Recovery from udder cleft dermatitis in dairy cows.

Udder cleft dermatitis (UCD) is a common skin problem in dairy cows, localized at the fore udder attachment or between the udder halves. The main objectives of this study were to investigate spontaneous recovery from UCD in a longitudinal study and to investigate the treatment effect on UCD of a topical spray containing chelated copper and zinc in an additional treatment trial. Spontaneous recovery was investigated during a 1-yr longitudinal study in which 7 Swedish dairy herds were visited 9 times each, at 6-wk intervals. During the visits, all cows milked in the milking parlor were examined for mild and severe UCD, udder conformation traits, hygiene, and hock lesions. Additional cow and herd data were obtained from the Swedish official milk recording scheme. Recovery was defined as 2 consecutive observations of no UCD after a UCD case (1 or more consecutive observations of UCD). The recovery rate was calculated and factors associated with recovery were analyzed using discrete-time survival analysis. A treatment study was conducted in 4 of the herds after completion of the longitudinal study. Cows with UCD were allocated to treatment or a control group, and cows in the treatment group were treated once every day for 14 to 28 d. At follow-up visits on d 14, 28, and 56, all cows were scored for UCD. To investigate the effect of treatment, an ordered logistic regression model was used, with UCD score on d 56 (no, mild, or severe) as the outcome. Other potential explanatory variables were also included in the model. A total of 38% (126 of 329) of the cows in the longitudinal study made a spontaneous recovery from UCD. A long duration of UCD, severe lesions and higher parity reduced the chance of recovery. Among the recovered cows, 47% (59 of 126 cows) had a recurrent case of UCD after the recovery. In the treatment study, there was no difference in UCD score on d 56 between the treatment and control groups. Factors that affected the UCD score on d 56 were the duration of UCD before the treatment study started, UCD score on d 1 and udder conformation. Our findings emphasize the importance of further studies to identify effective treatment regimens as well as further studies to unravel the pathophysiology of UCD to improve the recommendations on how to prevent these lesions.