count (Diagnostic Products Corp., Los Angeles, CA). In brief, 100 μL of serum was added to polypropylene tubes coated with rabbit antibodies to progesterone followed by the addition of 1 mL of iodinated progesterone. Tubes were incubated at room temperature for 3 h and then decanted, allowed to dry overnight, and counted for 1 min in a gamma counter. Standards of 0 to 40 ng/mL were used to develop a calibration curve, and pooled samples were used for intra- and interassay CV calculations. Cows were considered estrous cyclic when progesterone concentrations of either sample exceeded 1.0 ng/mL. Samples of corn, soybean meal, soybeans, OmegaFlax, and Energy Booster 100 were taken from each
load and stored at −20°C until they could be analyzed. Feed samples were dried at 55°C, ground in a Wiley mill (2-mm screen; Arthur H. Thomas, Philadelphia, PA), and composited for analysis. Total fatty acids were determined by gas chromatography (Shimadzu GC-17A, Shimadzu Scientific Instruments Inc., Columbia, MD) of fatty methyl esters formed by acidcatalyzed transesterification (Sukhija and Palmquist, 1988). Chemical composition of all dietary ingredients was ascertained by Rock River Laboratory Inc. (Watertown, WI).
Statistical Analysis Cow and calf performance were analyzed using the GLM procedure of SAS (SAS Institute Inc., Cary, NC) using single degree of freedom orthogonal contrasts [SY vs. FLX; SY vs. EB; and CON vs. SY, FLX, and EB
589 (FT)], with pen serving as the experimental unit. Reproductive parameters were analyzed using the GLIMMIX procedure of SAS using single degree of freedom orthogonal contrasts (SY vs. FLX, SY vs. EB, and CON vs. FT). Block was fitted as a fixed effect and pen(block) and cow(pen) were random effects. Milk production, milk composition, and milk component production were also analyzed using the GLM procedure of SAS using single degree of freedom orthogonal contrasts (SY vs. FLX, SY vs. EB, and CON vs. FT), with individual animal serving as the experimental unit. Treatment effects were considered significant at an α level of 0.05.
RESULTS AND DISCUSSION The performance and milk production data are presented in Table 3. There were no differences in initial BW in any of the contrasts. There were also no differences in initial BCS for SY versus FLX (P = 0.31) or for SY versus EB (P = 0.31). However, cows supplemented with FT had a 0.1 higher (P = 0.02) initial BCS than did the cows fed CON supplement. The SEM for initial BCS was very low (0.03), which may have allowed for very small numerical differences to be detected. This difference in initial BCS (0.1) is not likely to have any significant biological effect. There were no differences in BW or BCS change in any of the contrasts. There were also no differences in final BW or BCS in any of the contrasts. Fat supplementation has resulted in no effect on BW or BCS (Webb et al., 2001; Alexander et al., 2002). In contrast, fat supplementation has increased either BW or BCS (Espinoza et al., 1995, 1997; De Fries et al., 1998). The response of BW and BCS to fat supplementation may be dependent on initial BCS. Webb et al. (2001) hypothesized that cows with >5 BCS may not respond to fat supplementation the same as cows in poorer body condition. The cows in this experiment were above a BCS of 5 at the start and completion of the experimental period. Although there
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Table 2. Supplement composition Item Ingredient, % DM Corn Soybean meal Soybeans5 OmegaFlax6 Energy Booster 1007 Chemical composition, % DM CP NDF ADF Ether extract Ca P NEm,8 Mcal/kg NEg,8 Mcal/kg
SY1
FLX2
0 0 100 0 0 41.05 16.17 7.13 20.36 0.41 0.70 2.35 1.65
50 7 0 43 0 18.89 13.42 6.46 18.76 0.17 0.58 2.44 1.71
EB3
58 25 0 0 17 18.89 10.02 3.23 21.52 0.14 0.46 2.61 1.83
CON4
80 20 0 0 0 18.34 6.70 3.24 5.69 0.13 0.51 2.17 1.49
Supplement containing whole raw soybeans. Supplement containing OmegaFlax (ADM Alliance Nutrition Inc., Quincy, IL). 3 Supplement containing Energy Booster 100 (Milk Specialties Company, Dundee, IL). 4 Supplement containing corn and soybean meal. 5 Whole, unprocessed soybeans. 6 Ground flaxseed (ADM Alliance Nutrition Inc., Quincy, IL). 7 Hydrolized animal fat (Milk Specialties Company, Dundee, IL). 8 NEm and NEg values are from NRC (2000) except for flaxseed (“Alternative Feeds for Ruminants,” Lardy and Anderson, 1999). 1 2
