Lactational response of dairy cows to increased dietary crude protein with added fat.
Thirty-six Holstein cows were assigned to one of three diets containing soybean meal (16% CP), added fat from extruded soybeans (16% CP), and added fat and protein from extruded soybeans plus soybean meal (18% CP) to determine whether feeding additional protein would prevent the depression in milk protein percentages usually experienced when cows are fed additional fat. Total mixed diets containing 25% corn silage, 25% alfalfa hay, and 50% of respective concentrate mixtures were fed individually wk 4 through 16 postpartum; pretreatment (wk 3 postpartum), milk production, and composition data were used as covariates. Milk production (33.0, 35.8, and 34.2 kg/d) was higher for cows fed added fat. Milk protein (2.92, 2.88, and 2.83%) and casein (2.16, 2.13, and 2.09%) tended to decrease for cows fed added fat and did not increase with higher dietary protein. Dry matter intakes (20.9, 20.7, and 19.8 kg/d) and BW were similar for all diets. Supplementing additional CP to a diet containing added fat did not prevent depression in milk protein percentage.
Kim
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YK
Dairy Science Department, South Dakota State University, Brookings 57007-0647.
Schingoethe
D J
DJ
Casper
D P
DP
Ludens
F C
FC
D000596:Amino Acids / Q000097:blood; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D002364:Caseins / Q000032:analysis; D002417:Cattle / Q000502:physiology*; D004041:Dietary Fats / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D005260:Female; D007774:Lactation / Q000502:physiology*; D007785:Lactose / Q000032:analysis; D008055:Lipids / Q000032:analysis; D008892:Milk / Q000032:analysis / Q000378:metabolism; D008894:Milk Proteins / Q000032:analysis*; D011897:Random Allocation; D012417:Rumen / Q000737:chemistry; D013025:Glycine max
D000596:Amino Acids; D002364:Caseins; D004041:Dietary Fats; D004044:Dietary Proteins; D008055:Lipids; D008894:Milk Proteins; D007785:Lactose