| With the increased intensive and large-scale of dairy goat industry development, more and more people pay attation to the breeding techniques application and promotion, such as estrus synchronization and semen storage. These techniques can improve the quality of the goat population and facilitate management. Breeding buck has excellent genetic merits, can rapidly improve the production performance. It is significance to seek potential buck fertility for expanding coverage of high quality goats in dairy goat industry development.This research focus on dairy goat, we carry out the relevant research based on the estrus synchronization project selection, semen liquild storage and cryopreservation test, parameters of XY sperm sorting, low dose insemination with sexed semen and copy number variation of y-linked ZNF280 BY among different dairy goat breeds. The results are as follows:1. Study the effect of different estrus synchronization treatments during breeding and non-breeding seasons. The results showed that the estrus rate and duration of estrus period after the treatment 2(CIDR+300 IU PMSG+5 μg LHRH-A3) and treatment 3(CIDR+450 IU PMSG+5 μg LHRH-A3) were significantly higher than that in treatment 1(CIDR+150 IU PMSG+5 μg LHRH-A3)(P<0.05). There was no significant difference in pregnancy rate and kidding rate among these 3 treatments(P>0.05). Detection of goat blood LH during 24 h after estrus in different treatments showed that the LH peak presented at 10 h after estrus in breeding season. Study of effect of different estrus synchronization treatments on the reproductive performance of dairy goat during the breeding season showed that treatment ?(CIDR+300 IU PMSG) and treatment П(CIDR+300 IU PMSG+5 μg LHRH-A3) had positive effect on the goat pregnancy rate and kidding rate than in treatment Ш(P<0.05). 1 parity and and 2 paritywere significantly higher than that in parity 3 in each treatment(P<0.05).2. The results on the effect of seasonal changes on semen quality of Xinong Saanen dairy goats showed that the rapidly progressive motile sperm, the volume of semina, the density, sperm number of single ejaculate and plasma membrane integrity rate collected in spring, summer and autumn were significantly higher than that in winter(P<0.05), and the acrosome integrity rate in summer and autumn was significantly higher than that in spring and winter(P<0.05). Semen cryopreservation from each season and showed that the rapidly progressive motile sperm, plasma membrane integrity and acrosome integrity rate were significantly higher in summer and autumn than that in spring and winter(P<0.05).3. Study the effect of two diluents(Tris Citric acid Glucose buffer, TCG and Glucose Milk buffer, GM) for semen cryopreservation of Xinong Saanen dairy goats. It is illustrated that TCG and GM with seminal plasma was significantly more suitable to cryopreservation than that removal of seminal plasma(P<0.05). There was significant difference in acrosome integrity between TCG and GM with seminal plasma(P<0.05). The results of artificial insemination by using two kinds of diluents with seminal plasma is that both the pregnancy rate(45.9±2.06%) and kidding rate(159.6±3.25) of does in TCG were higher than that in GM(33.3±3.15%与 150±4.34%).4. Study the effect of two kinds of diluents TRIS_M and TRIS_A on semen liquid storage of Xinong Saanen dairy goats. TRIS_M and TRIS_A were stored under at 19℃ for 12 h had better results than stored in 4 ℃ and 15 ℃(P<0.05). Semen from Xinong Saanen dairy buck was diluted in TRIS_M and TRIS_A, stored in 19 ℃ and transported(10h) to sorting center. The key steps for X, Y sperm sorting(Hoechst33342 concentration and the laser intensity) were determined. The Hoechst 33342 optimal concentration is 28 μM/m L, the ultraviolet laser intensity is 6 W. After semen sorting, the results showed that the rapidly progressive motile sperm was not significantly different before and after Hoechst33342 staining(P>0.05). The rapidly progressive motile sperm was significantly higher in TRIS_M after separation and cooling than that in TRIS_A(P<0.01). The sorted sperm was cryopreserved with TCG, the rapidly progressive motile sperm of semen samples after frozen-thawed in TRIS_A was 40.3±2.3% and TRIS_M was 58.7±3.3%, and the difference between them was significant(P<0.01). When the frozen thawed sorted sperm detected the separation purity of Y sperm was 95.3±2.2% and X sperm was 95.2±1.8%(P>0.05). Plasma membrane integrity rate and acrosome intact rate of sperm X was higher than that of Y, but the difference was not significant(P>0.05).5. Carry out the artificial insemination by using of laparoscopic with the insemination low dose of 2.2×106 and 4.4×106 effective sperms, respectively. The pregnancy rates were 25% and 50%, the kidding rates were 100% and 187.5%, and the offspring sex ratio were 100% and 93.3%, respectively. The pregnancy rate was 8.3%, the kidding rate was 100%, and the offspring sex ratio were 100% by using sexed semen with AI. The safety assessment of offspring showed that the birth weight, weaning weight and gestation period were not significantly different compared with non-sex sorted offspring(P>0.05).6. Analyzed copy number variation of ZNF280 BY in Y chromosome between different breeds of bucks. ZNF280 BY in the 6 breeds showed copy number variation had non-normal distribution. The median copy number of Meigu goat was the lowest(19), Guanzhong dairy goat was the highest 151, and Xinong Saanen dairy goat was 113. It is showed that the difference of copy number among Xinong Saanen dairy goat, Guanzhong dairy goat, Laoshan dairy goat, Wendeng dairy goat and Yunnan Guishan goats were not significant(P>0.05), while the copy number of Meigu goat and other breeds were all significantly different(P<0.05).This study suggests that the estrus synchronization treatments in our study can improve estrus rate, pregancy rate and kidding rate; Spring, summer and autumn of buck semen showed high quality; the preparation of frozen semen with TCG can improve the pregancy rate and kidding rate; TRIS_M is better for semen liquid storage and X, Y sperm sorting, using sexed semen can obtain predict offspring and there is no different between the sexed offspring and non-sex sorted offspring; ZNF280 BY exist copy number variation among goat breeds and with high copy number in dairy goat. Results above can be concluded that expanding buck utilization and improve production performances establish the important scientific basis in dairy goat industry. |
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