Q.
Do I need to worry about tapeworms in my sheep/goats?
A.
Probably not.
Because they are the only worm that you can see in the feces, tapeworms often cause alarm. However, they tend to be non-pathogenic. There is no hard evidence that tapeworms cause production losses or ill health in small ruminants, especially sheep. According to most veterinary parasitologists, treating specifically for tapeworms is unlikely to be beneficial. In fact, it may contribute to dewormer resistance, if dewormers which also target stomach worms are used to control tapeworms.
The tapeworm that most commonly affects sheep/goats is Moniezia expansa. It is sometimes called the “milk tapeworm” because it infects mostly nursing lambs/kids. Sheep/goats seem to develop immunity to tapeworms at an early age. Unlike roundworms, tapeworms have an indirect life cycle, requiring another organism (pasture or grass mites) to complete their life cycle. Sheep/goats get infected when they ingest the mites containing tapeworm larvae. The larvae can overwinter in infected mites.
Tapeworms are flat and ribbon-like in appearance. When eggs are passed, they look like small grains of cooked rice. You may also see an animal passing an entire tapeworm (a long “string”). While tapeworm eggs (triangular in appearance) can be observed in fecal flotations, fecal exams are not considered to be a good diagnostic tool (for many reasons).
Heavy tapeworm infestation may result in mild unthriftiness and GI disturbances. Intestinal blockages with tapeworms are considered rare. There is some evidence that heavy tapeworm infestations may affect gut motility and predispose animals to enterotoxemia. More often, tapeworms are blamed for problems which probably have other causes. Where parasites are concerned, the focus should be on the less visible parasites that are likely causing more problems: stomach worms and coccidia.
If you decide you need to treat for tapeworms, praziquantel is the drug of choice. Praziquantel is not available in any form for small ruminants in the US. It is an ingredient in several horse deworming pastes. Albendazole (Valbazen®) is labeled for tapeworm removal in sheep. A related drug, fenbendazole (SafeGuard®, while not labeled for tapeworms, is another option (if labeled dosage is increased). Use of any unlabeled drug to control tapeworms in small ruminants requires extra label drug use and a valid veterinarian-client-patient relationship.
5/6/21
Additional reading
Disgusting Tapeworms: Timely Topics (WormX)
Tapeworms: Problem or Not - Maryland Small Ruminant Page
What about tapeworms in sheep? - WormBoss