Keeping digital dermatitis under control

18 December 2018

Lameness is a common problem on many farms in Northern Ireland and can lower intakes, reduced milk yield and weight gain, poorer fertility, and loss of milk due to antibiotic treatment.

Of all the possible causes of lameness, digital dermatitis is the number one worldwide cause in indoor managed dairy herds.

Digital dermatitis is typically seen as a strawberry-red raw sore that slowly develops in size just above the heels, most commonly involving the hind feet. Sometimes a grey layer of dead tissue covers the red sore and this bleeds when cleaned. With on-going digital dermatitis, the skin responds and can grow into what looks like a large ‘hairy wart’ or a paintbrush at the heel. All these sores are usually very painful, and when touched cows will often pull their foot back.

Digital dermatitis is caused by a combination of infectious bacteria, meaning that it spreads from infected cattle to non-infected cattle. Infection is more common in herds if cow’s feet are frequently exposed to slurry. This is because when a cow with digital dermatitis stands in slurry, the bacteria can survive until the next cow walks on the same spot. In addition, when cows’ feet are continuously wet, the skin around the heels is softer, meaning that bacteria can more easily penetrate the skin. Therefore, in an infected herd, scraping floor surfaces more often will reduce the risk of spread between cows.

As digital dermatitis is infectious, it is extremely difficult to eradicate from a herd. Therefore, if a herd is infection-free, it is important not to introduce new animals that may bring infection in, and to make sure visitors’ foot-ware and hoof trimming equipment is clean.

To treat cows with digital dermatitis, thoroughly clean and dry the affected foot before applying an antibiotic spray (with your vet’s advice) or copper sulfate and then bandaging. Repeat this process for 3 to 5 days until clear. Although isolating infected cows is best, bandaging may help reduce the risk of digital dermatitis spreading.

A good footbath protocol can control digital dermatitis at a herd level. If many cows in the herd are affected, your vet may advise that an antibiotic footbath is used. In herds with lower numbers affected, using a 5% copper sulfate, zinc sulfate or organic acid footbath three times a week can help control digital dermatitis.

Maintaining a clean footbath is vital as a dirty footbath will spread digital dermatitis. Don’t forget to put heifers and dry cows through the footbath, as the immune suppression at calving and when entering the milking herd, means that any dormant infection can reactivate. In beef units, implementing an ‘all in – all out’ pen policy does also help reduce digital dermatitis.

Ensuring that a good mineral pack is included in compound feed can help reduce herd lameness. Biotin has a dual role in the formation of keratin (the building block of hooves) and the strength of links between these building blocks. Zinc helps maintain immune function and has a role in the formation of keratin, which builds a resilient hoof.

Comparing all the mineral sources, both organic and inorganic, IntelliBond Z is unique as it is the most bioavailable source of supplemental zinc, while IntelliBond’s protected properties ensure that optimal rumen function is maintained. It is important to note that as zinc and biotin are incorporated into the hoof structure, it can take a few months before the hoof is strengthened.