Wintertime Pests and Goats

Wintertime Pests and Goats

Reading Time: 5 minutes

Winter can be a difficult time to maintain goat health and production. In addition to the feed and housing requirements necessary to meet energy requirements with low temperatures, goats can also have increasing energy losses due to the external parasite burden. Though warm sunny days may seem a more likely time to find creepy crawlies on your critters, there are several varieties of external parasites that are more prevalent in winter than summer. 

Infestations of lice in goats are generally more severe in winter months than summer. There are two types of lice that infest goats. Sucking lice and chewing lice. Sucking lice feed on the blood of the animal, while chewing lice feed on skin surface particles. Both varieties of lice have a similar life cycle, in which the lice live on the host. Because of this, transfer of lice is from animal to animal. Goats infested with lice have an unthrifty appearance, with dull hair coat, and are often itching and scratching on whatever is available. Infested animals, due to the chronic irritation, also have decreased milk production or weight gain.  

Sucking lice have sharp biting mouthparts. There are a variety of sucking lice found in the United States, including the African blue louse, goat sucking louse, and foot louse. The African blue louse is found primarily in semi-tropical regions in the US. These lice are primarily located on the head neck and body of goats. The goat sucking louse is found worldwide in temperate regions. This louse will distribute over the body of the goat. The foot louse, unsurprisingly, is found on the legs and underbelly of infested animals. In addition to infestations causing hair loss and lack of thrift, severe infestations can result in anemia due to excessive blood loss.  

Chewing louse. Uwe Gille / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/)

Chewing lice have wide mouthparts designed to scrape the skin. There are several species of biting louse in the United States. The most notable are the goat biting louse, the Angora goat biting louse, and the hairy goat louse. The goat biting louse primarily infests short-haired goats, while the Angora goat biting louse and the hairy goat louse prefer longer-fibered animals.  

The diagnosis of goats with a lice infestation is based on identifying goats with lice crawling in the hair or eggs attached to the hair. Animals will have clinical signs dependent upon the severity of the infestation, ranging from poor hair coat to ill-thrift, to weakness and anemia. When lice are identified on one animal in a herd, all goats in the herd should be treated. Goats with sucking lice may be treated via off-label use of injectable ivermectin or moxidectin. However, these medications will not treat a goat with chewing lice infestation. Treatment for both sucking and chewing lice is topical residual products, primarily those containing permethrin as the active ingredient. When treating lice infestations, it is necessary to treat animals twice, two weeks apart. Residual eggs during the first treatment will hatch within 10-12 days after treatment. Without a second treatment, the infestation will not be controlled.  

Mites are another variety of external parasite that flourishes on goats during winter months. The two most common varieties are the mange mite, Sarcoptes scabiei, and the ear mite, Psoroptes cuniculi. Sarcoptes mites burrow into the skin of the host animal’s body and limbs, causing inflammation. Goats will show varying clinical signs depending upon the severity of infestation. These signs range from mild crusting and hair loss to severe hair loss and pruritus. Psoroptes cuniculi, or the ear mite, unsurprisingly primarily nests in the ears of goats. These mites burrow into the skin of the ear, causing crusting, foul odor, and even head shaking or loss of equilibrium.  

Sarcoptes scabiei. Credit: Kalumet / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/)

Mites in goats are difficult to treat, as there are few labeled products. Lime sulfur dips or sprays can be used, repeating every 12 days. Topical permethrin products, such as those used for lice, may also be used, as well, with repeat application in two weeks. Ivermectin products are not approved for use as mite treatment and should be used only if advised by your veterinarian.  

Keds, though most commonly associated with sheep, can also be found to infest goats. These creatures are a large wingless fly. During their life span of up to six months, meds continually reproduce while dwelling on an animal. Adult keds have sucking mouthparts that pierce the skin of their host and suck their blood. This behavior results in irritation to the host animal, such as itching and scratching. In well-fed animals, keds cause limited clinical signs. In more severe infestations, the feeding of keds can result in anemia or cause such damage as to reduce the value of the hide in animals raised for slaughter. Keds can be treated with topical permethrin products. Due to the pupal stage of the ked life cycle lasting for three to four weeks, keds should be treated with a long-acting product or retreated in one month from the first treatment.  

Melophagus ovinus, sheep-ked; male, female and puparium; a blood-feeding ectoparasite of sheep. Credit: Acarologiste / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)

There are a variety of external parasites that can affect goats during winter months. These parasites can result in significant losses in production within a herd. External parasites such as lice, mites, and keds, are spread easily via goat to goat contact. If one animal is infected within a herd, they easily infect the rest of the animals. When addressing an infestation within your herd, it is imperative to treat all animals, to ensure eradication of the infestation. The ideal treatment for most of these infestations is a topical pour or dip. As these infestations are often found during the cold winter months, the medication must be applied during a fair day to avoid inducing illness.  

As with most diseases, it is much better to prevent an infestation in your flock, than it is to treat one. These parasites are primarily spread from animal to animal during close contact. Preventing contact with animals outside the herd is key to prevention. While this may be a breeze on a small farm, larger or range operations may have more difficulty. Developing a management plan for external parasites in your herd is very helpful. Simple procedures, such as quarantining new animals for two weeks prior to introduction to the herd, can make a large difference in parasite control. The impact of parasite infestations is also reduced by having healthy animals with balanced nutritious diets. Once a parasite infestation is established in your herd, treatment of all animals is necessary to achieve control. As many parasiticide medications are off label use, or not for use in dairy goats, working closely with your veterinarian will ensure that you use the right products for your flock.  

Sources:

Watson, Wes; Luginbuhl, JM. Oct 1, 2015. Lice: What They Are and How to Control Them: Animal Science facts. NC State Extension 

https://content.ces.ncsu.edu/lice-what-they-are-and-how-to-control-them

Talley, Justin. External Parasites of Goats Oklahoma Cooperative Extension Service EPP-7019: 

http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-5175/EPP-7019web.pdf

Kaufman, P. E., P. G Koehler and J. F. Butler. 2009. External parasites of sheep and goats. ENY-273. UF/IFAS Extension. Gainesville, FL. 

https://edis.ifas.ufl.edu/pdffiles/IG/IG12900.pdf

Originally published in the November/December 2020 issue of Goat Journal and regularly vetted for accuracy.

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