de Morais J P G, da S Cruz A P, Minami N S, Veronese L P, Del Valle T A, Aramini J
Departamento de Biotecnologia Vegetal e Animal, Universidade Federal de São Carlos, Campus Araras, Araras, SP 13600-970, Brazil.
Fundação de Apoio Institucional (FAI), Campus São Carlos, São Carlos, SP 13565-905, Brazil.
J Dairy Sci. 2017 Jul;100(7):5945-5956. doi: 10.3168/jds.2016-11965. Epub 2017 Apr 27.
The objectives of this controlled study were to compare the effects of 2 different formulations of recombinant bovine somatotropin (rbST) on milk yield, milk composition (fat and protein), milk somatic cell count, and body condition score (BCS) among dairy cattle in a large commercial herd. Regulatory approved 500-mg zinc sesame oil base rbST (ZSO-rbST; Elanco Animal Health, Greenfield, IN) and vitamin E lecithin base rbST (VEL-rbST; LG Life Sciences, Seoul, South Korea) formulations were administered per the manufacturers' recommendations every 14 d over 17 injection cycles starting at 57 to 70 d of lactation (90 cows per rbST group). Control cows (n = 60) received no rbST. Somatotropin-treated animals (VEL-rbST and ZSO-rbST combined) had increased average milk yield and protein percentage and lower average BCS compared with control cows. For primiparous cows, average milk yield was 37.75 kg/d with the ZSO-rbST treatment and 35.72 kg/d with the VEL-rbST treatment. For multiparous cows, average milk yield was 40.13 kg/d with the ZSO-rbST treatment and 38.81 kg/d with the VEL-rbST treatment. There were no differences in milk fat percentage between VEL-rbST and ZSO-rbST treatments, but milk protein content was greater with VEL-rbST treatment than with ZSO-rbST treatment. Nonetheless, cows treated with ZSO-rbST yielded more kilograms of fat and protein per day than cows treated with VEL-rbST. No significant differences in BCS were found between both rbST treatment groups. The differential increase in milk yield between cows treated with ZSO-rbST and VEL-rbST was driven by rbST response differences both within the 14-d cycle and throughout the 17 injection cycles. The cows treated with VEL-rbST demonstrated a more variable 14-d milk yield response curve, with more pronounced valleys between injections compared with the ZSO-rbST formulation. In addition, only the ZSO-rbST treatment was effective in modifying the lactation persistency compared with control cows. Compared with the VEL-rbST formulation, the ZSO-rbST formulation yielded more kilograms of milk, fat, and protein with less milk variation throughout the seventeen 14-d lactation cycles for both primiparous and multiparous cows.
这项对照研究的目的是比较两种不同配方的重组牛生长激素（rbST）对大型商业牛群中奶牛的产奶量、牛奶成分（脂肪和蛋白质）、牛奶体细胞计数和体况评分（BCS）的影响。按照制造商的建议，在泌乳57至70天开始的17个注射周期内，每14天给奶牛注射一次已获监管部门批准的500毫克芝麻油基rbST（ZSO-rbST；美国礼来动物保健公司，印第安纳州格林菲尔德）和维生素E卵磷脂基rbST（VEL-rbST；韩国LG生命科学公司）配方（每个rbST组90头奶牛）。对照奶牛（n = 60）不接受rbST注射。与对照奶牛相比，接受生长激素治疗的动物（VEL-rbST和ZSO-rbST合并）平均产奶量和蛋白质百分比增加，平均BCS降低。对于初产奶牛，ZSO-rbST处理组的平均产奶量为37.75千克/天，VEL-rbST处理组为35.72千克/天。对于经产奶牛，ZSO-rbST处理组的平均产奶量为40.13千克/天，VEL-rbST处理组为38.81千克/天。VEL-rbST和ZSO-rbST处理组之间的乳脂百分比没有差异，但VEL-rbST处理组的牛奶蛋白质含量高于ZSO-rbST处理组。尽管如此，ZSO-rbST处理的奶牛每天产的脂肪和蛋白质千克数比VEL-rbST处理的奶牛多。两个rbST处理组之间的BCS没有显著差异。ZSO-rbST和VEL-rbST处理的奶牛产奶量的差异增加是由14天周期内以及整个17个注射周期内rbST反应差异驱动的。与ZSO-rbST配方相比，VEL-rbST处理的奶牛表现出更可变的14日产奶量反应曲线，注射之间的低谷更明显。此外，与对照奶牛相比，只有ZSO-rbST处理在改变泌乳持续性方面有效。与VEL-rbST配方相比，对于初产和经产奶牛，在整个17个14天的泌乳周期中，ZSO-rbST配方产奶量、脂肪和蛋白质的千克数更多，且牛奶变化更小。
