Two necropsies of cattle dead from blackleg were performed. Fragments of skeletal muscle from these two cattle were immersed in paraffin for multiplex polymerase chain reaction (PCR) analysis.
Twelve calves up to nine months of age developed signs of blackleg and eight died. Ten of those 9-month-old calves had received only the first dose of a blackleg vaccine at 4 months of age, but no booster. The last two affected calves belonged to a herd that had never been vaccinated. Four out of five calves treated with penicillin for 6-7 days recovered from the disease. The diagnosis of blackleg was based on necropsy, histopathological findings and detection of C. chauvoei in skeletal muscle samples of two necropsied calves using PCR.
The occurrence of cases only in calves that did not receive a booster dose or were not vaccinated indicated that the vaccine used was effective when performed as recommended by the manufacturer. However, neglecting the booster resulted in casualties due to blackleg.
Copyright (c) 2020 Carolina C Guizelini, Otavio AC Silvestre, Carlos AN Ramos, Danilo C Gomes, Ricardo Antonio A Lemos.