feed ration.” Treatments – and prevention – for DD include foot baths and application of various products to the lesions. On the prevention front, Casey Jacobs at University of Calgary in Canada found in her recent Master’s thesis that no foot- bath protocol was superior to any other. For treatment, Jacobs found that routine use of commercially-available topical products was no more effective than saline in curing active lesions over eight weeks. In 2019, Guatteo and his colleagues published an analysis of how a new commercial biocide foot-bath product affected lesion healing, under different treatment regimens. In a trial with 1036 cows on dairy farms in western France, the scientists found the product to be effective when used in an intensive regimen. Use of this particular product also shortened time to healing in inactive lesions, but the scientists also point out that time to healing was delayed in feet that received hoof trimming in cows with a contralateral DD lesion, in cows in late lactation and in cows on farms with more than 100 cows. “These findings reinforce the crucial role of hygiene in DD dynamics and highlight the importance of implementing multiple control measures simultaneously,” states the team, “such as hygiene improvements in the barn, early detection and treatment of DD lesions and the correct usage of individual and collective treatments.”


Salicylic acid and more Salicylic acid has been shown to be very effective for treating DD. It promotes removal of the epidermis and its low pH may also make it bacteriocidal. In 2019, several scientists in Ger- many published results comparing salicylic acid paste with polyurethane wound dressings for the treatment of active DD lesions and found both to be effective therapies. Dr Andrea Fiedler, a veterinarian in Munich Germany, provides the following recommendations that she and her colleagues (Dr Katharina Grimm and Dr Charlotte Kröger) have found to provide impressive success in DD management, some of which involves salicylic acid. (Note first that DD lesions are classified according to size and other characteristics: M1 are active granulomatous area up to 2 cm, M2 are ulcerative lesion , M3 are lesions covered by a scab, M4 involved an chronic alteration of the skin, and M4.1 are lesions that are a combination of M4 and M1). For M1 lesions, Fiedler recommends spray, preferably Repiderma but tetracyclin is also available. For M2 less than 1.5-2 cm, spray and cover with a bandage for three to five days. (All bandages should be the self-adhesive type and always have artificial cotton padding within. Fiedler also notes that whilst spray is seldom combined in European herds with a bandage, it always should be). For M2 bigger than 1.5-2 cm (and also M3, M4 and M4.1 lesions), treatment should begin with Novaderma (containing 66% salicylic acid + methylsalicylat for pain) and a padded bandage for five days. This should be followed by spray and a bandage (again, with padding inside)


for five more days. At that point, Novaderma should be applied again with a bandage and padding for five more days, if an alteration is still visible. (Alternatively for these types of lesions, apply spray with a polyurethane bandage for 14 days and repeat twice more, or apply Novaderma and a padded bandage for five days, then two 14-day treatments of spray with a polyurethane bandage).


Microbe discovery needed Going forward, Guatteo and colleagues state in their paper ‘Missing pieces of the puzzle’ to effectively control DD that “efforts to definitively determine the consortium of organisms necessary for DD disease induction should be a top priority.”


Although this will be costly and challenging, they note that “without knowing what specific bacterial organisms are necessary and sufficient for disease induction, all other efforts focused on better understanding organism ecology, immunity and treatment have the potential to focus on the wrong bacteria.”


References are available on request ▶ COW HEALTH | AUGUST 2020 23


Digital dermatitis (DD) is the leading cause of


lameness in dairy cattle.


PHOTO: DR GUATTEO


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