- Do not use the same type of acaricide for more than three years. Ticks become resistant due to overuse.
- Always use the recommended strength in dips as printed on the chemical label by the manufacturer.
- If using a plunge dip, always re-dip the cattle twice.
- Never under-dose animals during treatment with pour-on or injectable applications. Treat the mob at the rate of the heaviest animal, reducing the chance of under-dosing.
- Import only tick-free livestock onto your farm/premises. If this is unavoidable, treat livestock on arrival and only turn out tick-free cattle onto the paddock.
- If you suspect poor tick kill, notify a veterinary officer in your area for investigation and testing of the acaricide.
What causes acaricides resistance
- Treatment frequency — the more often ticks are exposed to the chemical, the more likely they will develop resistance to it.
- Wrong dosage risks tick survival. It enhances resistance to the chemical.
- Consistent use of one chemical group for tick control. The same type of chemical should not be used for more than three years.
How to use acaricides
Acaricide resistance refers to the ability of ticks to overcome adverse effects of acaricides to survive. When resistant ticks survive an acaricide, they pass on this genetic capability to their offspring.
Initially, this resistant gene is low in a tick population.
However, with continued use of the chemical, a population of resistant ticks develops. The implication of acaricide resistance is that the chemical being used becomes ineffective to kill and control cattle ticks.
This reduces the number of available effective acaricides in the market.
The ‘ideal’ acaricide is one that, can be easily administered by a number of methods, such as pour-on, plunge dip, spray dip or injection, is rapidly metabolised and excreted to reduce the level of chemical residue in the animal, which requires long withholding periods and has a high level of toxicity towards all stages of the life cycle of cattle ticks.
One of the reasons why acaricides are abused is that they are packed in larger containers than what the average farmer may need to use.
So, what happens is that when a farmer asks for part of the acaricide, the container is opened, the farmer is given whatever quantity they asked for and then it is closed again. However, by this time, it is already compromised.
Production of smaller containers to take care of farmers with small herds is the way to go.