Tick Infestation and Control in Horses

Ticks are a common finding on horses living outdoors, particularly horses whose pastures include long grass, dense brush, or forested areas. Horses ridden in densely vegetated areas are also at risk of exposure. The risk of tick exposure varies depending on the region and climate, with many tick species having seasonal peaks where the chances of encountering a tick are much more common.

Ticks climb onto a host to feed for several days, then drop off and don’t feed again for as long as a year. Many tick species are able to transmit serious disease through their saliva.Transmission of some diseases takes only 3-6 hours of tick feeding, so removing ticks promptly is important in preventing tick-borne illnesses.

The spinose ear tick (Otobius megnini) is a common finding in the ears of horses in the western United States and Canada. These ticks attach deep within the ear canal or on the inner surface of the ear, making them difficult to locate. Local irritation often causes horses to react negatively to inspection of their ears, making inspection and removal even more difficult.

Ticks are abundantly found worldwide and commonly affect horses due to their outdoor lifestyle. Finding a tick on a horse is not an emergency, but prompt removal of ticks is important to reduce the risk of disease transmission and other complications.

Some tick species release a toxin that causes tick paralysis.

Symptoms of tick paralysis require immediate veterinary attention.

Tick infestation can happen to any mammal living in a region with a population of ticks. Ticks have peak seasons of activity throughout the year during which the likelihood of horse exposure increases. The outdoor lifestyle of horses, especially those who spend time in long grasses or dense forests, further increases equine exposure to ticks.

Most ticks are easily seen on the horse’s coat, often appearing as a dark, raised lump on the skin. Further inspection reveals the characteristic features of a tick, such as 8 legs, a round body, and the head embedded in the horse’s skin. Recently attached ticks have flat bodies, which expand as the tick feeds and fills itself with blood.

Tick attachment produces a local skin reaction that typically appears as a scab or oozing sore.These sores usually heal without any intervention within 1-2 weeks.

Spinose ear ticks cause unique symptoms affecting the muscles through an unknown mechanism.

Finding ticks on a horse is not an emergency, and testing for tick-borne disease is unnecessary. The only indication for testing is developing symptoms suggestive of a tick-borne disease.

To effectively remove a tick, use tweezers to grasp the tick close to the skin, and pull straight away, using steady pressure until the skin tents, then pause. Most of the time the tick lets go. If it does not, continue pulling steadily away until it does. Do not squeeze, crush, or puncture the tick during removal. Common folk remedies such as petroleum jelly, fingernail polish, alcohol, or matches may stimulate the tick to regurgitate into the horse, increasing the risk of disease transmission. After removing the tick, clean the bite wound with soap and water. Methods for disposing of ticks include sealing them in a container, wrapping them in tape, or flushing them down the toilet.

It is common for tick bites to develop redness, swelling, or crusting after tick removal. If these symptoms persist or get worse, consultation with a veterinarian is recommended.

Two primary strategies exist for preventing ticks in horses: regular inspection for and removal of ticks, and the use of tick-control products.

A systematic examination of the places where ticks are most commonly found is the best way to find ticks on a horse:

• Inside the ears
• Inside the false nostrils
• Under the forelock and in the mane
• Under the jaw
• In the armpits and flank regions
• Underneath the fetlocks
• In the udder/sheath region
• Under the tail

Several anti-tick products are available for horses, and act as both a treatment and a preventative. Most products are pyrethroid-based, and come in several forms, including:

• Topical sprays
• Pour-on, dust-on, wipe-on, or spot-on products
• Blankets or leg wraps containing an antitick product

Pyrethroid products are also available for treating the horse’s environment, including their pasture. Following label directions for these products is critical, as many are toxic to other animals and/or the environment.

Products containing Amitraz are toxic to horses. These products are commonly used in other species, but are not safe for use on horses.

Topical tick-control products are applied before the horse is turned out to pasture or before riding in vegetated areas. Focusing product application to the horse’s tail, chest, armpits, legs, and under the jaw is the most effective, as these are the main areas where ticks latch on.

Other environmental control measures include:

• Mowing tall grass
• Mowing overgrown fence lines
• Adding fencing to prevent horses from accessing areas with dense vegetation
• Altering fencing to reduce tick-laden wildlife movement through pastures

Tick bites are common in areas with a high tick population. Many ticks have a seasonal lifecycle, making ticks more prevalent during certain times of year.

• Topical tick products
• Manual removal