Controlling Parasites in Sheep and Goats
There are many reasons that sheep and goats are far more susceptible to gastrointestinal parasites than cattle. Their grazing habits make them far more likely to consume fecal matter, allowing worms to complete their life cycle. They are also more susceptible to the parasite Haemonchus contortus (the “barberpole worm”), which causes blood loss and anemia in addition to the diarrhea and weight loss that are more typical side effects of intestinal worms. While worms can be a significant health issue in these animals, it is imperative that dewormers only be used with caution as part of an integrated parasite management program. Overuse of dewormers will lead to rapid development of resistance in parasites, which can lead to life-threatening health crises with no tools to combat the worms.
Avoid overstocking and rotate pasture to minimize parasite loads. Feed hay in a raised feeder to minimize fecal contamination. Be aware that females generally shed large numbers of eggs around the time of lambing/kidding, contaminating the environment that babies are born into. It is critical to monitor this situation closely to avoid a crisis that spirals out of control.
FAMACHA is a system that utilizes eyelid color to monitor for anemia as an indicator of infection with the barberpole worm. With proper training, producers can use this system to minimize the number of animals that are dewormed and identify individuals with increased susceptibility to parasites. All sheep and goat owners can benefit from training in this method. Potential pitfalls of FAMACHA is that the system fails to identify parasites other than the barberpole worm. Also, it is possible that anemia can be caused by health issues other than barberpole worm. Therefore, it is important to use FAMACHA only with training and only as one tool as part of a complete parasite management program.
Fecal examinations can also help monitor for parasites, especially those that are not identified by the FAMACHA system. They can also be used to perform a fecal egg count reduction test to assess the efficacy of dewormers in your herd and identify resistance. When used for monitoring, they can decrease the need for deworming. Work with your veterinarian to develop a parasite management plan that will minimize treatment and maximize the health of your herd or flock!