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Wet Corn Distillers Grains in Lactating Dairy Cow Rations1
Wet Corn Distillers Grains in Lactating Dairy Cow Rations 1 D. J. SCHINGOETHE, A. K. CLARK, and H. H. VOELKER Dairy Science Department South Dakota State University Brookings 57007
ABSTRACT
INTRODUCTION
A switchback design experiment with eight cows was used to evaluate wet corn distillers grains (33.9% dry matter) as a feed for lactating cows. All cows were fed corn silage ad libitum and 3.2 kg of alfalfa hay daily. Cows on the control diet were fed an 18.6% crude protein concentrate mix of corn, oats, and soybean meal at 1 kg/2.5 kg milk produced. Cows on the experimental diet were fed 13.6 kg wet distillers grains (34% crude protein, dry) and a 10.9% crude protein concentrate mix of corn and oats at 1 kg/2.5 kg milk produced in excess of 11 kg milk daily. The reduced amount and reduced protein content of the concentrate mix fed to cows on the experimental ration was to compensate for protein and energy consumed as wet distillers grains. Cows averaged 12 wk postpartum at the start of the experiment, which consisted of three 4-wk periods. Cows fed control and wet distillers grains rations produced 27.0 and 27.6 kg of milk daily. No differences in milk fat (3.44 and 3.41%), milk protein (3.09 and 3.10%), or total solids (12.1 and 12.16%) were observed. Total dry matter consumption was similar for control and wet distillers grains rations (20.3 and 20.8 kg dry matter/day). Rumen volatile fatty acids, pH, and ammonia were similar for cows fed control and distillers grains rations. Wet distillers grain can be effective in rations for lactating dairy cattle as a protein and energy source.
Because of the rapid increase in costs o f fossil fuel, research has been directed towards production of alcohol fuels from grain crops. Several feed by-products are generated in the process of alcohol production. Whole stillage (6 to 10% dry matter) and carbon dioxide are the two initial by-products. Water can be removed from the whole stillage by centrifugation or screening and pressing to form wet distillers grains [(WDG, 30 to 40% dry matter (DM)] and thin stillage (2 to 4% DM). Wet distillers grains can be dried to distillers dried grains (DDG), a common feedstuff. Thin stillage can be recycled to the alcohol plant for refermentation or evaporated to condensed distillers solubles or distillers solubles or distillers dried solubles. Loosli et al. (10, 11) and Warner (20) noted that DDG were utilized as efficiently as soybean meal and other protein sources for milk production. Other researchers (8, 9, 18) reported decreased ruminal degradation of protein in distillers grains, indicating its role as a bypass protein. Interest in feeding wet distillers grains has evolved from increased cost of drying wet grains as well as increase in on-farm and other small alcohol still operations. Most information available about the feeding value of WDG as well as wet brewers grains for dairy cattle was obtained by predictions based on studies with the dried products. Limited research data are available based on feeding WDG or wet brewers grains. Wet brewers grains may be more digestible than the equivalent dried grains (16). Murdock et al. (12) ascertained that wet brewers grains can be utilized as a protein supplement with crude protein equivalent to soybean meal for milk production. Grenawalt et al. (7) observed satisfactory milk production from cows fed 20% of ration dry matter as pressed brewers grains, but milk production was reduced by 30 and 40% pressed brewers grains.
Received June 14, 1982. 1Published with the approval of the Director of the South Dakota Agricultural Experiment Station as Publication No. 1820 of the Journal Series. 1983 J Dairy Sci 66:345-349
345
346
SCHINGOETHE ET AL.
