The effect of semen age on conception rate

Abstract

1. The relationship of semen age to conception rate was studied at two artificial-insemination centres and a subcentre of one of these. Data relating to 50,213 first inseminations were included in the analysis.2. It is shown that external conditions can affect the rate of decrease of conception rate with semen age.3. Records giving c.r.'s for each day of semen age may reveal centre differences that cannot be detected in records giving mean c.r.'s only.4. Information may be lost if data are grouped by months rather than recorded by collections.5. The rate of decrease should not be used for comparing centres until the various factors affecting it (e.g. breed differences) are more fully understood. Further investigations should not be limited to one centre.