PROGESTERONE CONCENTRATIONS OF PREGNANT REPEAT BREEDER COWS FOLLOWING POST INSEMINATION PRID and GnRH TREATMENTS
Ergene Osman, Alaçam Erol
The objective of this study is to determine the effects of application of progesterone (PRID) and GnRH injection after artificial insemination on serum progesterone concentrations in the pregnant repeat breeder cows. In this experiment, 45 repeat breeder Holstein cows were divided into 3 treatment groups. In group I, repeat breeder cows received an injection of GnRH on day 12 after artificial insemination. In group II, repeat breeder cows received a PRID from day 4 to day 11 and in group III, materials received a PRID from day 11 to day 18. Before and 7 days after the treatments, and on 21 days after artificial insemination blood samples were obtained from all treated cows to assay serum progesterone concentrations. In control group 15 repeat breeder cows did not receive any treatment. After artificial insemination, blood samples were periodically obtained from all control repeat breeder cows to assay serum progesterone concentrations.. Pregnancy rates were %20 in group I, %26,6 in group II, %40 in group III and %20 in group IV. There were no significant differences between four groups (P>0.05). In all treatment groups progesterone concentration of pregnant repeat breeder cows are numerically greater than the progesterone concentration of pregnant repeat breeder cows in control group. In conclusion, serum progesterone concentrations of pregnant repeat breeder cows were numerically higher in treatment groups. But the treatments did not improve pregnancy rates in repeat breeder cows.
Key words: Cow, Repeat breeder, PRID, GnRH