were numerical trends in milk production, there were no differences in milk production in any of the contrasts. There were also numerical trends in calf ADG, but again there were no
differences in any of the contrasts. Calf ADG corresponded to numerical differences in milk production. Higher calf ADG from cows supplemented with fat has been observed (Espinoza
et al., 1997; De Fries et al., 1998; Bellows et al., 2001). Fat supplementation has resulted in increased milk production (Espinoza et al., 1997; Johnson et al., 2002). The milk composition and component production data are exhibited in Table 4. The cows supplemented with SY had 0.57 percentage units lower (P = 0.05) milk protein percent than did the cows supplemented with FLX. There were no differences for SY versus EB (P = 0.28) or for FT versus CON (P = 0.15) in protein percentage. In contrast, fat supplementation often decreases the protein percentage of the milk (Coppock and Wilks, 1991). There were no differences in protein production for SY versus FLX (P = 0.61) or for SY versus EB (P = 0.99). However, the FT-supplemented cows did have 0.03 kg/d more (P = 0.03) protein production than did the cows fed the CON supplement. The SY-supplemented cows had a 1.5 percentage units higher (P = 0.03) milk fat percent than did the FLX-supplemented cows, and this resulted in 0.13 kg/d more (P = 0.001) fat yield. The SY-supplemented cows had 2.17 percentage units higher (P = 0.002) milk fat percent than did the EB-supplemented cows, and this resulted in 0.16 kg/d more (P < 0.001) fat yield. The FT-supplemented cows had 1.23
Table 3. Effects of fat sources on cow performance and milk production Treatment Item Initial BW, kg Final BW, kg BW change, kg Initial BCS Final BCS BCS change Milk production, kg/d Calf ADG, kg/d
Contrast
SY1
FLX2
EB3
CON4
SEM
SY vs. FLX
SY vs. EB
FT5 vs. CON
572 532 −40 6.0 5.7 −0.3 5.8 0.89
570 525 −45 5.9 5.1 −0.8 5.0 0.84
569 532 −37 5.9 5.9 −0.1 5.1 0.93
566 536 −30 5.8 5.4 −0.4 4.7 0.80
9 16 10 0.03 0.3 0.3 0.5 0.06
0.90 0.77 0.73 0.31 0.26 0.29 0.29 0.53
0.87 1.00 0.88 0.31 0.73 0.73 0.37 0.64
0.72 0.75 0.43 0.02 0.74 0.96 0.23 0.27
Supplement containing whole raw soybeans. Supplement containing OmegaFlax (ADM Alliance Nutrition Inc., Quincy, IL). 3 Supplement containing Energy Booster 100 (Milk Specialties Company, Dundee, IL). 4 Supplement containing corn and soybean meal. 5 FT = SY + FLX + EB. 1 2
591
Evaluation of differing fat sources in beef cows
Table 4. Effects of fat sources on cow milk composition and component production Treatment
Contrast
Item
SY1
FLX2
EB3
CON4
SEM
SY vs. FLX
SY vs. EB
FT5 vs. CON
Protein, % Protein, kg/d Fat, % Fat, kg/d Lactose, % Lactose, kg/d Other solids, % Other solids, kg/d MUN,6 mg/dL
2.72 0.16 7.47 0.43 4.80 0.28 5.69 0.33 35.18
3.29 0.16 5.97 0.30 4.93 0.25 5.86 0.29 25.14
3.02 0.15 5.30 0.27 4.62 0.24 5.53 0.28 24.47
2.68 0.13 5.02 0.24 4.98 0.24 5.87 0.28 23.50
0.19 0.01 0.44 0.03 0.13 0.02 0.12 0.03 1.70
0.05 0.61 0.03 0.001 0.48 0.39 0.35 0.41 <0.001
0.28 0.99 0.002 <0.001 0.34 0.24 0.36 0.27 <0.001
0.15 0.03 0.02 0.001 0.20 0.42 0.22 0.37 0.03
Supplement containing whole raw soybeans. Supplement containing OmegaFlax (ADM Alliance Nutrition Inc., Quincy, IL). 3 Supplement containing Energy Booster 100 (Milk Specialties Company, Dundee, IL). 4 Supplement containing corn and soybean meal. 5 FT = SY + FLX + EB. 6 MUN = milk urea nitrogen. 1 2
