Sole Ulcers and White Line Disease

Lameness in dairy cattle is a symptom of an underlying disease, most commonly of the hoof or surrounding skin. Two of the most common diseases of the hoof are sole ulcers and white line disease, each with causal factors that increase their risk of development. Some of these risk factors are overlapping, but the areas that are unique to each disease can help focus our efforts on prevention, if that disease has been identified as a major cause of lameness on a particular dairy.

Sole Ulcers

Identification of a sole ulcer lesion is based on location. The site of sole ulcer development is at the junction of the sole and the heel. There is a bump in the bone within the hoof that can put pressure on the connective tissue (corium) between the bone and the hoof and cause damage to the tissue that grows the horn of the hoof. This damage process may be observed as red discoloration at this location (hemorrhage), or as a full thickness ulcer where the sole of the hoof is gone and the soft corium underneath is exposed. There are hormonal and nutritional factors that can predispose animals to this problem, but excessive pressure on the corium is what allows the disease to develop. Therefore, control of sole ulcers is achieved through reducing this pressure by minimizing time standing on hard surfaces and by preventive hoof trimming.

The best way to minimize time standing on hard surfaces (concrete) is to maximize time spent lying down by providing comfortable beds. Deep, dry bedding, adequate size stalls with lunge space, and maintaining less than 120% cow to stall stocking density all increase lying times. Reduce forced standing time by ensuring that time spent away from the pen for milking is less than three hours per day, and that cows are locked away from beds for management or cleaning for as little time as possible. Cows are better able to dissipate heat from their body while standing, so heat stress increases standing times and the risk of sole ulcer development. Cow cooling efforts, like sprinklers and fans, can reduce this impact. As cows’ hooves grow the claws tend to grow unevenly, with the outer claw of the hind hoof growing the largest. This claw naturally bears more of the cow’s weight, and as it grows thicker it takes even more weight, increasing the pressure at the sole ulcer site and the risk of disease. Therefore, routine trimming to rebalance the claws and hooves distributes the weight of the cow more evenly over both claws, helping prevent excessive pressure on any one claw.

White Line Disease

The white line is the junction between the wall of the hoof and the sole. It extends from the heel to the toe on the outside edge of the claw, and from the toe along about one third of the inner edge of the claw. The white line is softer and less resilient than the wall and sole. The bone within the hoof is suspended in connective tissue between it and the walls and sole of the hoof, and part of this tissue (laminar corium) is where the white line is grown. If the hoof is jostled around, this connective tissue can be damaged and cause issues with the growth of horn, especially the sensitive white line. Injury to the white line can occur from trauma and is also thought to occur from damage to the inner structure of the foot that can be nutritional, hormonal, or related to systemic disease. Lesions of the white line can be hemorrhage (red discoloration), fissure (a gap or dead area), or abscess (pus pocket) anywhere along the white line.

The management factors related to white line disease are facilities and handling causing trauma to the hoof. This can occur from slipping, sudden turns, and trauma or excessive wearing due to rough flooring. Handling has a lot to do with this – cows can compensate for floor issues if they are allowed to walk at their own pace and not pushed. Further, many nutritional factors contribute to the quality of hoof horn, so a balanced ration including necessary micronutrients is crucial. Hoof trimming is important to maintain even weight distribution because overloaded weight on one claw can cause trauma. However, improper trimming can also cause issues with the white line – especially rolling a grinder or a knife around the hoof to round out the edges. This removal of the wall destroys the white line and the best weight bearing part of the wall. Over trimming of the wall is an easy thing to watch out for when judging hoof trimming technique.

Treatment

Treatment of sole ulcers and white line disease is by corrective trimming and application of a block to shift weight to the opposite claw. Dead or loose tissue should be removed, and all hooves should be trimmed to balance. A wooden or plastic block is glued to the other claw of the same hoof such that all the cow’s weight is placed on the unaffected claw. This block should stay in place for about 6 weeks, or until the lesion is healed and no longer painful. Lameness is painful, production limiting, detrimental to reproduction and costly - and prevention is key to reducing it. Identifying the major cause of lameness on your dairy and understanding how it occurs allows targeted strategies for prevention.