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Sulfur Supplementation of Urea-containing Silages and Concentrates. I. Feed Intake and Lactation Performance
Sulfur Supplementation of Urea-containing Silages and Concentrates. I. Feed Intake and Ladation Performance D. G. GRIEVE 1, C. E. COPPOCK, W. G. MERRILL, and H. F. TYRRELL ~ Department of Animal Science Cornell University, Ithaca, New York 14850
Abstract
Thirty-two lactating cows were in a 2 x 2 factorial experiment; factors were corn silage treated with .5% urea or 2.8% soybean meal at ensiling time and concentrates containing 0 or .9% added sodium sulfate. In a 19-week experiment cows fed soybean corn silage consumed more dry matter per unit body weight and produced more milk than cows on urea corn silage (P < .05). Sulfur supplementation did not affect feed intake or milk yield, nor was there interaction between silage nitrogen source and sulfur treatments. In a second experiment 24 cows arranged in a 2 x 2 x 2 factorial were fed .5% urea silage or 3.57O soybean meal silage and concentrates containing 0 or .87O added urea, each with 0 or .8% added sodium sulfate. No treatment differences were detected in feed intake or milk yield during 40 weeks. Sulfur supplementation increased sulfur in ration dry matter from .13~ to .22% (Experiment I) and .11 to .18% (Experiment II) and also changed the ratio of nitrogen to sulfur from 19:1 to 11:1 (Experiment I) and 21:1 to 13:1 (Exper/ment II). Introduction
Utilization of urea in dairy rations based oll corn silage has been reviewed extensively (7, 12). Corn silage treated with .5% urea at ensiling time produced equal lactation responses to control silages supplemented with higher protein concentrates (14, 26, 35). When ureatreated silage was fed with concentrates conReceived for publication August 18, 1972. 1Present address: Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada. Present address: Nutrition Institute, Ruminant Nutrition Laboratory, USDA, Beltsville, Maryland 20705. 218
taining 1% urea, feed intake and milk yield were comparable to that for control silages (8, 24, 31, 32). Decreased feed intake and milk production have been reported when cows received 20% of ration nitrogen from content-rate urea (13) or more than .5?o urea in con~ silage (6, 26). There are no reports of additions of plant protein to whole plant corn at ensiling time as a means of increasing crude protein content of corn silage. The first objective of our study was to compare ureatreated corn silage with corn silage having an equivalent amount of nitrogen from soybean meal when fed to dairy cattle in coniunction with urea-containing concentrates. Information on sulfur requirement of dairy cattle is limited (23), but rations based on corn silage supplemented with urea may contain wider nitrogen to sulfur ratios than 10:1 as recommended by Moir et al. (21) for sheep. Dairy cattle can incorporate sulfur from sodium sulfate into eystine and methionine (3), and sulfur supplementation improves cellulose digestion of low sulfur diets (2, 4, 10). However, supplementation of low sulfur diets with sodium sulfate did not produce lactation response by dairy cows in two trials (5, 9), although in another report (15) feed intake and milk production were higher for cows receiving .12% dietary sulfur than those receiving .10~ dietary sulfur by the 9th wk on experiment. But milk production was relatively low on all three trials (5, 9, 15). Our second objective, therefore, was to determine the effect of supplemental sulfur from sodium sulfate (anhydrous) on response of lactating cows fed corn silage rations supplemented with urea. Experimental Procedure
Experiment I. Thirty-two Holstein cows (16 first lactation and 16 second or later lactation) were allotted randomly within age groups to corn silage nitrogen additive and concentrate sulfur treatments arranged in a 2 x 2 factorial. Silage treatments consisted of whole plant corn (33?o dry matter) treated at ensiling with either .57o urea (45?o N), UCS, or 2.87O soybean meal (5070 crude
219
SULFUR SUPPLEMENT PERFORMANCE
TABLE 1. Ingredient composition~ of concentrates. Experiment I
Experiment II Concentrate mixture
Ingredients
1
2
High-moisture ear corn Ground shelled corn Soybean meal (50% crude protein) Urea (45~ N) Dicalcium phosphate Trace mineralized salt Sodium sulfate (anhydrous')
83.0 ..• 13.6 .8 1.7 .8 ..
82.3 ... 13.5 .8 1.7 •8
3
4
84.0 4.6 8.2 .8 1.4 1.0
5
6
(z)
.9
.
.
84.0 4.6 7.4 .8 1.4 1.0 .
.
8
~.0 84.0 . . . . . . 13.6 12.8 . . . . . . 1.4 1.4 1.0 1.0 .
.
.
.
8
" Expressed as fed. protein), SCS; concentrates were unsupplemented (control) and supplemented with .9~ sodium sulfate (anhydrous). Treated silages were made by simultaneous filling of two silos with alternate loads of fresh chopped corn. Urea and soybean meal were added at 5 kg and 28 kg, respectively, per metric ton of fresh weight material by spreading the appropriate amount on top of each weighed load prior to unloading into the silo blower. Concentrates were prepared by mixing ground high-moisture ear corn (about 70% dry matter at ensiling) with other ingredients daily in proportions shown in Table 1. Both concentrates contained .8% urea. Silage treatments were imposed at parturition and corn silage was fed ad libitum to the experiment's end. The UCS had been fed 30 days before parturition. Control concentrate was fed from parturiTABLE 2. Chemical composition of silages and concentrates as fed. Dry matter ( DM ) (%)
Crude protein
Acid detergent fiber
Sulfur
(% of dry matter)
Experiment I Urea silage Soy silage Concentrate 1 Concentrate 2
33.9 35.2 72.6 72.9
11.4 10.8 20.8 20.7
.... .... .... ....
