Influence of ovsynch-treatment on concentration of progesterone in blood serum and pregnancy rates after artificial insemination in cows [Einfluss einer Ovsynch-Behandlung auf die Progesteronkonzentrationen im Blutserum und Trächtigkeitsraten bei Kühen na

Abstract

Fertiliy rate in high milk-yield dairy cows, with prolonged postpartum anestrus, was investigated after treatment by Ovsynch protocol. Thirty cows with follicular cysts or unovulated follicles (around 1.2 cm in diameter), without detected estrus up to 60 days post partum, were treated by Ovsynch protocol. The date of the first GnRH injection was defined as day 0. On day 6. was given prostaglandin F2α (PGF2a) and second GnRH injection 48 h after PGF2 α (day 8). All treated cows were terminally inseminated at day 9 (without estrus detection), i.e. 12-14 h after the last GnRH injection. The blood serum progesterone concentration was determined by ELISA method, in blood samples taken from v. jugularis, at the day of AI.The blood serum concentration of progesterone on the day of AI was low in Ovsynch treated (1.8 ng/mL) and in control cows (1.5 ng/mL). Obtainedcalving rate was not significant different between treated and control cows (57:60%, respectively, p > 0.05). Our results show that Ovsynch protocol treatment can be a successful method for control of prolonged postpartum anestrus in high milk-yield cows