Hoof health is essential for the overall health of the heifer, as these are the “wheels” she motors around on for going to the parlor or walking to the feed bunk. Just like her mature milking cow counterpart, heifers are not immune to digital dermatitis, also known as hairy heel warts.
University of Wisconsin School of Veterinary Medicine research supports findings of negative impacts of digital dermatitis on health, milk production and reproductive performance during the first lactation of a heifer diagnosed with DD pre-calving. The cost of DD can range between $3 and $239, based on individual first-lactation milk yield per heifer.
How do cattle get digital dermatitis?
The environment predisposes heifers to the pathogen Trepronema sp. Many times, pre-calving heifers are not in optimal housing, and may be found in calving pens neighboring sick and dry cows. Facilities may be older, repurposed housing for heifers with cleanliness and ventilation challenges. Heifer barns may not be cleaned as often, or they may be overstocked, providing an abundance of manure, moisture and exposure of pathogens to the feet.
Digital dermatitis control in pre-calving heifers is the best chance for prevention and control of hairy warts in lactating cows. Keeping the feet as clean and dry as possible minimizes the amount of organic matter and possible pathogen load on the feet. Alleyways may need to be scraped more often or stocking density reduced to lessen the amount of manure in the alleys. Additional bedding, lower stocking density and properly sized stalls will encourage heifers to lie in stalls for long periods of time.
Penn State’s Jud Heinrichs suggests evaluating the prevalence of hairy heel warts in heifers at the time of or shortly after calving. If more than 5% (ideally less than 1%) of heifers have DD lesions at calving, evaluate your heifer program for DD onset and prevention in heifers.
UW School of Veterinary Medicine’s Dr. Dorte Dopfer says when going on the hunt for hairy heel warts, conduct pen walks looking for active DD lesions on the rear feet. Start with the oldest heifer group and work toward the youngest to find the source of infection. Identify the pen of heifers with the maximum prevalence of hairy heel warts — those animals acutely lame with large ulcerative lesions.
There may be heifers in the older groups who have chronic DD, with occasional flare-ups of active lesions, but the key is to look for the pen or age group where the highest prevalence of active lesions is occurring. Once the pen has been identified, calculate the age of heifers 60 to 90 days earlier and look at this age group. This is the pen where hairy heel warts prevention and control measures such as foot baths, topical treatment and cleanliness must start.
Treatment and control
Acute lesions are treated topically with oxytetracycline. The lesion should be cleaned and dried, removing all organic matter. Many facilities are not equipped to handle the individual applications for heifers; therefore, work with your veterinarian and team to determine the best course of application.
Digital dermatitis is extremely difficult, if not impossible, to eliminate, so the focus should be on managing and controlling it. Foot baths do not cure hairy warts. Copper sulfate foot baths are used to help maintain chronic hairy heel wart lesions in an inactive (M4) state, thus preventing the spread of DD to noninfected animals.
However, foot baths are not always the easiest to implement or maintain in a heifer facility. Foot baths can be an excellent way to prevent hairy warts, but if not maintained properly, they can do more harm than good to foot skin health, or even be a source of infection if they are not removed after use and instead are left to collect manure and urine between treatments.
Hoof health starts with the heifer and begins with an ongoing system to prevent, manage and control the impact of hairy heel warts in the milking herd.
Kohlman is the Extension dairy and livestock agent in Fond du Lac County, Wis.