The disease was characterized by ulcerative granulomatous lesions, which occurred in an epidemic form.
Thirty-two cows and two heifers were affected, the ratio of the number affected to number at risk being 17.5 : 1 and 9.5 : 1, respectively.
The culling rate was 50% of the affected animals.
Most of the affected animals were cows (91.2%), with one first-calving cow (2.9%) and two heifers (5.9%) also affected.
The infection occurred during the summer to autumn months (August-December), and lasted 118 days.
The incubation period is about 2 months.
The disease appeared in two clinical forms cutaneous and mastitic or as a mixed form.
C. pseudotuberculosis organisms that were isolated from the ulcerative granulomatous lesions and from milk samples failed to reduce nitrate.
A decrease in milk production (4%) and an increase in the bulk-milk somatic cell count from a herd mean of 240 103 mL1 to 460 103 mL1 were noted during the morbidity period.
The organism was isolated from milk samples of eight animals (25%).
Source: YERUHAM, ISRAEL, FRIEDMAN, SAMUEL, PERL, SAMUEL, ELAD, DANIEL, BERKOVICH, YAIR & KALGARD, YORAM (2004) :A herd level analysis of a Corynebacterium pseudotuberculosis outbreak in a dairy cattle herd. In: Veterinary Dermatology 15 (5), 315-320.
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