Sheep and goats are much more prone to die from infestations. According to Elizabeth Walker, assistant professor in animal science at the Missouri State University William H. Darr School of Agriculture, de-worming sheep and goats is just one tool for combating internal and external parasites. “De-worming should only be used as part of an integrated parasite management plan.”
Another method of parasite control is to avoid overgrazing pastures and to keep at least 4 inches of vegetative cover. “Most parasite larvae will only go about 2 inches up a plant, so keep your animals grazing above about 4 inches so they will not be able to consume majority of the larvae,” Walker added.
The two biggest offending parasites with sheep and goats are Haemonchus contortus (barber pole worm) and Ostertagia circumcincta (brown stomach worm), said Whitney Whitworth, associate professor of animal science at the University of Arkansas in Monticello.
Signs of an animal with an internal parasite infestation are anemia, loss of appetite, rough hair coat, bottle jaw, diarrhea and overall ill health.
“Identification of the parasites can be done by your veterinarian or by anyone with a little parasite training,” Walker added.
Whitworth and Walker recommend the use of FAMANCHA scores and fecal egg counts are more precise ways of determining parasite loads.
“De-worming either prior to or after kidding/lambing is often a good idea,” Walker said. “Lambs should not be de-wormed until they are several months old and only if they are showing some signs of parasite infestation.”
De-wormers are sorted into three different drug classes. Producers should work with their local veterinarian to determine the best de-wormer for their animals.
“Producers should not switch from class to class, instead, find a de-wormer that works for you and stick with it until it quits working,” Walker said.
Accurate weights of their animals are necessary to determine the proper de-wormer to use. “Never feed the de-wormer, especially to group fed animals,” Walker said. “If oral de-wormers are given, animals can be fasted for 12 hours prior to de-worming to help slowdown their rate of passage. This may help with the efficacy of the de-wormer.”
Whitworth reminded producers that there is nothing more beneficial than putting the animals on a fresh/clean pasture after the administration of an anthelmintic.
