Wishart D F, Young I M, Drew S B
Vet Rec. 1977 May 14;100(20):417-20. doi: 10.1136/vr.100.20.417.
Four studies are described involving 2573 Friesian heifers treated with norgestomet and oestradiol valerate to control the ovarian cycle. All treated animals were inseminated at fixed times following treatment. In study 1 insemination 48 and/or 60 hours after treatment resulted in a non-significant greater proportion of heifers becoming pregnant than at 48 X 72 hours. Large variations in fertility among farms were recorded in field trials of norgestomet (Searle) and oestradiol valerate. In study III the effect on fertility of nutrition, weight and body condition was studied. In section IV a pregnancy rate to fixed time insemination of 66-8 per cent of 500 heifers inseminated at 48 and 60 or at 48 and 72 hours after norgestomet/oestradiol valerate treatment was obtained. Heifers in study IV were fed a balanced ration designed to provide a predicted daily liveweight gain of 0-7 kg for a 12-week period starting six weeks prior to the date of insemination. The range of fertility was from 59-0 per cent to 85-7 per cent.
描述了四项研究，涉及2573头用诺孕美特和戊酸雌二醇处理以控制卵巢周期的弗里斯兰小母牛。所有接受处理的动物在处理后的固定时间进行授精。在研究1中，处理后48小时和/或60小时授精导致怀孕的小母牛比例比在48×72小时时略高，但差异不显著。在诺孕美特（ Searle）和戊酸雌二醇的田间试验中记录到各农场之间的繁殖力有很大差异。在研究III中，研究了营养、体重和身体状况对繁殖力的影响。在第四部分中，对500头在接受诺孕美特/戊酸雌二醇处理后48小时和60小时或48小时和72小时进行固定时间授精的小母牛，获得了66 - 8%的怀孕率。研究IV中的小母牛从授精日期前六周开始的12周期间，被喂食一种平衡日粮，旨在提供预测的每日体重增加0 - 7千克。繁殖力范围为59 - 0%至85 - 7%。
