Vaccinating for overeating disease

Recently, my biggest and best Katahdin ewe lamb died, most likely from overeating disease. She was about 10 months old. It was my fault. I had bought her from another farm when she was about 6 months old and had neglected to vaccinate her. Since the start of the breeding season, she had receiving grain to support her continued growth during pregnancy.

A few years ago, Cornell University carried out a study to determine the proper vaccination schedule for enterotoxemia (overeating disease). Researchers looked at different vaccination regimes to determine which produced the most antibody response to Clostridium perfringins, the organism that causes overeating.

Clostridium perfringins is a normal inhabitant of the ruminant's gut, but under certain situations it proliferates and produces a toxin which causes clinical disease in sheep and goats. Enterotoxemia, also called "pulpy kidney" disease can be a costly disease. It is characterized by sudden death of generally the fastest growing, most vigorous lamb(s) in the flock. Occurrences are predisposed by abrupt changes in feed, usually to a diet richer in carbohydrates, such as from grass to a high concentrate diet. Lamb being creep fed or nursing heavy-milking dams are also susceptible, as are lambs in feedlots. Irregular feeding, in adequate feeder space, stress and changes in weather can also contribute to incidences of the disease.

Ewe with triplets

Efforts to treat lambs and kids for overeating usually do not meet with much success. Treatment is usually administration of the antitoxin, high doses of antibiotics and supportive therapy such as fluids and vitamins. As with most disease conditions, it is far better to prevent than treat overeating disease. Vaccination is cheap insurance. But when and who do you vaccinate, as recommendations vary?

Researchers at Cornell vaccinated half of 200 Finn x Dorset ewes three weeks prior to lambing. They collected blood serum samples from 20 vaccinated and 20 non-vaccinated ewes prior to vaccination and at week 2, 1, and 0 prior to the start of lambing. Lambs from each of the first 13 and the first 14 sets of triplets from vaccinated and non-vaccinated ewes, respectively, received one of three different vaccination treatments: no vaccine (control), vaccination on day 1 and 21 of age, or vaccination on day 21 and 42 of age.

According to the data, vaccination of lambs did not increase blood sera levels of the antibody, whereas pre-lambing vaccination of ewes significantly increased lamb antibody concentrations compared to lambs reared by non-vaccinated ewes. Vaccination of ewes resulted in lambs with higher antibody concentrations until 10 weeks after lambing: 16 IU/ml compared to 2 IU/ml (IU=international units), indicating that vaccination of ewes prior to lambing imparts passive immunity to lambs via the colostrum. The results of this experiment indicate that ewes should be vaccinated 3 to 4 weeks prior to lambing and that there is no benefit to vaccinating lambs prior to 6 weeks of age.

It is important to note that animals that have not previously been vaccinated require two doses of the vaccine approximately 4 to 6 weeks apart. The toxoid product should be used in vaccination programs. The antitoxin only imparts immediate, short-term immunity. A subcutaneous (under the skin) injection is preferred to an intramuscular (in the muscle) injection, to prevent damage to the carcass. In most cases, a vaccine that combines overeating disease type C and D and tetanus, commonly referred to as CD-T, is sufficient; the 7 and 8-way vaccines are generally not necessary.

Enterotoxemia appears to be less understood in goats, and the vaccine is not known to be as effective. Consequently, it is usually recommended that goats be vaccinated every six months, including a month prior to kidding.


Created or last updated by Susan Schoenian on 27-Jul-2010 .

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