We have all seen it before: goats acting restless, scratching incessantly, sliding down the hill on their briskets, and sometimes even losing patches of hair, especially on their legs. Upon investigation, little bitty critters can be found inhabiting their coats. These are lice, and they can cause intense irritation and itching, usually during the winter and in early spring.
Lice are wingless, flat insects that are very tiny in size. Two kinds of lice may affect goats: biting and sucking. The biting lice feed on dead cells on the skin surface and cause itching. Sucking lice suck blood from their host, but also cause itching. Severe infestations of these can lead to anemia and in extreme conditions, death due to blood loss.
The scientific name for the biting louse that affects goats is Bovicola capra; the sucking louse is Lithognasus stenopsis.
Interestingly, different animals have different lice that have evolved specifically to them. This means that goat lice will not affect humans and human lice will not affect goats. In addition, because the lice are dependent on the animal, if removed they will soon die. This means that they spend all of their time on the animal that is their host.
How are lice diagnosed? Diagnosing lice is not hard. Lice can usually be assumed to be affecting the goat if patches of hair are missing or hair is seen attached to fences, trees and other areas that can be rubbed against to relieve the itching.
Since the lice may inflame the hair follicles, another sign of infestation may be a rough, or poor quality, coat.
Upon close examination in good light, or with a magnifying glass, lice and their eggs, called nits, can be seen attached to the hairs. They are more likely to congregate along the topline in goats, so that area should be checked first. The nits are grayish white and can be found in large numbers on the hairs next to the skin.
A close look under a microscope will verify whether the lice are the sucking or biting variety. A sucking louse has a head that is larger than the thorax (middle section of the body); a biting louse has a thorax that is larger than the head. They have small claws to hold onto the hairs of the animal.
The nits hatch into larval lice, called nymphs. They then feed and molt three times before becoming adults. The whole life cycle takes about 30 days.
How can lice be prevented? The best control for lice is regular brushing of the animals. However, for breeders with a large number of goats, this may not be feasible. Healthy goats are also more likely to be able to keep their lice burden down, as well as not showing the secondary effects caused by these pesky critters.
Fresh air and rain are reputed to prevent lice. Related to this is the fact that overcrowding can lead to more severe infestations, as the goats infect one another.
What treatments are available for a goat that has lice? Often the lice are not severe enough to require treatment; in fact, when the weather warms up and they can be clipped for shows (or comfort), the lice will leave of their own volition. Sunny, hot weather and lack of a nice warm place to burrow makes the goat a less friendly home.
If the lice infestation is bad enough to require treatment, or summer is a long way off, a number of insecticides are recommended for treating goat lice.
These insecticides may be applied by dipping the animal in a vat (not very practical or affordable for many goat owners); spraying; dusting; pour-on (either spot-on or down the back); or by giving orally or by injection (e.g., Ivermectin).
Many people prefer pyrethrins for insecticidal treatment because they are the most "natural". Pyrethrins are insecticides that are produced by certain species of the chrysanthemum. The flowers are dried and the oils removed. The dusts that come out of this process are poisons that penetrate the nervous systems of insects. In some cases, other chemicals are added to provide a more toxic effect.
Pyrethrins are not known to be stored in the animal’s body, or excreted in milk. This does not mean that they are not without risk, however. Use of dust with pyrethrins should be done in a well-ventilated area, with care taken not to inhale the powder.
Two other nice things about pyrethrins is that 1) they decompose and lose their toxicity through exposure to sunlight and air, and 2) they can be used on lactating goats, unlike other chemical treatments.
Other insecticidal powders, such as Co-Ral® 1% dust, can be used on kids and pregnant or lactating does. According to Michele Konnersman, DVM, a goat veterinarian in Arcata, California, the dust should be applied to the entire body, including the belly, once weekly for three weeks.
For those with just a few small goats, she recommends using cat/kitten flea powder, which is safe even on the tiniest kids.
Dr. Konnersman believes that the pour-on and injectable anthelmintics are not a cost-effective way to eliminate lice.
For goat breeders or owners who prefer to avoid insecticides entirely, other treatments may work. Some people dust their animals with diatomaceous earth (DE). DE is the fossilized remains of the diatom, a single celled aquatic plant that lived about 20 million years ago. It dehydrates soft bodied insects. The food grade DE is claimed to be a good antiparasitic when added to feed.
A number of oils and herbs are also known to have insecticidal properties. There are several natural products on the market for head lice in children that might be worth trying. But for people who have more than one or two goats, the cost and the time to comb it through, and rinse it out, make this method less desirable.
Most well-known of the insecticidal oils are tea tree and neem. Rosemary, lavender, lemon and geranium essential oils also have properties known to repel insects.
Regardless of which method is used, re-treatment is recommended after about two weeks. This is because the pesticide does not kill the nits, so they hatch and start the problem all over again.
For goats that are healthy and minimally infested with lice, the time-tested "ignore it and it will go away" is an option. Breeders should keep an eye on the goats’ behavior and the appearance of their coats, and look for any negative changes. This will tell whether treatment is necessary. In many cases, when the warm weather comes back, breeders can clip their goats and let them go out in the sun for the truly natural cure.