Many factors play a role in a bull’s fertility and breeding ability, including semen quality, reproductive tract soundness, limb structure and libido.
There are 5 general factors that can affect bull fertility:
There are 5 general factors that can affect bull fertility:
- structural soundness: Structural soundness, including functional feet, legs and associated joints, is critical for the bull to effectively travel the breeding pasture and service females in heat.
- capability of the reproductive organs: Various conditions can affect the function of the reproductive tract. If the testicles cannot move because of fat pads, scar tissue or a small scrotum, proper temperature cannot be maintained and semen quality may suffer. Soft testicles indicate degeneration of tissue and poor semen quality. Very small testicles indicate unsatisfactory development of sperm-producing tissue. Severe frost-bite scabs, tumours or abscesses also indicate potential problems.
- quality of semen: The criteria commonly used to evaluate semen quality include sperm morphology (structure) and motility (rate and percent of progressive forward movement).
- level of libido: Libido (sex drive) is a critical component of fertility. It is independent of scrotal circumference, semen quality, body weight, growth rate or masculinity. When 2 or more bulls are used at the same time, in the same pasture, social interactions affect breeding performance. Social rank is related to age and seniority in the herd. The most dominant bulls tend to complete the highest number of services
- plane of nutrition: Proper nutrition is necessary for good reproductive performance. Balanced amounts of protein and energy are required for sperm production and the physical activity associated with breeding. Adequate amounts of vitamins and minerals are also important in reproduction.