Comparison of Density Gradient and Swim-up Methods on Sperm Quality and in vitro Embryo Development in Sahiwal Cows

Low blastocyst yield and conception rate following in vitro fertilization and embryo transfer is one of the major limitations. To address this issue, semen separation methods are analyzed.

The study was conducted on sahiwal donor cows and non-descript recipient cows. Frozen semen of a Sahiwal bull was used for in vitro fertilization purpose following its preparation either by density gradient method (Group-I, n=10) or by swim-up method (Group-II, n=10).

After semen separation by Group-I and Group-II, semen motility was noted to be 87.50±1.54% and 69.50±1.35%, respectively and viability was 80.70±1.43% and 57.10±2.20%, respectively. The plasma membrane intact spermatozoa was observed to be 83.80±1.47% and 61.70±1.95%, respectively and DNA fragmentation index was noted to be 5.20±0.84% and 7.80±0.59%, respectively following semen separation in Group-I and Group-II. From the ovum pick-up sessions, total 161 and 167 oocytes were aspirated in Group-I and Group-II. These oocytes were in vitro matured and in vitro fertilized using the semen sample prepared by Group-I and Group-II. On day 7^th of the in vitro culture, blastocysts conversion rate of 98 (60.87%) and 46 (27.54%) was noted Group-I and Group-II of semen separation. Following transfer of in vitro fertilized embryos by the semen sample prepared by Group-I and Group-II of semen separation, average conception rate of 27.55% (27 pregnancies) and 15.22% (7 pregnancies) had been reported.