percentage units higher (P = 0.02) milk fat percent than did the cows fed the CON supplement, and this resulted in 0.09 kg/d more (P = 0.001) fat yield. Fat supplementation can have negative effects on fiber digestion, which can result in lower milkfat percentages (Coppock and Wilks, 1991). Johnson et al. (2002) reported that supplementing oilseeds resulted in higher fat production. Negative effects of fat supplementation are more common with oil than with oilseeds. Feeding oilseeds results in a slower release of the oil and less negative effects on digestion (Coppock and Wilks, 1991). There were no differences in percentage of lactose or lactose production for any of the contrasts. There were also no differences in percentage of other solids or other solids production for any of the contrasts. The SY-supplemented cows had 10.04 mg/dL higher (P = 0.001) milk urea nitrogen (MUN) concentration than did the FLX-supplemented cows and 10.71 mg/dL higher (P = 0.001) MUN concentration than did the EBsupplemented cows. The differences in MUN between the SY-supplemented cows and the FLX- and EB-supplemented cows are likely because of the differences in protein content of the
supplements; the SY supplement had greater protein concentration than did the other supplements. The focus of the experiment was to evaluate different fat sources, and thus the FLX and EB supplements were formulated to have the same concentration of crude fat as SY and were not formulated to be isonitrogenous with SY. The FTsupplemented cows had 4.76 mg/dL higher (P = 0.03) MUN concentration than did the cows fed the CON supplement. This difference is primarily due to the elevated MUN of the SY-supplemented cows. The reproductive performance data are shown in Table 5. There were no differences (P ≥ 0.22) in the percentage of cows cycling before the breeding season for any of the contrasts. However, fat supplementation previously has increased the percentage of cows cycling (Espinoza et al., 1995; Bader et al., 2000). There were no differences (P ≥ 0.31) in first-service AI conception for any of the contrasts. Previous work has found that fat supplementation has increased firstservice conception rates (Bader et al., 2000; Graham et al., 2001). However, Hess et al. (2007) concluded that feeding high-linoleate supplements postpartum may have deleterious ef-
fects on reproduction. Funston (2004) reported in a review that in some research, fat supplementation had limited benefit when supplementation began prepartum and continued through the postpartum period. There was no difference in overall pregnancy rates for FT versus CON (P = 0.81). Fat supplementation has resulted in improved pregnancy rates (Espinoza et al., 1995; Lammoglia et al., 1997; Bellows et al., 2001) and no effect on pregnancy rates (Alexander et al., 2002; Bottger et al., 2002). Several mechanisms have been proposed for beneficial effects of supplemental fat. Elevated levels of PGF2α later in the postpartum interval could result in early embryonic mortality (Troxel and Kesler, 1984; Funston, 2004). Polyunsaturated fatty acids, such as linoleic and linolenic acid, may inhibit PGF2α (Mattos et al., 2000). Thomas et al. (1997) reported that polyunsaturated fat (soy oil) supplementation resulted in a greater rate of ovarian follicular growth than did supplementation with saturated fat (tallow). Although potential mechanisms exist for improved reproductive performance in fat-supplemented cows, this experiment found no improvement for fat supplementation compared with
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Table 5. Effects of fat sources on cow reproductive performance Treatment Item Cyclicity,6 % AI conception,7 % Bull conception,8 % Overall pregnancy,9 % Embryonic loss,10 %
Contrast
SY1
FLX2
EB3
CON4
83 (100/120) 59 (71/120) 67 (32/48) 82 (97/119) 8 (6/71)
91 (106/117) 64 (75/117) 88 (36/41) 92 (107/116) 5 (4/75)
81 (95/117) 59 (69/117) 76 (35/46) 89 (102/114) 1 (1/69)
81 (93/115) 66 (76/115) 77 (30/39) 89 (101/114) 5 (4/76)
SEM SY vs. FLX SY vs. EB FT5 vs. CON 3 5 8 3 3
0.22 0.45 0.22 0.01 0.38
0.92 0.93 0.45 0.06 0.06
0.57 0.31 0.92 0.81 0.94
Supplement containing whole raw soybeans. Supplement containing OmegaFlax (ADM Alliance Nutrition Inc., Quincy, IL). 3 Supplement containing Energy Booster 100 (Milk Specialties Company, Dundee, IL). 4 Supplement containing corn and soybean meal. 5 FT = SY + FLX + EB. 6 Percentage of cows that were estrous cyclic before breeding. 7 Cows determined pregnant to first-service AI via rectal ultrasonography at 32 d after AI. 8 Cows that were open at time of ultrasound but were pregnant at time of palpation. 9 Cows determined pregnant via rectal palpation 64 d after bulls were removed (45 d of exposure). 10 Cows that were pregnant at time of ultrasound but were open at time of palpation. 1 2
