Hormonal treatment and estrus synchronization in cows: A mini-review

Ashit Paul,Napolean Bunaparte,Ton Yoisungnern

doi:10.5455/javar.2015.b45

Abstract

Perfect detection of estrus is crucial for good husbandry practice of cow. Estrus synchronization is the alternative strategy to bypass the critical problem of estrus detection. Synchronization program allows fixed timed artificial inseminations (FTAI) to evade the estrus detection. The most recently developed programs include protocols for re-synchronization following first or subsequent inseminations. These re-synchronization protocols may involve selected forms of hormonal intervention during the diestrus and pro-estrus periods following FTAI, or following pregnancy diagnosis by ultrasound from 28 days after FTAI. Almost all programs involve strategically timed treatment of prostaglandin F2α (PGF) and gonadotropin releasing hormone (GnRH). Treatment of an estradiol ester and progesterone supplementation per vaginum may be included in some programs. The basic program is the “Ovsynch” regimen. This mini-review discusses a number of key points related to external hormonal stimulation on ovarian follicular wave to improve pregnancy rate following timed AI.

Highlights

The reproductive performance of high yielding cows with high genetic merit declines in many dairy industries
The same management advantages are less relevant to reproductive management where each animal must be considered as an individual within its own estrus cycle so that estrus, ovulation, insemination, fertilization and conception occur within a sequence that is within restricted behavioral and biological limits
The percentage detected in estrus from 3 to 10 days after injection increased from 81 to 98% with advancing stage of diestrus at the time of prostaglandin F2α (PGF) injection. These results clearly showed that synchronizing luteolysis did not result in the synchronized onset of estrus and ovulation

Summary

Introduction

The reproductive performance of high yielding cows with high genetic merit declines in many dairy industries. When dairy cows were injected with PGF on Day 6 of their cycles, the average interval to estrus and insemination was 3.7 days, increasing to 4.9 days for injections at Day 10 and declining to 3.4 days at Day 16 (Macmillan and Henderson, 1984).

Results

Conclusion