Martínez Marcelo, Mapletoft Reuben J, Kastelic John P, Carruthers Terry
Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B4.
Can Vet J. 2003 Feb;44(2):125-31.
The objective was to determine luteinizing hormone (LH) secretion and follicular dynamics in cattle following administration of 3 gonadorelin formulations that are commercially available in Canada. In experiment 1, nonlactating Holstein cows (n = 4 per group) were randomly assigned to receive 100 micrograms gonadorelin diacetate tetrahydrate, intramuscularly (C; Cystorelin, or FE; Fertagyl). Blood samples (for LH analysis) were collected 0, 1, 2, and 4 hours after treatment. In experiment 2, nonlactating Holstein cows (n = 10 per group) were randomly allocated to receive 100 micrograms gonadorelin, intramuscularly as follows: 2 mL of C; 1 mL of FE; or 2 mL of Factrel (FA, gonadorelin hydrochloride). Gonadorelin treatment was done on days 6 or 7 after ovulation and blood samples for LH analysis were collected at 0, 1, 2, 4, and 6 hours after treatment. Ovaries were examined by ultrasonography, twice daily, to detect ovulation. A replicate was conducted using only C (n = 10) or FE (n = 10); blood samples were collected at 0, 1, 2, 3, and 4 hours. In experiment 3, beef heifers (n = 10 per group) were randomly assigned to receive 1 of 3 GnRH gonadorelin treatments (as in the first phase of experiment 2) on days 6 or 7 after ovulation and blood samples were collected at 0, 0.5, 1, 1.5, 2, and 4 hours. In experiments 2 and 3, both mean and mean peak plasma LH concentrations were higher (P < 0.05) in cattle treated with C. The proportion of dominant follicles that ovulated was higher (P < 0.02) in Holstein cows treated with C than in those treated with FE or FA (18/19, 11/19, and 4/7, respectively), but there was no significant difference among the products in beef heifers (6/10, 6/10, and 4/10, respectively). No significant differences were found in the interval from treatment to the emergence of the next follicular wave. In summary, C induced a greater LH release and this resulted in a higher ovulatory rate in Holstein cows but not in beef heifers.
目的是确定在加拿大市售的3种促性腺激素释放激素制剂给药后牛的促黄体生成素（LH）分泌和卵泡动态。在实验1中，将非泌乳荷斯坦奶牛（每组n = 4头）随机分配接受100微克二乙酸四水合促性腺激素释放激素，肌肉注射（C组；Cystorelin，或FE组；Fertagyl）。在处理后0、1、2和4小时采集血样（用于LH分析）。在实验2中，将非泌乳荷斯坦奶牛（每组n = 10头）随机分配接受100微克促性腺激素释放激素，肌肉注射如下：2毫升C组制剂；1毫升FE组制剂；或2毫升Factrel（FA组，盐酸促性腺激素释放激素）。在排卵后第6或7天进行促性腺激素释放激素处理，并在处理后0、1、2、4和6小时采集血样用于LH分析。每天两次通过超声检查卵巢以检测排卵。仅使用C组（n = 10）或FE组（n = 10）进行重复实验；在0、1、2、3和4小时采集血样。在实验3中，将肉用小母牛（每组n = 10头）随机分配在排卵后第6或7天接受3种促性腺激素释放激素（GnRH）处理中的1种（如实验2的第一阶段），并在0、0.5、1、1.5、2和4小时采集血样。在实验2和3中，用C组制剂处理的牛的平均和平均峰值血浆LH浓度均较高（P < 0.05）。用C组制剂处理的荷斯坦奶牛中排卵的优势卵泡比例高于用FE组或FA组处理的奶牛（分别为18/19、11/19和4/7）（P < 0.02），但在肉用小母牛中各产品之间无显著差异（分别为6/10、6/10和4/10）。在从处理到下一个卵泡波出现的间隔时间上未发现显著差异。总之，C组制剂诱导了更大的LH释放，这导致荷斯坦奶牛的排卵率更高，但在肉用小母牛中并非如此。
