PUTTING your bull team through annual breeding soundness examinations ahead of joining is an undertaking every breeder should commit to do.

The Bull Breeding Soundness Evaluation is a complete assessment of a bull’s soundness for breeding, and if it is done early enough, there is time to make some plans for those bulls that fail an initial BBSE.

As has been noted in previous Beef Central genetics columns, a BBSE not only provides clarity around the fitness of the team for the joining season, but it can also be the basis for reconsidering joining percentages and ultimately the size of the team for the season.

There are still many producers – particularly in northern and extensive pastoral regions – that have very high joining percentages. It’s not unusual to hear of bull ratios (joining percentages) of five to seven percent.

In talking percentages, five to seven percent may not cause too many raised eyebrows for some people.  However, in raw numbers, a joining percentage of 5pc means one bull for every 20 cows.

Over a herd of 5000 cows this equates to a team of 250 bulls. This is a significant requirement, and in many instances this size team is unnecessary. Work presented from research in northern Australia has proven that joining percentages can be reduced to 2pc + 1, if the bull team is subjected to an annual BBSE.

Although organising and conducting BBSE, particularly over a large team has costs associated both with testing and logistics around moving and examining bulls, the alternative costs associated with unnecessary bull numbers exceeds these testing costs.

Setting a time-frame to conduct the breeding soundness examinations ahead of the bull sale season is equally important to assist in planning around replacements and setting a realistic budget.

What to do with ‘fails?’

While much of the focus on BBSE is on finding those bulls fit and ready to take their place in the team for the season ahead, making decisions about the bulls that fail a BBSE is not something that is often considered. There is often a general assumption that every bull that fails a BBSE is automatically placed into a cull group destined for the meatworks.

However, as with any assumption, this is an area worth considering more closely.

Firstly, there are a number of aspects to a Bull Breeding Soundness Exam. The Australian Cattle Veterinarians (ACV) has developed BullCheck as the standardised method of conducting a bull breeding soundness examination. The components of BullCheck include identification, health history (including vaccinations) and the five key areas of assessment. These are:

• A general physical examination including structure (conformation) and upper reproductive tract
• An examination of the testes and measurement of scrotal size
• A serving assessment to evaluate libido and mating ability
• Collection and assessment of a semen sample
• Laboratory examination of sperm morphology.

With these standards, it is important to look at the results of the tests across the team. There are some failures that will prevent bulls from ever being considered as part of the team for the season ahead. Physical damage or abnormalities that will impact on the ability to walk and serve cows being the most frequent cause of failure.  These bulls can be considered culls without too much consideration.

More consideration needs to be given to bulls who may fail part of the exam, for instance with lower than desirable results for semen morphology.

There can be reasons for a bull to have less than acceptable results. Infections can see the amount of white blood cells greater than normal among sperm cells, or in yearling bulls still maturing there can be lower than average normal cells.

It’s important to note that semen morphology is an assessment that is highly effective in identifying bulls that are reproductively sound. However, if a bull fails an initial assessment, it shouldn’t mean that it is an automatic cull. The impact of stress or slight illness may cause a bull to fail an examination.

Bulls that have the genetic potential to produce high levels of normal sperm may actually recover. The process of spermatogenesis (production of sperm cells) is continuous, and a single cycle takes around 60 days for bulls.

Second chance

With this in mind, producers have an opportunity to give some bulls a second BBSE. In most cases this opportunity would be given only to those bulls that have failed in this area or in the case of bulls with minor injuries that were obvious in the first tests.

This approach allows producers options to make the most of the BBSE process.

In the first round the bulls that will never pass can be removed. Retesting around six to eight weeks later on those bulls that had a question mark then provides more clarity about the team composition. A second failure then becomes a cull.

In approaching bull team assessments in this way, producers have a chance to make more considered team decisions, rather than using a “cull everything that fails” approach which may result in purchasing bulls that could be unnecessary.

However, this approach will only work if the initial and follow up BBSE can be done ahead of sale events so that the right replacement bulls can be purchased.

Alastair Rayner is the General Manager of Extension & Operations with Cibo Labs and Principal of RaynerAg.  Alastair has over 28 years’ experience advising beef producers & graziers across Australia.   He can be contacted here or through his website www.raynerag.com.au