An investigation into the relationship between the metabolism of pyruvate in bull spermatozoa and fertility

Abstract

1. Two hundred and ninety-one samples of semen from seventy-four dairy bulls in use at seven artificial insemination centres and one bull-rearing centre were tested and graded according to the type of metabolic response under the experimental conditions described by Melrose & Terner (1953).2. Conception rates of bulls were obtained from the breeding records based on not less than 150 first inseminations. Since the mean conception rates of centres varied, the fertility of each bull was assessed in relation to the mean conception rate of the centre at which the bull was standing. Bulls were considered of ‘high’ fertility when their conception rates were above, and of ‘low’ fertility when their conception rates were below a dividing line 5% below the mean conception rate of the centre.3. A highly significant relationship (P< 0·001) was found between the groups of the metabolic responses and the fertility levels of the bulls. The practical application of the test in the assessment of the potential fertility of individual bulls is discussed.