Predicting Male Fertilizing Capacity in High and Low Fertility Strains of Chickens

FERTILITY has been shown to be highly correlated with certain semen measurements in chickens under conditions of artificial insemination (Cooper and Rowell, 1958). Their results indicate that fertility of individual cocks may be predicted relatively well from the semen measurements of motility, percentage of dead spermatozoa, and reduction time. Reduction time is a measure of metabolic activity and is accomplished by the mixing of a given amount of semen with a resazurin solution and recording the time required to reach a pink end point. The technique is described by Cooper and Rowell (1958). Density of live spermatozoa also was significantly correlated with fertility but it had less predictive value. Other studies (Parker et al, 1942; Shaffner and Andrews, 1948; Allen and Champion, 1955; and McDaniel and Craig, 1959) support various aspects of these general results. The present investigation supplies further evidence on the relative magnitude of correlations of resazurin reduction …