Preliminary results of preventive spraying with a product containing aluminum and zinc in the milking parlor to prevent DD lesions

Objective

Digital dermatitis (DD) is an international problem on beef and dairy farms and predominantly caused by Treponema spp. (1,2) The infection with this most important infectious claw disease in cattle leads to damaged skin with erosive and painful lesions (3). A good on farm prevention strategy can reduce treatment costs, improve animal welfare and enhance a better long-term effect. To reduce the amount of dispensed drugs and number of lame animals it is necessary to establish a good long term on farm strategy (4). In this study a product containing aluminum sulfate complex and zinc sulfate as a monohydrate is tested as a preventive spraying solution in dairy herds affected with DD. It will be evaluated if the product has an impact on the occurrence of DD.

Materials and methods

The trial takes place on two different German dairy farms, which milk 70 cows on average respectively. In addition to the milking herd, dry cows and heifers that are due to calve within the next two months were integrated into the study. While routine hoof trimming every cow/heifer were additionally scored for DD (DD-M0 to DD-M4.1) in the trimming chute and treated according to the lesion that was found. Every animal with an DD-M1 lesion > 1,5 cm, a DD-M2 lesion, a DD-M4 or DD-M4.1 lesion was wrapped with a 66% Methyl-salicylic acid ointment for 6 days. Each DD-M0, DD-M1 <1,5 cm, DD-M3 or DD-M4 <1cm were sprayed with a copper- and zinc-chelate spray. After taking off all bandages no open DD-lesions were left. Lesion type and degree of severity were evenly distributed between the two hind legs and on both farms. Thus, it was possible to specify the two hind legs of an animal as treatment and control group respectively. Fourteen days after hoof trimming the implementation of the preventive spraying with a backpack sprayer in the milking parlor started. The used product contains an aluminum sulfate complex and zinc sulfate as a monohydrate. The test product was sprayed during the first 5 weeks three times per week and since then two times per week during one milking period per day. Heifers and dry cows were sprayed while fixed in the head locks. [...]