Rajkumar R R, Argo C M, Rodway R G
Department of Animal Physiology and Nutrition, University of Leeds.
Vet Rec. 1989 Mar 4;124(9):215-7. doi: 10.1136/vr.124.9.215.
The administration of melatonin via intravaginal sponges is an effective method of advancing the breeding season in ewes. In the present study the fertility of melatonin-treated ewes has been compared with that of ewes induced to ovulate by conventional treatment. On June 25, 15, 15-month-old ewes (group 1) were given intravaginal implants containing melatonin in silastic tubing. On August 8, 13 similar ewes (group 2) were given Veramix sponges which were removed 12 days later, when they were given 500 iu pregnant mare's serum gonadotrophin (PMSG). Two intact raddled rams were introduced to the combined groups on August 21. The mean date of mating was September 3 +/- 1.5 for group 1 and August 21 +/- 0.2 for group 2 ewes. All the ewes in group 1 and 10 in group 2 (77 per cent) were mated. All the ewes were slaughtered approximately 50 days after mating and their reproductive tracts removed. The mean ovulation rates were 2.1 and 2.3 in groups 1 and 2, respectively. The results indicate that conception rates of 87 per cent and 61.5 per cent of ewes put to the ram were obtained in the melatonin-treated and PMSG-treated groups, respectively. At slaughter the melatonin-treated group were found to have a mean of 1.47 live fetuses per ewe put to the ram and the PMSG-treated group a mean of 1.08. It can therefore be concluded that melatonin implantation is an effective method for the advancement of seasonal breeding in anoestrous sheep, and that the fertility achieved is at least as good as that given by conventional progestogen-PMSG treatment.
通过阴道海绵体给药褪黑素是一种提前母羊繁殖季节的有效方法。在本研究中，已将经褪黑素处理的母羊的生育力与经传统处理诱导排卵的母羊的生育力进行了比较。6月25日，给15只15月龄的母羊（第1组）植入含褪黑素的硅橡胶管阴道内植入物。8月8日，给13只类似的母羊（第2组）放置维拉米克斯海绵，12天后取出，同时给它们注射500国际单位的孕马血清促性腺激素（PMSG）。8月21日，将两只未阉割的有性欲的公羊放入合并后的两组母羊中。第1组母羊的平均交配日期为9月3日±1.5天，第2组母羊为8月21日±0.2天。第1组的所有母羊和第2组的10只母羊（77%）进行了交配。所有母羊在交配后约50天被屠宰，并取出其生殖道。第1组和第2组的平均排卵率分别为2.1和2.3。结果表明，经褪黑素处理和经PMSG处理的两组母羊与公羊交配后的受孕率分别为87%和61.5%。屠宰时发现，经褪黑素处理的组每只与公羊交配的母羊平均有1.47个活胎儿，经PMSG处理的组平均有1.08个。因此可以得出结论，植入褪黑素是使季节性发情的绵羊提前繁殖季节的有效方法，并且所达到的生育力至少与传统的孕激素-PMSG处理一样好。
