Field Trials with Semen Containing Several Combinations of Antibacterial Agents

Numerous papers report studies of the value of antibacterial agents in semen diluters. Different antibacterial agents, singly or in combination, have been compared (4, 13, 21, 23, 25, 29, 3~) and different levels have been studied A number of investigations have also been reported concerning the effect of antibacterial agents upon metabolism of spermatozoa (12, 13, 28, 31, 3~). These studies of the action of antibacterial agents upon livability and metabolism of spermatozoa and upon bacteria contribute greatly to our knowledge of these compounds. The final test of their value, however, has to rest primarily upon their ability to aid in the production of calves by cows bred artificially. A number of direct comparisons have been made in breeding trials with different concentrations of antibacterial agents (1, 2, 6, 17, .'~2) or with different agents, singly or in combination (3, These experiments have, however, not given the final answers, in terms of fertility, concerning the most satisfactory combination or the optilnmn concentrations. The most informative experiment to date has been conducted by Campbell and Edwards (14). They compared all possible combinations of sulfanilamide, streptomycin, and penicillin in phosphate and citrate buffers.