Investigation of factors controlling fertility in Japanese quail (Coturnix japonica)

[Truncated abstract] Japanese quail breeding and production has been focused on increasing meat and egg yield but less attention has been paid to improvement of reproductive performance, in particular, fertility. The aims of this study were to determine true fertility of commercial quail over the production span, to estimate the contribution of each sex to egg fertility, and to identify fertility traits that, through selection, could be used to improve egg fertility. The general hypothesis driving this study was that the reproductive performance of Japanese quail could be improved by improving male and female fertility. The work in this thesis comprised four main components: i) investigation of flock fertility and its dependence on age and strain variances; ii) investigation of the contribution of each sex to egg fertility and identification of fertility traits associated with egg fertility; iii) validation of a method for measurement of sperm motility using CASA; and, iv) investigation and assessment of sperm motility and mobility traits that could be used to identify high and low fertility individuals and thus improve egg fertility.