The comparative fertility of bovine semen of four ages diluted with skim-milk and skim-milk + glycerol

A split-sample experiment involving 14,319 first inseminations was carried out at sixteen artificial insemination centres to compare the fertility of semen diluted with skim-milk and skim-milk containing 10% glycerol when used on the first, second, third and fourth days after the day of collections. The addition of glycerol to the heat-treated skimmilk diluent significantly reduced the decline in fertility with increasing age. However, there were indications that glycerolization also reduced initial fertility.