Study On The Technique Of Boar Semen Freezing And Application

It is known that boar semen differs in several aspects from the semen of other domesticanimals. Boar sperm are very susceptible to cold shock. So it is difficult to produce and operateduring boar sperm freezing. And the application and development of the boar sperm freezingsystem were limited. However, the technique of boar semen freezing is important to be used incommercial breeding to reduce generation intervals, to produce genetically improved pigs and toprotect some fine sires. Moreover, the technique of boar semen freezing combined with in vitrofretilization and artificial inseminaton, can providedmany well embryos to biotechnology andanimal production. So it is important to study further on the technology and mechanism of boarsperm cryopreservation, to investigate the factors influencing on frozen sperm motility and fertility,optimizing the method of boar sperm freezingsystem.In order to improve the thawed sperm quality and make the cryopreserved sperm available inSwine industry, the effects of Equex. STM, different extenders and freezing system on boar spermcryopreservation were studied. Thawed sperm quality evaluated by motility, acrosome integrity; invitro fertilization (IVF) and artificial insemination (AI) result. Ejaculated semen was collected bythe gloved-hand method from healthy adult boars, sperms were diluted in two steps by differentextenders and with or without Equex.STM froze by dropping on dry ice or on copper mesh whichwere cooled by liquid nitrogen. The first extender was better than the others. The thawed motilityand acrosome integrity of sperms frozen by dry ice or by liquid nitrogen was 48.8±4.7％and78.2±4.0％or was 33.3±5.6％and 55.84±6.8％, both the thawed motility and acrosome integrity ofsperm frozen by dry ice is significantly higher (P＜0.05) than the sperms frozen by liquid nitrogen.The thawed sperm acrosome integrity percentage in extender with or without Equex.STM was79.54±2.8％, and 57.94±7.7％, respectively. Extender with Equex.STM improved the acrosomeintegrity significantly (P＜0.01). Improved the in vitro maturation system of porcine oocytethrough adding 10％PFF and 10％FCS .Thawed sperms from exterder with Equex.STM and frozeby dry ice were used to do IVF, the cleavage rate and blastocyst rate was 53.24±1.3％, 21.6±5.3％respectively. And the thawed sperms from extender with Equex.STM and froze by dry ice wereused to do low-dose artificial insemination, intrauterine insemination in 50 million sperms can be tosucceed in pregnancy, the litter size was 6; in 100 million sperms the litter size was 9. These resultsindicated The first extender, Equex.STM and dry ice freezing system can provide high quality frozen sperms.