When the cause of sudden death of a calf is blackleg bacterial toxins (poisons), the first point to make would be the calf swallowed blackleg spores from the soil. This means the premises are contaminated with the spores, which never die. During rains, these spores are normally concentrated by surface water in various spots in the ground, and drought or rains will cause them to surface from the soil. When the spores are ingested, they go to muscles and remain dormant. A trigger breaks them out of dormancy sometime later, perhaps months or years. Then the bacteria rapidly multiply and produce toxins in the muscles, killing the muscles (black, dead muscles), causing blood poisoning and sudden death. The most common trigger is fast growth. Another trigger is muscle exertion as caused during working, weaning, and hauling. Affected calves may become infected at an early age and die of blackleg at a later age. When blackleg occurs, the transmission was not necessarily recent but possibly months ago. The death is so rapid that treatment is normally ineffective. All dead calves should be burned with untreated wood products to prevent ground contamination. Since other calves can have the bacteria in dormancy, guarding against triggers is suggested. The remaining calves should be vaccinated, but if other calves die, they were already infected with dormant blackleg bacteria before vaccination. Vaccination after exposure will not prevent the dormancy from breaking out. The 7-way (or 8-way) blackleg vaccine should be used since other strains in addition to blackleg can be present that also cause sudden death. The seven strains can only be diagnosed in a dead calf by necropsy and laboratory tests. In addition to blackleg, the other six clostridial diseases that cause sudden death are black neck, black liver, malignant edema, and B, C, and D enterotoxemia. The proper vaccination program includes annual vaccination of the entire herd (calves, cows, heifers, bulls), not just calves. Grown cattle die from four of the seven different blackleg-type bacteria. Cows should be vaccinated during the last three months of pregnancy or twice a year.