White Line Disease (Intro)

Lameness results in major economic losses on dairy farms. Hoof abnormalities such as white line disease are a distinct contributor to lameness in the dairy herd.

Healthy bovine hoof horn provides protection and support to the inner structure of the digit. It aids in the dispersal of the stress and weight placed upon the floor during locomotion. Hoof horn also provides resistance to excessive abrasion. Therefore, the most important mechanical properties are its hardness, toughness, strength, and viscoelasticity. These positive qualities largely depend upon the structure and chemical composition of the keratins, which form the horn. In addition, hoof horn moisture content contributes to these qualities. Too much moisture compromises the integrity of the hoof horn.

The white line lies between the hard coronary wall horn and the more pliable sole horn. It allows some elasticity and mobility within the hoof. Reduced horn quality and hardness leaves the structure more susceptible to damage and vascular disturbances. It is known that when the white line is weakened foreign material may be caught in the distal surface. If foreign material ascends the white line and penetrates the sensitive tissue of corium, infection will most likely occur, which leads to lameness and further damage to the white line at the point of origin.

A sound hoof trimming program and attention to the movement quality of the individuals of the herd will assist in spotting potential white line disease. The elimination of standing water and maintenance of high quality walkways will help to ensure healthy hoof horn structure.