31 July 2015

MLA’s recently released Priority list of endemic diseases for the red meat industries  report placed cattle tick as the number one disease impacting the Australian cattle industry. Here, we take a closer look at the impacts, prevention and treatment of cattle tick.

An overview

The cattle tick , Rhipicephalus microplus, causes anaemia by virtue of blood sucking. As well, it is the vector for three tick fever organisms. Of emerging importance is the Bush Tick (Haemaphysalis longicornis) which transmits Theileria and the Scrub Tick, or Paralysis Tick (Ixodes holocyclus) which reportedly causes significant calf loss in northern NSW. Both these are multi-host ticks, which present additional management difficulties.

Ticks favour warm moist conditions in their nonparasitic stage which is between when the engorged female leaves its host to lay eggs, and when larval ticks reattach for their 21-day feeding period. The non-parasitic stage can be as long as seven months and as short as six weeks.  In south-east  Queensland the tick has four generations/year.

When cattle are heavily infested, ticks can be found anywhere on the body. On a lightly infected animal the main places to look are the escutcheon, tail butt, belly, shoulder, dewlap and ears.

The impact

Cattle tick costs the Australian cattle industry $156 million/year or $7,902/herd. If the cattle tick was controlled in Australia and reduced to its lowest level, the average cattle producer would gain $3,104/year.

Research found in years with highest tick burdens, Droughtmaster cattle in a dry tropical environment were up to 25kg heavier through a reproductive cycle, had conception rates up to 30% higher and weaned calves up to 24 kg heavier when tick infestation was fully controlled.  Research had previously found average annual live weight effects of 10 kg without affecting maiden pregnancy rates.

Cattle ticks transmit the organisms that cause tick fever, which is a serious blood parasite disease of cattle. The disease can be lethal to susceptible animals. Others may suffer severe loss of condition. Hides of heavily infested animals are damaged by tick bites which reduces their value. In severe cases hides may be unsaleable.

Prevention

Increasing Bos indicus content is associated with higher resistance to tick attachment.

Producers are encouraged to seek genetics from tick resistant cattle. It has been estimated that selection of the right genetics could reduce the effect of ticks on live weight production by 60%.

Using a combination of chemical treatments, and pasture spelling can help control cattle ticks. 

Tick fever is prevented by using the tick fever vaccine.

Treatment

There are a number of online resources to help producers understand the life cycles of cattle tick and the treatment options available:

Overview of cattle tick

Managing tick fever in cattle

Treatments for control of cattle tick

Disease control

Original link