Freezing of stallion semen with addition of glycine betaine

The effect of addition of glycine betaine to a lactose-EDTA freezing medium on the post-thaw motility of stallion semen was determined. The first thre e semen-rich fractions of nine stallions were collected with an open-end Kr akow artificial vagina on consecutive weekdays. Semen was frozen using the Hannover method with freezing media containing glycine betaine in various c oncentrations from 0 to 5%. After thawing, sperm motility was analysed both by a light microscope and by a Hamilton-Thorn Motility Analyser. Total and progressive post-thaw motilities of semen containing 0.25-3% glycine betai ne did not differ significantly from the total and progressive post-thaw mo tilities of semen frozen without glycine betaine. The total and progressive post-thaw motilities of semen containing 4 or 5% glycine betaine mere sign ificantly lower (P < 0.001) than those of semen without glycine betaine. In conclusion, glycine betaine did not show any beneficial effect on the post -thaw motility of stallion semen when semen was frozen using the Hannover m ethod.