Observations on claw abnormalities in beef cows

Part one: Physical characteristics and claw growth

Abstract

In June 1994, a study began on a herd of cattle in Canada. The herd was visited 5 times. A second herd was examined in October 1994, and visited in spring and autumn until October 1997. A further 10 herds were examined at least once in a supplementary study. Front feet of all cows and hind feet of most were examined and a detailed record of lesions observed was made. Sandcracks were classified into 5 categories (types 1 to 5), depending on the location of the lesion. The degree of severity of the sandcrack was defined by its width (2 to 10 mm). Several possible causes were identified, including increased body weight, the presence of horizontal defects and bending of the dorsal surface of the claw. Not all cracks originated from cracks at the coronary band (type 1). In 2 groups of heifers it was found that the rate of claw growth was approximately 0.46 cm/month during the summer and 0.32 cm/month during the winter. Applying these growth rates to the position of a horizontal defect relative to the skin/horn junction permitted the date on which the defect was formed to be estimated. The incidence of horizontal defects was exceptionally high in some herds of beef cows and was found to vary from 29 to 100% of the cows in 6 of the herds in the study.