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Estrus Detection and Synchronization of Dairy Cattle in Large Herds

The Agricultural Laboratories, The Upjohn Company, Kalamazoo, Michigan 49001

ABSTRACT

Introduction

To set the stage for this discussion I shall assume that average herd size has increased and that estrus detection has been and is a problem in large dairy herds. The following documentation is presented to substantiate this assumption.

Hodgson (5) reported total number of cows decreased by about 43%, but total number of herds decreased by about 85% over the past 20 yr in the United States. These differential rates of change have resulted in fewer herds containing greater numbers of cows. Changes in herd size are not confined to the United States. King (7) reported dairy herds in England and Wales with 50 or more cows account for 45% of the total cows as compared to 13% in 1942. While herd size has increased, number of cows per cowman has increased also (7), but man hours per cow have decreased (5).

These literature reports suggest the following question. What percent of the decrease in man hours per cow is related to decreased time spent observing cows for signs of estrus; or if less time is spent on estrus detection, is the time being used more efficiently?