Endo Natsumi, Kuroki Reimi, Tanaka Tomomi
Laboratory of Veterinary Reproduction, Tokyo University of Agriculture and Technology, Fuchu-city, Tokyo, Japan.
Anim Sci J. 2017 Oct;88(10):1506-1512. doi: 10.1111/asj.12828. Epub 2017 May 26.
The productive and reproductive characteristics of Brown Swiss (B) cross-bred cows were investigated by comparing with those of Holstein (H) cows housed in the same barn. Additionally, their hair cortisol levels were analyzed to evaluate the extent of stress experienced during dry and lactation periods. B cross-bred cows had lower milk yields and higher milk fat rates than H cows. Reproductive records showed that days from parturition to first artificial insemination (AI) in B cross-bred (n = 16) and H (n = 27) cows were not significantly different, but conception rate at first AI of B cross-bred cows tended to be higher than that of H cows. Percentage of B cross-bred cows that resumed ovarian cyclic activity within 45 days after parturition was higher than that of H cows (6/6 (100%) and 5/11 (45.5%), P < 0.05), and B cross-bred cows had higher body condition scores at that time. Hair cortisol level at 60 to 90 days after parturition in H cows increased significantly compared with in the dry period, and it was higher than that of B cows during the same period. These results suggest that B cross-bred cows experience less metabolic stress during early lactation, which may result in earlier resumption of reproductive function.
通过与饲养在同一牛舍的荷斯坦（H）奶牛进行比较，研究了瑞士褐牛（B）杂交奶牛的生产和繁殖特性。此外，还分析了它们毛发中的皮质醇水平，以评估干奶期和泌乳期所经历的应激程度。B杂交奶牛的产奶量低于H奶牛，但乳脂率高于H奶牛。繁殖记录显示，B杂交奶牛（n = 16）和H奶牛（n = 27）从分娩到首次人工授精（AI）的天数没有显著差异，但B杂交奶牛首次AI时的受孕率往往高于H奶牛。分娩后45天内恢复卵巢周期活动的B杂交奶牛百分比高于H奶牛（6/6（100%）和5/11（45.5%），P < 0.05），且此时B杂交奶牛的体况评分更高。与干奶期相比，H奶牛分娩后60至90天的毛发皮质醇水平显著升高，且同期高于B奶牛。这些结果表明，B杂交奶牛在泌乳早期经历的代谢应激较少，这可能导致生殖功能更早恢复。
