SYNCHRONIZATION OF OVULATION IN POSTPARTUM SAHIWAL COWS

Abstract

Present investigation was conducted to evaluate two different Ovsynch protocols for synchronization of
ovulation in postpartum Sahiwal cows. Experimental animals (n=12) were randomly divided in to 2 groups; each
group consisted of 6 animals. Animals of group I were treated with traditional Ovsynch protocol, while animals of
group II were treated with a modified Ovsynch protocol where first GnRH injection was replaced with hCG. Treated
animals were inseminated at fixed time of 14 to 20 hrs after second GnRH injection without estrus detection.
Blood sample were collected from the experimental animals on days -10, 0, 8 and 16 of Ovsynch protocol (day60
postpartum = day O of Ovsynch protocol) to estimate serum progesterone concentrations. Animals were classified
as cyclic (n=8, P4 e" 1ng/ml) and acyclic (n=4, P4 < 1ng/m1) based on serum progesterone concentration on days
-10 and 0. Response to treatment was assessed in treated animals on the basis of progesterone concentration on
day 8 (PG treatment); 83.3% (5/6) animals responded to first GnRH treatment in group I and 100% (6/6) animals
responded to hCG treatment in group II. Two cyclic animals each from both the treatment groups got conceived to
fixed time Al giving conception rate of 40% (2/5) in group I and 33.3% (2/6) in group II. Three cyclic and 4 acyclic
animals did not conceive after responding to treatment, while one cyclic animal did not respond to first GnRH
treatment. No any beneficial effect of replacing first GnRH injection with hCG could be obtained in ovulation
synchronization and conception rate with Ovsynch protocol in Sahiwal cows during early postpartum period