Merino and crossbred ewes were used to evaluate whether previously ram exposure In late winter could improve the response to further progestagen oestrus synchronization treatment in terms of luteal function and fertilization rate. Fifty-six adult Merino and crossbred ewes were used randomly and allocated in two groups: control (C; n= 27) and male effect (ME; n= 29). All ewes had been isolated from rams for at least 2 months. On the 20th of February and for 5 days (DO-D5), 15 males-were introduced into ME group to induce male effect. Oestrous synchronization of animals from both groups began on D20 by the introduction of vaginal sponges containing 40 mg of FGA for 12 days and the administration of 500IU of eCG on the day of sponge withdrawal (D32). Cervical. AI with refrigerated semen (400 x 10~6 spz) was performed 55 h (D34) after sponge withdrawal. Progesterone levels were measured by RIA on blood samples collected twice a week for two weeks before DO, and on days 0, 3,5,12,20, 27, 32, 34,42 and 52 for ovarian activity evaluation. Blood samples were also collected each 4 hours, during 24 hours, starting 44 hours after sponge withdrawal to identify LH preovulatory surge in 5 animals of each group. On ME group the number of cycle ewes on D12 and D20 was significantly (P< 0.05) higher than on DO. On D12, the number of cyclic ewes on ME group was significantly (P< 0.05) higher than, in C group. There were no differences between both groups for the number of ewes lambing and hot lambing, as well as for the number of ewes lambing as a result of AI or natural service.Introduction of rams enhanced the number of ewes cycling but this advantage relatively to the control did not last until the synchronisation treatment.In spite of this stimulatory effect of rams on ovarian activity, it was not enough to improve the lambing rate achieved at the end of the essay probably because the number of acyclic animals at synchronisation treatment was higher than cyclic ewes. It was concluded that when ewes of this region are in deep anoestras they do not respond favourably to the ram effect and no improvements on fertility are expected to occur.
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机译：美利奴羊和杂交母羊被用来评估是否先前公羊曝光在晚冬能提高黄体功能和受精率方面进一步孕激素发情同步治疗的反应。五十六个成年美利奴和杂交母羊随机使用，并且在两组分配：对照组（C; N = 27）和男性效应（ME; N = 29）。所有母羊已经从公羊隔离至少2个月。在2月和5天（DO-D5），15名20男性-引入ME组以诱导雄性效果。从两组动物的动情同步通过引入含12天40毫克FGA和ECG的500IU的海绵上撤回（D32）的日给药阴道海绵的开始D20。颈椎。 AI与冷藏精液（400×10 -6 SPZ）进行海绵停药后55 H（D34）。孕酮水平通过RIA测定DO上之前，每周两次收集两周血样，并在0天，第3,5,12,20，27，32，34,42和52，用于卵巢活性评价。血液样本还收集各4个小时，在24小时期间，在开始撤回海绵44小时后，以确定在每组5只动物的排卵前LH激增。上ME组上D12和D20周期母羊的数目是显著（P <0.05）比DO更高。上D12，环状母羊上ME组数为显著（P <0.05）高于，在C组。有两组之间对于母羊产羔和热产羔的数量母羊产羔增强的母羊循环的数量AI或公羊的天然service.Introduction的结果的数目这个优点没有差异，以及为但相对于控制并没有持续，直到同步treatment.In尽管对卵巢活动的公羊这种刺激作用，这是不够的，提高在文章的结尾可能是因为非循环动物在同步治疗的人数明显高于取得的产羔率循环母羊。得出的结论是，当该区域的母羊在深anoestras他们并不赞成这一冲压效应作出反应，预计对生育没有改善发生。
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