SEMEN CHARACTERISTICS AND PRODUCTION OF GERM-CELLS IN MALE SHEEP-GOATCHIMERAS

Semen from 11 male sheep-goat chimeras and one male sheep-goat hybrid- sheep chimera was evaluated on criteria commonly used as in vitro meas ures of semen quality. In addition, the species origin of germ cells w as determined. Five males that were sex chimeras produced spermatozoa only from their XY cells. Three XY/XY sheep-goat males were shown by e lectrophoretic separation of sperm isozymes to produce both sheep and goat spermatozoa; one male produced live young from both ewes and does inseminated with his semen, The sheep-hybrid male produced only sheep spermatozoa. Significant variation in semen quality was observed amon g individual males, but semen characteristics were not strictly associ ated with the male's sex chromosome complement, the species origin of his gametes or the degree of somatic chimerism. These results demonstr ate that male interspecies sheep-goat chimeras are fertile and that XY /XY chimeras can produce fertile gametes of both species.