Controlling Worms in Small Ruminants during the Spring

Presently, the ground has been relatively dry as rain has been below normal for the last few months. But spring is here and warmer weather is around the corner and the expected spring showers. May usually has the highest rainfall of the year.

Worms, or internal parasites, are one of the biggest problems of small ruminants and especially meat and dairy goats. Worms not only kill both young and old animals, they contribute to poor growth rates, an unthrifty appearance, coughing, diarrhea, and, in severe cases, bottle jaw. Lack of control of worms can destroy a herd or flock. In order to control worms, you must set up sanitation and deworming programs and then adhere to them. To minimize contamination of uninfected goats, maintain a dry, clean environment to reduce worm growth. Depending on location and density of animals in the field, deworming may have to be repeated at different times during the year. Sanitation programs to control worms in small ruminants include sound manure management with frequent removal of manure. The facilities need to be clean to minimize potential contamination with parasitic eggs in the manure. Rotate pastures at least every three weeks to break the life cycle of the worms if possible and decrease stocking rates when the livestock density is too high. Taller pastures for goats will minimize exposure to larva of internal parasites. Depending on the type of forage, goats should graze four to six inches above the ground to minimize exposure to larvae of internal parasites which are primarily located in the bottom four inches of grass.

During summer months, it is critical that height of forage be monitored closely as lack of rain may slow growth of the forage and the pasture may quickly become too short. Other sanitation methods include having feed goats in troughs or racks that are sufficiently high above the ground to prevent manure contamination and thus exposure to parasitic eggs. A bar down the middle of the feed trough prevents goats from playing in the trough and dropping manure in the feed. Watering troughs should be constructed to prevent manure contamination. A concrete pad extended around the base of the trough can prevent goats from getting close enough to get manure in the water. Utilize high, well-drained pastures, especially when the ground is wet, and avoid low, wet pastures when rains are frequent.

There are different types of deworming programs that can be effective for goats. One of the most effective programs includes monitoring the level of parasite eggs in the feces, i.e. fecal egg counts (FECs), which provides an indication of the quantity of worms (and also coccidia, a protozoan parasite in the small intestine). You or your veterinarian may conduct FECs either on a routine schedule or when an animal is suspected of having worms and then deworm animals that have high FECs.

Fecal egg counts can be used not only to monitor the level of infestation of internal parasites in goats but also to determine the effectiveness of the dewormers used to treat the goats. Many producers now use a dewormer until it is no longer effective before switching to another dewormer. This technique is believed to save effective products of unrelated compounds for future use in the parasite control program. For beginning goat owners, it is best to work with your veterinarian or an experienced goat owner on internal parasite control in the herd. For producers who deworm all goats on a 4 or 6 week schedule, there is greater risk of build-up of parasite resistance to a dewormer than with less frequent deworming. Goats that consistently need deworming should be culled from the herd.

Some experienced caretakers may be able to deworm only 20 to 30 percent of the herd by routinely watching goats for signs of abnormal appearance and/or behavior plus monitoring levels of anemia in the mucous membrane of the eyelids, gums, or vulva. One approach, called the FAMACHA system for monitoring of the mucous membranes of the lower eyelid (not the eye), works well with a knowledgeable caretaker and when Haemonchus contortis, or the barber pole worm, is the primary internal parasite. H. contortis is a blood sucker, and heavy infestation results in anemia. Other techniques include monitoring the pigmentation of the vulva or gums to determine level of anemia.  However, if tape worms, Trichostrongylus, or other worms are the primary worm infecting the herd, monitoring anemia levels may not adequately diagnose the problem, since these worms are not primarily blood suckers.

In summary, worms in small ruminants can be controlled by good sanitation and a deworming program. Goats and sheep should be dewormed only as often as needed to control worms. However, the need for deworming varies greatly among herds, depending on sanitation, forage management, and observation skills of the caretaker.

(By: Jodie Pennington, LU Small Ruminant Specialist)