Sahu S K, Cockrem J F, Parkinson T J, Laven R A
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
Aust Vet J. 2017 Aug;95(8):281-288. doi: 10.1111/avj.12611.
The aim of this research was to study the roles of the day 0 energy balance and gonadotrophin-releasing hormone (GnRH) and progesterone levels on dominant follicle (DF) and corpus luteum (CL) development during the first 7 days of a gonadotrophin-prostaglandin-gonadotrophin (GPG) + progesterone (P4) program in anoestrous dairy cows.
Cows (n = 81) were allocated to one of the three treatments: (1) GPG + P4 (days 0 and 9, 100 µg GnRH; day 0-7, intravaginal P4 device; day 7, 500 µg PGF ); (2) GPG (as for treatment 1 but excluding the P4 device) and (3) prostaglandin + GnRH + P4 (as for treatment 1, but excluding day 0 GnRH). DF and CL size, plasma concentrations of insulin, insulin-like growth factor-I (IGF-I) and non-esterified fatty acid (NEFA) were measured on days 0 and 7.
The proportion of cows with a CL on day 7 was significantly different between groups (GPG: 78%, GPG+P4: 69%, PGF + GnRH + P4: 42%, P = 0.02). The CL volume on day 7 was significantly associated with treatment, treatment by time postpartum and plasma concentrations of insulin, IGF-I and NEFA.
In cows without a CL present on day 0 of an oestrus synchronisation program, removal of the day 0 GnRH treatment led to reduced CL development; however, no effect of adding progesterone was found. In contrast, in cows with a CL present on day 0 inclusion of a progesterone device led to a higher CL volume, but removal of the first GnRH injection had no effect. Response to the treatment was affected by plasma concentrations of insulin, IGF-I and NEFA.
本研究旨在探讨在乏情期奶牛的促性腺激素 - 前列腺素 - 促性腺激素（GPG）+孕酮（P4）方案的前7天，第0天能量平衡以及促性腺激素释放激素（GnRH）和孕酮水平对优势卵泡（DF）和黄体（CL）发育的作用。
将奶牛（n = 81）分配到三种处理之一：（1）GPG + P4（第0天和第9、10天，100 μg GnRH；第0 - 7天，阴道内放置P4装置；第7天，500 μg PGF）；（2）GPG（与处理1相同，但不包括P4装置）；（3）前列腺素+ GnRH + P4（与处理1相同，但不包括第0天的GnRH）。在第0天和第7天测量DF和CL大小、胰岛素、胰岛素样生长因子 - I（IGF - I）和非酯化脂肪酸（NEFA）的血浆浓度。
第7天有CL的奶牛比例在各组之间有显著差异（GPG组：78%，GPG + P4组：69%，PGF + GnRH + P4组：42%，P = 0.02）。第7天的CL体积与处理、产后时间的处理以及胰岛素、IGF - I和NEFA的血浆浓度显著相关。
在发情同步方案第0天没有CL的奶牛中，去除第0天的GnRH处理导致CL发育减少；然而，未发现添加孕酮有效果。相反，在第0天有CL的奶牛中，放置孕酮装置导致CL体积更大，但去除首次GnRH注射没有影响。对处理的反应受胰岛素、IGF - I和NEFA的血浆浓度影响。
