Prevalence and clinical relevance of udder thigh dermatitis in dairy cows

Udder thigh dermatitis (UTD) is especially common in heifers. Skin alterations and necrosis of muscle tissue characterise this condition and, although the disease is well understood, systematic analysis concerning prevalence, risk factors and consequences of UTD is lacking. The aim of this study, therefore were such systematic clinical examinations.

Statistical analyses of data were performed to objectively evaluate the supposed higher risk of heifers developing UTD. The study included a total of 317 animals that were examined and classified as UTD positive or negative on the day of calving. The size of skin alterations and the severity of tissue damage were assessed on days 7, 14 and 21 p. p.

The overall prevalence resulted in 18 % UTD with a higher risk in heifers (36.8 %) than in cows (4.3 %; P < 0.0001). A significant link was found between the size of tissue lesions and severity of UTD (day 7: P = 0.007; day 14: P = 0.002; day 21: P = 0.011). Peripartal udder oedemas were strongly associated with UTD (P < 0.05). The milk yield and the concentration of milk protein was found to have decreased.

UTD appears to be a multi-factorial disease that is supposed to be painful due to the obvious avoidant behaviour in affected animals. In respect to the reduction in daily milk yield and an enhancement of pain related stress, neither the economic impact of UTD, nor the adverse effects on animal welfare should be underestimated.

Heifers with udder oedema are advised to be examined for the presence of UTD in order to start an early treatment and diminish disease related negative impacts.