Responses of dairy cows to additions of distillers dried grains with solubles in alfalfa-based diets.
Twenty-four Holstein cows in wk 3 through 12 of lactation were used to evaluate distillers dried grains with solubles as a protein source for alfalfa-based diets. Diets were formulated containing 0, 10.1, 20.8, or 31.5% distillers dried grains with solubles. Crude protein in these diets was 13.9, 16.0, 18.1, and 20.3%. Milk yield increased linearly with increasing dietary CP, whereas DMI was not affected. Dry matter intake averaged over 4% of BW for all treatments. Intake of undegraded intake protein was .93, 1.27, 1.63, and 1.97 kg/d. Yields of milk protein, casein, and lactose all increased linearly with increasing dietary CP. The proportion of milk N as whey N decreased, whereas N as NPN increased, with increasing dietary CP. Plasma urea N and essential and branched-chain AA increased linearly, and nonessential AA decreased linearly, with increasing dietary CP. Increasing the concentration of CP in the diet from 13.9 to 18.1% by the addition of distillers dried grains with solubles was beneficial to cows fed alfalfa-based diets in early lactation. Little additional benefit was observed by feeding greater than 18.1% dietary CP.
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Department of Animal and Veterinary Science, University of Idaho, Moscow 83843.
Roffler
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Deitelhoff
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D000596:Amino Acids / Q000008:administration & dosage; D000821:Animal Feed; D000818:Animals; D002364:Caseins / Q000032:analysis; D002417:Cattle / Q000502:physiology*; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000378:metabolism; D004063:Digestion; D004435:Eating; D002523:Edible Grain; D005260:Female; D007421:Intestine, Small / Q000378:metabolism; D007774:Lactation / Q000502:physiology*; D007785:Lactose / Q000032:analysis; D000455:Medicago sativa; D008892:Milk / Q000032:analysis / Q000378:metabolism; D008894:Milk Proteins / Q000032:analysis; D009584:Nitrogen / Q000032:analysis
D000596:Amino Acids; D002364:Caseins; D004044:Dietary Proteins; D008894:Milk Proteins; D007785:Lactose; D009584:Nitrogen