What to watch out for when buying bulls to boost fertility

DAF researchers look at fertility payoffs in Northern Australian beef business

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The study modelled fertility for beef enterprises in the Northern Territory and the Fitzroy natural resource management region of Queensland

The study modelled fertility for beef enterprises in the Northern Territory and the Fitzroy natural resource management region of Queensland


Science should be paired with sound economics, the authors warned.


New research has identified some of the pitfalls that producers should keep an eye on when buying bulls to improve herd fertility.

Researchers from Queensland's Department of Agriculture and Fisheries have been looking at the relationship between farm profitability and herd fertility in central Queensland and Northern Territory beef systems.

The study found that selecting bulls on the basis of fertility could have "unexpected outcomes" down the track when assessing a beef business's "riskiness" and profitability.

Authored by DAF researchers Fred Chudleigh and Maree Bowen, and former DAF employee Bill Holmes, the study specifically tested whether selecting bulls to boost weaning rates had a significant impact on profits.

The study modelled beef enterprises in Katherine region of the Northern Territory and the Fitzroy region of central Queensland over a 30-year period.

Several different scenarios were looked at, including overhauling the breeding bull herd in a single year and buying replacement bulls selected to boost fertility, and gradually replacing the breeding bull herd over a longer period.

The models showed that replacing herd bulls with more fertile bulls could generate economic benefits but these were likely to only be realised over longer time periods and were sensitive to other costs.

Paying to replace herd bulls also created risky spending deficits, the study found.

"The marginal returns from the genetic change of fertility in the Fitzroy NRM region were negative where additional capital was required to replace the bull herd," the authors wrote.

"Gradually introducing bulls with different genes for fertility with no additional costs produced a negligible change in returns."

In the Katherine scenario, the study found a substantial amount of patience would be needed to reap the rewards.

"Immediately and completely replacing the current bull herd with bulls that change reproduction efficiency in the Katherine herd model appeared unlikely to improve economic performance within the first two decades after the investment due to the 15-year payback period.

"Herd managers may improve economic performance over three decades if they fully replaced their current bull herd with bulls showing strong indicators for fertility but paid no more for them.

"Replacing the bulls over the first 4 years in the Katherine region improved the profitability of the property at low risk when incurring no additional costs.

"Incurring an additional $500 per head to access bulls with different genes almost halved the returns compared to the scenario that replaced bulls over time at no additional cost."

The study also stressed that other simple steps should not be overlooked when thinking about fertility improvements and herd management.

"In the Fitzroy region, it is evident that even the relatively simple strategy of targeting the optimum age to sell steers will likely produce more benefits for Fitzroy producers than targeting the genetic improvement of fertility."

The value of genetics, particularly the genetics of fertility, should not be assessed in isolation, the study concluded.

"Good quality science in the area of genetic improvement of fertility needs to be paired with equally sound economic methods to ensure appropriate conclusions are reached about value to beef producers and industry."

The research was presented at a recent meeting of the Australian Agricultural and Resource Economics Society.


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