by Sally Colby
Veterinarian and researcher Dr. Doerte Doepfer has seen a lot of foot problems in cattle, but said the two standouts are foot rot and hairy heel wart.
Hairy heel wart (also known as strawberry foot, raspberry heel, interdigital papillomatosis or digital dermatitis) has been an ongoing problem for dairy farmers. More recently, the issue has been showing up in beef herds.
Although both foot rot and digital dermatitis manifest as lameness, there are distinct differences in the two diseases. Doepfer explained that cows with foot rot will exhibit toe tipping and sudden lameness, and within about 72 hours, the skin between the claws splits open and exudes pus. Skin damage or trauma between the claws helps move bacteria into the deeper layers of tissue. During the healing process, extra skin forms to close the gaps, resulting in corns. The presence of these corns makes cattle more prone to developing hairy heel wart or digital dermatitis (DD), but that’s just one way it starts. Untreated DD can lead to septic arthritis and potential euthanasia, so it’s important to catch hoof issues early.
Doepfer said DD was first reported in 1972 in Italy and appeared in the U.S. in the mid-1980s. “In contrast to foot rot, the lameness associated with DD does not develop overnight,” she said. “There are chronic, irreversible lesions – animals stand in their pens like statues and tend not to move much. They lose weight and don’t do well.” Doepfer noted that manure-crusted hooves are common with DD.
Treponemes are the anaerobic bacteria believed to be associated with DD. Although there are many other microbes present on hooves, treponemes thrive deep in the skin. Upon exposure to oxygen or UV light, treponema die within 30 minutes. However, treponemes in soil, manure or skin – anywhere it’s dark – survive for months.
Doepfer refers to cattle doing the “DD dance” when they’re in pain from DD infection, and because they’re lame and in pain, cattle may present worker safety issues due to the animals’ social structure being disrupted, more laying down and difficulty moving. In addition, cattle experiencing pain can become irritated and aggressive.
There are several risk factors for DD, including poor hygiene such as muddy and crowded pens, especially during wet periods of the year. Mixing of cattle on a farm and mixing cattle of different origins can also introduce DD. Certain breeds, such as Holstein crossbreds, are more likely to develop DD lesions.
Doepfer explained the critical DD checkpoints in the feedyard and in cow-calf operations. One is the receiving area where cattle are unloaded then move through alleyways as they’re guided into pens. “Those areas are muddy and heavy in organic matter,” said Doepfer. “If cattle are being herded across any surface and make abrupt breaks or short turns, microtrauma to the interdigital skin will happen.”
Although a good walking surface is important for both cattle and handler safety, a surface that’s too abrasive or rough can lead to DD. “We’re focused on having walking surfaces where cattle don’t slip, but the profile of those surfaces sometimes have sharp edges and deep gradients,” said Doepfer. “If one claw steps onto a ridge and the other hangs down, the consequence is overstretching of the skin between the claws and microtrauma. This is the port of entry for bacteria.” Doepfer emphasized the importance of slow handling at unloading as well as walking profiles that are less sharp to avoid claw bruises.
In some cases, young cattle coming from pasture or very moist soils are transported in trailers where prolonged standing on metal flooring bruises the claw, predisposing the animal to DD. “Sometimes calves are unloaded with lesions already,” said Doepfer, adding that it’s worth having footbaths ready for cattle upon unloading. “We have to train our eyes to recognize this as a chronic deviation.”
In the feedyard, conditions that may result in DD include uneven footing, different consistency of walking surfaces and changes between dry and moist soil that disrupt the integrity of the interdigital skin. Where cattle are crowded, especially in hot months, bacteria thrive, so it’s important to drain and scrape any areas where cattle congregate.
Slatted floors combined with hygiene problems and high stocking density are risk factors for DD. Gaps in the concrete can cause tears in the interdigital skin and lead to DD. Cattle that have to tiptoe over manure ridges on a slatted floor are at risk for DD because that walking action stretches the interdigital skin.
Doepfer said if she sees banged up walls in the alleyways leading to the handling chutes, it likely means cattle have been forced to make a series of short turns, potentially tearing the interdigital skin. In this case, a handler is probably pushing cattle too hard and not using good stockmanship techniques. In addition to calm handling, Doepfer suggested providing good traction for cattle up to and inside the squeeze chute. Cattle that are anxious in the squeeze often paddle their feet, which results in bruising and overstretching the interdigital skin.
Cattle handlers should consider the compromise required to provide good footing without too much profile that causes overstretching. “If you use tractor tire-type mats, the profiles are so high and the overstretching of interdigital skin is a given,” said Doepfer.
Areas where cattle cross paths can create conditions that result in DD. In many cases, cattle are moved to a hospital receiving area where hooves will come into contact with mats, then cattle stay for treatment, then move along different surfaces to the next area. Doepfer suggested disinfecting the area or constructing a small square hole filled with sand to cushion the impact of cattle jumping out of the squeeze chute to avoid interdigital skin tears.
Footbaths can help with DD management, but it’s important to have the right setup for effective therapy. The flooring in front of and after the trough should be high enough for the cattle to slow down and walk through the footbath. The flooring in the footbath should not be abrasive, but have sufficient traction so cattle don’t slip.
Formalin footbaths result in sediment after a certain amount of use, and since it’s a carcinogen, Doepfer cautioned producers to be sure children do not handle the product or any sediment remaining after treatment. Copper sulfate solutions are a potential environmental hazard, so caution is necessary with that. Doepfer urged producers to use the proper PPE when handling footbath chemicals and moving cattle through footbaths, and to dispose of chemicals properly.
Early detection of lesions not due to lameness and prompt topical treatment with a product that isn’t too caustic can help stop DD. “Think about mixing cattle and hygiene, crowding, muddy areas, drainage,” said Doeper. “Train someone to trim feet to make the conformation of the claws better. Reduce infectious pressure at every turn where cattle transition between pens. Think about when you take some cattle out and mix with others – this is when DD transmission happens.”