Motility and fertility of stallion spermatozoa isolated in bovine serum albumin

Semen from three mature stallions was used in an attempt to isolate a population of highly motile spermatozoa. An ejaculate of semen, collected from each stallion at 7-day intervals for 35 days, was evaluated for percentage of motile spermatozoa and rate of progressive motility (scale 1 to 4). Two milliliters of semen were layered over 6 ml of 3% bovine serum albumin (BSA) in 13 × 125 mm columns at room temperature (RMT) or in a warm water bath (WB). After a 30-minute separation period, the top semen layer and the upper and lower halves of the BSA fraction were separately withdrawn from columns and reevaluated. In both the RMT and WB separation columns, percent motile spermatozoa and progressive motility decreased in the top semen fraction as compared to initial values for these parameters. Percentage of motile spermatozoa in the lower BSA fractions increased (P<.01) to 58.7 and 65.7 following separation at RMT and in a WB, respectively. Also, there was a significant increase in rate of progressive motility rate for spermatozoa in the lower BSA fraction of both the RMT and WB treatments.In a second experiment 30 Quater Horse mares were artificially inseminated to compare fertility of spermatozoa isolated in BSA with raw semen diluted with either Tyrode's solution or BSA. The pregnancy rate for 10 mares inseminated with 100 × 10⁶ live isolated spermatozoa was not different from that of control mares inseminated with the same number of live untreated spermatozoa. Foaling rates were 70, 40 and 60% for the isolated, Tyrode and BSA treatment groups respectively.