Papillomatous digital dermatitis in 458 dairies.

OBJECTIVE

To estimate prevalence of papillomatous digital dermatitis (PDD) in California dairies during 1993, to describe temporal and spatial patterns of PDD and response of cows to treatment, and to evaluate herd-related risk factors for PDD.

DESIGN

Epidemiologic survey.

SAMPLE POPULATION

All southern California dairies and a 50% random sample of the rest of California dairies.

PROCEDURE

A questionnaire was mailed to managers of 1,429 selected dairies.

RESULTS

Prevalence of PDD during 1993 was significantly higher for dairies in the south (75.3%) and central (68.8%) regions, compared with north coast (33.3%) and north (23.1%) regions of the state. Herd mean and median proportions of affected cows in PDD-affected herds were 11.6 (SEM = 0.9) and 5%, respectively. Most (74%) dairy managers surveyed observed PDD for the first time during 1992 or 1993. Highest PDD activity was reported as taking place in summer in the south and in fall and winter in the north coast and north regions; an obvious pattern was not determined for the central region.

CLINICAL IMPLICATIONS

PDD was widespread in California dairies during 1993 and affected a high proportion of cows, especially in the south and central regions of the state.