OVULATION SYNCHRONISATION FOR IMPROVING FERTILITY IN POSTPARTUM DAIRY COWS

Abstract

The aim of the study was to evaluate the different ovulation synchronisation protocols for improving fertility in postpartum dairy cows. The work was conducted in 28 lactating crossbred cows at University Livestock Farm, Mannuthy starting on day 40 postpartum (day 0) in three experimental and one control group comprising seven cows each.The cows in Group I (Ovsynch group) were administered GnRH on day 0 followed by PGF2á on day 7 and a second dose of GnRH on day 9. Cows in Group II (Doublesynch group) were administered PGF2á on day 0, GnRH on day 2, a second PGF2á on day 9 and a second GnRH on day 11. Cows in Group III (CIDR group) were inserted with CIDR followed by administration of GnRH on day 0. The CIDR insert was removed and PGF2á administered on day 7 and a second dose of GnRH on day 9. Timed artificial insemination (TAI) was performed 18 h after the second GnRH injection in all experimental groups. Cows in Group IV (Control group) that showed natural postpartum oestrus after day 0 were inseminated at detected oestrus. Pregnancy diagnosis was conducted 45 days post AI by transrectal palpation. The first service conception rate in animals of groups I to IV were 42.86, 28.57, 42.86, 28.57 per cent and the overall conception rates were 71.43, 71.43, 85.71, 57.14 per cent, respectively. The results demonstrated that the CIDR progesterone insert protocol with highest overall conception rate was superior to Ovsynch and Doublesynch protocols. However, Ovsynch and Doublesynch protocol had better overall conception rates than control. Hence it is recommended that ovulation synchronisation protocols viz., Ovsynch, Doublesynch and CIDR can be effectively employed for improving the fertility in post partum dairy cows.

Keywords

• ovulation synchronisation
• post partum dairy cows