提高奶牛受胎率的卵泡和黄体活动调控研究

Study on Regulating Ovarian and Luteal Activities in Improving Conception Rate in Holstein Cows

在夏季和秋季对经产荷斯坦奶牛进行定时排卵-输精程序(TAI)处理并在输精后进行HCG处理(第5d和第10d分别肌注HCG2000IU/头),另于冬季单独对自然发情人工授精母牛进行输精后HCG处理。从各季节HCG处理组及其对照组中抽取部分奶牛,在输精后第0d(输精当天)、7d、14d、和21d分别采血,以测定孕酮和雌二醇水平。所有试验牛在输精后45￣60d进行直肠妊娠检查以确定是否受胎。结果显示:夏季TAI+HCG组、TAI组、对照组母牛输精后的受胎率差异不显著(p>0.05),分别为26.67%(4/15)、16.67%(2/12)和10.71%(3/28)。秋季TAI+HCG组、TAI组、对照组情期受胎率差异也不显著(p>0.05),分别为:55.00%(11/20)、42.11%(8/19)和31.43%(11/35)。冬季HCG组和对照组的受胎率分别为63.16%(12/19)和45.00%(9/20)(p>0.05)。在夏秋冬三个季节,输精后HCG处理相应显著提高第7d、14d和21d血液中孕酮水平(p<0.05),但稍稍降低雌二醇水平(p>0.05),显著降低E2/P比值(p<0.05)。与受胎率的差异相关,秋冬季各组牛输精后血浆P水平高于(p>0.05)或(极)显著高于(p<0.01或p<0.05)夏季相应组;血浆E2水平则稍高于(p>0.05)夏季相应组。以上结果说明,TAI单独处理可以将受胎率提高约10～15个百分点;输精后单独HCG处理可以将受胎率又提高约10～15个百分点,这主要是促进黄体功能的结果,而且提高的幅度在秋冬季要高于夏季。

Postparious Holstein cows were selected to receive Timed Artificial Insemination （TAI） and post-insemination HCG treatment（on 5th and lOth day after insemination with HCG 2000IU/cow） in summer and autumn,while in winter were treated with HCG only,with appropriate numbers of non-treated control cows.Blood samples were withdrawn from HCG treated and the non-HCG treated control cows on 0th,7th, 14th and 21st day post-inseminaiton in each season for measurement of progesterone and estradiol.Conception was determined by rectal palpation between 45th to 60th day post-insemination,Conception rate（CR） for TAI＋HCG,TAI,and control cows were not statistically different in summer, being 26.67%（4/15）,16,67%（2/12） and 10.71%（3/28） respectively;nor were the parameters different （19〉0,05） in autumn, being 55,00%（11/20）, 42.11%（8/19） and 31.43%（11/35） respectively. In winter CR in HCG treated cows was 63.16%（12/19） in contrast to the 45.00%（9/20）（P〉0.05） in nontreated control cows. In all 3 seasons, HCG treatment significantly（P〈0.05） increased blood progesterone levels on 7th,14th and 2hh day postinsemination, but only slightly （P〉0.05） reduced estradiol levels, resulting significant （P〈0.05） reductions in E2/P ratio. In relation to seasonal variations in CR, progesterone levels in blood in autumn and winter were generally higher than those in summer and estradiol levels also slightly higher than summer values （P〉0.05）. These results demonstrated that CR of TAI alone was capable of increasing by10-15 percentage, and CR of post- insemination HCG treatment also increased by 10-15 percentage.