Visualization of pig sperm chromosomes by in-vitro penetration of zona-free hamster ova

: Zona-free hamster eggs were penetrated by pig spermatozoa capacitated using bovine follicular fluid and Percoll gradients. A mean penetration rate of 80.1% was obtained from 5 ejaculates from 2 boars. Penetrated eggs were cultured and analysable metaphase chromosome spreads were obtained from 16.8%. The analysis of 20 pig sperm complements indicated that 9 were 19, Y, 10 were 19, X and 1 appeared to have an XY sex chromosome constitution.