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Risk management strategies for tick fever

You can use this page to assess the advantages and disadvantages of a range of strategies to minimise the risk of a tick fever outbreak.

Vaccination against tick fever

Advantages

  • It provides protection against all 3 parasites and takes the guesswork out of tick fever control.
  • You can vaccinate cattle of any age, provided you take precautions, though it is best to vaccinate calves.
  • One vaccination is usually enough to protect cattle for life. In some circumstances a second vaccination may be warranted, especially if introducing cattle into the tick-infested areas from tick-free country.
  • It markedly reduces the risk of losing your disease-free status for live cattle exports.
  • It provides essential protection if you are in a tick eradication project.

Disadvantages

  • Chilled tick fever vaccine has a short shelf life of 4 days.
  • Immunity takes 3 to 4 weeks to develop for both Babesia parasites, and longer for Anaplasma.
  • Although the risk is low, some adult animals can experience adverse vaccine reactions.

Resistant breeds of cattle

Advantages

  • Bos indicus breeds and Bos indicus cross cattle are more resistant to both cattle ticks and tick fever caused by Babesia bovis and Babesia bigemina.
  • Using Bos indicus breeds will reduce losses due to tick fever. However, resistance to Babesia bovis, the major cause of tick fever, reduces as the percentage of Bos indicus genotype in the herd is reduced.

Disadvantages

  • Despite their resistance to both Babesia organisms, Bos indicus breeds are still highly susceptible to anaplasmosis and historically nearly 20% of confirmed tick fever cases have involved these breeds.

Treatment with imidocarb (Imidox®)

Advantages

  • Imidocarb is the only registered treatment for tick fever cases. It is particularly effective against Babesia infections.
  • You can use imidocarb for short-term prevention of tick fever in cattle moving through tick-infested areas. A single injection of imidocarb at a high dose rate will provide protection from both types of Babesia parasites for about 4 weeks.

Disadvantages

  • Imidocarb used at a high dose rate will provide protection from Babesia parasites for only about 4 weeks. Longer protection will require further treatments.
  • Imidocarb has no protective effect against Anaplasma marginale.
  • Treating animals with imidocarb can interfere with the development of immunity to tick fever.
  • Restrictions apply to the use of imidocarb in lactating dairy cattle.
  • Imidocarb is costly, especially if using as a preventative for multiple animals or multiple times.

Keeping animals tick-free

Advantages

  • Regional tick eradication campaigns have worked well in areas not heavily infested with cattle ticks.

Disadvantages

  • It is very difficult and costly to maintain tick-free cattle on an individual property in the cattle tick-infested areas.
  • This approach means no natural immunity to tick fever develops, so if there is a breakdown in the tick-free status of the herd, large losses can occur.

Taking the risk and accepting the losses

Advantages

  • This is the easiest option.

Disadvantages

  • This option carries the greatest risk and is potentially the most expensive.
  • Relies on consistent tick populations being either so low that exposure and disease do not occur, or so high such that all calves become naturally immune to all 3 tick fever organisms before calfhood resistance wanes. However, tick populations can be quite variable.
  • Field research in Queensland shows that many cattle herds do not have enough cattle-tick exposure to ensure the development of natural tick fever immunity in calves.

Also consider...