Research with feeding WDG to ruminants is more limited, b u t preliminary studies with beef cattle (8) indicated that WDG appeared to be equal to the dried by-product. Our investigation was to evaluate a means of utilizing WDG in rations for lactating cows. Amounts fed and ration formulations were based on estimates from the literature cited (7, 8, 12, 16) for the amount of WDG to be near the maximum that could be fed without reducing dry matter intake and production. A t the same time, efforts were made to maintain total rations that contained adequate amounts of protein and energy (13). MATERIALS AND METHODS
Wet corn distillers grains (WDG) obtained from the Alcohol Fuels Laboratory at South Dakota State University was evaluated as a feed for lactating dairy cows. The WDG, which contained 30% dry matter after centrifugation, was obtained once each week and stored in barrels of 100-kg until fed. Based on preliminary estimates of dry matter (30%) and composition (30% crude protein in dry matter) of the WDG, it was estimated that 13.6 kg of WDG could replace 4.5 kg of concentrate mix and all of the soybean meal usually included in that concentrate mix. On that basis, two concentrate mixes were formulated (Table 1). Concentrate mix A contained only shelled corn and oats whereas concentrate mix B also contained soybean meal. The amounts of dicalcium phosphate, trace mineral salt, and vitamins A and D in the
TABLE 1. Ingredient composition of concentrate mixtures. Ingredient
Aa
Corn, rolled shelled Oats, rolled Soybean meal, 47% CP Dicalcium phosphate Trace mineral salt
47.9 47.9 ... 2.5 1.7
Bb (% as fed) 39.0 39.0 19.5 1.5 1.0
aplus 14,000 IU added vitamin A/kg and 3,500 IU added vitamin D/kg; fed with wet distillers grain. bplus 8,800 IU added vitamin A/kg and 2,200 IU added vitamin D/kg; fed as control grain mixture. Journal of Dairy Science Vol. 66, No. 2, 1983
two mixes were adjusted so that approximately equal amounts of these nutrients would be supplied in the total ration. Eight lactating Holstein cows averaging 84 days postpartum (41 to 145 days) were used in a complete switchback trial with three periods of 4 wk each. The 1st wk of each period was allowed for adjustment to new rations, and data from the last 3 wk were used for analyses. Treatments were WDG and control diets. The WDG diet consisted o f 13.6 kg WDG daily, concentrate mix A (Table 1) fed at 1 kg/2.5 kg milk produced in excess of 11 kg milk daily, corn silage ad libitum, and 3.2 kg alfalfa hay daily. The control diet consisted of concentrate mix B fed at 1 kg/2.5 kg milk produced, corn silage ad libitum, and 3.2 kg alfalfa hay daily. Cows were housed and fed individually in stanchions and milked in a double-five herringbone parlor during this trial, which was from late July to October. Milk production was recorded daily with 24-h milk samples collected once a week during the last 3 wk of each period. Milk samples were analyzed for fat by Babcock, protein by Kjeldahl (1), and total solids b y the procedure of Newlander and Atherton (14). Feed intakes and refusals were recorded daily for each cow. Samples of all feeds were obtained weekly and composited each period for analyses of dry matter, crude protein, ether extract, ash (1), and acid detergent fiber (6). Body weights of cows were obtained on 3 consecutive days at the start of the experiment and at the end of each period. During the 4th wk of each period samples of rumen contents were collected via esophageal tube and suction strainer 2 to 3 h after the morning feeding into 150-ml bottles containing .5 ml saturated mercuric chloride. Samples were analyzed immediately for pH. A 10-ml aliquot of rumen fluid was acidified with 2 ml of 25% metaphosphoric acid, centrifuged, and the supernatant frozen until analyzed for volatile fatty acids (VFA) by gas-liquid chromatography with a neopentylglycol succinate column as described by Baumgardt (2). Another 10-ml aliquot of rumen fluid was acidified with .5 ml of .1 N HC1, centrifuged, and the supernatant frozen and later analyzed for ammonical nitrogen as described by Chaney and Marbach (3). Data were subjected to analyses of variance
TECHNICAL NOTE
347
TABLE 2. Chemical composition of feeds fed.
Item
WDGa
Ab
Concentrate mixture Bc
Corn silage
Alfalfa hay
42.0
91.4
9.3 26.7 2.8 4.8
19.3 35.1 2.1 7.0
(%) Dry matter (DM)
33.9
88.5
Crude protein Acid detergent fiber Ether extract Ash
34.4 18.2 7.1 2.4
10.9 9.7 4.1 6.6
88.6 (% of DM) 18.6 9.5 4.0 5.6
awet distillers grain. bFed to cows receiving WDG. CControl concentrate mixture.
