CALF_News_December_2018_January_2019

22 CALF News • December 2018 | January 2019 • www.calfnews.net CALF ANIMAL HEALTH Chuteside Manner EXPLORING THE FRONTIER OF ANIMAL HEALTH Not Just Milk Cows By Patti Wilson Contributing Editor O ver the past twenty or so years, we have seen some problems considered to be dairy dilemmas slowly creep into the beef cattle population. This is not due to neglect or carelessness on the part of the dairy folks. There continues, however, to be an inevitable spread of common health issues into beef cow herds and feedlots. The first was Johne’s disease, M. paratuberculosis, which is a fatal wasting sickness. Easily carried by small wildlife such as rabbits, it is easy to understand the spread of this waxy-coated bacte- rium into beef cow herds. More recently, another recurring dairy malady has made its way our direction, this time, to the feeding sector. It is digi- tal dermatitis (DD), otherwise known as hairy heel wart. Most commonly found in dairies, the daily confinement and constant contact with abrasive, wet concrete flooring contributes significantly to the likeli- hood of foot infections. Likewise, the persistent presence of manure associated with livestock concentration adds to the problem. It’s easy to comprehend how hairy heel wart has jumped from dairies to beef cattle feedlots with the large number of dairy steers on feed and similar condi- tions on the ground. History Digital dermatitis was first described 34 years ago in Italy. It has spread literally around the world since then, reaching the United States in about 1995. Highly contagious, it primarily settled into dairy herds, who are most likely to live in close confinement situ- ations. Worldwide, it is estimated to affect almost 100 percent of dairy herds and 20 percent of all dairy cattle. Time has proven it to be an emerging threat to beef cattle. Although beef cows can suffer the disease, it is most likely to be found in feedlots. Interestingly, among beef cow herds, bulls are more likely to be affected than females. This is likely because they cover more ground in a year’s time and carry far more weight than a cow. Today Various university research projects conducted in packing houses shows that up to one-third of dairy cattle going to harvest have DD infection on at least one foot. (For some reason, the left hind foot is always used in research protocol). Four percent of beef cattle are found to be infected. Veterinarians report that hind feet are the most likely to be affected, about 85 percent of cases. According to the Merck Veterinary Manual, incidence of DD is low in coun- tries such as New Zealand and other places where dairy cattle are traditionally grazed in a pastoral setting. There is little information about the specific loss to feedlots in terms of performance parameters. Depending on the research source, cows can drop milk production by as much as 50 percent, and lose valuable time re-breeding after calving, an average of 20 days. What’s the cause? The exact cause of DD is still a whirlwind of theories. There seem to be many guilty bacteria and viruses allegedly involved in the development of the painful lesions. One hard fact among researchers, however, is the presence of one specific bacterium from the spirochete family called Treponema . It is generally agreed to be the primary organism causing hairy heel wart. The problem is, there are 80 strains of Treponema that can affect cattle. Which one do you treat for? The stewpot of various bacteria and viruses contributing to lameness makes effective treatment of DD difficult to pin down. Additionally, since no oral antibiotics have a DD claim, any use of feed-grade antibiotics is prohibited. Unfortunately, stressed cattle coming into feedlots with suppressed immune systems will have a greater likelihood of becoming infected. LEFT: Digital dermatitis (DD), alias hairy heel wart, has made its insidious way into our nation’s beef cattle population. It calls for a whole new set of management tools.