The effect of pre-calving environment on the development of digital dermatitis in first lactation heifers.

Digital dermatitis is commonly reported to be most severe in first lactation heifers. It has been suggested that this initial infection is followed by the development of a limited immunity to the organisms which cause digital dermatitis. If this is the case then exposure to digital dermatitis prior to calving should reduce its severity after calving. A study was undertaken to examine whether such exposure significantly affected the development of digital dermatitis post-partum. Twelve weeks prior to calving, 60 Holstein heifers were blocked on the basis of their antibody titre to Borrelia burgdorferi and randomly allocated to one of three pre-calving environments: clean straw, used straw or cubicles. There was no significant effect of pre-calving environment on the development of digital dermatitis after calving indicating that "exposure" pre-calving did not reduce the development of digital dermatitis after calving. The most important factors determining the development of digital dermatitis after calving were presence of absence of visible lesions of digital dermatitis at Week-12 and at calving.