applied to switchback trials as described by Patterson and Lucas (15). RESULTS AND DISCUSSION
Compositions of feeds are in Table 2. The WDG contained slightly more dry matter and slightly more crude protein than anticipated, but its composition was similar to reports for WI)G and dried distillers grains (4, 19). The WDG generally remained acceptable during the week of storage although some surface molds appeared occasionally during warm weather. Other studies at South Dakota State University (17) indicated that additions of 1% propionic acid could extend preservation of WDG to 2 wk. Milk yields and composition (Table 3) were similar from cows fed WDG and control diets. Acceptable production was achieved b y other researchers from cows fed dried distillers grains (10, 11, 20). Feed intake and body weight data are in Table 3. The WDG was consumed readily with no apparent problems of palatability. It provided 22% of total ration dry matter. Cows fed WDG consumed slightly more dry matter from concentrates (stillage and concentrate mix A) than cows fed the control concentrate mix B, primarily because the WDG contained more dry matter than anticipated. This was offset partially by reduced (P<.01) consumption of corn silage with WDG. Total intake of dry matter averaged about 3.4% of body weight for cows fed WDG
and control diets. Body weight gains were small and similar with both diets. Conversely, Grenawalt et al. (6) found that increasing the amount of wet brewers grains in rations of cows in midlactation decreased dry matter consumption and increased losses of body weight. Cows fed WDG and control diets consumed 3.4 and 3.0 kg of crude protein daily, respectively, and 4.4 and 4.0 kg of acid detergent fiber. The slightly higher protein intake with WDG was because the WDG available during the experiment contained more protein and dry matter than anticipated from preliminary analyses. For estimated nutrient requirements (13), protein intake calculated f r o m . o u r analyses, and intake of net energy for lactation (NEL) calculated using NE L reported (13) for dried distillers grains as well as for other feeds fed, all cows were consuming sufficient protein and energy with the ratio of protein to energy almost ideal. Crude protein intake averaged 126 and 112% of requirements for WDG and control diets whereas NEL intake averaged 121 and 114% of requirements. This amount of intake is typical for cows during midlactation (21) although higher than would have been desired if this experiment had been intended to estimate precisely the feeding value of WDG. Additional experiments would be required in which protein and energy intakes were more limiting to evaluate more precisely for dairy cattle. Rumen VFA, pH, and ammonia (Table 4) Journal of Dairy Science Vol. 66, No. 2, 1983
348
SCHINGOETHE ET AL.
TABLE 3. Milk yield and composition, feed intake, and body weights for cows fed wet distillers grains (WDG) and control diets. Diet Item
WDG
Milk, kg/day Fat, % Protein, % Total solids, % Feed intake, kg DMa/day Wet distillers grains Concentrate mix Low protein b High protein c Corn silage Alfalfa hay Total dry matter Body weight, kg Body weight gain, kg/day
27.6 3.41 3.10 12.16 4.6 6.3 .... 7.1 * * 2.9 20.8 601.2 .10
Control 27.0 3.44 3.09 12.10
SE .85 .09 .03 .13
.... .... 9.4 7.9 2.9 20.3 599.2 .01
.41 .19 21.0 .12
aDM, dry matter. bconcentrate mix A in Table 1, 10.9% crude protein. Cconcentrate mix B in Table 1, 18.6% crude protein. *t
Different from control, P<.01.
were similar for cows fed WDG and c o n t r o l diets although with slight variations. Molar c o n c e n t r a t i o n s of p r o p i o n a t e were higher (P<.05) for WDG, possibly reflecting cons u m p t i o n of a diet that was higher in energy. However, this difference was of questionable biological significance and had no a p p a r e n t TABLE 4. Rumen volatile fatty acids (VFA), pH, and ammonia from cows fed wet distillers grains (WDG) and control diets. Diet Item
WDG
Control
SE
VFA Acetate a Propionate a Isobutyrate a Butyrate a lsovalerate a Valerate a Total, #m/ml pH Ammonia, mg/lO0 ml
53.4 24.5 * 1.0 16.2 3.1 1.9 57.4 6.54 8.4
54.8 21.9 1.2 17.2 3.1 1.9 53.9 6.59 8.0
.40 .80 .09 .73 .31 .07 2.61 .03 1.16
aMoles per 100 moles total VFA. Different from control, P<.05. Journal of Dairy Science Vol. 66, No. 2, 1983
affect on milk c o m p o s i t i o n (Table 3). R u m e n a m m o n i a was measured because distillers grains usually contain proteins of low solubility (8, 9, 18), which m a y be degraded m o r e slowly in the r u m e n with resulting decrease in c o n c e n t r a t i o n s of a m m o n i a in rumen. Solubility of nitrogen in dilute mineral buffer (5) f r o m WDG averaged 2.5% of total nitrogen for a n u m b e r of samples of WDG p r o d u c e d in t h e S D S U A l c o h o l Fuels Laboratory. Soluble nitrogen as p e r c e n t of total nitrogen was estimated to average a b o u t 20 and 27% for WDG and control diets. Wet distillers grains can be an effective feed source in rations for lactating dairy cattle. The WDG was utilized as effectively as corn, oats, and soybean meal it replaced in the control ration for milk p r o d u c t i o n and m a i n t e n a n c e of b o d y weight u n d e r the practical feeding system in which it was tested. A d d i t i o n a l e x p e r i m e n t s m a y be necessary to measure m o r e precisely the protein and energy value of WDG in rations of lactating cows. Cattle c o n s u m e d 20 to 25% of their dry m a t t e r as WDG with no problems. However, if results of studies with w e t brewers grains (6) are applicable to WDG, care should be exercised in feeding m o r e WDG because o f p o t e n t i a l p r o b l e m s of intake.
