Tick Management in Cattle
The cattle tick (Rhipicephalus microplus) is an important external parasite of cattle although other animals such as horses, buffalo, sheep and camelids can be affected too. Cattle ticks are found widely in northern Australia from northern parts of Western Australian and the Northern Territory, eastern and northern regions of Queensland and into northern New South Wales. In Queensland there is a demarcation between the tick free zone and the tick infested zone and reports of infestations in the free zone must be reported to Biosecurity Queensland.
The cattle tick is classified as a single-host tick because it lives its parasitic stages on one host. The time spent on the host is about 21 days. During this time the immature or nymphal stages feed on blood and gradually develop and grow. The female ticks engorge with blood then drop off onto pasture and lay up to 3000 eggs. The eggs hatch to release the larval stages which infest the next host. Larvae need to infect a new host or they will die and they are sensitive to climatic conditions of temperature and moisture but they can survive for up to two months in summer and as long as seven months in winter. Over wintering larvae are responsible for the rise in tick numbers in the following spring. It is important to note here are other tick species that affect cattle such as scrub or bush ticks and in some regions, paralysis ticks. It is important to be able to tell the difference between them because treatment and control can be different for the other types of ticks.
NSW Department of Primary Industries “Cattle Tick Program” with the Rural Land Protection Board and district vets.
Cattle tick infestations severely affect productivity due to tick-worry and can cause disease and death due to anaemia from loss of blood. Ticks also act as vectors for three tick borne parasites which cause tick fever. Cattle can become resistant to the effects of cattle ticks with ongoing exposure but naïve cattle that have come from uninfected areas are particularly vulnerable at first. Bos indicus cattle breeds and their crosses have more resistance than do Bos taurus breeds although there is significant variation in resistance within Bos indicus cattle. Ticks also cause serious damage to hides reducing their value and even making them unusable. Meat and Livestock Australia (MLA) list cattle tick as the most costly disease affecting cattle in Australia at $156M per annum in lostproduction, treatment and prevention costs (B.AHE.0010. Final Report: Priority list of endemic diseases for the red meat industries, 2015).
The most common tool in the management of cattle tick is the use of acaricides (chemicals that killticks) however the development of resistance to various chemicals has been an ongoing problem. Chemicals can be applied in various ways such as cattle dip or spray (e.g. Bayticol Dip and Spray®), by backline pour on (e.g. Baymec® pour on) or by injection (e.g. Baymec Gold®). It is important to always follow label instructions. Timing of treatments is important. Applying treatments early in the season can reduce the spring rise in tick numbers. An integrated management approach can reduce the need for chemical treatments and should incorporate selecting for cattle with resistant genetics, spelling pasture to reduce environmental contamination and inspecting, treating and quarantining infected stock before introduction to the herd.