MANUAL SEMEN COLLECTION FROM A GREVYS ZEBRA STALLION (EQUUS-GREVYI), ONSET OF SPERM PRODUCTION, SEMEN CHARACTERISTICS, AND CRYOPRESERVATIONOF SEMEN, WITH A COMPARISON TO THE SPERM PRODUCTION FROM A GRANTS ZEBRA STALLION (EQUUS-BURCHELLI-BOEHMI)
Jp. Crump et Jw. Crump, MANUAL SEMEN COLLECTION FROM A GREVYS ZEBRA STALLION (EQUUS-GREVYI), ONSET OF SPERM PRODUCTION, SEMEN CHARACTERISTICS, AND CRYOPRESERVATIONOF SEMEN, WITH A COMPARISON TO THE SPERM PRODUCTION FROM A GRANTS ZEBRA STALLION (EQUUS-BURCHELLI-BOEHMI), Theriogenology, 41(5), 1994, pp. 1011-1021
A manual technique was used to collect representative ejaculates from
an unrestrained Grevy's zebra stallion beginning at 13 mo of age to de
termine the onset of sperm production. to calculate the number of sper
matozoa produced per ejaculate, and to determine any seasonality assoc
iated with sperm production. Spermatozoa first appeared in the ejacula
te at 31 mo of age. By 48 mo of age the zebra was producing up to 40 b
illion spermatozoa per ejaculate. Progressive sperm motility ranged fr
om 75 to 95%. Gel-free semen volume averaged 75 to 120 ml/ejaculate. G
el volume ranged from 0 to 1100 ml/ejaculate. Semen was frozen in 2 di
fferent extenders in 0.5-ml PVC straws. The post-thaw motility of cryo
preserved spermatozoa ranged from 30 to 70%. A domestic horse mare bec
ame pregnant on the first cycle after insemination with frozen-thawed
spermatozoa from this zebra. Sperm production data obtained from semen
collections made on a Grant's Zebra stallion from 3 to 8 yr of age is
presented for comparison of the 2 species.