TECHNICAL NOTE
REFERENCES 1 Association of Official Analytical Chemists. 1975. Official methods of analysis. 12tb ed. Assoc. Offic. Anal. Chem., Washington, DC. 2 Baumgardt, B. R. 1964. Practical observations on the analysis of free volatile fatty acids (VFA) in aqueous solutions by gas-liquid chromatography. Bull. 1, Dep. of Dairy Sci., Univ. Wisconsin, Madison. 3 Chancy, A. L., and E. P. Marbach. 1962. Modified reagents for determination of urea and ammonia. Clin. Chem. 8:130. 4 Clark, P. 1981. Feeding wet brewers and distillers by-products to dairy cattle. Page 9 in Proc. 10th Annu. Kentucky Dairymen's Conf. 5 Crooker, B. A., C. J. Sniffen, W. H. Hoover, and L. L. Johnson. 1978. Solvents for soluble nitrogen measurements in feedstuffs. J. Dairy Sci. 61:437. 6 Goering, H. K., and P. J. Van Soest. 1970. Forage fiber analysis (apparatus, reagents, procedure, and some applications). US Dep. Agric., Agric. Handbook 379. 7 Grenawalt, D. A., G. C. McCoy, and C. L. Davis. 1981. Performance of lactating dairy cows fed rations containing varying amounts of pressed brewers grains. J. Dairy Sci. 64(Suppl. 1):116. (Abstr.) 8 Klopfenstein, T., and R. Stock. 1981. Distillers grains for ruminants. Feedstuffs 53(41):26. 9 Klopfenstein, T., J. Waller, N. Merchen, and L. Petersen. 1978. Distillers grains as a naturally protected protein for ruminants. Page 38 in Proc. 33rd Distillers Feed Conf. 10 Loosli, J. K., K. L. Turk, and F. B. Morrison. 1952. The value of distillers feeds for milk production. J. Dairy Sci. 35:868. 11 Loosli, J. K., R. G. Warner, and H. F. Hintz. 1961.
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Value of corn distillers dried grains, soybean oil meal, heated soybeans, and soybean oil meal plus starch for milk production. J. Dairy Sci. 44:1910. 12 Murdock, F. R., A. S. Hodgson, and R. E. Riley, Jr. 1981. Nutritive value of wet brewers grains for lactating dairy cows. J. Dairy Sci. 64:1826. 13 National Research Council. 1978. Nutrient requirements of dairy cattle. 5th rev. ed. Natl. Acad. Sci., Washington, DC. 14 Newlander, J. A., and H. V. Atherton. 1964. The chemistry and testing of dairy products. Olsen Publ. Co., Milwaukee, WI. 15 Patterson, H. D., and H. L. Lucas. 1962. Changeover design. Tech. Bull. No. 147, North Carolina Agric. Exp. Stn., Raleigh. 16 Porter, R. M., and H. R. Conrad. 1975. Comparative nutritive value of wet and dried brewers grains. J. Dairy Sci. 58:747. (Abstr.) 17 Rakshit, C. C., and H. H. Voelker. 1981. Effects of additives on preservation of alfalfa silage, corn silage, and corn stillage. J. Dairy Sci. 64(Suppl. 1):115. (Abstr.) 18 Satter, L. D., L. W. Whitlow, and G. L. Beardsley. 1977. Resistance of protein to rumen degradation and its significance to the dairy cow. Page 63 in Proc. 32nd Distillers Feed Conf. • 19 Ward, G. M., and J. K. Matsushima. 1980. Feeding value of dried distillers grains in beef feedlot rations. Feedstuffs 55(51):22. 20 Warner, R. G. 1970. The place of distillers feeds in dairy cattle rations - a review. Page 11 in Proc. 25th Distillers Feed Conf. 21 Wohlt, J. E., and J. H. Clark. 1978. Nutritional value of urea versus preformed protein for ruminants. I. Lactation of dairy cows fed corn based diets containing supplemental nitrogen from urea and/or soybean meal. J. Dairy Sci. 61:902.
