Remond B, Cisse M, Ollier A, Chilliard Y
Laboratoire Lactation et Elevage des Ruminants, Institut National de la Recherche Agronomique, Saint-Genès-Champanelle, France.
J Dairy Sci. 1991 Apr;74(4):1370-81. doi: 10.3168/jds.S0022-0302(91)78292-1.
Fifty-two Holstein dairy cows (27 primiparous) were used in a 2 x 2 factorial design during wk 9 to 39 of lactation to assess the effects of slow release recombinant bST (500 mg injected at 14-d intervals) and the effects of the level of energy concentrate in the diet on dairy performance. After a winter period, cows were turned out to pasture at wk 24 of lactation. During winter, cows given low concentrate (2.5 vs. 5.4 kg DM/d) ate significantly more corn silage (13.9 vs. 11.9 kg DM/d), so that treatment had no significant effect on any measured parameter. The milk yield of bST-supplemented cows increased by 2.1 kg/d (11.0%) throughout the total experimental period. The response did not differ according to parity. Milk fat content and SCC were not altered, but milk protein was lower (.8 g/kg) from cows receiving bST during winter, and lactose increased (.5 g/kg). Lactation curves of bST-supplemented cows showed a cyclic response in milk production. Gross efficiency of milk yield was improved (.18 units) by bST administration without change in diet digestibility. No difference due to bST was found in the health or reproduction of cows. Live weight change did not differ among the groups. Multiparous cows gained body condition (bST-supplemented animals gained less than controls: .1 vs. .7 point on a five-point scale; NS). Control primiparous cows gained body condition (.1 point) but bST-supplemented cows significantly lost body condition (1.4 point).
52头荷斯坦奶牛（27头初产牛）在泌乳第9至39周采用2×2析因设计，以评估缓释重组牛生长激素（每隔14天注射500毫克）以及日粮中能量精料水平对奶牛生产性能的影响。经过一个冬季后，奶牛在泌乳第24周转至牧场放牧。冬季，低精料组奶牛（2.5千克干物质/天对5.4千克干物质/天）采食的玉米青贮显著更多（13.9千克干物质/天对11.9千克干物质/天），因此该处理对任何测量参数均无显著影响。在整个试验期，补充牛生长激素的奶牛产奶量提高了2.1千克/天（11.0%）。该反应不受胎次影响。乳脂率和体细胞数未改变，但冬季接受牛生长激素的奶牛乳蛋白较低（低0.8克/千克），乳糖增加（增加0.5克/千克）。补充牛生长激素的奶牛泌乳曲线显示产奶量呈周期性反应。通过注射牛生长激素提高了产奶总效率（提高0.18个单位），而日粮消化率未改变。在奶牛的健康或繁殖方面未发现因牛生长激素导致的差异。各组间体重变化无差异。经产奶牛体况评分增加（补充牛生长激素的动物增加幅度小于对照组：在五分制评分中为0.1分对0.7分；无显著差异）。对照初产奶牛体况评分增加（0.1分），但补充牛生长激素的初产奶牛体况评分显著下降（下降1.4分）。
