Studies On The Fertilizing Capacity Of Sex-sorted Sperm From Different Bulls

Bull semen quality was considered to be closely related to the pregnancy rate in artificialinsemination (AI) and the embryo developmental rate after in vitro fertilization (IVF). Both AI and IVFtechniques were largely dependent on the high semen fertility. In order to evaluate the fertility ofsex-sorted (sexed) frozen-thawed semen(SS) from different bulls and extensively utilize the elite bullsexed semen, the morphology and biology of the SS and normal frozen-thawed semen(NS) which camefrom different bulls were explored by the computer-assisted sperm analysis technique, the fertility of NSand SS from different bulls were examined by IVF and the pregnancy rate of AI of3bulls were alsoexamined in the same dairy farm.1、 The morphological parameters of NS and SS from different bulls were analyzed bycomputer-assisted sperm analysis(CASA). Results showed that there were significant differencesbetween the sperm motility of fresh, thawed, unsorted or sorted semen from different bulls. The spermmotility of NS was significantly higher than SS from the same bull. The quality of semen from twobulls(No.37310038and37310022) were better than other’s, it showed that the sperm motility of freshsperm（76%and75%）were higher than other bulls, the sperm motility of thawed sperm（65%and60%）,the motility of sorted sperm（48%and47%）were also higher than other bulls, and the sperm deformityrate was lower（15%and13.9%）than other bulls.2、The fertility of SS from7bulls was checked by IVF(NS as control). The results showed that:(1)The development rates of embryos produced from SS lower than those from NS;(2)The fertilizationrate of SS was lower than the NS from the same bull;(3) Embryonic cleavage rates were significantlyaffected by different bulls, the cleavage rate of SS was lower than the NS from the same bull;(4) SSresulted in fewer blastocysts than NS, but there was no significant difference on embryonic quality;(5)High rates of fertilization and blastocyst obtained from two bulls(No.37310038and37310022),indicating the high semen quality of these two bulls.3、The fertility of SS from3Holstein bulls was compared by sperm analysis, IVF and AI. Theresults shown that the cleavage rate, the blastocyst rate and ICM rate from the bull (NO.614H005042)were the highest in the three bulls; However, the pregnancy rate which was from607H08698was thehighest in the three bulls.