Journal of Dairy Science Vol. 66, No. 2, 1983
ABSTRACT
INTRODUCTION
A switchback design experiment with eight cows was used to evaluate wet corn distillers grains (33.9% dry matter) as a feed for lactating cows. All cows were fed corn silage ad libitum and 3.2 kg of alfalfa hay daily. Cows on the control diet were fed an 18.6% crude protein concentrate mix of corn, oats, and soybean meal at 1 kg/2.5 kg milk produced. Cows on the experimental diet were fed 13.6 kg wet distillers grains (34% crude protein, dry) and a 10.9% crude protein concentrate mix of corn and oats at 1 kg/2.5 kg milk produced in excess of 11 kg milk daily. The reduced amount and reduced protein content of the concentrate mix fed to cows on the experimental ration was to compensate for protein and energy consumed as wet distillers grains. Cows averaged 12 wk postpartum at the start of the experiment, which consisted of three 4-wk periods. Cows fed control and wet distillers grains rations produced 27.0 and 27.6 kg of milk daily. No differences in milk fat (3.44 and 3.41%), milk protein (3.09 and 3.10%), or total solids (12.1 and 12.16%) were observed. Total dry matter consumption was similar for control and wet distillers grains rations (20.3 and 20.8 kg dry matter/day). Rumen volatile fatty acids, pH, and ammonia were similar for cows fed control and distillers grains rations. Wet distillers grain can be effective in rations for lactating dairy cattle as a protein and energy source.
Because of the rapid increase in costs o f fossil fuel, research has been directed towards production of alcohol fuels from grain crops. Several feed by-products are generated in the process of alcohol production. Whole stillage (6 to 10% dry matter) and carbon dioxide are the two initial by-products. Water can be removed from the whole stillage by centrifugation or screening and pressing to form wet distillers grains [(WDG, 30 to 40% dry matter (DM)] and thin stillage (2 to 4% DM). Wet distillers grains can be dried to distillers dried grains (DDG), a common feedstuff. Thin stillage can be recycled to the alcohol plant for refermentation or evaporated to condensed distillers solubles or distillers solubles or distillers dried solubles. Loosli et al. (10, 11) and Warner (20) noted that DDG were utilized as efficiently as soybean meal and other protein sources for milk production. Other researchers (8, 9, 18) reported decreased ruminal degradation of protein in distillers grains, indicating its role as a bypass protein. Interest in feeding wet distillers grains has evolved from increased cost of drying wet grains as well as increase in on-farm and other small alcohol still operations. Most information available about the feeding value of WDG as well as wet brewers grains for dairy cattle was obtained by predictions based on studies with the dried products. Limited research data are available based on feeding WDG or wet brewers grains. Wet brewers grains may be more digestible than the equivalent dried grains (16). Murdock et al. (12) ascertained that wet brewers grains can be utilized as a protein supplement with crude protein equivalent to soybean meal for milk production. Grenawalt et al. (7) observed satisfactory milk production from cows fed 20% of ration dry matter as pressed brewers grains, but milk production was reduced by 30 and 40% pressed brewers grains.
Received June 14, 1982. 1Published with the approval of the Director of the South Dakota Agricultural Experiment Station as Publication No. 1820 of the Journal Series. 1983 J Dairy Sci 66:345-349
345
346
SCHINGOETHE ET AL.
