Metronidazole for the treatment of bovine pyometra

Metronidazole, an antibiotic with specific activity against anaerobic bacteria, was assessed as a treatment for bovine pyometra. A preliminary experiment with metronidazole-neomycin was followed by an experiment in which metronidazole-ampicillin was compared with povidone iodine. Each treatment was given as a single intrauterine infusion. The success of therapy was judged by clinical examination, bacteriological examination before and after treatment and, in the second experiment, by post treatment reproductive performance. Before treatment 45 of the 84 cows in both experiments were infected with a mixture of anaerobic and aerobic bacteria, 23 cows were infected with aerobes alone and significant bacteria were not isolated from 16 cows. Complete bacteriological and clinical cures were achieved in 23 of 32 cows treated with metronidazole-neomycin, 15 of 32 cows treated with metronidazole-ampicillin and 1 of 20 cows treated with iodine. When only those cows with mixed anaerobe/aerobe infections were considered, complete cures occurred in 12 of 17 cows treated with metronidazole-neomycin, and 11 of 16 cows treated with metronidazole-ampicillin, but none of the 12 cows treated with iodine. Twenty-two of 29 cows treated with metronidazole-ampicillin conceived after treatment (mean 51.4 days), while 9 of 18 cows treated with iodine conceived (mean 58.7 days). Statistically, metronidazole-ampicillin treatment produced significantly better clinical and bacteriological cure rates than iodine treatment (P less than 0.05), but the differences in reproductive parameters were not significant.