DeNicolo G, Morris S T, Kenyon P R, Morel P C H, Parkinson T J
College of Sciences, Massey University, Palmerston North, New Zealand.
Anim Reprod Sci. 2008 Dec;109(1-4):124-33. doi: 10.1016/j.anireprosci.2007.10.012. Epub 2007 Nov 9.
The effects of melatonin implants on out-of-season breeding in New Zealand Romney composite ewes, was determined by comparison of reproductive performance in ewes treated with progesterone+equine chorionic gonadotrophin (eCG) (control; n=107), melatonin+progesterone+eCG (n=97) or melatonin+progesterone (n=96). Conception rates in melatonin+progesterone+eCG-treated ewes (67%) were higher than in the control ewes (P<0.01; 47%). Pregnancy rates were higher in melatonin+progesterone+eCG-treated ewes (55%; P<0.001) compared with the control ewes (40%). Fewer melatonin+progesterone-treated ewes displayed oestrus (14%; P<0.001) and subsequently became pregnant (6%). Oestrus rates in melatonin+progesterone-treated ewes (14%) were lower than both the melatonin+progesterone+eCG-treated (82%) and control ewes (86%; P<0.001), which were similar to each other. The number of foetuses per pregnant ewe was similar in all three treatment groups. Serum melatonin concentrations at Day -9 were higher in the ewes treated with melatonin and there was a large variation between individual ewes, but concentrations were similar for pregnant and nonpregnant ewes. The combination of higher conception rate and the trend for more lambs per pregnant ewes resulted in more lambs being born per ewe treated in melatonin+progesterone+eCG-treated ewes compared to the other two treatment groups. These results suggest that melatonin implants, in conjunction with administration of progesterone and eCG, may be suitable as a means of increasing the number of lambs born per ewe treated in an out-of-season breeding program in New Zealand sheep flocks while melatonin and progesterone is not.
通过比较用孕酮 + 马绒毛膜促性腺激素（eCG）处理的母羊（对照组；n = 107）、褪黑素 + 孕酮 + eCG 处理的母羊（n = 97）或褪黑素 + 孕酮处理的母羊（n = 96）的繁殖性能，确定了褪黑素植入物对新西兰罗姆尼杂交母羊非繁殖季节配种的影响。褪黑素 + 孕酮 + eCG 处理的母羊的受孕率（67%）高于对照母羊（P<0.01；47%）。与对照母羊（40%）相比，褪黑素 + 孕酮 + eCG 处理的母羊的妊娠率更高（55%；P<0.001）。接受褪黑素 + 孕酮处理的母羊发情的较少（14%；P<0.001），随后怀孕的也较少（6%）。接受褪黑素 + 孕酮处理的母羊的发情率（14%）低于接受褪黑素 + 孕酮 + eCG 处理的母羊（82%）和对照母羊（86%；P<0.001），而后两者彼此相似。所有三个处理组中每只怀孕母羊的胎儿数量相似。在第 -9 天，接受褪黑素处理的母羊血清褪黑素浓度较高，且个体母羊之间存在很大差异，但怀孕母羊和未怀孕母羊的浓度相似。与其他两个处理组相比，褪黑素 + 孕酮 + eCG 处理的母羊受孕率较高，且每只怀孕母羊产羔数有增加的趋势，导致每只处理母羊所产羔羊数更多。这些结果表明，在新西兰羊群的非繁殖季节配种计划中，褪黑素植入物与孕酮和 eCG 联合使用，可能适合作为增加每只处理母羊产羔数的一种方法，而褪黑素和孕酮则不适合。
