Reproductive endocrinology of the cow: Part 2

Superovulation

Abstract

In Part 1 the intricate hormonal relationships involved in the bovine estrous cycle were described. The widespread growth of the embryo transfer industry has made manipulation of reproductive events of both donors and recipients a commonplace practice in reproductive programs. This article presents a review of the various methods used to produce a superovulatory response in cows and the basic endocrinological changes which allow this response to occur.

Superovulation can be defined as the increased ovulatory response induced in an individual above the normal range of ovulation rates for that individual. In cattle, therefore, three or more ovulations are considered as superovulatory responses.