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Recent wet season rains over the north of Australia provide ideal conditions for development and survival of cattle ticks and their larvae. This means that springtime could pose a serious risk to cattle unless producers clean up tick numbers this autumn.
Cattle vs Ticks
Ticks suck blood, slow growth and production, transmit tick fever, cause hide damage and lead to the deaths of cattle right across northern Australia. But we know their weak points and have a strategy to beat them.
To maximise return from the effort you put into tick control, preparation is key. The main factors are:
Biology and life cycle
Australian cattle ticks (Rhipicephalus australis) spend their lives either on the cattle (about 3 weeks) or on the paddock (minimum 3 weeks). They start off as eggs, which develop on the ground and hatch. The larvae then crawl up the grass and wait for a beast to jump onto.
Once aboard, they feed, moult, feed, moult again then turn their minds to mating. Male and female ticks become intimate, and the female ticks fall pregnant. This is the signal for her to begin feeding, not just for herself but for her 3,000 babies. The ticks suck more blood over the next few days than over their entire lives to date.
The blood they suck is quickly converted into thousands of ripe tick eggs. This results in the big, round female ticks that we see clinging like fat peas to the skin of cattle. Each tick that engorges takes away 0.6 to 0.9g of growth from the beast. Once they’ve engorged, the female ticks drop off onto the ground and start to lay the eggs.
Autumn clean-up
Cattle ticks can be seen at any time of the year with the numbers found on cattle increasing rapidly from summer to autumn in NSW and southern QLD, and during the wet season and early dry season in NT, WA and north of Queensland. Larvae laid in pasture to survive the winter season are responsible for the rise in tick numbers in the following spring.
This makes now the best time to monitor cattle tick numbers to control ticks using a tactical treatment.
Larvae (hatched eggs) in the environment are sensitive to climatic conditions but can survive up to two months in summer and as long as seven months in winter. Larvae need to infect a new host or they will die. Rotational grazing, making hay or pasture spelling also give ticks time to die out before a new mob of cattle arrive for them to infest.
Impact of treatment
Smashing numbers on cattle now will decrease the risk in springtime. Treating cattle, then moving them to a fresh paddock will minimise the ticks that could potentially seed the pastures with larvae. Check local advisers or do a resistance test to know resistance status of different products.
Table 1: Types of tick treatments to use in autumn to stop tick larvae contamination on pastures over winter
|
Type of treatment |
Chemicals |
Effective period |
Treatment interval |
Comments |
|
Short-acting dips, sprays, pour-ons |
Amitrazâ Organophosphatesâ Synthetic pyrethroidsâ Pour on mectins |
18-21 days |
21 days |
Check product label for meat and milk withholding periods (WHP), export slaughter interval (ESI) and re-treatment intervals |
|
Medium-acting |
Injectable mectins e.g. doramectin injectable |
28-30 days |
28 days |
|
|
|
|
|
|
â resistance to these chemicals is widespread in Queensland, (but not in WA or NT)- consult local authorities for regional resistance status and submit ticks for resistance testing to know best chemical choice for your herd
Long-acting treatments such as moxidectin LA injection are best used in springtime to treat successive waves of ticks (protection period against tick eggs laid is 65 days), rather than for tactical treatment in autumn.
Strategic control
To make sure ticks do not cause any damage to your herd, follow these steps:
Timing is critical. Act now to make sure that you count your ticks before they hatch!
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