INDUCTION OF FERTILE OESTRUS USING PROGESTERONE RELEASING INTRAVAGINAL DEVICE (PRID) IN JERSEY CATTLE

MOHAMAD BIN NGAH

SUMMARY

This study was conducted to determine the effect of Progesterone Releasing Intravaginal Device (PRID) (Abbott Laboratories) on conception rate of Jersey cattle following fixed time insemination. Sixty-two Jersey cows were allotted into: Group I - Control females (n : 31 ) received no steroid (PRID) treatment but were heat checked twice daily at 7 am and 7 pm. Animals in standing oestrus were inseminated once in the 25-day trial, 8-12 hr after detected oestrus. Group 2 - Females (n : 31) were implanted with PRID for 12 days. Oestrus detection was done similarly as in Group 1, however, females were inseminated once at 54 hr following PRID removal. Frozen semen from the same bull diluted at 50 x 106 sperm/dose in 0.25 ml French straw were used in both groups. Pregnancy was determined per rectum 60 days after breeding. The overall pregnancy rates of PRID-treated and control animals were 65% and 55%, respectively. The rate of PRID loss or rejection during the trial was 6.5 percent. This study demonstrates that fertile oestrus can be induced by using PRID as an agent for synchronization, particularly, cows with palpatable CL. The satisfactory conception rate following fixed time insemination at 54 hr poost-PRID removal eleviate the need for oestrus detection.

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