Butler S A A, Phillips N J, Boe-Hansen G B, Bo G A, Burns B M, Dawson K, McGowan M R
The School of Veterinary Science, The University of Queensland, Gatton, Qld, Australia.
Reprod Domest Anim. 2012 Jun;47(3):463-71. doi: 10.1111/j.1439-0531.2011.01905.x. Epub 2011 Oct 3.
The primary objective of this study was to investigate the impact of animal-level factors including energy balance and environmental/management stress, on the ovarian function of Bos indicus heifers treated to synchronize ovulation. Two-year-old Brahman (BN) (n = 30) and BN-cross (n = 34) heifers were randomly allocated to three intravaginal progesterone-releasing device (IPRD) treatment groups: (i) standard-dose IPRD [Cue-Mate(®) (CM) 1.56 g; n = 17]; (ii) half-dose IPRD [0.78 g progesterone (P(4)); CM 0.78 g; n = 15]; (iii) half-dose IPRD + 300 IU equine chorionic gonadotrophin at IPRD removal (CM 0.78 g + G; n = 14); (iv) and a control group, 2× PGF(2α) [500 μg prostaglandin F(2α) (PGF(2α))] on Day -16 and -2 (n = 18). Intravaginal progesterone-releasing device-treated heifers received 250 μg PGF(2α) at IPRD insertion (Day -10) and IPRD removal (Day -2) and 1 mg oestradiol benzoate on Day -10 and -1. Heifers were managed in a small feedlot and fed a defined ration. Ovarian function was evaluated by ultrasonography and plasma P(4) throughout the synchronized and return cycles. Energy balance was evaluated using plasma insulin-like growth factor 1 (IGF-I) and glucose concentrations. The impact of environmental stressors was evaluated using plasma cortisol concentration. Heifers that had normal ovarian function had significantly higher IGF-I concentrations at commencement of the experiment (p = 0.008) and significantly higher plasma glucose concentrations at Day -2 (p = 0.040) and Day 4 (p = 0.043), than heifers with abnormal ovarian function. There was no difference between the mean pre-ovulatory cortisol concentrations of heifers that ovulated or did not ovulate. However, heifers that ovulated had higher cortisol concentrations at Day 4 (p = 0.056) and 6 (p = 0.026) after ovulation than heifers that did not ovulate.
本研究的主要目的是调查包括能量平衡以及环境/管理应激等动物层面因素，对接受排卵同步处理的印度瘤牛小母牛卵巢功能的影响。将两岁的婆罗门牛（BN）（n = 30）和婆罗门杂交牛（n = 34）小母牛随机分配到三个阴道内孕酮释放装置（IPRD）处理组：（i）标准剂量IPRD [Cue-Mate(®)（CM）1.56 g；n = 17]；（ii）半剂量IPRD [0.78 g孕酮（P₄）；CM 0.78 g；n = 15]；（iii）半剂量IPRD + 在取出IPRD时注射300 IU马绒毛膜促性腺激素（CM 0.78 g + G；n = 14）；（iv）以及一个对照组，在第-16天和-2天注射2×PGF₂α [500 μg前列腺素F₂α（PGF₂α）]（n = 18）。接受阴道内孕酮释放装置处理的小母牛在插入IPRD时（第-10天）和取出IPRD时（第-2天）接受250 μg PGF₂α，并在第-10天和-1天接受1 mg苯甲酸雌二醇。小母牛在一个小型饲养场中饲养，并饲喂特定日粮。在整个同步周期和返情周期中，通过超声检查和血浆P₄评估卵巢功能。使用血浆胰岛素样生长因子1（IGF-I）和葡萄糖浓度评估能量平衡。使用血浆皮质醇浓度评估环境应激源的影响。卵巢功能正常的小母牛在实验开始时IGF-I浓度显著更高（p = 0.008），在第-2天（p = 0.040）和第4天（p = 0.043）血浆葡萄糖浓度显著更高，高于卵巢功能异常的小母牛。排卵或未排卵的小母牛排卵前平均皮质醇浓度之间没有差异。然而，排卵的小母牛在排卵后第4天（p = 0.056）和第6天（p = 0.026）的皮质醇浓度高于未排卵的小母牛。
