Animal Production Department, Faculty of Agriculture (El-Shatby), Alexandria University, Alexandria, Egypt.
Theriogenology. 2011 Apr 15;75(7):1327-35. doi: 10.1016/j.theriogenology.2010.12.004. Epub 2011 Feb 4.
The correlations between some meteorological parameters and fertility data were evaluated in Barki x Rahmani crossbred ewes using the records of five consecutive years (2003-2007). Additionally, estrus detection and ultrasonic evaluation were applied on eighteen mature dry ewes during breeding and non-breeding seasons. The effect of lactation was evaluated by monitoring estrus behavior in ninety four lactating ewes from 40 to 120 d after parturition. Moreover, ultrasonography was used to identify ovarian activity in six cyclic and six acyclic non-lactating ewes. Results revealed that relative estrus occurrence and fertile mating were positively correlated (P <0.05) with high temperature and long photoperiod (conditions of summer season), and were negatively correlated (P < 0.01) with rainfall (condition of winter season). During breeding season, estrus rate, serum progesterone concentration, and diameter of largest follicle were significantly (P < 0.05) higher than those observed during the non-breeding season. Furthermore, month of parturition had a significant effect (P < 0.05) on estrus rate of lactating ewes where ewes that lambed in August, September, and October recorded higher estrus rate than those lambed in November and December. However, the lactational strength did not exert any deleterious effect on the reproductive performance of lactating ewes. In conclusion, in Egypt under subtropical conditions, Barki x Rahmani crossbred ewes exerted optimum estrus behavior and fertile mating during summer season. The reduction in estrus activity during lactation was due to the seasonal effect rather than lactational stress.
本研究利用五年（2003-2007 年）的连续记录，评估了一些气象参数与巴尔克和拉曼杂交母羊繁殖数据之间的相关性。此外，在繁殖和非繁殖季节，对 18 只成熟的干母羊进行了发情检测和超声评估。通过监测 94 只泌乳母羊产后 40-120 天的发情行为，评估了泌乳的影响。此外，对 6 只循环和 6 只非循环非泌乳母羊进行了超声检查，以确定卵巢活动。结果表明，相对发情发生和可育交配与高温和长光照期（夏季条件）呈正相关（P<0.05），与降雨（冬季条件）呈负相关（P<0.01）。在繁殖季节，发情率、血清孕酮浓度和最大卵泡直径均显著高于非繁殖季节（P<0.05）。此外，分娩月份对泌乳母羊的发情率有显著影响（P<0.05），8、9 和 10 月分娩的母羊发情率高于 11 月和 12 月分娩的母羊。然而，泌乳强度对泌乳母羊的繁殖性能没有产生任何不利影响。总之，在亚热带条件下的埃及，巴尔克和拉曼杂交母羊在夏季表现出最佳的发情行为和可育交配。泌乳期间发情活动减少是季节性的，而不是泌乳应激所致。
