A Comparison of the Effects of Aureomycin, Penicillin and Streptomycin upon Spermatozoan Livability and Control of Bacteria in Bovine Semen1,2

Abstract

Studies were conducted to determine the effects of aureomycin upon spermatozoan motility and bacterial control in bovine semen and to compare the results with those obtained using penicillin and streptomycin. Preliminary data from eight ejaculates showed that concentrations of 12.5 and 25 µg. per ml. of aureomycin did not affect the motility of spermatozoa but that higher levels were toxic. The 50 µg. per ml. level was toxic during the last half of the 14-day storage period. In the main experiment involving 24 semen samples, levels of aureomycin ranging from 50 to 1,000 µg. per ml. of diluted semen brought about highly significant decreases in spermatozoan livability during 14 days of storage as compared to semen containing no aureomycin. These levels of aureomycin inhibited bacterial growth except that the 50 µg. per ml. level was not as efficient as higher amounts. Aureomycin was relatively stable in diluted semen stored at 4.5° C. but lost much of its activity in semen stored at room temperature. Penicillin, streptomycin and penicillin plus streptomycin were much less spermicidal than aureomycin. A concentration of aureomycin of 1,000 µg. per ml. was highly significantly more toxic to the spermatozoa than either 1,000 units of penicillin per ml., 1,000 µg. of streptomycin or a combination of 1,000 units of penicillin plus 1,000 µg. of streptomycin per ml. of diluted semen. Aureomycin compared favorably with the other antibiotics for the control of bacteria in diluted semen. Levels of from 100 to 1,000 µg. per ml. were about equally effective to the above mentioned amounts of penicillin and/or streptomycin.