10 12 15 37
Experiment II Urea silage Soy silage Concentrate Concentrate Concentrate Concentrate
35.8 37.2 66.1 66.4 66.6 66.7
12.5 12.2 17.8 18.1 18.4 17.8
20.4 19.8 7.8 8.2 7.7 7.9
.09 .11 .12 .30 .13 .32
3 4 5 6
tion for 11 wk when concentrate sulfur treatments were imposed for 19 wk. Amount of concentrate fed individual cows was adjusted weekly according to NRC (22) energy recommendations for maintenance and lactation considering forage intake. Feed intake and milk yield were recorded daily with milk composition taken from samples of four consecutive milkings at weekly intervals and analyzed for fat (1) and protein (27). Feed samples were analyzed for dry matter by freeze drying and for crude protein according to AOAC (1). Sulfur was determined by x-ray emission spectrography (17) and corrected to a curve prepared from chemical analysis of samples having a range of sulfur content (1, 11, 28). Results are in Table 2. Variance was analyzed for feed intake and milk yield data for the 19 wk; significance of treatment differences was determined by F tests according to Steele and Torrie (29). Experiment II. Twenty-four Holstein cows wore in a full lactation study of three treatment factors in a 2 x 2 x 2 factorial arrangement. Factors were (i) corn silage nitrogen additive, whole plant corn (35% dry matter) treated with either .5% urea (UCS) or 3.5% soybean meal (SCS) on a fresh weight basis at ensiling time, and urea and soybean meal added at rates of 5 kg and 35 kg per metric ton, respectively, as in Experiment 1; (ii) concentrate nitrogen sources, either .8% urea or equivalent nitrogen from soybean meal; and (iii) concentrate sulfur, either unsupplemented or supplemented with .8% sodimn sulfate (anhydrous), Concentrate mixtures (Table 1) were formulated to be isonitrogenous and isocaloric. Ensiled high-moisture ear corn (60% dry matJOURNAL OF DAIRY SCIENCE VOL. 56, NO. 2
220
G R I E V E E T AL
ter) was mixed daily with the balance of concent-rate ingredients. Treatments were imposed at parturition and continued for 280 days with UCS fed 30 days before parturition. Corn silage was fed ad libitum throughout, concentrate was adjusted weekly to individual requirements, and silage intake as in Experiment 1. Feed intake, milk yield, and milk composition as well as feed composition were measured as in Experiment 1. In addition, acid detergent fiber (33) analyses were on all feed samples. Freeze-ground (with dry ice) fresh samples of silages and concentrates were analyzed for urea, ammoniacal, and total nitrogen according to AOAC procedures (1). Protein nitrogen was determined by precipitation of sample with cold 5~ trich!oroacetie acid solution, followed by Kjeldahl nitrogen deterlnination on precipitate. Variance was analyzed on feed intake adjusted by least squares and milk yield data for the 280-day experiment. During the course of the experiment four cows were removed (one each from four of the eight treatment combinations) due to acute coliform mastiffs. Separate analyses of variance on least squares adjusted data for weeks 1 to 13, 14 to 26, and 27 to 40 failed to yield significant additional information over that of the 280-day analysis. Results and Discussion
Experiment I. Cows fed SCS consumed more total dry matter (expressed as a percent of body weight) and produced more (P < .05) actual and solids-corrected milk (Table 3) than those fed UCS. Most of the difference in dry matter intake was due to inereased silage dry matter consumption by SCS cows although
this difference was not statistically different (P < .05). There were no reports of direct comparisons between urea and soybeantreated corn silage, but when urea corn silage has been compared to control silages and both were fed in conjunction with concentrates containing 1.0% urea, no differences in feed intako (8, 24, 32) or milk yield (8, 24, 31, 32) were reported. Sulfur supplementation at a rate which decreased N:S ratios in the total ration from 19:1 to 11:1 and increased sulfur content of the ration dry matter from .13 to .22f~ did not affect (P < .05) measures of feed intake or milk production (Table 3). Neither was there any statistical evidence for interaction between sulfur supplementation and silage nitrogen treatment for any measurements. Our data complement those of Jaeobson et al. (15) who fed diets containing .10 and .125 sulfur and reported higher feed intake and milk yield by sulfur supplemented cows by the 9th wk on experiment. Results suggest that supplemental sulfur above .137o does not increase feed intake or milk production. Experiment II. Analysis of several nitrogen fractions in corn silage and concentrate samples revealed only about 32% nitrogen in trichloroacetie acid precipitate for UCS compared to 4370 for SCS (Table 4). Values for UCS are in general agreement with those from data of Miron and Otterby (20) and Owens et al. (25) but lower than those of Johnson and McClure (16) when silages were treated with limestone as well as urea. Considerable hydrolysis of soybean meal protein took place during ensiling as well.
