When we decided in 1998 to experiment with raising sheep we sat down and brainstormed. We had many important factors to consider: What kind of capital we had to invest. How we wanted to raise them (intensive or pasture based.) And whether we wanted hair sheep or wool sheep. But what we decided was the most important factor was herd health.
We had just watched a neighbour go through the horrible experience of buying a flock with a disease. The disease couldn’t be corrected with vaccines or management so he had no choice but to ship them all at a loss. It also resulted in the neighbour not being able to use any pastures or buildings that the sheep had been in or on for a year. We didn’t have the monetary or real estate assets to have this happen.
Before deciding what breed or anything else, we did extensive research into the common diseases and conditions that had an impact on sheep in our area. The local veterinarian and seasoned sheep producers were very helpful. The most prevalent diseases were parasite load, Caseous lymphaditis, ovine progressive pneumonia, Johnes disease and clostridial diseases. Another disease that warrants knowledge of, although it is not prevalent, is scrapie. With this research we were able to pose the right questions to the sellers and hopefully acquire healthy breeding stock.
Although this isn’t a disease, it is an extremely important economic factor. A sheep with a worm load isn’t healthy and isn’t productive. Drug companies are not experimenting with any new wormers and there is a growing amount of parasite resistance in sheep and goats. That makes establishing a parasite control protocol very important — especially for people planning on raising sheep in a confined area, such as in renovated hog barns, instead of rotating them around pastures. Most veterinarians will do fecal testing for a nominal charge, and then prescribe the best wormer for the load the sheep are carrying. Not all wormers kill all species of worms so this is important. We view a parasite load as manageable, but do cull ewes that have a low resistance to parasites.
We treat all animals that come onto our farm immediately and keep them in quarantine for 21 days.
CASEOUS LYMPHADENITIS (CLA)
This is a contagious bacterial disease caused by the Corynebacterium pseudotuberculosis, which leads to the formation of interior and exterior lymph node abscesses in sheep and other mammals. These lumps can be hard to spot on wool sheep and are chronic. They are untreatable with antibiotics, but can be controlled with vaccines. When the lumps pop there is thick pus that contains millions of bacterium that will stay alive on surfaces for other animals, as well as yourself, to get infected with. Therefore, if a flock is infected there are usually visible lumps or scars. We take this disease seriously because it is a major cause of carcass condemnation, therefore making it an economic as well as health issue. We only purchase very young animals if we are unsure of the sellers’ CLA status, and we keep them in quarantine with daily inspection for the six-month incubation period. This PDF file provides excellent pictures of CLA abscesses on sheep
OVINE PROGRESSIVE PNEUMONIA (OPP)
OPP is a viral disease of sheep in North America. OPP virus closely resembles Maedi-Visna, which is a similar slow moving virus that some provinces have screening programs for. The OPP virus can cause disease with any of the following signs: severe and progressive weight loss, laboured breathing or pneumonia, paralysis, swollen joints associated with lameness, and palpably hard, unproductive udders. However, most infected sheep never show clinical signs of disease. Once a sheep is infected with the virus, that animal stays infected for its lifetime and serves as a carrier even in the presence of high levels of circulating antibodies. Unlike some viral diseases, the presence of antibodies is not indicative of immunity. This disease is spread at lambing by the infected ewes feeding their young. Most ewes with this disease