Last week we discussed at length ticks as an example of an external parasite. There was a lot of feedback from readers.
Among the issues raised was control of these external parasites. Today, I will address precautionary measures when controlling external parasites.
External parasites can be controlled through spraying or dipping in an insecticide wash, shampooing, pouring on or injection of the insecticides. In most farms, these are simple operations that are carried out by farmers themselves.
Nonetheless there are precautions that must be taken. Insecticides are poisons that can harm the farmer and the animal.
The first thing to do always before using any insecticide is to carefully read the manufacturer’s instructions.
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WHEN DIPPING
If you are controlling external parasites by dipping, there are precautions you should follow.
If the animal has a wound, consider getting the wound treated and healed first before you take it to the dip. The dip wash can cause a lot of irritation when in contact with wounds and can interfere with the healing.
Dipping requires animals to be in good health and physically fit to be able to swim through the dip to the other end. Any fatigued animals and calves below four months shouldn’t be dipped.
Dipping has the advantage of good insecticide penetration and it is relatively faster especially when dealing with a huge herd. However, it comes with the challenge of maintaining the dip concentration amid extreme weather conditions.
Hot weather can over concentrate the wash while rain water runoff can dilute it. To reduce this, all dips should be sheltered. Contamination of the dip with organic matter like soil and cow dung lowers the concentration of the acaricide in the dip.
Animals should be dipped early in the morning when they aren’t thirsty. The animals should also be allowed adequate time for the dip to drain from the body before they go into pastures to avoid contamination of the pastures with the acaricide.
WHEN SPRAYING
For spraying, you will need a sprayer. There several in the market, each with its pros and cons.
There is a knapsack sprayer which is either hand held or secured on the back of the person doing the spraying.
There is a rocking pump sprayer that requires a minimum of two people to operate; one doing the pumping and the other person doing the spraying.
RULE OF THUMB
You can also have a spray race where animals walk through an alley as they are sprayed from all sides by insecticide sprays.
It is important to note that good or high delivery nozzle pressure is required for effective parasite control.
High pressure ensures that the insecticide reaches areas where external parasites hide for example in between the hooves, ears, tail switch, skin folds around the area where legs attach to the body.
Knapsack sprayers have been used effectively on smaller farms where up to five animals are sprayed. It is however a challenge when you have a large herd, as it can be tiring.
The rule of the thump when spraying is that the whole animal’s body be soaked in the insecticide.
Rocking pump sprayer; though relatively expensive is the best option as it has a higher delivery nozzle pressure coupled with a longer nozzle pipe that can reach all parts of an animal’s body. This pump is also suited for large herd.
Other methods of external parasite control include pour-ons which are liquid and oily insecticides that are applied on the back line of the animal.
Pour-ons are effective in external parasite control but are relatively costly.
How regular to spray or dip your animal will depend on many factors among them the parasite burden which is dictated by seasonal changes, the external parasite life cycle and the potency of insecticide you are using.
Spraying your animals twice a week is recommended as this can effectively make your herd clean at all times.
Lastly, it is important that when in an area with many farms, exercise movement controls of your stock to avoid contact with animals from other farms that mayn’t be practicing any control.
Remember external livestock parasite control is best done by a group of farmers in a given area for it to have a lasting impact.
-The writer is a veterinary surgeon working with the Kenya Tsetse and Trypanosomiasis Eradication Council - KENTTEC)