TABLE 3. Effect of corn silage nitrogen source and sulfur supplementation on daily feed intake and lactation performance, Experiment I. Silage N additive
Sulfur
Urea
Soy
Feed intake Silage DM (kg) Concentrate DM (kg) Total DM (kg) DM (% of body weighl) Dicta1T S (% of DM)
8.2 6.5 14.7 2.63" .17
9.1 6.3 15.4 2.86" .18
8.4 6.6 15.0 2.78 .13r'
8.9 6.2 ]5.1 2.7J .22b
Milk production Milk yield (kg) Milk fat (%) Milk protein (~) Solids-corrected milk (kg)
18.0" 3.80 3.29 17.6a
20.2" 3.90 3.30 20.0 ~l
19.3 3.91 3.31 19.1
19.0 3.79 3.28 18.5
.~.b.o.aMeans with same superscript are significantly different (P ~ .05). No. 2
JOURNAL OF DAIRY SCIENCE VOL. 56,
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TABLE 4. Distribution of nitrogen o~ feeds, Experiment II. Feed
Total nitrogen
Trichloroacetic acid-N
Urea-N
(~ of dry matter) Fresh chopped corn (before ensiling) Urea corn silage Soy corn silage Ground ear corn (before ensiling) Ensfled ear corn Concentrate 3 Concentrate 4 Concentrate 5 Concentrate 6
NH3-N
Unaccounted-N
~; of total N
1.35 2.00 1.95
91.6 32.4 42.8
1.1 15.9 .8
1.5 18.1 9.2
5.8 33.6 47.2
1.58 1.58 2.83 2.90 2.95 2.85
92.4 57.4 61.4 59.2 79.0 75.5
.3 .1 16.1 17.3 1.2 1.1
.6 4.5 3.5 3.2 2.5 2.3
6.7 38.0 19.0 20.3 17.3 21.1
Urea and soybean nitrogen were in the same proportion to corn-plant dry matter when removed as silage as they were when added at ensfling. Thus, it was estimated that about 50% of urea nitrogen was recovered intact, the balance being degraded to ammonia. Relatively large percentages of the total nitrogen of silages remained unaccounted for by analyses agreeing with other reports (16, 20, 25). Ensiling ground ear corn also decreased the amount of trichloroacetie acid precipitable nitrogen and increased undetermined nitrogen. Urea added daily to concentrates based on high-moisture ear corn remained relatively intact; ammonia in these feeds was only slightly higher than in concentrates containing no urea. Feeding UCS did not result in any significant (P ~ .05) effect on feed intake or milk
production measurements when compared to SCS (Table 5), contrary to results of Experiment 1 where SCS fed cows produced more actual and solids-corrected milk. Concentrate nitrogen source also had no effect on any measurements, solids-corrected milk averaging 18.1 and 18.2 kg per cow per day on urea and soybean meal concentrates. There was no statistical evidence for interaction between silage and concentrate nitrogen treatments, indicating that urea-containing silages and concentrates are compatible in dairy rations as reported (8, 24, 31). Sulfur supplementation b y addition of .8% anhydrous sodium sulfate did not produce a significant lactation response although there was a difference at about 2 kg actual and solids-corrected milk in favor of sulfur supplemented cows fed concentrates containing .8% urea (Table 5). This difference
TABLE 5. Effect of corn silage and concentrate nitrogen sources and sulfur on daily feed intake and lactation perfommnce, Experiment II. Item N source sulfur
Silage treatment
Concentrate treatment
Urea
Soy
Urea
Urea + sulfur
Soy
Soy + sulfur
Feed intake Silage DM (kg) Concentrate DM (kg) Total DM (kg) DM (~ of body weight) Dietary S (~; of DM)
9.4 4.6 14.0 2.36 .13
9.0 5.1 14.t 2.32 .15
9.7 4.3 14.0 2.37 .11
9.0 5.2 14.2 2.38 .17
9.1 4.8 13.9 2.32 .11
8.9 5.1 14.0 2.30 .18
Milk production Milk yield (kg) Milk fat (%) Milk protein (~) Solids-corrected milk (kg)
19.5 3.69 3.25 18.7
19.0 3.37 3.26 17.8
18.1 3.48 3.28 17.1
20.1 3.63 3.29 19.1
19.3 3.40 3.26 17,9
19.5 3.61 3.20 18.5
No significant differences (P < .05) between treatments. JOURNAL OF DAIRY SCIENCE VOL. 56, NO. 2
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GRIEVE E T AL
was not significant (P < .05) as an interaction between concentrate nitrogen source and sulfur supplementation. In fact, the trend is opposite of that in Experiment 1. These data, as those of Jacobson et al. (15), suggest a small response to sulfur supplementation; but in this study the response was not significant. Dietary N:S ratios were reduced from 21:1 to 13:1 on unsupplemented and sulfur-containing diets over the whole experiment and from 19:1 to 11:1 during the first trimester of lactation when higher concentrate was fed. Ratios in these supplemented diets are close to values of 10:1 as recommended by Moir et al. (21) and Whanger (34). In addition, dietary sulfur of at least .175 of ration dry matter in supplemented diets appears adequate for maximal cellulose digestion (2). In this experiment, these values were increased from .11 to .185. Data, therefore, suggest that either sulfur was not a first limiting element or that other factors were involved. Unexplainable are the relatively low average dry matter intakes, especially for concentrates, compared to other trials under generally similar circumstances (18, 19, 30). Milk production also was lower than anticipated. None of the other trials (18, 19, 30) used here as a general comparison involved the combination of all corn silage forage plus concentrates based primarily on highmoisture corn. Whether this circumstance and any relationships to supplementation of such a ration are factors involved is only speculation. The supplemental sulfur was inefficiently utilized (11). Data of Jaeobson et al. (15) also indicated that supplemental sodium sulfate was not well utilized. Differences in response to silage nitrogen treatments between Experiments I and II is unexplained. However, it is apparent that SCS in Experiment I was slightly more palatable than UCS. Both soybean meal and urea can be used as satisfactory nitrogen additives to increase crude protein content of corn silage.
Acknowledgments The authors express their appreciation to Dr. W. H. Allaway and Mr. V. Lazar, U.S. Plant Soil and Nutrition Laboratory, Ithaca, New York, for assistance in sulfur determinations and to Messrs. L. Bernholz and T. Kuntz for their technical assistance.
References (1) A.O.A.C. 1965. Official Methods of Analysis, 10th ed. Association of Official Agricultural Chemists. Washington, D. C. JOURNAL OF DAIRY SCIENCE VOL. 56, No.
