The School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
Anim Reprod Sci. 2013 Mar;137(3-4):129-36. doi: 10.1016/j.anireprosci.2012.12.013. Epub 2013 Jan 11.
The aim of this study was to investigate the effects on follicle stimulating hormone (FSH) secretion and dominant follicle (DF) growth, of treatment of Bos indicus heifers with different combinations of intra-vaginal progesterone releasing devices (IPRD), oestradiol benzoate (ODB), PGF2α and eCG. Two-year-old Brahman (BN; n=30) and Brahman-cross (BNX; n=34) heifers were randomly allocated to three IPRD-treatments: (i) standard-dose IPRD [CM 1.56g; 1.56g progesterone (P4); n=17]; (ii) half-dose IPRD (CM 0.78g; 0.78g P4; n=15); (iii) half-dose IPRD+300IU eCG at IPRD removal (CM 0.78g+G; n=14); and, (iv) non-IPRD control (2×PGF2α; n=18) 500μg cloprostenol on Days -16 and -2. IPRD-treated heifers received 250μg PGF2α at IPRD insertion (Day -10) and IPRD removal (Day -2) and 1mg ODB on Day -10 and Day -1. Follicular dynamics were monitored daily by trans-rectal ultrasonography from Day -10 to Day 1. Blood samples for determination of P4 were collected daily and samples for FSH determination were collected at 12h intervals from Day -9 to Day -2. A significant surge in concentrations of FSH was observed in the 2×PGF2α treatment 12h prior and 48h after follicular wave emergence, but not in the IPRD-treated heifers. Estimated mean concentrations of total plasma P4 during the 8 days of IPRD insertion was greater (P<0.001) in the CM 1.56g P4 treated heifers compared to the CM 0.78g P4 treated heifers (18.38ng/ml compared with 11.09ng/ml, respectively). A treatment by genotype interaction (P=0.036) was observed in the mean plasma P4 concentration in heifers with no CL during IPRD insertion, whereby BN heifers in the CM 1.56g treatment had greater plasma P4 than the BNX heifers on Days-9, -7, -6, -5, and -4. However, there was no genotype effect in the CM 0.78g±G or the 2×PGF2α treatment. Treatment had no effect on the DF growth from either day of wave emergence (P=0.378) or day of IPRD removal (P=0.780) to ovulation. This study demonstrates that FSH secretion in B. indicus heifers treated with a combination of IPRD's and ODB to synchronise ovulation was suppressed during the period of IPRD insertion but no significant effect on growth of the DF was observed.
本研究旨在探讨不同阴道内孕酮释放装置（IPRD）、苯甲酸雌二醇（ODB）、PGF2α 和 eCG 组合处理对促卵泡激素（FSH）分泌和优势卵泡（DF）生长的影响。2 岁婆罗门（BN；n=30）和婆罗门杂交（BNX；n=34）小母牛被随机分配到三种 IPRD 处理中：（i）标准剂量 IPRD [CM 1.56g；1.56g 孕酮（P4）；n=17]；（ii）半剂量 IPRD（CM 0.78g；0.78g P4；n=15）；（iii）半剂量 IPRD+300IU eCG 在 IPRD 去除时（CM 0.78g+G；n=14）；和（iv）非 IPRD 对照组（2×PGF2α；n=18）在第-16 和-2 天给予 500μg 氯前列烯醇。IPRD 处理的小母牛在 IPRD 插入时（第-10 天）和 IPRD 去除时（第-2 天）接受 250μg PGF2α，并在第-10 天和第-1 天接受 1mg ODB。从第-10 天到第 1 天，通过直肠超声监测卵泡动态。每天采集血液样本以测定 P4 的浓度，从第-9 天到第-2 天每隔 12 小时采集一次 FSH 测定样本。在卵泡波出现前 12 小时和出现后 48 小时，2×PGF2α 处理中观察到 FSH 浓度的显著激增，但在 IPRD 处理的小母牛中没有观察到。在 IPRD 插入的 8 天期间，CM 1.56g P4 处理的小母牛的总血浆 P4 估计平均浓度显著更高（P<0.001）（分别为 18.38ng/ml 与 11.09ng/ml）。在 IPRD 插入期间无 CL 的小母牛中观察到处理与基因型的交互作用（P=0.036），即 CM 1.56g 处理的 BN 小母牛在第-9、-7、-6、-5 和-4 天的血浆 P4 浓度高于 BNX 小母牛。然而，在 CM 0.78g±G 或 2×PGF2α 处理中没有基因型效应。从卵泡波出现的那一天（P=0.378）或 IPRD 去除的那一天（P=0.780）到排卵，处理对 DF 的生长均无影响。本研究表明，在使用 IPRD 和 ODB 组合同步排卵的印度野牛小母牛中，FSH 分泌在 IPRD 插入期间受到抑制，但对 DF 的生长没有明显影响。
