Management of udder-thigh dermatitis on dairy cattle: epidemiological and bacteriological data

Abstract

Udder-thigh dermatitis (UTD) is a common illness in cattle but few descriptions are reported. UTD is a more-or-less symmetrical lesion of the groin skin, between the medial thigh and the lateral udder. Five clinical stages can successively occur from an erythema to a necrotic dermatitis. Recovery always takes a long time (at least three weeks), especially in the final stage, with pain and increased recumbency. This study aims at defining incidence, risk factors and involved pathogens of UTD in France. Firstly, a survey was conducted among 74 dairy farms (4,393 cows) randomly selected in a defined area (Cantal, France) in which general practices, breeds, levels of production, feeding and housing were very variable. Secondly, bacterial investigations were conducted from swabs obtained on UTD lesions (n=14). Epidemiological data showed a high herd prevalence (97%) and annual cow incidence (6%) of UTD in the studied population. Relative risk of primiparous affection compared to multiparous was 15.3. Breed and season were not associated with UTD occurrence (P>0.05) whereas moving (non tied animal) has a preventive effect (P<0.05, linear model). Udder oedema was the major risk factor of UTD. Bacterial cultures showed the presence of several aerobic and anaerobic bacteria. Some of them were considered as opportunist pathogens but Fusobacterium spp was commonly isolated from affected skins: Fusobacterium nucleatum and Fusobacterium necrophorum were regularly identified, suggesting their particular involvement in UTD. According to the epidemiological results, management of UTD should include prevention and cure of udder oedema (especially in heifers) and increasing moving. For affected cows and before apparition of extended lesions, UTD therapy should also include local disinfection to avoid development of Fusobacterium spp. and to limit the use of systemic antibiotics.