Research with feeding WDG to ruminants is more limited, b u t preliminary studies with beef cattle (8) indicated that WDG appeared to be equal to the dried by-product. Our investigation was to evaluate a means of utilizing WDG in rations for lactating cows. Amounts fed and ration formulations were based on estimates from the literature cited (7, 8, 12, 16) for the amount of WDG to be near the maximum that could be fed without reducing dry matter intake and production. A t the same time, efforts were made to maintain total rations that contained adequate amounts of protein and energy (13). MATERIALS AND METHODS
Wet corn distillers grains (WDG) obtained from the Alcohol Fuels Laboratory at South Dakota State University was evaluated as a feed for lactating dairy cows. The WDG, which contained 30% dry matter after centrifugation, was obtained once each week and stored in barrels of 100-kg until fed. Based on preliminary estimates of dry matter (30%) and composition (30% crude protein in dry matter) of the WDG, it was estimated that 13.6 kg of WDG could replace 4.5 kg of concentrate mix and all of the soybean meal usually included in that concentrate mix. On that basis, two concentrate mixes were formulated (Table 1). Concentrate mix A contained only shelled corn and oats whereas concentrate mix B also contained soybean meal. The amounts of dicalcium phosphate, trace mineral salt, and vitamins A and D in the
TABLE 1. Ingredient composition of concentrate mixtures. Ingredient
Aa
Corn, rolled shelled Oats, rolled Soybean meal, 47% CP Dicalcium phosphate Trace mineral salt
47.9 47.9 ... 2.5 1.7
Bb (% as fed) 39.0 39.0 19.5 1.5 1.0
aplus 14,000 IU added vitamin A/kg and 3,500 IU added vitamin D/kg; fed with wet distillers grain. bplus 8,800 IU added vitamin A/kg and 2,200 IU added vitamin D/kg; fed as control grain mixture. Journal of Dairy Science Vol. 66, No. 2, 1983
two mixes were adjusted so that approximately equal amounts of these nutrients would be supplied in the total ration. Eight lactating Holstein cows averaging 84 days postpartum (41 to 145 days) were used in a complete switchback trial with three periods of 4 wk each. The 1st wk of each period was allowed for adjustment to new rations, and data from the last 3 wk were used for analyses. Treatments were WDG and control diets. The WDG diet consisted o f 13.6 kg WDG daily, concentrate mix A (Table 1) fed at 1 kg/2.5 kg milk produced in excess of 11 kg milk daily, corn silage ad libitum, and 3.2 kg alfalfa hay daily. The control diet consisted of concentrate mix B fed at 1 kg/2.5 kg milk produced, corn silage ad libitum, and 3.2 kg alfalfa hay daily. Cows were housed and fed individually in stanchions and milked in a double-five herringbone parlor during this trial, which was from late July to October. Milk production was recorded daily with 24-h milk samples collected once a week during the last 3 wk of each period. Milk samples were analyzed for fat by Babcock, protein by Kjeldahl (1), and total solids b y the procedure of Newlander and Atherton (14). Feed intakes and refusals were recorded daily for each cow. Samples of all feeds were obtained weekly and composited each period for analyses of dry matter, crude protein, ether extract, ash (1), and acid detergent fiber (6). Body weights of cows were obtained on 3 consecutive days at the start of the experiment and at the end of each period. During the 4th wk of each period samples of rumen contents were collected via esophageal tube and suction strainer 2 to 3 h after the morning feeding into 150-ml bottles containing .5 ml saturated mercuric chloride. Samples were analyzed immediately for pH. A 10-ml aliquot of rumen fluid was acidified with 2 ml of 25% metaphosphoric acid, centrifuged, and the supernatant frozen until analyzed for volatile fatty acids (VFA) by gas-liquid chromatography with a neopentylglycol succinate column as described by Baumgardt (2). Another 10-ml aliquot of rumen fluid was acidified with .5 ml of .1 N HC1, centrifuged, and the supernatant frozen and later analyzed for ammonical nitrogen as described by Chaney and Marbach (3). Data were subjected to analyses of variance
TECHNICAL NOTE
347
TABLE 2. Chemical composition of feeds fed.
Item
WDGa
Ab
Concentrate mixture Bc
Corn silage
Alfalfa hay
42.0
91.4
9.3 26.7 2.8 4.8
19.3 35.1 2.1 7.0
(%) Dry matter (DM)
33.9
88.5
Crude protein Acid detergent fiber Ether extract Ash
34.4 18.2 7.1 2.4
10.9 9.7 4.1 6.6
88.6 (% of DM) 18.6 9.5 4.0 5.6
awet distillers grain. bFed to cows receiving WDG. CControl concentrate mixture.