the control supplement. The SYsupplemented cows had 10 percentage units lower (P = 0.01) overall pregnancy rate compared with the FLX-supplemented cows and tended (P = 0.06) to have lower pregnancy rates than the EB-supplemented cows. The cows supplemented with SY had numerically poorer conception rates to the clean-up bulls (67 vs. 88%; P = 0.22) compared with the cows supplemented with FLX. There were no differences in conception to the bulls for SY versus EB (P = 0.45) or for FT versus CON (P = 0.92). The numerically poorer conception to the bulls for the cows fed SY was unexpected. One potential reason is the phytoestrogen content of soybeans. Phytoestrogens that are present in some legumes have been shown to have negative effects on reproduction (Adams, 1995). Lightfoot et al. (1967) reported a failure of sperm transport through the cervix in ewes that had prolonged grazing of estrogenic pastures. The numerically lower conception to bulls for the SY-supplemented cows in this experiment could possibly be due to impaired sperm transport. The phytoestrogen content of the soybeans was not measured.
Another possible explanation of the poorer overall pregnancy rates of the SY-supplemented cows could be their elevated MUN concentrations. The SY-supplemented cows had a MUN concentration of ~35 mg/dL, and the other treatment groups had MUN concentrations of ~23 to 25 mg/dL. Butler et al. (1996) reported that dairy cows that had MUN >19 mg/ dL had 21 percentage units poorer pregnancy rates than did cows with MUN concentrations <19 mg/dL. Beck et al. (2005) reported that firstcalf heifers that were grazing tended to have greater MUN concentrations and poorer pregnancy rates compared with heifers that were developed in drylots. Although there are data supporting the relationship of elevated MUN concentrations and poorer pregnancy rates, Shike et al. (2009) reported cows fed corn coproducts and hay had MUN concentrations of >30 mg/dL and still had first-service AI conception rates of >67%. There was no difference in AI embryonic loss between SY and FLX (P = 0.38), but the SY-supplemented cows tended (P = 0.06) to have greater AI embryonic loss than did the EB-supplemented cows. There was no difference in AI
embryonic loss between FT and CON (P = 0.94). One proposed mechanism for improved reproductive performance from supplemental fat is that polyunsaturated fatty acids, such as linoleic and linolenic acid, may inhibit prostaglandin F2α, which could reduce early embryo mortality (Mattos et al., 2000). This study only detected embryonic loss after ultrasound (32 d after AI), and thus early embryonic losses (before d 32) would not have been detected.
IMPLICATIONS Supplementing fat to cows grazing endophyte-infected tall fescue, red clover, and white clover pastures did not affect cow BW or BCS compared with cows fed the control supplement (corn–soybean meal). Fat supplementation also did not affect milk production or calf ADG, although there were some numerical trends. Fat supplementation increased percentage of fat in the milk. Fat supplementation did not affect first-service AI conception rate, overall pregnancy, or embryonic loss compared with cows supplemented with the control supplement. However, there were a few differences
Evaluation of differing fat sources in beef cows
between the different fat sources. The cows fed soybeans had higher fat and MUN concentrations in their milk than did the cows fed OmegaFlax (flaxseed) or Energy Booster 100 (hydrolyzed animal fat). The cows fed soybeans had lower overall pregnancy rates than did the cows fed OmegaFlax (flaxseed), which was due to lower conception rates to the cleanup bulls. The cows fed soybeans also had more embryonic loss than did the cows fed Energy Booster 100 (hydrolyzed animal fat). Fat supplementation during the pre- and postpartum period to cows that are in good condition (BCS >5) may not be beneficial compared with a control supplement; thus, supplement decisions should be based on supplement cost.
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