Does Evaluation of One or Two Ejaculates of Rooster Semen Provide a Valid Basis for Culling Inferior Males?

Despite the practice of spiking flocks with younger males, reproductive problems increasingly impact the capability of flock managers to produce needed chicks and increase the cost of chick production. The problem also impacts breeders and producers using artificial insemination (AI). Recognizing that the problem is partially caused by poor semen quality, flock managers might consider evaluation of young males and culling those whose semen is of low quality. This logically leads to two questions. What should be evaluated and how many ejaculates should be evaluated before deciding to cull a rooster or tom? Important semen attributes include volume and number of sperm per milliliter (concentration) plus attributes of sperm function such as motion, exclusion of vital dyes, capability to bind to the oviduct epithelium, or capability to bind to the perivitelline membrane of an ovum.