Haley Zynda, OSU Extension Educator ANR, Wayne County
(Image Source: Texas A&M Department of Entomology)
I’ve been hearing so much about ticks lately that it’s really been bugging me. The Asian Longhorned Tick is certainly one to keep an eye out for in our herds and flocks, but another ectoparasite that may affect sheep is the sheep ked, Melophagus ovinus. Keds are a like a tick, but only found on domestic and wild sheep and goats. Typically, keds are most prevalent in the Western United States, but with the ability to ship animals all over the country, it’s important to know what’s really out there.
I already mentioned that keds are similar to ticks, meaning it takes bloodmeals from our stock. Keds only take one bloodmeal per day and it can last from 5-10 minutes. When examining sheep for keds, they actually look like hairy wingless flies, not at all like a tick. They tend to hang out on the neck, breast, flanks, and rump. Rarely are adults found on the belly or the back of sheep because the skin in those areas can become dirtied with mud, dust, or bedding. Profit losses from ked infections may be direct or indirect. Infected fine wool sheep may produce low-quality, scraggly wool. Similar to how other bloodmeal insects can cause skin itching and inflammation, keds are no exception. Sheep may rub themselves on fences or feeders to relieve the itch, potentially damaging the wool. Further, the excrement (frass) the keds produce will permanently stain the wool. On the other end of the spectrum, meat breeds may need to spend more days on feed (hello increased feed cost) due to their poor performance. Even more, severe, untreated infections may result in permanent skin damage, lessening the value of the hide when harvested.
Spring is when most ked infections are diagnosed and they are most often on lambs. Ewes can be shorn before lambing to prevent ked infections from being spread to dam to lamb. Lambs can also be shorn if they are starting to look poor and unthrifty. However, shearing will only control about 75% of adult keds. Pupae are likely still attached the wool fibers close to the skin. Thankfully, there are residual insecticides that exist for treatment of keds. They can be very effective when applied to freshly shorn sheep and are active for 3-4 weeks post shearing, meaning they can also control the keds that once were in pupae but have hatched.
There are several types of insecticides that are labeled for use in sheep to control keds. They may be sprays, dusts, or pour-ons. Spraying may be difficult to apply on full-fleeced sheep because the product will have a difficult journey arriving to the skin with several inches of fleece in the way. Pressures of 200 and 350 lb./square inch should be used for short fleeced and long fleeced sheep, respectively. Out west, sheep may be run through a dip tank to completely submerge them in insecticide; the same practice may be applied with smaller flocks in portable galvanized tanks. Dusts and pour-ons are the most economical for small flocks and can easily be included as part of the shearing day set-up. Dusts are nice because the sheep don’t get soaked (and you’ll probably walk away cleaner, too).
If you need help deciding on a treatment protocol, your veterinarian can help. Always consult your veterinarian before integrating new health management practices in your flock. Even though keds aren’t a major problem for Ohio flocks, the world is showing us anything is possible.