External parasites of goats
External parasites of goats can cause a loss of production throughout the year. Producers should be aware of the potential parasites and be ready to treat their animals when necessary.
Insect and other arthropod pests of goats can limit production in many ways. External parasites feed on tissues such as blood, skin and hair. The bites and skin irritation caused by these parasites can result in discomfort and irritation to the animal. These parasites can transmit diseases to healthy animals from sick animals. They can also reduce weight gain and milk production. External parasites common to Michigan include lice, flies, mites and ticks.
Lice are wingless parasites that affect many different types of animals. Lice are also species specific, meaning that lice that affect goats only affect goats. There are two different types of lice, biting or chewing lice and sucking lice. Biting or chewing lice have a chewing mouth part and they feed on pieces of hair, scabs and skin. Sucking lice have mouth parts that allow the louse to pierce the skin of the goat and feed on blood and tissue fluid. The spread of lice is usually direct from animal to animal but can also be from grooming equipment, trailers or housing. Lice can only survive a few days in the environment. Lice infestations are usually seasonal and during the cooler months. Goats in poor condition are more vulnerable to infestation. Infected animals may rub or scratch which can cause loss of hair and ultimately raw areas on the skin. Weight loss, poor milk production and overall poor performance can result from a lice infestation. Goats should be treated with an insecticide that kills lice and retreated in two weeks as the insecticide will not kill the lice eggs. Michigan State University Extension suggests that producers check with their veterinarian for products safe to use on goats.
Several different types of flies can cause problems for goat producers. House flies can spread diseases such as mastitis and pinkeye which can severely reduce production in goats. House flies can also annoy livestock when present in large numbers. Stable flies are bloodsucking flies that have a painful bite. These bites mainly occur on the legs and flanks of goats. Stable fly larvae develop in decaying organic matter often found around barns and loafing sheds. Fly control starts with keeping the area clean from manure, bedding and spilled feed as this is where flies tend to lay their eggs. Fly traps and fly predators can also be used.
Many different types of mites can infest goats. The two most common types of mites on goats found in Michigan are the follicle mite which causes demodectic mange and the scabies mite. The goat follicle mite causes hair follicles to become obstructed causing swelling and the mites to be trapped. As the mites reproduce, the lesions become enlarged. Demodectic mange occurs mainly in young animals, pregnant does and dairy goats. Saanen breeds tend to be more sensitive than other dairy breeds. Scabies mites burrow under the skin causing dermatitis known as sarcoptic mange. While many cases go unnoticed, some goats will develop crusty lesions and severe hair loss around the muzzle, eyes and ears, and dry scaly skin on the body. There are several treatments for mites in goats, although a systemic treatment is best. Consult your veterinarian for treatment options in your herd.
There are several species of ticks found in Michigan. Tick bites can result in blood loss and transmit disease. Ticks that are commonly found in goats are three-host ticks, meaning that they infest three different hosts throughout their life cycle. This makes them difficult to control. Ticks are not commonly found on goats. Michigan State University Extension recommends that you consult with your veterinarian when selecting insecticides to use to control ticks on your animals.
Controlling external parasites can help your animals produce better by increasing their comfort. By controlling lice, flies, mites and ticks you will increase the comfort of your animals and may also increase the profitability of your farm.