New Guidelines for the Evaluation of Bulls For Breeding Soundness

Abstract

New guidelines for bull breeding soundness examinations (BSE) were recently adopted by the American Society for Theriogenology. Major new features included the abandonment of numerical scores in favor of threshold values which must be achieved for scrotal circumference (minimum threshold of 30 cm at 15 months of age), spermatozoal motility (minimum threshold of 30% individual motility) and spermatozoal morphology (minimum threshold of 70% normal sperm). The latter requirement is seen to reduce the emphasis on classification systems (e.g. "primary'' and "secondary'' abnormalities) for sperm morphology assessment. Bulls are classified as being either "satisfactory'' or "unsatisfactory" or they are placed in a "classification deferred" category. Forms and explanatory notes are available to members of the society for Theriogenology from the Society office.