Milk Yield and Composition of Lactating Cows Fed Steam-Flaked Sorghum and Graded Concentrations of Ruminally Degradable Protein
| Autor: | K.H. Chen, R. S. Swingle, J.T. Huber, Flávio Augusto Portela Santos, J.M. Simas, P. Yu, C.B. Theurer |
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| Rok vydání: | 1998 |
| Předmět: |
Hot Temperature
Rumen Cottonseed Oil Soybean meal Biology Cottonseed chemistry.chemical_compound Fish meal Fish Products Genetics Animals Lactation Urea Dry matter Food science Dairy cattle food and beverages Starch Diet Neutral Detergent Fiber Milk chemistry Plant protein Animal Nutritional Physiological Phenomena Cattle Digestion Female Animal Science and Zoology Dietary Proteins Soybeans Edible Grain Food Science |
| Zdroj: | Journal of Dairy Science. 81:215-220 |
| ISSN: | 0022-0302 |
| DOI: | 10.3168/jds.s0022-0302(98)75568-7 |
| Popis: | To determine the effect of various amounts of ruminally undegradable protein in the diets of lactating cows fed steam-flaked sorghum, 24 Holstein cows (90 +/- 50 d in milk) were assigned to three treatments: 0.8% urea, 6% soybean meal, or 5% fish meal. Respective percentages of ruminally undegradable protein in the diets (as a percentage of crude protein) were 30, 35, and 39%. All diets contained 37% alfalfa hay; 3 to 5% cottonseed hulls; 10 to 13% whole cottonseed; 39% steam-flaked sorghum (360 g/L); 5% of a molasses, mineral, and vitamin supplement; and the different protein supplements. Intake of dry matter was higher for cows fed urea than for cows fed soybean meal or fish meal diets. In cows that yielded more than 40 kg/d of milk (4 cows per treatment), the soybean meal and fish meal diets resulted in higher yields of milk and 3.5% fat-corrected milk and a greater efficiency of conversion of feed to milk than did the urea diet. Cows that yielded less than 40 kg/d of milk (4 cows per treatment) at the beginning of treatment tended to yield more milk when fed urea than when fed the protein supplements. Nutrient digestibilities were not greatly affected by source of N, suggesting a beneficial effect of urea supplementation on nutrient digestibilities because replacement of protein supplements with cottonseed products caused the neutral detergent fiber content of the urea diet to be about 7% higher than that of the other diets. These data show that response to ruminally undegradable protein in diets of lactating cows fed steam-flaked sorghum was related to milk yield. |
| Databáze: | OpenAIRE |
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