Heritability of Semen Quantity, Concentration and Motility in White Rock Roosters, and Their Genetic Correlation with Rate of Gain

MALE fertility, by virtue of its influence on net chick production per laying hen, and hence on chick costs, is of considerable importance in broiler production. A number of papers have been published indicating a positive relationship between semen characteristics and fertility in artificial insemination (for reviews see Lorenz, 1959; Smyth and Jeffrey, 1960; and Lake, 1962). It has also been shown that a slight positive correlation may exist between semen characteristics and fertility in natural mating as well (McDaniel and Craig, 1959; Soller et al., 1965; Szumowski, 1963). It is of interest, therefore, to estimate the heritability of various semen traits. Such estimates will provide information on the possibility of improving semen characteristics, and hence fertility, by selection. In view of the strong selection for rate of gain carried out in broiler lines, it is also of interest to estimate the genetic correlation between semen characteristics and rate of…