2
(2) Barton, J. S., L. S. Bull, and R. W. Hemken. 1971. Effects of various levels of sulfur upon cellulose digestion in purified diets and lignocellulose digestion in corn fodder pellets in vitro. J. Anim. Sci., 33:682. (3) Block, R. J., and J. A. Stekol. 1950. Synthesis of sulfur amino acids from inorganic sulfate by ruminants. Pree. Soc. Exp. Biol. Med., 73:391. (4) Bray, A. C., and J. A. Hemsley. 1969. Sulfur metabolism of sheep. IV. The effect of varied dfetarv sulfur content on some body fluid sulfate levels and on the utilization of urea supplemented roughage by sheep. Australian J. Agr. Res., 20:759. (5) Burgess, P. L., and J. W. G. Niehotson. 1971. Effect of sulfur supplementation on the performance of lactating dairy cows fed ureacontaining diets. Can. J. Anhn. SCI., 51:711. (6) Conrad, H. R., and J. W. Hibbs. 1961. Urea treatment affects utilization of corn silage. Ohio Farm and Home Res., 46:13. (7) Coppock, C. E., and J. B. Stone. 1968. Corn silage in the ration of dairy cattle. A review. Cornell Misc. Bull. 89. (8) Dalrymple, J. M. 1969. Adaptation to urea by the lactating cow. M.Se. Thesis, University of Guelph, Guelph, Ontario, Canada. (9) Davis, R. F., Constance Williams, and J. K. Loosli. 1954. Studies on sulfur to nitrogen ratios in feeds for dairy cows. J. Dairy Sci., 37:813. (10) Evans, J. L., and G. K. Davis. 1966. Influence of sulfur, molybdenum, phosphorus and copper interrelationships in cattle upon cellulose in vivo and in vitro. J. Anim. Sci., 25:1014. (11) Grieve, D. G. 1971. Utilization of urea nitrogen in corn silage and concentrate rations of lactating dairy cattle with or without sulfur supplementation. Ph.D. Thesis, Cotnell University, Ithaca, New York. (12) Huber, J. T., C. E. Polan, and D. Hillman. 1968. Urea in high corn silage rations for dairy cattle. J. Anita. Sci., 27:220. (13) Huber, J. T., R. A. Sandy, C. E. Polan, H. T. Bryant, and R. E. Blaser. 1967. Varying levels of urea for dairy cows fed corn silage as the only forage. J. Dairy Sci., 50:1241. (14) Huber, J. T., and ]. W. Thomas. 1969. Urea° txeated corn silage in low protein rations for lactating cows. J. Dairy Sci., 52:944. (Abstr.) (15) Jacobsou, D. R., J. W. Barnett, S. B. Carr, and R. H. Hat-ton. 1967. Voluntary feett intake, milk production, tureen content, and plasma-free amino acid levels of lactating cows on low sulfur and sulfur-supplemented diets. 1. Dairy Sci., 50:1248. (16) Johnson, R. R., and K. E. McClure. 1968. Corn plant maturity. IV. Effects on digestibility of corn silage in sheep. J. Anim. Sei., 27:535.
SULFUR SUPPLEMENT
(17) Kubota, J., and V. A. Lazer. 1967. Routine X-ray emission spectographic analysis of common forage plants. Soil testing and plant analysis, Part II - Plant Analysis. Soil Science of America Inc., Madison, Wisconsin. (18) McCaffree, J. D., and W. G. Merrill. 1968. High moisture corn for dairy cows in early lactation. J. Dairy SCI., 51:553. (19) McCaffree, J. D., W. G. Merrill, and N. E. Smith. 1972. Concentrate mixtures based on high moisture ear corn versus multi-ingreclients for dairy cows in early lactation. J. Dairy Sci., 55:269. (20) Miron, A. E., and D. E. Otterby. 1969. Utilization of urea nitrogen in corn silage J'. Dairy Sci., 52:907. (Abstr.) (21) Molt, R. J., M. Seiners, andA. C. Bray. 1968. Utilization of dietary sulfur and nitrogen by ruminants. The Sulfur Inst. J., 3:15. (22) National Academy of Sciences - National Research Council, Committee on Animal Nutrition. 1966. Nutrient requirements of dairy cattle. 3rd revised ed., publication 1349. (23) National Academy of Sciences - National Research Council, Committee ou Animal Nutrition. 1971. Nutrient requirements of dairy cattle. 4th revised ed., no. 3, Washington, D.C. (24) Owen, F. G. 1968. Value of urea in corn silage when fed with or without urea in the grain ration. J. Dairy Sci., 51:980. (Abstr.) (25) Owens, F. N., J. C. Meiske, and R. D. Goodrich. 1969. Effects of calcium sources and urea on corn silage fermentation. J. Dairy Sci., 52:1817. (26) Schmutz, W. G., L. D. Brown, and J. W. Thomas. 1969. Nutritive value of corn si-
PERFORMANCE
(27) (28) (29) (30)
(31)
(32)
(33)
(34) (35)
223
lages treated with chemical additives for lactation. J. Dairy Sci., 52:1408. Sherbon, J. E. 1967. Rapid determination of protein in milk by dye binding. J. Ass. Ofl]c. Anal. Chem., 50:542. Standard methods for the examination of water, sewage and industrial wastes. 1955. Amer. Public Health Ass., Inc., New York. Steel, Robert G. D., and James H. Torrie. 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., Inc., New York. Trimberger, G. W., H. F. Tyrrell, D. A. Morrow, J. T. Reid, M. J. Wright, W. F. Shipe, W. G. Merrill, J. K. Loosli, C. E. Coppock, L. A. Moore, and C. H. Go~don. 1972. Effects o~? liberal concentrate feeding on health, reproductive efficiency, economy of milk production and other related responses of the dairy cow. N.Y. Food and Life Sci. Bull., 8. VanHorn, H. H., C. F. Foreman, and J. E. Rodriguez. 1967. Effect of high-urea supplementation on feed intake and milk production of dairy cows. J. Dairy Sei., 50:709. VanHorn, H. H., D. R. Jacobsen, and A. P. Graden. 1969. Influence of level and source of nitrogen on milk production and blood components. ]. Dairy Sci., 52:1395. Van Soest, P. J. 1963. The use of detergents in the analysis of fibrous feeds: II. A rapid method for the determination of fiber and lignin. J. Ass. Offlc. Agr. Chem., 46:829. Whanger, Philip D. 1969. Sulfur in NPN Rations. Anim. Nutr. Health, 9:10. Wise, G. H., J. H. Mitchell, J. P. LaMaster, and D. B. Roderiek. 1944. Urea-treated corn silage vs. untreated corn silage as a feed for lactating dairy cows. J. Dairy Sei., 27:649. (Abstr.)