applied to switchback trials as described by Patterson and Lucas (15). RESULTS AND DISCUSSION
Compositions of feeds are in Table 2. The WDG contained slightly more dry matter and slightly more crude protein than anticipated, but its composition was similar to reports for WI)G and dried distillers grains (4, 19). The WDG generally remained acceptable during the week of storage although some surface molds appeared occasionally during warm weather. Other studies at South Dakota State University (17) indicated that additions of 1% propionic acid could extend preservation of WDG to 2 wk. Milk yields and composition (Table 3) were similar from cows fed WDG and control diets. Acceptable production was achieved b y other researchers from cows fed dried distillers grains (10, 11, 20). Feed intake and body weight data are in Table 3. The WDG was consumed readily with no apparent problems of palatability. It provided 22% of total ration dry matter. Cows fed WDG consumed slightly more dry matter from concentrates (stillage and concentrate mix A) than cows fed the control concentrate mix B, primarily because the WDG contained more dry matter than anticipated. This was offset partially by reduced (P<.01) consumption of corn silage with WDG. Total intake of dry matter averaged about 3.4% of body weight for cows fed WDG
and control diets. Body weight gains were small and similar with both diets. Conversely, Grenawalt et al. (6) found that increasing the amount of wet brewers grains in rations of cows in midlactation decreased dry matter consumption and increased losses of body weight. Cows fed WDG and control diets consumed 3.4 and 3.0 kg of crude protein daily, respectively, and 4.4 and 4.0 kg of acid detergent fiber. The slightly higher protein intake with WDG was because the WDG available during the experiment contained more protein and dry matter than anticipated from preliminary analyses. For estimated nutrient requirements (13), protein intake calculated f r o m . o u r analyses, and intake of net energy for lactation (NEL) calculated using NE L reported (13) for dried distillers grains as well as for other feeds fed, all cows were consuming sufficient protein and energy with the ratio of protein to energy almost ideal. Crude protein intake averaged 126 and 112% of requirements for WDG and control diets whereas NEL intake averaged 121 and 114% of requirements. This amount of intake is typical for cows during midlactation (21) although higher than would have been desired if this experiment had been intended to estimate precisely the feeding value of WDG. Additional experiments would be required in which protein and energy intakes were more limiting to evaluate more precisely for dairy cattle. Rumen VFA, pH, and ammonia (Table 4) Journal of Dairy Science Vol. 66, No. 2, 1983
348
SCHINGOETHE ET AL.
TABLE 3. Milk yield and composition, feed intake, and body weights for cows fed wet distillers grains (WDG) and control diets. Diet Item
WDG
Milk, kg/day Fat, % Protein, % Total solids, % Feed intake, kg DMa/day Wet distillers grains Concentrate mix Low protein b High protein c Corn silage Alfalfa hay Total dry matter Body weight, kg Body weight gain, kg/day
27.6 3.41 3.10 12.16 4.6 6.3 .... 7.1 * * 2.9 20.8 601.2 .10
Control 27.0 3.44 3.09 12.10
SE .85 .09 .03 .13
.... .... 9.4 7.9 2.9 20.3 599.2 .01
.41 .19 21.0 .12
aDM, dry matter. bconcentrate mix A in Table 1, 10.9% crude protein. Cconcentrate mix B in Table 1, 18.6% crude protein. *t
Different from control, P<.01.
were similar for cows fed WDG and c o n t r o l diets although with slight variations. Molar c o n c e n t r a t i o n s of p r o p i o n a t e were higher (P<.05) for WDG, possibly reflecting cons u m p t i o n of a diet that was higher in energy. However, this difference was of questionable biological significance and had no a p p a r e n t TABLE 4. Rumen volatile fatty acids (VFA), pH, and ammonia from cows fed wet distillers grains (WDG) and control diets. Diet Item
WDG
Control
SE
VFA Acetate a Propionate a Isobutyrate a Butyrate a lsovalerate a Valerate a Total, #m/ml pH Ammonia, mg/lO0 ml
53.4 24.5 * 1.0 16.2 3.1 1.9 57.4 6.54 8.4
54.8 21.9 1.2 17.2 3.1 1.9 53.9 6.59 8.0
.40 .80 .09 .73 .31 .07 2.61 .03 1.16
aMoles per 100 moles total VFA. Different from control, P<.05. Journal of Dairy Science Vol. 66, No. 2, 1983
affect on milk c o m p o s i t i o n (Table 3). R u m e n a m m o n i a was measured because distillers grains usually contain proteins of low solubility (8, 9, 18), which m a y be degraded m o r e slowly in the r u m e n with resulting decrease in c o n c e n t r a t i o n s of a m m o n i a in rumen. Solubility of nitrogen in dilute mineral buffer (5) f r o m WDG averaged 2.5% of total nitrogen for a n u m b e r of samples of WDG p r o d u c e d in t h e S D S U A l c o h o l Fuels Laboratory. Soluble nitrogen as p e r c e n t of total nitrogen was estimated to average a b o u t 20 and 27% for WDG and control diets. Wet distillers grains can be an effective feed source in rations for lactating dairy cattle. The WDG was utilized as effectively as corn, oats, and soybean meal it replaced in the control ration for milk p r o d u c t i o n and m a i n t e n a n c e of b o d y weight u n d e r the practical feeding system in which it was tested. A d d i t i o n a l e x p e r i m e n t s m a y be necessary to measure m o r e precisely the protein and energy value of WDG in rations of lactating cows. Cattle c o n s u m e d 20 to 25% of their dry m a t t e r as WDG with no problems. However, if results of studies with w e t brewers grains (6) are applicable to WDG, care should be exercised in feeding m o r e WDG because o f p o t e n t i a l p r o b l e m s of intake.
