The Effect of Time and Other Factors on the Non-Return to Service Estimate of Fertility Level in Artificial Insemination of Cattle

For the successful operation of an artificial breeding unit, reliable estimates of fertility are essential. The dairyman is primarily interested in the number of services per live calf born. As a practical estimate Of the efficiency of the technique of artificial insemination, this measure of fertility is impossible to obtain for a large population. Therefore, quicker and easier methods are required. Manual pregnancy diagnosis and the non-return to service estimate are the two most logical methods available at the present time. While pregnancy diagnosis might appear to be the more useful estimate of fertility, in reality it contains most of the errors inherent in any estimate of fertility made before calving and is more difficult to obtain routinely.