JOURNAL OF DAIRY SCIENCI~ VOL. 56, NO. 2
Abstract
Thirty-two lactating cows were in a 2 x 2 factorial experiment; factors were corn silage treated with .5% urea or 2.8% soybean meal at ensiling time and concentrates containing 0 or .9% added sodium sulfate. In a 19-week experiment cows fed soybean corn silage consumed more dry matter per unit body weight and produced more milk than cows on urea corn silage (P < .05). Sulfur supplementation did not affect feed intake or milk yield, nor was there interaction between silage nitrogen source and sulfur treatments. In a second experiment 24 cows arranged in a 2 x 2 x 2 factorial were fed .5% urea silage or 3.57O soybean meal silage and concentrates containing 0 or .87O added urea, each with 0 or .8% added sodium sulfate. No treatment differences were detected in feed intake or milk yield during 40 weeks. Sulfur supplementation increased sulfur in ration dry matter from .13~ to .22% (Experiment I) and .11 to .18% (Experiment II) and also changed the ratio of nitrogen to sulfur from 19:1 to 11:1 (Experiment I) and 21:1 to 13:1 (Exper/ment II). Introduction
Utilization of urea in dairy rations based oll corn silage has been reviewed extensively (7, 12). Corn silage treated with .5% urea at ensiling time produced equal lactation responses to control silages supplemented with higher protein concentrates (14, 26, 35). When ureatreated silage was fed with concentrates conReceived for publication August 18, 1972. 1Present address: Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada. Present address: Nutrition Institute, Ruminant Nutrition Laboratory, USDA, Beltsville, Maryland 20705. 218
taining 1% urea, feed intake and milk yield were comparable to that for control silages (8, 24, 31, 32). Decreased feed intake and milk production have been reported when cows received 20% of ration nitrogen from content-rate urea (13) or more than .5?o urea in con~ silage (6, 26). There are no reports of additions of plant protein to whole plant corn at ensiling time as a means of increasing crude protein content of corn silage. The first objective of our study was to compare ureatreated corn silage with corn silage having an equivalent amount of nitrogen from soybean meal when fed to dairy cattle in coniunction with urea-containing concentrates. Information on sulfur requirement of dairy cattle is limited (23), but rations based on corn silage supplemented with urea may contain wider nitrogen to sulfur ratios than 10:1 as recommended by Moir et al. (21) for sheep. Dairy cattle can incorporate sulfur from sodium sulfate into eystine and methionine (3), and sulfur supplementation improves cellulose digestion of low sulfur diets (2, 4, 10). However, supplementation of low sulfur diets with sodium sulfate did not produce lactation response by dairy cows in two trials (5, 9), although in another report (15) feed intake and milk production were higher for cows receiving .12% dietary sulfur than those receiving .10~ dietary sulfur by the 9th wk on experiment. But milk production was relatively low on all three trials (5, 9, 15). Our second objective, therefore, was to determine the effect of supplemental sulfur from sodium sulfate (anhydrous) on response of lactating cows fed corn silage rations supplemented with urea. Experimental Procedure
Experiment I. Thirty-two Holstein cows (16 first lactation and 16 second or later lactation) were allotted randomly within age groups to corn silage nitrogen additive and concentrate sulfur treatments arranged in a 2 x 2 factorial. Silage treatments consisted of whole plant corn (33?o dry matter) treated at ensiling with either .57o urea (45?o N), UCS, or 2.87O soybean meal (5070 crude
219
SULFUR SUPPLEMENT PERFORMANCE
TABLE 1. Ingredient composition~ of concentrates. Experiment I
Experiment II Concentrate mixture
Ingredients
1
2
High-moisture ear corn Ground shelled corn Soybean meal (50% crude protein) Urea (45~ N) Dicalcium phosphate Trace mineralized salt Sodium sulfate (anhydrous')
83.0 ..• 13.6 .8 1.7 .8 ..
82.3 ... 13.5 .8 1.7 •8
3
4
84.0 4.6 8.2 .8 1.4 1.0
5
6
(z)
.9
.
.
84.0 4.6 7.4 .8 1.4 1.0 .
.
8
~.0 84.0 . . . . . . 13.6 12.8 . . . . . . 1.4 1.4 1.0 1.0 .
.
.
.
8
" Expressed as fed. protein), SCS; concentrates were unsupplemented (control) and supplemented with .9~ sodium sulfate (anhydrous). Treated silages were made by simultaneous filling of two silos with alternate loads of fresh chopped corn. Urea and soybean meal were added at 5 kg and 28 kg, respectively, per metric ton of fresh weight material by spreading the appropriate amount on top of each weighed load prior to unloading into the silo blower. Concentrates were prepared by mixing ground high-moisture ear corn (about 70% dry matter at ensiling) with other ingredients daily in proportions shown in Table 1. Both concentrates contained .8% urea. Silage treatments were imposed at parturition and corn silage was fed ad libitum to the experiment's end. The UCS had been fed 30 days before parturition. Control concentrate was fed from parturiTABLE 2. Chemical composition of silages and concentrates as fed. Dry matter ( DM ) (%)
Crude protein
Acid detergent fiber
Sulfur
(% of dry matter)
Experiment I Urea silage Soy silage Concentrate 1 Concentrate 2
33.9 35.2 72.6 72.9
11.4 10.8 20.8 20.7
.... .... .... ....
