The Veterinary Bull Breeding Soundness Evaluation (VBBSE), previously known as Bull Breeding Soundness Evaluation (BBSE) was developed by veterinarians to standardise bull fertility testing and to provide a consistent descriptor of bull fertility. The evaluation indicates whether a bull has met a set of standards for key fertility components which indicate whether a bull has a high probability of being fertile. The components are:

• Scrotal circumference (cm) and tone or resilience
• Physical examination for faults in the head, legs, joints, feet, sheath and penis
• Semen analysis for motility,
• Morphology (or structure of the individual sperm cells), and

The Australian Cattle Veterinarians (ACV) oversees the VBBSE practices with appropriate certification. The certificate provides a standard of assessment for veterinary evaluation of the various reproductive traits important to beef producers. This evaluation is conducted prior to sale and details the identification of the sire, date and location where the evaluation was conducted, the assessments made and relevant disease information

The VBBSE is not a genetic evaluation of reproductive traits, but an indication of the animal’s present reproductive function

Understanding the morphology and why it is important

Morphology in a VBBSE is basically the ‘structure’ of individual sperm cells. The structural attributes that are not clearly visible (or that require a microscope to view) are frequently just as important, if not more important as far as affecting a bulls fertility.

Unlike the female that has her ‘quota’ of eggs at the start of life, the bull is continuously producing semen within the tubules in the testicles. The testicles are about 2°C cooler than body temperature. Between the head, body and tail of the epididymis there is a long tube for storage and maturation of the spermatozoa produced. This production pipeline takes about 9 weeks from the start of production to when the semen is ready for ejaculation. As semen is continually produced, unused semen is excreted in the urine of all bulls.