Since the new year, I have travelled to many dairy farms across Western Canada and conducted a personal survey about lameness in dairy cattle. At each visit, I asked producers “What was their biggest cause of hoof problems?” Almost unanimously, their answer was “hairy heel warts!” This is no surprise, since multiple surveys conducted over the last few decades, mapped its spread across North American dairy farms. Fortunately, early detection, constant vigilance and prevention is the key to controlling this major hoof disease.
Hairy heel wart, also known as strawberry foot disease, is a digital dermatitis which affects the heel tissues above and proximal to the meeting of the hoof claws (interdigital space). It’s a rather insidious virus, specifically a bacterium in the spirochete family called treponema. It is highly contagious and can spread rapidly to susceptible animals such as dairy cattle around calving, first-calf replacement heifers and malnourished cattle. Interestingly, some infected cattle do not show clinical lesions, yet are contagious carriers often to break with disease later on when they become stressed. Wet conditions and poor manure sanitation play a significant role in its spread throughout the dairy barn.
Close inspection of the photo of this cow’s hoof illustrates the early stages of hairy heel wart, which is literarily a raw hole, prone to bleeding when broken open (strawberry warts). As these growths mature, they become larger (2 cm) lesions with hair-like projections giving hairy heel wart its name.
Needless to say, hairy heel warts are an extremely painful condition for dairy cattle, which affects hind hooves in 85 per cent in confirmed cases. Dairy producers may first observe that afflicted cattle tend to walk on their toes, because the developing warts may also cause abnormal heel overgrowth.
Such dairy cows also do not perform well. For example, a lame dairy cow with hairy heel warts in early lactation often has a reduction in milk production by 20 to 50 per cent. It’s likely a matter that a lame lactating cow doesn’t want to go up to the feed bunk. As a result, it reduces the dry matter intake (DMI) that provides dietary energy and other essential nutrients. In some hairy wart cases, such a reduction in DMI may cause a severe negative energy balance; a rapid and abnormal breakdown of bodyfat to ultimately end in detrimental metabolic ketosis.
Fortunately, over the years I have seen that many hairy wart problems can be successfully treated. Medicated soluble powder recommended by the herd’s veterinarian is often applied directly to the lesion and then the hoof is wrapped with an elastic bandage. In a few days, these once limping animals seem to be walking and up to the feed bunk as if nothing ever happened.
As a dairy nutritionist, I believe in preventative medicine against hairy heel warts, which in this case means making the dairy cows’ skin around the hooves healthier and the hoof horn harder by nutritional means. A few years ago, I instructed a dairy producer to add four grams per head per day of zinc methionine to his lactation dairy premix, which in turn was added to his daily milking TMR. After seven months of zinc addition, a successful reduction in general lameness including hairy heel warts was observed. Even the hoof trimmer made the comment — the condition of the skin around the hooves and general hardness of the hooves in the cow herd had improved.
Aside from this nutritional testimony, I am also an advocate of having cows biweekly walk through a clean acidified copper or acidified copper-zinc sulphate foot bath. This routine can be tailor-made to one’s situation, which should help disinfect cow herd hooves, which in turn should prevent the spread of hairy warts.
Proper foot care should be parallel with good sanitary barn conditions. I know of one producer who runs alley manure scrapers in his free-stall barn more frequent than most people normally practice. Another producer, whom operates a robot-barn, washes the concrete pad and metal grate under each milking station. In both cases, the lactating cows’ feet are notably cleaner and hairy heel warts are not much of a problem compared to my other barn visits.
Whether it comes to turning on the scrapers or washing down the barn each day or even treating each case as it pops up, dairy cows need our help when it comes to controlling hairy heel warts. Healthy cows should easily stand on their feet and go up to the bunk at their leisure. When they are able to eat their fill and without the pain of hairy heel warts, they are able to contribute to optimum milk performance.