10 12 15 37
Experiment II Urea silage Soy silage Concentrate Concentrate Concentrate Concentrate
35.8 37.2 66.1 66.4 66.6 66.7
12.5 12.2 17.8 18.1 18.4 17.8
20.4 19.8 7.8 8.2 7.7 7.9
.09 .11 .12 .30 .13 .32
3 4 5 6
tion for 11 wk when concentrate sulfur treatments were imposed for 19 wk. Amount of concentrate fed individual cows was adjusted weekly according to NRC (22) energy recommendations for maintenance and lactation considering forage intake. Feed intake and milk yield were recorded daily with milk composition taken from samples of four consecutive milkings at weekly intervals and analyzed for fat (1) and protein (27). Feed samples were analyzed for dry matter by freeze drying and for crude protein according to AOAC (1). Sulfur was determined by x-ray emission spectrography (17) and corrected to a curve prepared from chemical analysis of samples having a range of sulfur content (1, 11, 28). Results are in Table 2. Variance was analyzed for feed intake and milk yield data for the 19 wk; significance of treatment differences was determined by F tests according to Steele and Torrie (29). Experiment II. Twenty-four Holstein cows wore in a full lactation study of three treatment factors in a 2 x 2 x 2 factorial arrangement. Factors were (i) corn silage nitrogen additive, whole plant corn (35% dry matter) treated with either .5% urea (UCS) or 3.5% soybean meal (SCS) on a fresh weight basis at ensiling time, and urea and soybean meal added at rates of 5 kg and 35 kg per metric ton, respectively, as in Experiment 1; (ii) concentrate nitrogen sources, either .8% urea or equivalent nitrogen from soybean meal; and (iii) concentrate sulfur, either unsupplemented or supplemented with .8% sodimn sulfate (anhydrous), Concentrate mixtures (Table 1) were formulated to be isonitrogenous and isocaloric. Ensiled high-moisture ear corn (60% dry matJOURNAL OF DAIRY SCIENCE VOL. 56, NO. 2
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ter) was mixed daily with the balance of concent-rate ingredients. Treatments were imposed at parturition and continued for 280 days with UCS fed 30 days before parturition. Corn silage was fed ad libitum throughout, concentrate was adjusted weekly to individual requirements, and silage intake as in Experiment 1. Feed intake, milk yield, and milk composition as well as feed composition were measured as in Experiment 1. In addition, acid detergent fiber (33) analyses were on all feed samples. Freeze-ground (with dry ice) fresh samples of silages and concentrates were analyzed for urea, ammoniacal, and total nitrogen according to AOAC procedures (1). Protein nitrogen was determined by precipitation of sample with cold 5~ trich!oroacetie acid solution, followed by Kjeldahl nitrogen deterlnination on precipitate. Variance was analyzed on feed intake adjusted by least squares and milk yield data for the 280-day experiment. During the course of the experiment four cows were removed (one each from four of the eight treatment combinations) due to acute coliform mastiffs. Separate analyses of variance on least squares adjusted data for weeks 1 to 13, 14 to 26, and 27 to 40 failed to yield significant additional information over that of the 280-day analysis. Results and Discussion
Experiment I. Cows fed SCS consumed more total dry matter (expressed as a percent of body weight) and produced more (P < .05) actual and solids-corrected milk (Table 3) than those fed UCS. Most of the difference in dry matter intake was due to inereased silage dry matter consumption by SCS cows although
this difference was not statistically different (P < .05). There were no reports of direct comparisons between urea and soybeantreated corn silage, but when urea corn silage has been compared to control silages and both were fed in conjunction with concentrates containing 1.0% urea, no differences in feed intako (8, 24, 32) or milk yield (8, 24, 31, 32) were reported. Sulfur supplementation at a rate which decreased N:S ratios in the total ration from 19:1 to 11:1 and increased sulfur content of the ration dry matter from .13 to .22f~ did not affect (P < .05) measures of feed intake or milk production (Table 3). Neither was there any statistical evidence for interaction between sulfur supplementation and silage nitrogen treatment for any measurements. Our data complement those of Jaeobson et al. (15) who fed diets containing .10 and .125 sulfur and reported higher feed intake and milk yield by sulfur supplemented cows by the 9th wk on experiment. Results suggest that supplemental sulfur above .137o does not increase feed intake or milk production. Experiment II. Analysis of several nitrogen fractions in corn silage and concentrate samples revealed only about 32% nitrogen in trichloroacetie acid precipitate for UCS compared to 4370 for SCS (Table 4). Values for UCS are in general agreement with those from data of Miron and Otterby (20) and Owens et al. (25) but lower than those of Johnson and McClure (16) when silages were treated with limestone as well as urea. Considerable hydrolysis of soybean meal protein took place during ensiling as well.