TECHNICAL NOTE
REFERENCES 1 Association of Official Analytical Chemists. 1975. Official methods of analysis. 12tb ed. Assoc. Offic. Anal. Chem., Washington, DC. 2 Baumgardt, B. R. 1964. Practical observations on the analysis of free volatile fatty acids (VFA) in aqueous solutions by gas-liquid chromatography. Bull. 1, Dep. of Dairy Sci., Univ. Wisconsin, Madison. 3 Chancy, A. L., and E. P. Marbach. 1962. Modified reagents for determination of urea and ammonia. Clin. Chem. 8:130. 4 Clark, P. 1981. Feeding wet brewers and distillers by-products to dairy cattle. Page 9 in Proc. 10th Annu. Kentucky Dairymen's Conf. 5 Crooker, B. A., C. J. Sniffen, W. H. Hoover, and L. L. Johnson. 1978. Solvents for soluble nitrogen measurements in feedstuffs. J. Dairy Sci. 61:437. 6 Goering, H. K., and P. J. Van Soest. 1970. Forage fiber analysis (apparatus, reagents, procedure, and some applications). US Dep. Agric., Agric. Handbook 379. 7 Grenawalt, D. A., G. C. McCoy, and C. L. Davis. 1981. Performance of lactating dairy cows fed rations containing varying amounts of pressed brewers grains. J. Dairy Sci. 64(Suppl. 1):116. (Abstr.) 8 Klopfenstein, T., and R. Stock. 1981. Distillers grains for ruminants. Feedstuffs 53(41):26. 9 Klopfenstein, T., J. Waller, N. Merchen, and L. Petersen. 1978. Distillers grains as a naturally protected protein for ruminants. Page 38 in Proc. 33rd Distillers Feed Conf. 10 Loosli, J. K., K. L. Turk, and F. B. Morrison. 1952. The value of distillers feeds for milk production. J. Dairy Sci. 35:868. 11 Loosli, J. K., R. G. Warner, and H. F. Hintz. 1961.
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Value of corn distillers dried grains, soybean oil meal, heated soybeans, and soybean oil meal plus starch for milk production. J. Dairy Sci. 44:1910. 12 Murdock, F. R., A. S. Hodgson, and R. E. Riley, Jr. 1981. Nutritive value of wet brewers grains for lactating dairy cows. J. Dairy Sci. 64:1826. 13 National Research Council. 1978. Nutrient requirements of dairy cattle. 5th rev. ed. Natl. Acad. Sci., Washington, DC. 14 Newlander, J. A., and H. V. Atherton. 1964. The chemistry and testing of dairy products. Olsen Publ. Co., Milwaukee, WI. 15 Patterson, H. D., and H. L. Lucas. 1962. Changeover design. Tech. Bull. No. 147, North Carolina Agric. Exp. Stn., Raleigh. 16 Porter, R. M., and H. R. Conrad. 1975. Comparative nutritive value of wet and dried brewers grains. J. Dairy Sci. 58:747. (Abstr.) 17 Rakshit, C. C., and H. H. Voelker. 1981. Effects of additives on preservation of alfalfa silage, corn silage, and corn stillage. J. Dairy Sci. 64(Suppl. 1):115. (Abstr.) 18 Satter, L. D., L. W. Whitlow, and G. L. Beardsley. 1977. Resistance of protein to rumen degradation and its significance to the dairy cow. Page 63 in Proc. 32nd Distillers Feed Conf. • 19 Ward, G. M., and J. K. Matsushima. 1980. Feeding value of dried distillers grains in beef feedlot rations. Feedstuffs 55(51):22. 20 Warner, R. G. 1970. The place of distillers feeds in dairy cattle rations - a review. Page 11 in Proc. 25th Distillers Feed Conf. 21 Wohlt, J. E., and J. H. Clark. 1978. Nutritional value of urea versus preformed protein for ruminants. I. Lactation of dairy cows fed corn based diets containing supplemental nitrogen from urea and/or soybean meal. J. Dairy Sci. 61:902.
Journal of Dairy Science Vol. 66, No. 2, 1983