Evaluation of semen from individual male domestic fowl by assessment of sperm: perivitelline interaction in vitro and in vivo.

1. Spermatozoa in semen samples from 8 individual male domestic fowls were shown to have a differential and characteristic ability to hydrolyse holes in the inner perivitelline layer from laid eggs in an in vitro assay. 2. The number of holes produced by samples of spermatozoa per unit area of inner perivitelline layer in vitro was linearly correlated with sperm ATP content (r = 0.85) and motility (r = 0.76). 3. The number of holes formed in the inner perivitelline layer in vitro was also linearly correlated with the numbers of holes formed in the inner perivitelline layer of eggs fertilised in vivo, in inseminated hens (r = 0.90); and was correlated logarithmically with the proportion of fertile eggs laid by these hens.