Studies On Oestrus Induction On Crossbred Boer Goats In Non-breeding Season

In this experiment,the Crossbred Boer goats in Jianghuai region were induced oestrus in non-breeding season.The Crossbred Boer goats were induced oestrus with norethindrone vaginal suppository plus PMSG;and the results showed that the rate of eatrus induction were 100%,when dosage per Kg bodyweight were 5IU and 8IU PMSG, and they were significantly higher than that of 10IU,12IU and 15IU PMSG dose groups(72.22%,78.57%and 77.78%,P＜0.05),which were no significantly difference in the rate of oestrus induction(P＞0.05).When the oestrus goats were injected hCG before hybridization,there was on significantly difference in the oestrus pregnancy rate of all experiment groups.But the oestrus pregnancy rate was highest(68.75%),when PMSG dose was 8IU/KgBW.The oestrus induction rate of Crossbred bore goats was 73.53%with norethindrone vaginal suppository plus CLO and FSH.The oestrus pregnancy rate and treatment pregnancy rate of the groups injected hCG or LRH-A₃ were 58.25%,61.54%or 43.75%,44.44%,and the pregnancy rate was not significantly difference between the two groups,but was most significantly higher than the control group.The experiment results showed that there was no significantly difference in the oestrus induction rate and pregnancy rate of the Crossbred Bore goats.The experiment determined the level of E₂ and P₄ of Crossbred Boer goats in peripheral blood.The result showed that the concentration of E₂ reached its peak at the time of oestrus(119.85±1.63 pg/ml).The concentration of P₄ was high on the 10th day during the experiment(0.69±0.18 ng/ml),which was significantly different from basal level of the control group.The concentration of P₄ decreased on the oestrus and mating day,and were lower than the basal level of the control group.The experiment compered the oestrus induction effect of multiparity goats and primiparity goats.The total oestrus induction rate of multiparity goats and primiparity goats has cignificantly difference(88.41%vs 68.89%,P＜0.05),and the oestrus pregnancy rate(67.21%vs 45.16%,P＜0.05) and the treatment pregnant rate(59.42%vs 31.11%, P＜0.05) of multiparity goats and primiparity goats had highly significant difference.The effect of oestrus induction of multiparity goats and primiparity goats with two different oestrus induction scheme has no significantly difference.The experiment determined the sperm quality of ram goats,and compered the effect of sperm vigor on the pregnancy rate of oestrus goats.When the sperm vigor were 0.5,0.6,0.7,0.8,the pregnancy rate of the Crossbred Boer goats were 51.28%,68.00%,61.54%and 64.29%,which were not significantly different among these four groups,but were significantly higher than the group when the sperm motility was 0.4(33.33%,P＜0.05).The total treatment pregnancy rate of Crossbred Boer goats with two scheme has no significantly difference.But the treatment pregnancy rate of 5IU/KgBW and 8IU/KgBW groups were significantly different from those of 10IU/KgBW,I2IU/KgBW and 15IU/KgBW groups,and were significantly different from the treatment pregnancy rate of experiment goats with norethindrone vaginal suppository plus CLO and FSH.It was included that the best scheme of oestrus induction for the Crossbred Boer goat in non-breeding season was to treat the goats with norethindrone vaginal suppository plus lower does of PMSG.