Before the development of modern clostridial vaccines in the 1970s, losses of up to 15% of the lamb crop could occur due to pulpy kidney<sup>3</sup>. The vaccines used today are effective against a variety of clostridial diseases and some vaccines are combined for effects against ''Pasteurella''. The vaccines consist of toxoids which are inactivated forms of the toxins produced by clostridial organisms. The principles of vaccination are the same whether a clostridium-only or ''Pasteurella''-combined product is used: a sensitising dose must be given 4-6 weeks before a second, confirming dose<sup>3</sup>. As immunity wanes over a period of a year, booster doses are required annually. Therefore, ewes should receive the primary vaccination course before entering the breeding flock and an annual booster approximately six weeks before lambing. Timing the booster vaccination in this way affords passive protection to lambs until they are around 16 weeks of age. Lambs born to unvaccinated ewes should be vaccinated between 3 and 12 weeks old, with a second injection given at least four weeks later. | Before the development of modern clostridial vaccines in the 1970s, losses of up to 15% of the lamb crop could occur due to pulpy kidney<sup>3</sup>. The vaccines used today are effective against a variety of clostridial diseases and some vaccines are combined for effects against ''Pasteurella''. The vaccines consist of toxoids which are inactivated forms of the toxins produced by clostridial organisms. The principles of vaccination are the same whether a clostridium-only or ''Pasteurella''-combined product is used: a sensitising dose must be given 4-6 weeks before a second, confirming dose<sup>3</sup>. As immunity wanes over a period of a year, booster doses are required annually. Therefore, ewes should receive the primary vaccination course before entering the breeding flock and an annual booster approximately six weeks before lambing. Timing the booster vaccination in this way affords passive protection to lambs until they are around 16 weeks of age. Lambs born to unvaccinated ewes should be vaccinated between 3 and 12 weeks old, with a second injection given at least four weeks later. |