Bartolome J, Hernandez J, Sheerin P, Luznar S, Kelbert D, Thatcher W W, Archbald L F
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Theriogenology. 2003 May;59(9):1991-7. doi: 10.1016/s0093-691x(02)01286-4.
The objective of this study was to determine the effect of pretreatment with bovine somatotropin (bST) and/or gonadotropin-releasing hormone (GnRH) 7 days prior to initiation of a protocol for synchronization of ovulation and timed insemination (Ovsynch) on conception rate (CR) of cows with ovarian cysts. A total of 254 lactating dairy cows with ovarian cysts was divided into four groups (Day 0). On Day 0, cows in Group 1 (n = 61) were pretreated with 500 mg bST, s.q., and 100 microg GnRH, i.m.; cows in Group 2 (n = 73) were pretreated with 100 microg GnRH, i.m.; cows in Group 3 (n = 59) were pretreated with 500 mg bST, s.q.; and cows in Group 4 (n = 61) received no pretreatment. All cows were subjected to the Ovsynch protocol 7 days later. All cows previously received routine bST treatment every 14 days until milk production decreased to a minimum level established by the management of the herd. CR was assessed using logistic regression after adjusting for timing of concurrent bST treatment relative to Day 0, parity, season at time of insemination, and days in milk (DIM) on Day 0. CR for cows in Group 3 (12%) was significantly lower (P < 0.05) than that for cows in Group 4 (27%), and CR for cows in Group 1 (18%) and Group 2 (15%) tended to be lower (P < 0.10) than that for cows in Group 4 (27%). From the results of this study, it was concluded that bST pretreatment decreased CR, and pretreatment with GnRH, and GnRH with bST tended to decrease CR in lactating dairy cows with ovarian cysts concurrently treated with bST and subjected to the Ovsynch protocol.
本研究的目的是确定在启动排卵同步和定时输精（Ovsynch）方案前7天，用牛生长激素（bST）和/或促性腺激素释放激素（GnRH）对患有卵巢囊肿的奶牛进行预处理对受胎率（CR）的影响。总共254头患有卵巢囊肿的泌乳奶牛被分为四组（第0天）。在第0天，第1组（n = 61）的奶牛经皮下注射500 mg bST和肌肉注射100 μg GnRH进行预处理；第2组（n = 73）的奶牛经肌肉注射100 μg GnRH进行预处理；第3组（n = 59）的奶牛经皮下注射500 mg bST进行预处理；第4组（n = 61）的奶牛未进行预处理。7天后，所有奶牛都接受Ovsynch方案。所有奶牛此前每14天接受一次常规bST治疗，直到产奶量降至牛群管理规定的最低水平。在对相对于第0天的同期bST治疗时间、胎次、输精时的季节以及第0天的泌乳天数（DIM）进行调整后，使用逻辑回归评估CR。第3组奶牛的CR（12%）显著低于第4组奶牛的CR（27%）（P < 0.05），第1组（18%）和第2组（15%）奶牛的CR低于第4组奶牛的CR（27%），但差异趋于显著（P < 0.10）。从本研究结果得出结论，在同时接受bST治疗并采用Ovsynch方案的患有卵巢囊肿的泌乳奶牛中，bST预处理降低了CR，GnRH预处理以及GnRH与bST联合预处理也趋于降低CR。
