Evaluation of the Effect of intravenous PGF2α administration at the time of artificial insemination on conception rate of dairy cattle synchronized with heatsynch protochol

Given to the proven role of endogenous PGF2α on ovulation, the aim of the present study was to evaluate the effect of exogenous PGF2α (D-cloprostenol) administration on conception rate in a large dairy herd. Total number of 362 lactating dairy cows in Zagrous Company of Shahrekord were selected for this study in summer (From 20 August to 6 September, 2014). The estrus of all cows was synchronized by the Heatsynch protochol and following heat detection the cows were artificially inseminated according to am-pm rule. The animals were submitted to two groups; the treatment group that received 150µg D-cloprostenol intravenously at the time of AI and the control group that didn’t receive any more treatment at the time of AI. To measure the concentration of serum progesterone, blood samples were obtained from 13 cows of each group at the time of insemination and 4 and 15 days later. Pregnancy was diagnosed by rectal ultrasound examination on 35-40 days after insemination. There was no significant difference between both groups in terms of conception rate and the serum progesterone levels (P>0.05). In conclusion, this study showed no beneficial effects of intravenous administration of D-cloprostenol on conception rate of dairy cows.