Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz 71345, Iran.
Animal. 2012 Aug;6(8):1253-60. doi: 10.1017/S1751731112000043.
This study investigated the relationships of thyroid hormones, serum energy metabolites, reproductive parameters, milk yield and body condition score with the different patterns of postpartum luteal activity in the postpartum period. A total of 75 multiparous healthy (free of detectable reproductive disorders) Holstein dairy cows (mean peak milk yield = 56.5 ± 7.0 kg/day) were used in this study. Transrectal ultrasound scanning and blood sample collection were performed twice weekly. Serum concentrations of progesterone (P4) were measured twice weekly and beta-hydroxybutyrate (BHBA), non-esterified fatty acids, thyroxine (T4), 3,30,5-tri-iodothyronine (T3), free thyroxine (fT4) and free 3,30,5-tri-iodothyronine (fT3) were measured every 2 weeks from the 1st to the 8th week postpartum. On the basis of the serum P4 profile of the cows, 25 (33.4%) had normal luteal activity (NLA), whereas 30 (40%), 10 (13.3%), 6 (8%) and 4 (5.3%) had prolonged luteal phase (PLP), delayed first ovulation (DOV), anovulation (AOV) and short luteal phase, respectively. Serum T4 concentrations in PLP cows were higher than that in NLA cows at the 3rd week postpartum and did not change during the period of study, whereas in the NLA cows the concentrations increased (P < 0.05). Further, the least square (LS) mean of serum fT4 concentrations in the DOV and AOV cows were significantly lower than in the NLA cows during the study period (P < 0.05). In addition, the AOV cows had higher LS mean serum BHBA and T4 concentrations than the NLA cows in early weeks postpartum (P < 0.05). In conclusion, the serum thyroid hormones' profile differs in high-producing dairy cows showing PLP, AOV and DOV in comparison with the postpartum NLA cows.
本研究旨在探讨甲状腺激素、血清能量代谢物、生殖参数、产奶量和体况评分与产后黄体活动不同模式之间的关系。本研究共使用了 75 头经产健康（无明显生殖障碍）荷斯坦奶牛（平均产奶高峰为 56.5 ± 7.0 kg/天）。每周进行两次直肠超声扫描和采血。每周两次测量血清孕酮（P4）浓度，每隔两周测量一次血清β-羟丁酸（BHBA）、非酯化脂肪酸、甲状腺素（T4）、3,30,5-三碘甲状腺原氨酸（T3）、游离甲状腺素（fT4）和游离 3,30,5-三碘甲状腺原氨酸（fT3），从产后第 1 周到第 8 周。根据奶牛血清 P4 谱，25 头（33.4%）具有正常黄体活动（NLA），30 头（40%）、10 头（13.3%）、6 头（8%）和 4 头（5.3%）分别具有延长黄体期（PLP）、延迟首次排卵（DOV）、无排卵（AOV）和黄体期短。产后第 3 周，PLP 奶牛的血清 T4 浓度高于 NLA 奶牛，且在研究期间没有变化，而 NLA 奶牛的浓度则有所增加（P < 0.05）。此外，在研究期间，DOV 和 AOV 奶牛的血清 fT4 浓度的最小二乘（LS）均值明显低于 NLA 奶牛（P < 0.05）。此外，与 NLA 奶牛相比，AOV 奶牛在产后早期具有更高的 LS 均值血清 BHBA 和 T4 浓度（P < 0.05）。综上所述，与产后 NLA 奶牛相比，表现出 PLP、AOV 和 DOV 的高产奶牛的血清甲状腺激素谱存在差异。
