Lewis G S, Caldwell D W, Rexroad C E, Dowlen H H, Owen J R
Reproduction Laboratory, US Department of Agriculture, Beltsville, MD 20705.
J Dairy Sci. 1990 Jan;73(1):66-72. doi: 10.3168/jds.S0022-0302(90)78647-X.
This study was to determine if gonadotropin-releasing hormone, human chorionic gonadotropin, or their interaction would affect pregnancy rate or milk progesterone profiles in dairy cattle. Cows and heifers eligible for first, second, and third services were assigned to four treatments: 1) saline i.m. within 5 min after AI (d 0) and saline 15 d after AI (n = 222 AI); 2) gonadotropin-releasing hormone (100 micrograms) i.m. within 5 min after AI and saline on d 15 (n = 223); 3) saline after AI and human chorionic gonadotropin (3500 IU) i.m. on d 15 (n = 196); 4) gonadotropin-releasing hormone at AI and human chorionic gonadotropin on d 15 (n = 195). Progesterone was quantified in milk samples collected twice weekly for 5 wk from all cows. Neither gonadotropin-releasing hormone, human chorionic gonadotropin, gonadotropin-releasing hormone x human chorionic gonadotropin interaction, age, nor service number affected pregnancy rate, which averaged 46.2%. Pregnancy and human chorionic gonadotropin affected milk progesterone profiles. Pregnancy maintained progesterone concentrations and human chorionic gonadotropin on d 15 increased them. This study does not support the general use of gonadotropin-releasing hormone at AI or human chorionic gonadotropin 15 d after AI as methods for enhancing pregnancy rates of dairy cattle.
本研究旨在确定促性腺激素释放激素、人绒毛膜促性腺激素或它们之间的相互作用是否会影响奶牛的妊娠率或乳中孕酮水平。符合首次、第二次和第三次输精条件的母牛和小母牛被分配到四种处理组：1）人工授精（第0天）后5分钟内肌肉注射生理盐水，人工授精后15天注射生理盐水（n = 222次人工授精）；2）人工授精后5分钟内肌肉注射促性腺激素释放激素（100微克），第15天注射生理盐水（n = 223）；3）人工授精后注射生理盐水，第15天肌肉注射人绒毛膜促性腺激素（3500国际单位）（n = 196）；4）人工授精时注射促性腺激素释放激素，第15天注射人绒毛膜促性腺激素（n = 195）。从所有母牛中每周采集两次乳样，持续5周，对乳样中的孕酮进行定量分析。促性腺激素释放激素、人绒毛膜促性腺激素、促性腺激素释放激素×人绒毛膜促性腺激素的相互作用、年龄或输精次数均不影响妊娠率，妊娠率平均为46.2%。妊娠和人绒毛膜促性腺激素会影响乳中孕酮水平。妊娠可维持孕酮浓度，第15天的人绒毛膜促性腺激素可使其升高。本研究不支持在人工授精时普遍使用促性腺激素释放激素或人工授精后15天使用人绒毛膜促性腺激素作为提高奶牛妊娠率的方法。
