The strategic application of a long-acting chemical treatment at the start of the tick season plays a critical role in minimising the build-up of the tick population on pastures and cattle.

Cattle tick (Rhipicephalus microplus) is one of the most economically significant parasites in the Australian beef industry, according to MLA’s Priority list of endemic diseases for the red meat industry – 2022 update.

Infestations can cause significant economic losses arising from tick worry, tick fever, anaemia, weakness, reduced appetite, weight loss, reduced fertility, and death.

Research published in Veterinary Parasitology has shown just one tick can reduce weight gain by 1g/head/day or milk production by 8.9mL/head/day.

Assuming an ‘average’ burden of 50 ticks per head, that equates to 1.5kg of lost live weight gain worth $4.88/head or 13.4 litres of lost milk production every 30 days.

Elanco technical consultant Craig Stevenson says an integrated approach is required to achieve effective control of cattle ticks and prevention of tick fever.

“This includes having a good understanding of the cattle tick life cycle, breeding tick-resistant cattle, vaccination to increase immunity against tick fever, and strategic pasture management.”

Mr Stevenson said the life cycle of the cattle tick comprises of two stages:

During the parasitic stage, the cattle tick lives on the host animal for 18 to 35 days and undergoes two moults to develop from a seed (larval) tick to a nymph and then to an adult tick.

During the non-parasitic stage on pasture, the engorged female adult ticks drop off the animal back to the ground and lay up to 3000 eggs each, and then die.

Under favourable conditions (15–40°C), eggs hatch to become larvae that climb up the pasture sward, where they wait to be picked up by a host animal.

Survival during the non-parasitic stage can vary from two to nine months, depending on the time of the year, geographic location, and seasonal conditions.

“Regardless of the level of Bos indicus content in your cattle, the strategic application of effective chemical treatments remains an important method of controlling ticks,” Mr Stevenson said.

“Chemical treatment should commence once tick infestations reach the economic threshold, which is generally accepted to be 30 ticks per side.

“In Northern NSW, Southern Queensland and Central Queensland, apply the first treatment in spring once the first ticks are identified coinciding with the ‘spring rise’.

“In Northern Queensland, Northern Territory, and Northern Western Australia, apply the first treatment in late summer/early autumn before the ‘autumn rise’ at the end of the wet season.”

Mr Stevenson said Acatak Duostar is ideal for early season tick control, providing knockdown and long-lasting residual control of susceptible ticks and other parasites in a single, ready-to-use treatment.

Applied early in the season as part of a strategic control program, Acatak Duostar helps to minimise the build-up of the tick population on both cattle and pastures.

Acatak Duostar contains two modes of action (15 g/L fluazuron and 5 g/L ivermectin) that work in combination to break the life cycle of cattle ticks.

“The ivermectin component provides rapid knockdown control and short-term residual activity against all stages of cattle tick present on cattle,” Mr Stevenson said.

“Ivermectin is a member of the macrocyclic lactone class of compounds and causes paralysis and death of sensitive cattle ticks, in addition to roundworms, lungworm, sucking and biting lice, mites and buffalo flies.

“Fluazuron is a powerful insect growth regulator that provides long-term protection from ticks picked up from infested pastures.

“It breaks the lifecycle of cattle ticks by interrupting the moulting process of tick larvae and nymphs and inhibits egg-laying and hatching.

“Having two modes of action also helps to mitigate the risk of resistance developing and prolongs the life of all available chemistry.”

The length of protection from Acatak Duostar varies according to the livestock class treated.

Australian research has shown that treating dry cattle with Acatak Duostar can prevent re-infestations of seed ticks for up to nine weeks and the presence of fully engorged female ticks for up to 12 weeks.

However, a reduced period of protection can occur in lactating cows or rapidly growing young cattle. Calves that suckle Acatak Duostar treated cows do not need to be treated.

Acatak Duostar has a minimum re-treatment interval of 42 days and can be applied a maximum of three times per tick season.

Mr Stevenson said that the use of Acatak Duostar should ideally be alternated with an effective product that has a different mode of action.

“Unfortunately, multi-resistant ticks are present in many geographic regions where cattle ticks are present.

“For this reason, producers are encouraged to conduct a tick resistance test to help determine which products will be effective on their property and to alternate between effective chemistries,” he said.

“Good agricultural practice is essential for optimal cattle tick control. Always read and follow label directions.”