Ninpetch Nattapong, Badrakh Dagvajamts, Kawano Kohei, Yanagawa Yojiro, Nagano Masashi, Katagiri Seiji
Laboratory of Theriogenology, Department of Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
Laboratory of Theriogenology, Department of Clinical Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
J Reprod Dev. 2022 Jun 1;68(3):209-215. doi: 10.1262/jrd.2021-142. Epub 2022 Feb 28.
Factors associated with high milk production levels have been linked to alterations in the endometrial epidermal growth factor (EGF) profile, a cause of reduced fertility in dairy cows. Therefore, we examined the leptin system that connects nutritional status and reproduction in dairy cattle related to reduced fertility in repeat breeder cows. Plasma leptin concentrations were measured in 18 heifers, 20 high-yielding control cows, and 26 repeat breeder cows, showing an altered EGF profile. Then, all repeat breeder cows were infused with seminal plasma (SP) into the vagina at the next estrus to normalize the EGF profile, while heifers and control cows were infused with vehicle alone. All animals were examined for EGF profiles. Eighteen repeat breeder cows, nine heifers, and nine control cows were also determined for leptin receptor (Ob-R) expression levels in the estrous cycle before and after the infusion. SP normalized the EGF profile in 53.8% of the repeat breeder cows. Leptin concentrations were similar in all groups, regardless of the treatment results for the EGF profile. In contrast, Ob-R levels in repeat breeder and control cows were similar and higher than those in heifers before SP treatment. Ob-R in repeat breeders showing a normal EGF profile after treatment decreased to an intermediate level between heifers and control cows and may provide a clue to take measures against repeat breeding in dairy cows.
与高产奶量相关的因素已被认为与子宫内膜表皮生长因子（EGF）谱的改变有关，这是奶牛繁殖力下降的一个原因。因此，我们研究了与屡配不孕奶牛繁殖力下降相关的、连接营养状况和繁殖的瘦素系统。对18头小母牛、20头高产对照奶牛和26头EGF谱改变的屡配不孕奶牛测量了血浆瘦素浓度。然后，在下一个发情期，给所有屡配不孕奶牛经阴道注入精浆（SP）以使EGF谱正常化，而小母牛和对照奶牛只注入赋形剂。检查了所有动物的EGF谱。还测定了18头屡配不孕奶牛、9头小母牛和9头对照奶牛在注入前后发情周期中的瘦素受体（Ob-R）表达水平。SP使53.8%的屡配不孕奶牛的EGF谱正常化。无论EGF谱的处理结果如何，所有组中的瘦素浓度相似。相比之下，屡配不孕奶牛和对照奶牛中的Ob-R水平相似，且高于SP处理前小母牛中的Ob-R水平。处理后EGF谱正常的屡配不孕奶牛中的Ob-R降至小母牛和对照奶牛之间的中间水平，这可能为采取措施防治奶牛屡配不孕提供线索。
