Lameness affects everything a cow does. Feed intake, fertility, milk production and, in the end, profitability are all depressed when an animal has sore feet. Digital dermatitis is a prevalent and sometimes painful hoof lesion that develops when the hoof skin barrier weakens and Treponema species are able to invade it. According to Dörte Döpfer, at the University of Wisconsin-Madison, digital dermatitis is characterized by a raw, bright red or black circular erosion and inflammation of the skin above the heel bulbs. The edges of the lesion develop a white margin and overlong hairs that surround the sores or are adjacent to thick, hairy wart-like growths.
Digital dermatitis can be controlled or prevented, but once the bacteria have broken through the hoof skin, it is too late to prevent disease reservoirs from forming.
In a recent Kentucky Dairy Notes, Alexis Thompson and Jeffery Bewley discussed the three legs to the digital dermatitis prevention stool: the environment, cow comfort and footbath use.
Environment
The environment plays a pivotal role in the spread of digital dermatitis (DD). Cows that are housed in manure-laden environments express a greater risk of developing DD due to their heightened bacterial exposure.
Often, manure-laden areas are moist, which contributes to the creation of an oxygen-devoid environment, enabling certain bacterial species to multiply. Frequent immersion in manure provides time for bacteria to integrate and infect hooves.
Clean, dry hooves have a lower prevalence of DD. A study from the University of Wisconsin-Madison showed that scraping three times a day was the minimum frequency needed to control infectious hoof diseases. Automatic scrapers are a potential solution if operated over short distances.
When used across long distances, though, automatic scrapers soak the foot in a manure tsunami and can cause, rather than alleviate, problems.
Cow Comfort
Lying time is critical to cows' health and productivity. Improper stall dimensions deter cows from using stalls and elevate the amount of time spent standing on concrete. Concrete lacks cushion for the hoof's sole, and its abrasive surface can cause excessive wear. This further exposes the heel to invasive bacteria.
Footbaths
Footbaths are a critical piece to the DD prevention puzzle. Like a teat dip, though, footbaths are a preventative measure against a disease, not a treatment. Common footbath solutions prevent additional bacteria on the leg from gaining access to the wound.
These solutions bind to proteins on the surface of the bacteria, causing the deterioration of the outer bacterial cell membrane, which causes the cell to leak and die. Before using any footbath products, ask for data on the product's effectiveness.
The frequency with which footbaths are run is a Goldilocks scenario. Infrequent use will lack preventative power. Using footbaths too frequently or aggressively can exacerbate a DD problem.
Eradication of digital dermatitis is difficult, but prevention and control are possible. As will all diseases, prevention of DD should take precedence to treatment.
The author is an associate editor and an animal science graduate of Cornell University. Smith covers feeding, milk quality and heads up the World Dairy Expo Supplement. She grew up on a Medina, N.Y., dairy, and interned at a 1,700-cow western New York dairy, a large New York calf and heifer farm, and studied in New Zealand for one semester.
