tick-borne diseases; tick

Livestock production: The basic principles of tick control

Question: Can you help with some basic advice for tick control, please?

It is essential in livestock farming to control ticks and in this way prevent production losses and the spreading of diseases they transmit. Here are some pointers.

Effective tick control depends on having a basic understanding of the type of tick that needs to be managed. There are a number of key factors to consider.

ENVIRONMENTAL CONDITIONS

  • The combination of rainfall and temperature is important to the survival of ticks that occur on grazing.
  • A specific level of humidity is needed for tick eggs to hatch and for the ticks to survive until they can get onto the animals, where they will feed on the animal’s blood.
  • For this reason, tick-related problems occur most often in the warmer areas, where conditions are ideal for the hatching of eggs and the survival of high numbers of ticks.
  • Very few ticks can survive in drier areas, but there are some ticks – such as the bont-legged tick and sand tampans – that have adapted to survive even under these stringent conditions.

Also read: Watch for tick-borne diseases

TICK-BORNE DISEASES

  • Ticks need to be controlled for many reasons.
  • First of all, control will limit the negative effect they have on production – brought about because they suck blood which decreases the animal’s potential for meat and milk production.
  • Some ticks also damage the hide, and this can lead to wounds and skin infection.
  • Different types of ticks can also carry organisms that causes deadly diseases such as redwater and heartwater.

Also read: A comprehensive introduction to ticks and tick-borne diseases

TYPES OF TICKS THAT NEED TO BE CONTROLLED

  • Big female ticks, engorged with blood, fall off and produce thousands of eggs on the pasture. The eggs hatch after a specific period, depending on environmental conditions.
  • The small ticks – about the size of a pin head – that hatch from the eggs are called larvae. They climb up grass stalks and get onto animals that brush past the stalks as they graze.
  • Once on the animal, they attach themselves and suck blood.
  • They are engorged after about a week and they then move on to the next stage in their development.
  • If all the developmental stages (larva to nymph to adult tick) occur on a single animal, we classify the tick as a one-host type.
  • In practical terms, this means that it will develop and stay on the animal for a minimum of 21 days.
  • The life cycle of multi-host ticks are different, however, and the larvae fall off the animal after engorging.
  • The larvae then moult to the next developmental stage (nymphs).
  • They attach themselves to a different animal, where they feed. In practical terms, this means that the ticks stay and feed on the animal for about a week.

TICK CONTROL PRODUCTS

  • Most dipping remedies for tick control are formulated for external use.
  • The remedy is applied in a way that brings it into contact with the ticks.
  • They either die immediately and drop off the animal, or die over a few days while still on the animal.
  • Dipping remedies kill ticks on the animal during treatment and, for about a week afterwards, will also kill those that get onto the animal.
  • Dipping remedies are applied by using a dip tank, spraying the animal or using a pour-on mixture, put on the backs of cattle or – on goats and sheep – in places where ticks normally attach themselves.

Three main groups of dipping remedies are available to the farmer:
– amitraz, eg Triatix
– pyrethroid, eg Redline
– organophosphate, eg Coopers Supadip

  • Some dips have to be diluted with water before use.
  • Work carefully to ensure that the proportions are correct, so they will be effective but not so strong that they poison the animal.
  • Pour-on dips are not diluted but applied directly to animals, in the correct dosages for their weight.
  • Always read the instructions on the label for the correct mixing or dose (pour-on) of the dip and follow them meticulously.

Also read: Dipping and tick control

APPROACHES TO TICK CONTROL

Tactical control: Ticks are only controlled once they become a problem, and a dip is used to kill visible ticks. This is repeated as often as needed.

Strategic control: If the farmer understands the life cycle of the various types of ticks he can control them routinely during specific seasons in order to decrease their numbers.

  • For one-host ticks such as the blue tick, dips are applied every 3 weeks to prevent engorged female ticks falling off and producing thousands of eggs on the pasturage.
  • For multi-host ticks like the brown ear-tick, dips are applied every week to control and kill adult ticks that get onto cattle during the summer months.
  • This treatment is repeated every week because the specific tick engorges within a week.

Controlling diseases transmitted by ticks:
If animals are susceptible to diseases such as redwater and heartwater, a weekly treatment using a dipping remedy will be needed at specific times of the year, such as summer, to prevent the ticks’ transmitting the diseases to cattle.

It is advisable for farmers to obtain dipping remedies from a veterinarian or someone who can give them the correct advice about using the dips for the specific needs of their livestock.

  • This article was written by Dr. Danie Odendaal and first appeared in Farming SA.

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