McClary D G, Green H B, Basson R P, Nickerson S C
Lilly Research Laboratories, Eli Lilly & Co., Greenfield, IN 46140.
J Dairy Sci. 1994 Aug;77(8):2261-71. doi: 10.3168/jds.S0022-0302(94)77169-1.
The lactational effect of somidobove (recombinant bST) injections on dairy cows in a full lactation was measured in 193 primiparous and 159 multiparous Holsteins. Experimental animals, distributed across six study sites, were administered a sustained-release formulation of somidobove by subcutaneous injection every 28 d beginning 36 to 49 DIM. Randomization at each site determined which of the following somidobove treatments cows received: 0 mg (control), 160 mg (primiparous only), 320 mg, 640 mg, or 960 mg (multiparous only). In addition to lactation response, cows on study were monitored for mastitis. Clinical mastitis was detected by examination of quarter foremilk at each milking. Milk from 300 of 352 cows was monitored for new IMI by routine collection and culture of duplicate quarter milk samples. Somatic cell counts were conducted on individual composite milk samples collected weekly throughout the experiment. No evidence existed of an association between somidobove administration and the incidence or duration of clinical mastitis. Furthermore, somidobove administration was not associated with an increase in new IMI or prevalence of infection by common mastitis pathogens or pathogen groups. Somatic cell counts were low in all treatment groups, but a dose-related trend was found for increased SCC in both primiparous and multiparous cows.
在193头初产荷斯坦奶牛和159头经产荷斯坦奶牛中，测定了注射生长激素释放蛋白（重组牛生长激素）对处于整个泌乳期的奶牛的泌乳效果。分布在六个研究地点的实验动物，在产犊后36至49天开始，每28天皮下注射一次生长激素释放蛋白缓释制剂。每个地点的随机分组决定了奶牛接受以下哪种生长激素释放蛋白处理：0毫克（对照）、160毫克（仅初产奶牛）、320毫克、640毫克或960毫克（仅经产奶牛）。除了泌乳反应外，还对参与研究的奶牛进行乳腺炎监测。每次挤奶时通过检查每个乳区的前奶来检测临床乳腺炎。通过常规采集和培养两份乳区牛奶样本，对352头奶牛中的300头奶牛的牛奶进行新的隐性乳房炎监测。在整个实验过程中，每周对采集的个体混合牛奶样本进行体细胞计数。没有证据表明注射生长激素释放蛋白与临床乳腺炎的发病率或持续时间之间存在关联。此外，注射生长激素释放蛋白与新的隐性乳房炎发病率增加或常见乳腺炎病原体或病原体组的感染患病率增加无关。所有处理组的体细胞计数都很低，但在初产和经产奶牛中都发现了体细胞计数随剂量增加的趋势。
