Can we improve fertility with nutrition or just avoid disasters?

Abstract

The relationship between nutrition and reproduction is bidirectional; that is, reproductive status alters nutrient requirements but the nutrients assimilated by the cow also alter reproductive function. Most cows in production systems are pregnant, lactating or both thus her nutrient requirements consistently exceed maintenance requirements. For this author, the relation of nutrition to fertility can be divided into: 1) initiation of cyclicity in the pre-pubertal heifer or resumption of cyclicity in the post partum cow, 2) ovulation of a competent ovum, and 3) maintenance of the embryo and fetus in a competent reproductive tract. These steps are sequential, thus resumption of cyclicity must be achieved first. The antagonism between lactation and the resumption of cyclicity is also evident in the cow. The purpose of this presentation is to outline nutrient requirements of cows relative to her reproductive status and nutritionrelated factors associated with fertility in cows with a minor focus on nutrition and fertility in bulls