Dear Daktari, I keep sheep and goats with the aim of supplying them to hotels in the city. I have observed parasite control being done mostly in cows. I am just wondering if I need to care for my sheep and goats against external parasites like it is done in cows? If so what should I be worried about?

[William Asego, Homa Bay County]

Thanks Asego for your question. Many farmers assume that sheep and goats do not need external parasite control. This is not true. Sheep and goats also suffer external parasite infestation and will need control of such pests just like cows. Sheep and goats should be sprayed, dusted or injected to control such parasites. External parasites lead to reduced feed intake, low weight gain and milk production affecting the animal's market value. I will discuss common ones that target sheep and goats.

Lice

These are blood-sucking parasites that live their entire life on shoats. Lice have piercing and chewing mouth parts hence the grouping into biting and chewing lice. Lice infestation is characterised by matting of the hair coat, formation of scab, presence of pus, excessive scratching on walls, tree barks - this can result in anemia and wounds that can predispose to secondary infection, and self-licking. Affected shoats will appear dull. Lice move from one animal to another through contact within herds or introduced into herds by new entrants into farms of infested animal.

Control of lice

While there are many insecticides to control lice, application of the pesticide should be repeated after two weeks to target eggs which will hatch after 12 days and are not normally affected by the insecticide.

Nasal bot flies

As the name suggests, this parasitic fly infest the nostrils of sheep and goats and causes excess nasal discharge, nose rubbing and head shaking. The adults lay their larvae in the nostrils from there they migrate through nasal passages as they grow.

Control of nose bot flies: Oral drench and systemic pesticides can affectively control this parasite.

Mites

This are sometimes called mange or itch. They normally feed on the skin surface. They cause extreme irritation and itching. Mites can spread very fast in a herd and may affect all animals. Affected goats and sheep will rub against surfaces most of the time and subsequently lose weight. Other external parasites include -fly maggots/myiasis and fleas.

Factors to consider in control of external parasites;

Before using pesticides, check the expiry date of the product, read manufacturers' guidelines on use and how to give first aid in case of poisoning.

All pesticides are poisons and must be kept out of reach of children, pets and livestock. Always keep pesticides in their original containers and away from human food and animal feeds.

[Dr Othieno is a veterinary surgeon and head of communications at the Food and Agriculture Organisation of the United Nations (FAO) Kenya. The views expressed here are not necessarily those of FAO]