A trio of bulls

WOF of the Bull Team

Ivan Holloway

Written by Ivan Holloway


How well have your bulls come through the season, and how many may you need to replace at upcoming winter bull sales?

Bulls should be inspected for their general health and overall physical appearance. Are they lame, has the conformation of their feet deteriorated, or are their claws overgrown? Do their hips appear normal, or have they injured themselves while mounting a cow on a hillside?

Service testing the bull team prior to the commencement of winter sales can give a good indication of which bulls are fit for purpose and which bulls are not. Service testing bulls involves watching each one mate or attempt to mate a restrained heifer or a healthy mature cow.

Quantitative aspects of the test may involve:

  • Services per unit time
  • Reaction time to first and/or subsequent services.

Qualitative aspects of the test may involve:

  • Interest of the bull
  • Achievement of normal service
  • Absence of penile abnormalities
  • Absence of musculoskeletal abnormalities.

A common problem detected in older bulls is apparent back pain. It is difficult to determine unless watched in the act of mating. A bull will be keen to mate, and attempt to ride the cow, but fail to mount effectively. Such a bull is a problem in the bull team, especially if a dominant, mature bull. Such bulls may command cows in heat, preventing younger bulls from mating yet failing to mate themselves, so they need replacing.

Penile problems, such as a deviating or corkscrew penis, may also occur with age, but again are hard to detect without witnessing the bull in the action of mating. Small injuries to the penis through over-vigorous mating may cause adhesions which prevent the penis from extruding fully. Again, without witnessing these bulls in the act of mating and observing these deficiencies, you are running blind.

While variations occur in the interpretation of service tests, it is generally recommended that, for a bull to pass a service test with minimum requirements, it must:

  1. Complete at least one serve within 10 minutes
  2. Have a normal penis and musculoskeletal function
  3. Have no other factor that may limit service capability.

Observation of libido/service capacity testing of bulls under controlled conditions is a good means of assessing your bulls` WOF status prior to the bull-selling season. It largely helps to identify sub-fertile bulls with either penile or gait problems, and it also helps to identify and eliminate bulls with unacceptably low libido.

It is common to get an annual WOF for your car (depending on vehicle age) so why not do so for your bulls?