THE INFLUENCE OF BIOTIN SUPPLEMENTATION O N THE CONFIRMATION, HARDNESS AND HEALTH OF CLAWS OF DAIRY-COWS

The influence of a daily dietary supplementation of 20 mg biotin per c ow on the claw conformation, its hardness and diseases was examined in a clinical trial involving 28 dairy cows of the German black and whit e breed and 28 control animals, which had a similar age distribution a nd claw status, from the same herd. The trial was conducted over 11 mo nths. The conformation of one for limb claw and one rear limb claw was recorded at two month intervals. All claws were examined for disease and the sum of the severity scores was used in the analyses. Plasma bi otin concentrations were determined in both groups at three monthly in tervals. The effect of cow within the treatment group was significant for all claw conformations, claw horn hardness and a proportion of the claw diseases. Changes in claw conformation associated with elevated plasma biotin concentrations were angle of the dorsal border, length o f the dorsal border, length and height of heel and length of the diago nal and ground surface. The angle of the dorsal border steepened and t he height of the heel, the length of the diagonal and size of the grou nd surface increased. The biotin supplemented cows exhibited in the ma jority of replicated measurements a greater claw horn hardness, of the lateral wall. A positive effect of biotin supplementation was also ob served for the incidence and severity of inter digital dermatitis, sol e contusions at the Rusterholz and other locations, except around the white line. The results indicated that biotin supplementation resulted in a reduced incidence of sole ulceration and heel erosion.