Hectivac-P is a vaccine for sheep in the United Kingdom that protects sheep against 7 clostridial diseases and pneumonia. It should be administered subcutaneously at least 4 weeks before lambing. This results in the specific antibodies being produced by B-cells and secreted into the mammary glands. These antibodies in the colostrum of the vaccinated sheep provide immunity to her lambs. Booster injections are required to sustain immunity.
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Clostridium vaccine Wikipedia(Text) CC BY-SA