Managing Ticks on Horses

Ticks are bloodsucking creatures that attach to human or animal hosts at specific times during their life cycle to obtain a blood meal. When full, they drop off and remain hidden in thatch and overgrowth until it is time to feed again.

Ticks are most commonly found in overgrown, brushy areas which provide the shelter and humid conditions that ticks need.  These areas also harbor the small mice and other mammals that are important hosts during tick development. Avoidance of “ticky” areas, use of protectants, and keeping horses in mowed pastures where the vegetation dries out quickly and allows penetration of sunlight will reduce problems with ticks.

The lone star tick and the American dog tick are the most common ticks in Kentucky, and both feed on horses.  They are three-host ticks, which means that they attach to and feed upon three different animals during their life. The three animals may be of the same or different species.  Underbrush and a large population of small mice and other animals provides plenty of hosts.

Adult American dog ticks are brown and about the size of a small pencil eraser. They have a silvery-grey, shield-like plate covering part or all of their backs. Adult females that have filled themselves with blood are slate-grey and about the size of a raisin.  Early stages, larvae and nymphs are much smaller and difficult to identify.  They feed almost exclusively on small wild rodents. Dogs are the common host for adult ticks, but these adults also will feed on cattle, horses, and people.  They are most likely to be encountered in overgrown areas, woods, and fields. The adult ticks are active in Kentucky from spring through mid-summer.

The lone star tick gets its name from a distinct white spot on the back of the adult female. Adult males do not have this spot; instead, they have pale, lacy white markings on the rear edge of the back.  Lone star ticks are most prevalent in western and south-central Kentucky, but are spreading to other areas. They are especially abundant during spring and summer.  Lone star ticks have long mouthparts which can penetrate deeply into the skin and make a painful bite.  Deep sores can form at the site of attachment and may develop secondary infections.

Small numbers of attached ticks should be removed promptly. The mouth parts of a tick are shaped like tiny barbs. Therefore, the best way to remove a tick is to grasp it with tweezers as close to the skin as possible and pull it straight out with gentle, even pressure. Don't jerk or twist the tick because the head and mouth parts may remain embedded, increasing the chance of infection. If tweezers are unavailable, grasp the tick with a piece of tissue, trying not to squeeze or crush the tick's body since this may force disease organisms into the wound. Petroleum jelly, hot matches, and other "folk" methods of removal should not be used.

If there are large numbers on animals, it is impractical to remove them singly.  Curry combs will not do the job.  Use a fly wipe-on containing either the active ingredient permethrin or pyrethrins.  These fast-acting insecticides will tend to irritate the ticks and prompt them to detach.

For prevention, wipe-on’s or whole animal sprays containing permethrin are safe for use on horses and provide a relatively long term residual effect (in the range of 3 to 5 days).  Regular applications are needed to keep protection in place.  This is needed only when horses are in “tick country” such as overgrown pastures, edges of woods, etc.  See Figure 3 for information on using pesticides for tick control.




CONTACT:
Dr. Lee Townsend, (606) 257-7455, ltownsen@ca.uky.edu
Department of Entomology, University of Kentucky