Do not let the cost hinder clostridial vaccinations
The regional veterinary laboratories (RVL) provide a really useful service to livestock producers. Farmers, through their local veterinary surgeons, can submit carcasses and associated specimens, such as blood, faeces, placentas etc, for disease diagnosis.
Each month the RVLs produce a report on the most interesting cases that they have encountered. These monthly reports are readily accessible on the Department of Agriculture website, www.agriculture.ie.
What caught my eye on scanning through last year's monthly reports was the number of times that clostridial diseases were diagnosed as a cause of lamb deaths. The clostridial group of bacteria cause eight different diseases in ewes and lambs, including Lamb Dysentry, Pulpy Kidney, braxy, Blackleg and Tetanus.
Once precipitated, the disease occurs so rapidly that the animal is usually found dead before any treatment can be considered. However, on the positive side, there are well-established and excellent multivalent vaccines (ie, 7-in-1 or 8-in-1 products) available to prevent all these diseases. I do not know why, perhaps questionable economics, but many flock owners have discontinued routine clostridial vaccination that was considered an essential part of good flock management 30 and 40 years ago.
Breeding ewes, replacement ewe lambs and rams require comprehensive cover against all the important clostridial diseases and so should be treated with a 7-in-1 or 8-in-1 vaccine.
Unvaccinated flocks or ewes of unknown status require a primary course consisting of two injections four to six weeks apart. Subsequently the flock will require an annual booster that is given about four weeks pre-lambing. Flocks with an extended lambing period (six weeks or more) should be split into early and late lambers and vaccinated at the appropriate times.
The annual booster protects the ewe herself and elevates antibody levels in the ewe's colostrum. Lambs acquire their immunity through these antibodies in the colostrum. No clostridial antibodies are passed to the developing fetus by way of the maternal blood supply. In order for the lambs to acquire sufficient immunity, the ewes must be vaccinated and ewe-feeding pre-lambing must be adequate for quality colostrum production.