Mortality of cattle on farm, particularly in Northern Australia occurs due to the enormity of the properties, difficulties in achieving complete mustering and the impracticality of checking up on each individual animal. Deaths can be caused by a variety of factors, including old age, untreated injury, calving complications wild dogs and other feral attacks.
- In extensive beef properties, cattle may only be mustered once or twice in any one year. Unlike in Southern Australia, cattle farmers are not able to closely monitor their herd which can result in injuries and in instances deaths.
- Mortality rates in extensive north Australian cattle herds at the property and regional levels are not widely known due to the complexity of herd management and lack of aggregated data.
In order to gain a clearer picture of cow mortality the ‘Evaluation of breeder cow mortality in northern Australia’ project was recently undertaken and gives the best indication of the mortality rates in Northern Australia to date. The aim of this project was to determine breeder cow death rates on properties in northern Australia on a regional basis, identify likely causal factors, and develop a method of determining death rates over time at a property and regional level. The project team worked with 45 properties over nine regions and was able to extract useful information from 36 of these properties to produce data that covered periods varying from three to nine years. The regions included in the analysis were:
- Queensland southern Gulf
- Queensland northern Gulf
- Northern Territory Barkly Tableland
- Northern Territory Gulf/Katherine/Sturt Plateau
- Northern Territory Alice Springs
- Northern Territory Victoria River district
- Kimberley East
- Kimberley West
From a list of all properties in each region, properties were randomly selected and, if they met certain selection criteria such as herd size, these properties were contacted to confirm they met all the selection criteria and were willing to cooperate.
The results indicated:
- Median total female mortality rate for all the regions was 3.8%,
- Median total breeder mortality rate was 5.7%
- Median total steer mortality rate was 5.9%.
The results of the mortality research confirmed that many northern cattle producers underestimate the mortality rates in their herds. The analysis of the data shows strong statistical associations between mortality rate and a number of management practices such as:
- the age of females at last joining (Joining refers to the conception period)
- the age of females at last weaning (Weaning is when calves a removed from their mothers)
- the age at which cows were sold
- wet season phosphorus supplementation
- dry season segregation of breeders
- and continuous versus controlled mating.
It was identified that a reduction in on-farm mortality rates could be achieved by selling cows at 10 years of age.
From this research a mortality calculator has been developed. This allows producers to calculate their mortality rates over time. Knowing these mortality rates, producers can make informed management decisions on the implications to productivity and profitability by lowering mortalities.
There are other industry courses in place to assist producers in making management decisions. This includes the ‘Breeding EDGE’ and ‘Nutrition EDGE’ training courses that help producers to get better information on how to reduce mortality rates.
More information on the mortality research.