TABLE 3. Effect of corn silage nitrogen source and sulfur supplementation on daily feed intake and lactation performance, Experiment I. Silage N additive
Sulfur
Urea
Soy
Feed intake Silage DM (kg) Concentrate DM (kg) Total DM (kg) DM (% of body weighl) Dicta1T S (% of DM)
8.2 6.5 14.7 2.63" .17
9.1 6.3 15.4 2.86" .18
8.4 6.6 15.0 2.78 .13r'
8.9 6.2 ]5.1 2.7J .22b
Milk production Milk yield (kg) Milk fat (%) Milk protein (~) Solids-corrected milk (kg)
18.0" 3.80 3.29 17.6a
20.2" 3.90 3.30 20.0 ~l
19.3 3.91 3.31 19.1
19.0 3.79 3.28 18.5
.~.b.o.aMeans with same superscript are significantly different (P ~ .05). No. 2
JOURNAL OF DAIRY SCIENCE VOL. 56,
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TABLE 4. Distribution of nitrogen o~ feeds, Experiment II. Feed
Total nitrogen
Trichloroacetic acid-N
Urea-N
(~ of dry matter) Fresh chopped corn (before ensiling) Urea corn silage Soy corn silage Ground ear corn (before ensiling) Ensfled ear corn Concentrate 3 Concentrate 4 Concentrate 5 Concentrate 6
NH3-N
Unaccounted-N
~; of total N
1.35 2.00 1.95
91.6 32.4 42.8
1.1 15.9 .8
1.5 18.1 9.2
5.8 33.6 47.2
1.58 1.58 2.83 2.90 2.95 2.85
92.4 57.4 61.4 59.2 79.0 75.5
.3 .1 16.1 17.3 1.2 1.1
.6 4.5 3.5 3.2 2.5 2.3
6.7 38.0 19.0 20.3 17.3 21.1
Urea and soybean nitrogen were in the same proportion to corn-plant dry matter when removed as silage as they were when added at ensfling. Thus, it was estimated that about 50% of urea nitrogen was recovered intact, the balance being degraded to ammonia. Relatively large percentages of the total nitrogen of silages remained unaccounted for by analyses agreeing with other reports (16, 20, 25). Ensiling ground ear corn also decreased the amount of trichloroacetie acid precipitable nitrogen and increased undetermined nitrogen. Urea added daily to concentrates based on high-moisture ear corn remained relatively intact; ammonia in these feeds was only slightly higher than in concentrates containing no urea. Feeding UCS did not result in any significant (P ~ .05) effect on feed intake or milk
production measurements when compared to SCS (Table 5), contrary to results of Experiment 1 where SCS fed cows produced more actual and solids-corrected milk. Concentrate nitrogen source also had no effect on any measurements, solids-corrected milk averaging 18.1 and 18.2 kg per cow per day on urea and soybean meal concentrates. There was no statistical evidence for interaction between silage and concentrate nitrogen treatments, indicating that urea-containing silages and concentrates are compatible in dairy rations as reported (8, 24, 31). Sulfur supplementation b y addition of .8% anhydrous sodium sulfate did not produce a significant lactation response although there was a difference at about 2 kg actual and solids-corrected milk in favor of sulfur supplemented cows fed concentrates containing .8% urea (Table 5). This difference
TABLE 5. Effect of corn silage and concentrate nitrogen sources and sulfur on daily feed intake and lactation perfommnce, Experiment II. Item N source sulfur
Silage treatment
Concentrate treatment
Urea
Soy
Urea
Urea + sulfur
Soy
Soy + sulfur
Feed intake Silage DM (kg) Concentrate DM (kg) Total DM (kg) DM (~ of body weight) Dietary S (~; of DM)
9.4 4.6 14.0 2.36 .13
9.0 5.1 14.t 2.32 .15
9.7 4.3 14.0 2.37 .11
9.0 5.2 14.2 2.38 .17
9.1 4.8 13.9 2.32 .11
8.9 5.1 14.0 2.30 .18
Milk production Milk yield (kg) Milk fat (%) Milk protein (~) Solids-corrected milk (kg)
19.5 3.69 3.25 18.7
19.0 3.37 3.26 17.8
18.1 3.48 3.28 17.1
20.1 3.63 3.29 19.1
19.3 3.40 3.26 17,9
19.5 3.61 3.20 18.5
No significant differences (P < .05) between treatments. JOURNAL OF DAIRY SCIENCE VOL. 56, NO. 2
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was not significant (P < .05) as an interaction between concentrate nitrogen source and sulfur supplementation. In fact, the trend is opposite of that in Experiment 1. These data, as those of Jacobson et al. (15), suggest a small response to sulfur supplementation; but in this study the response was not significant. Dietary N:S ratios were reduced from 21:1 to 13:1 on unsupplemented and sulfur-containing diets over the whole experiment and from 19:1 to 11:1 during the first trimester of lactation when higher concentrate was fed. Ratios in these supplemented diets are close to values of 10:1 as recommended by Moir et al. (21) and Whanger (34). In addition, dietary sulfur of at least .175 of ration dry matter in supplemented diets appears adequate for maximal cellulose digestion (2). In this experiment, these values were increased from .11 to .185. Data, therefore, suggest that either sulfur was not a first limiting element or that other factors were involved. Unexplainable are the relatively low average dry matter intakes, especially for concentrates, compared to other trials under generally similar circumstances (18, 19, 30). Milk production also was lower than anticipated. None of the other trials (18, 19, 30) used here as a general comparison involved the combination of all corn silage forage plus concentrates based primarily on highmoisture corn. Whether this circumstance and any relationships to supplementation of such a ration are factors involved is only speculation. The supplemental sulfur was inefficiently utilized (11). Data of Jaeobson et al. (15) also indicated that supplemental sodium sulfate was not well utilized. Differences in response to silage nitrogen treatments between Experiments I and II is unexplained. However, it is apparent that SCS in Experiment I was slightly more palatable than UCS. Both soybean meal and urea can be used as satisfactory nitrogen additives to increase crude protein content of corn silage.
Acknowledgments The authors express their appreciation to Dr. W. H. Allaway and Mr. V. Lazar, U.S. Plant Soil and Nutrition Laboratory, Ithaca, New York, for assistance in sulfur determinations and to Messrs. L. Bernholz and T. Kuntz for their technical assistance.
