Varying protein levels of complete rations for dairy cows in early lactation
2001
Argete-Peters, E.C. | Trung, L.T.
A ninety day post partum feeding trial was conducted on twelve Holstein x Red Sindhi cows assigned in a randomized complete block design using corn silage-based complete rations with three levels of dietary crude protein (CP). Ration 1 - 9.84 percent CP; Ration 2 - 11.54 percent CP; Ration 3 - 13.50 percent CP. The dry matter and total digestible nutrient intakes increased with increasing crude protein intake but differences were not significant between treatments. Protein intake increased (P.05) proportionately with increasing percentage of protein in the ration. Performance of the animals in all treatment did not significantly differ in terms of average daily milk production, 4 percent fat-corrected milk yield, actual 90-day production, projected 305-day lactation, persistency of milk production and gross feed efficiency. In all cases, however, animals in ration 2 (11.54 percent CP) showed better performance. Except for milk protein which was significantly higher in ration 3 (P.05) than in Rations 1 and 2, all the other milk components (milk fat, total solids, solids-non-fat, ash) were not significantly different between treatments. After three months in lactation, an overall weight loss of 7.6 kg was obtained from cows in ration 1 against 2.5 and 9.9 kg average weight gain of cows from rations 2 and 3, respectively. The differences were significant (P.05). No significant differences were found in rumen pH, rumen ammonia-N, rumen urea-N, blood ammonia-N and blood urea-N in all treatments. Blood urea-N was found to be highly correlated with total protein intake (P.01) with 4
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