The effect on conception rates of semen diluents containing citrate or phosphate buffer, with all combinations of sulphanilamide, streptomycin and penicillin

Abstract

1. A 24 factorial experiment involving 68,713 first inseminations was carried out at four artificial insemination centres, to compare semen diluents containing citrate or phosphate buffers and all combinations of sulphanilamide, streptomycin and penicillin.2. The analysis of the results was carried out on punched card machines and on an automatic calculator (EDSAC), as well as on bench machines.3. The main results obtained were:(i) Unsupplemented phosphate buffer gave a conception rate 5·5% above that obtained with unsupplemented citrate buffer.(ii) Citrate buffer with sulphanilamide, streptomycin and penicillin gave a conception rate 6·8% above that obtained with unsupplemented citrate buffer; and(iii) Phosphate buffer with penicillin gave a conception rate 9·3% above that obtained with unsupplemented citrate buffer. This effect was not, however, significantly greater than that referred to in (ii).4. Phosphate buffer depressed conception rate when used with sulphanilamide or streptomycin.