Minimising the Risk of Bovine Johne’s Disease in a Dairy Bull Beef Operation
Note Number: AG0938
Published: December 2005
Updated: November 2010
Dairy bull beef is a popular enterprise for many properties in Victoria. The risks and impact of introducing bovine Johne's disease (bjd) can be minimised by taking the right precautions.
The risk
There is a risk of introducing bjd onto a property by buying dairy calves. Bjd is far more common in dairy herds than in beef herds. Calves can be infected before they are born or shortly afterwards, in fact this is when they are most susceptible. Therefore it is quite possible that dairy bobby calves are already infected with bjd before they arrive on a property for dairy bull beef production.
Minimising the risk of purchasing infected calves
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Fig 1. It is possible that seemingly healthy |
The National Dairy bjd Assurance Score Declaration forms are available from the Dairy Australia or the Department of Primary Industries (DPI). These allow vendors to declare the likelihood of their dairy herd having or spreading bjd. (Refer to Agriculture Note AG1187: The national Dairy bjd Assurance Score – the higher the score the higher the assurance. Once a score s is obtained, the risk of purchasing bjd affected calves can be assessed.
Owners of herds with 'Infected' or 'Suspect' status are obliged to inform the purchaser of their bjd status. It is possible to purchase calves from herds with these statuses without adversely affecting the bjd status of the purchaser’s herd or property. However, a program should be developed with the purchaser's private veterinarian prior to purchasing these stock. This program will minimise the risk of spread of disease if calves are infected with bjd.
Minimising the effects of purchasing infected calves
The dairy bull beef industry is based on producing bulls of optimum weight by two years of age. An infected bull under good husbandry is unlikely to break down with bjd (lose weight and scour) before 2 years. Good worm control and sufficient quality feed, as well as reducing the possibility of break down, means that the bulls will reach market weight quicker and more efficiently. This reduces the chances that any of these animals will contaminate the property with bjd.
Risks can be further reduced by not grazing beef cows with calves at foot, or replacement heifers, on paddocks grazed by dairy bulls in the previous 12 months.
Any suspicion of bjd (scouring and/or wasting) should be investigated by a veterinarian.
Options for infected herds
Refer to Agriculture Note AG0934: Control options for bovine Johne's disease in beef herds.
Further information
Further information about bjd can be obtained from your private veterinarian, DPI Animal Health staff or refer to DPI web site: http://www.dpi.vic.gov.au/farming/bjd.
Acknowledgements
This Agriculture Note was originally developed by Dr Katrina Rainsford in November 2001 and revised by Lachlan King in December 2005.
This November 2010 version was reviewed by Dr David Champness, Biosecurity Victoria.
ISSN 1329-8062
Published and Authorised by:
Department of Primary Industries
1 Spring Street
Melbourne, Victoria
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