Effects of the protein level in diets on milk productivity and reproduction in transition Holstain cow
2008
Tokita, Y.(Kumamoto-ken. Agricultural Research Center, Koshi (Japan)) | Ino, K. | Inada, T. | Kiyoshima, K. | Nonaka, T.
This study compared the effects of two levels of crude protein (CP) fed during transition period on milk production and reproductive performance of Holstein cows. Seventy pregnant cows and seventy heifers for three weeks before calving were assigned to two groups. They were fed diets containing low (cows:11.6% CP,heifer:12.7% CP) or high (cows:14.1% CP, heifer:15.3% CP). There were no differences in dry matter intake between each group. The milk yield of cows fed a high protein diet was higher than that of cows fed a low protein diet, but recovery body weight in early lactation was delayed. Conception rate of cows fed a low protein diet was higher than fed a high protein diet, but the heifer was not influenced by prepartum treatment. Nitrogen excretion in urine and nitrogen retention of cows fed a high protein diet were significantly higher than fed a low protein diet in transition period. In pregnant cows, the nitrogen excretion in urine increases more than the nitrogen retention, whereas in cows, the nitrogen retention increases more than the nitrogen excretion. These results suggest that, 12% CP diet seems to be adequate for prepartum CP content of cows, but pregnant heifer require about 14% CP.
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