Effects of increasing concentrations of minocin on the motility of bovine spermatozoa processed in various extenders.

The effect of minocycline hydrochloride (Minocin) on bovine spermatozoa was studied in eggyolk-citrate, Tris buffer and whole milk extenders. Each of the extenders contained penicillin, streptomycin, lincomycin-spectinomycin and four levels of minocin (10, 260, 510 and 760 mug/ml). Split ejaculates from Holstein sires were diluted in each of the extenders. This was followed by microscopic evaluation for progressive motility after initial dilution at 32 degrees C, after cooling at 5 degrees C and complete dilution, immediately after freezing and after 14 days of storage in liquid nitrogen. Under the experimental conditions employed, a decrease in the percent progressive motility was observed in the eggyolk-citrate and Tris buffer extenders with increasing concentration of minocin. Little or no difference in the percent progressive motility in the whole milk extender, either before or after freezing was observed when the minocin concentration was elevated.