摘要
Background
Artificial insemination (AI) can serve as a powerful tool to the sheep owners for making rapid genetic progress of their flock. The AI in sheep is mostly performed using fresh semen with two reasons i) lambing rate following trans-cervical AI with frozen semen is limited by the inability of frozen-thawed sperm to transit the cervix and ii) the need of circumventing the cervical barrier through laparoscope aided intrauterine AI. Therefore, AI with frozen-thawed semen is not as widespread in sheep as it is in other domestic species. However, to get maximum benefits through the use of AI, frozen-thawed semen is a prerequisite because instead of high fertility, the short shelf life of fresh semen coupled with a limitation on the number of insemination doses achievable per unit time restricts the widespread use of individual sires. Therefore, in order to enhance lambing rate, a total of 240 trans-cervical artificial inseminations with frozen-thawed semen were performed in Bharat Merino ewes during autumn season either once in the evening (G-I, 10 h after onset of estrus, n = 100) or twice (G-II, 14 h and 22 h after onset of estrus, n = 140) i.e. once in the morning and again in the evening.
摘要译文
背景人工授精（AI）可以作为一个强大的工具，以羊为业主做他们的羊群迅速的遗传进展用冷冻精液-cervical AI通过冻融精子无力过境子宫颈和ii）绕过通过腹腔镜宫颈屏障的需要辅助宫内人工智能不限因此，AI与冷冻精液解冻不是绵羊一样普及，因为它是在国内其他speciesHowever，通过利用AI来获得最大的利益，冷冻精液解冻，因为不是高生育率的先决条件，再加上授精剂量的每单位时间实现的数目的限制的新鲜精液中的保质期短限制的广泛使用个人siresTherefore的，为了增强产羔率，共有240冷冻精液解冻跨宫颈人工授精是在美利奴巴拉特在母羊秋冬季节无论是曾经在晚上进行的（G-I，发情发病后10小时，Ñ鈥鈥）或两次（G-II，14小时和发情发作后22小时，正鈥鈥）I竐一次在早晨和再次在晚上
Davendra Kumar [1] Syed Mohammed Khursheed Naqvi [1]. Effect of time and depth of insemination on fertility of Bharat Merino sheep inseminated trans-cervical with frozen-thawed semen[J]. Journal of Animal Science and Technology, 2014,56(1)