The effect of diluents containing glycine, and glycine and glycerol, on the fertility of diluted bovine semen

Abstract

The conception rate of semen diluted in four experimental diluents containing glycine, C.U.E., C.U.E.G. (C.U.E. plus 1.25 per cent glycerol), 14 (a simpler egg yolk-citrate-glycine-glucose diluent formulated in this laboratory), and 14G (14 plus 1.25 per cent glycerol, also formulated in this laboratory) gave significantly higher results than 2.9 per cent sodium citrate with semen used on the day of and day after collection. The superiority of the four diluents over 2.9 per cent sodium citrate was 2.2 per cent, 2.5 per cent, 2.2 per cent, and 2.1 per cent respectively with semen used on the day of collection, and 4.4 per cent, 4.1 per cent, 2.7 per cent, and 4.1 per cent respectively with semen used on the day after collection. The effect of glycerol addition to the two basic diluents, C.U.E. and 14, was estimated as + 0.1 per cent with semen used on the day of collection, and + 0.7 per cent with semen used on the day after collection. Neither difference was significant. However, there was a significant interaction between glycerol addition and basic diluent. The addition of glycerol to 14 significantly increased conception rate by 1.4 per cent. Two conclusions are drawn: that glycine and glucose added to a buffer solution significantly increase conception rates; and that glycerol added to certain diluents may improve conception rates.