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(2) Barton, J. S., L. S. Bull, and R. W. Hemken. 1971. Effects of various levels of sulfur upon cellulose digestion in purified diets and lignocellulose digestion in corn fodder pellets in vitro. J. Anim. Sci., 33:682. (3) Block, R. J., and J. A. Stekol. 1950. Synthesis of sulfur amino acids from inorganic sulfate by ruminants. Pree. Soc. Exp. Biol. Med., 73:391. (4) Bray, A. C., and J. A. Hemsley. 1969. Sulfur metabolism of sheep. IV. The effect of varied dfetarv sulfur content on some body fluid sulfate levels and on the utilization of urea supplemented roughage by sheep. Australian J. Agr. Res., 20:759. (5) Burgess, P. L., and J. W. G. Niehotson. 1971. Effect of sulfur supplementation on the performance of lactating dairy cows fed ureacontaining diets. Can. J. Anhn. SCI., 51:711. (6) Conrad, H. R., and J. W. Hibbs. 1961. Urea treatment affects utilization of corn silage. Ohio Farm and Home Res., 46:13. (7) Coppock, C. E., and J. B. Stone. 1968. Corn silage in the ration of dairy cattle. A review. Cornell Misc. Bull. 89. (8) Dalrymple, J. M. 1969. Adaptation to urea by the lactating cow. M.Se. Thesis, University of Guelph, Guelph, Ontario, Canada. (9) Davis, R. F., Constance Williams, and J. K. Loosli. 1954. Studies on sulfur to nitrogen ratios in feeds for dairy cows. J. Dairy Sci., 37:813. (10) Evans, J. L., and G. K. Davis. 1966. Influence of sulfur, molybdenum, phosphorus and copper interrelationships in cattle upon cellulose in vivo and in vitro. J. Anim. Sci., 25:1014. (11) Grieve, D. G. 1971. Utilization of urea nitrogen in corn silage and concentrate rations of lactating dairy cattle with or without sulfur supplementation. Ph.D. Thesis, Cotnell University, Ithaca, New York. (12) Huber, J. T., C. E. Polan, and D. Hillman. 1968. Urea in high corn silage rations for dairy cattle. J. Anita. Sci., 27:220. (13) Huber, J. T., R. A. Sandy, C. E. Polan, H. T. Bryant, and R. E. Blaser. 1967. Varying levels of urea for dairy cows fed corn silage as the only forage. J. Dairy Sci., 50:1241. (14) Huber, J. T., and ]. W. Thomas. 1969. Urea° txeated corn silage in low protein rations for lactating cows. J. Dairy Sci., 52:944. (Abstr.) (15) Jacobsou, D. R., J. W. Barnett, S. B. Carr, and R. H. Hat-ton. 1967. Voluntary feett intake, milk production, tureen content, and plasma-free amino acid levels of lactating cows on low sulfur and sulfur-supplemented diets. 1. Dairy Sci., 50:1248. (16) Johnson, R. R., and K. E. McClure. 1968. Corn plant maturity. IV. Effects on digestibility of corn silage in sheep. J. Anim. Sei., 27:535.
SULFUR SUPPLEMENT
(17) Kubota, J., and V. A. Lazer. 1967. Routine X-ray emission spectographic analysis of common forage plants. Soil testing and plant analysis, Part II - Plant Analysis. Soil Science of America Inc., Madison, Wisconsin. (18) McCaffree, J. D., and W. G. Merrill. 1968. High moisture corn for dairy cows in early lactation. J. Dairy SCI., 51:553. (19) McCaffree, J. D., W. G. Merrill, and N. E. Smith. 1972. Concentrate mixtures based on high moisture ear corn versus multi-ingreclients for dairy cows in early lactation. J. Dairy Sci., 55:269. (20) Miron, A. E., and D. E. Otterby. 1969. Utilization of urea nitrogen in corn silage J'. Dairy Sci., 52:907. (Abstr.) (21) Molt, R. J., M. Seiners, andA. C. Bray. 1968. Utilization of dietary sulfur and nitrogen by ruminants. The Sulfur Inst. J., 3:15. (22) National Academy of Sciences - National Research Council, Committee on Animal Nutrition. 1966. Nutrient requirements of dairy cattle. 3rd revised ed., publication 1349. (23) National Academy of Sciences - National Research Council, Committee ou Animal Nutrition. 1971. Nutrient requirements of dairy cattle. 4th revised ed., no. 3, Washington, D.C. (24) Owen, F. G. 1968. Value of urea in corn silage when fed with or without urea in the grain ration. J. Dairy Sci., 51:980. (Abstr.) (25) Owens, F. N., J. C. Meiske, and R. D. Goodrich. 1969. Effects of calcium sources and urea on corn silage fermentation. J. Dairy Sci., 52:1817. (26) Schmutz, W. G., L. D. Brown, and J. W. Thomas. 1969. Nutritive value of corn si-
PERFORMANCE
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lages treated with chemical additives for lactation. J. Dairy Sci., 52:1408. Sherbon, J. E. 1967. Rapid determination of protein in milk by dye binding. J. Ass. Ofl]c. Anal. Chem., 50:542. Standard methods for the examination of water, sewage and industrial wastes. 1955. Amer. Public Health Ass., Inc., New York. Steel, Robert G. D., and James H. Torrie. 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., Inc., New York. Trimberger, G. W., H. F. Tyrrell, D. A. Morrow, J. T. Reid, M. J. Wright, W. F. Shipe, W. G. Merrill, J. K. Loosli, C. E. Coppock, L. A. Moore, and C. H. Go~don. 1972. Effects o~? liberal concentrate feeding on health, reproductive efficiency, economy of milk production and other related responses of the dairy cow. N.Y. Food and Life Sci. Bull., 8. VanHorn, H. H., C. F. Foreman, and J. E. Rodriguez. 1967. Effect of high-urea supplementation on feed intake and milk production of dairy cows. J. Dairy Sei., 50:709. VanHorn, H. H., D. R. Jacobsen, and A. P. Graden. 1969. Influence of level and source of nitrogen on milk production and blood components. ]. Dairy Sci., 52:1395. Van Soest, P. J. 1963. The use of detergents in the analysis of fibrous feeds: II. A rapid method for the determination of fiber and lignin. J. Ass. Offlc. Agr. Chem., 46:829. Whanger, Philip D. 1969. Sulfur in NPN Rations. Anim. Nutr. Health, 9:10. Wise, G. H., J. H. Mitchell, J. P. LaMaster, and D. B. Roderiek. 1944. Urea-treated corn silage vs. untreated corn silage as a feed for lactating dairy cows. J. Dairy Sei., 27:649. (Abstr.)
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