Evaluation of Calcium Hydroxide (Ca(OH)2) Used in Footbaths as Treatment and Prevention of Digital Dermatitis in Danish Dairy Cattle

Summary

Digital dermatitis is a major problem in the dairy production in many countries. Footbaths have been the preferred method in the control of digital dermatitis, and various products are used in despite of a lack of scientific evidence of the effect.
The objective was to evaluate calcium hydroxide (Ca(OH)2) used in footbaths as treatment and prevention of digital dermatitis. The study was conducted as a clinical trial in 4 commercial Danish dairy herds including 405 cows. Ca(OH)2 is an alkaline disinfectant which is recommended in footbaths to control digital dermatitis by some Danish hoof trimmers. The footbath used in the study was a commercial available split-footbath, which made it possible to treat one side of the cow and using the other side as a negative control.
Digital dermatitis lesions were registered in a trimming chute at the start of the study. The prevalence of active digital dermatitis lesions in the hind legs was 40 % for treatment legs and 39.3 % for control legs. For the forelegs the prevalence was 4.0 % and 10.9 %, respectively.
All the cows walked through the footbath three times a week for the first two weeks and then only twice a week for six weeks. Registration of digital dermatitis lesions in the trimming chute was made again after two and eight weeks.
The cure effect was defined as a change from active at the first registration to inactive after two or eight weeks. The preventive effect was evaluated from the amount of new cases, which was defined as a case changing from inactive to active after two or eight weeks.
A difference was found with regard to the cure effect in the hind legs after eight weeks with cure of 84 % and 67 % of lesions on treatment and control legs, respectively. A difference was also found for new cases in the hind legs after both two and eight weeks with 0.8 % and 6.3 % new cases in treatment and control legs after eight weeks, respectively. In the forelegs differences between treatment and control legs were only significant with regard to the preventive effect after eight weeks with 0% and 2.7% new cases.
Chemical burns caused by the Ca(OH)2 were observed in 18 % of the treated hind legs after two weeks and in 0.5 % after eight weeks.