Work is being carried out at the University of Liverpool, in conjunction with AHDB Dairy, to establish an effective protocol for disinfecting hoof knives during foot-trimming.
Past research identified digital dermatitis (DD) treponeme DNA on hoof knives after trimming feet affected by DD, suggesting that foot-trimming should be a control point for preventing transmission of the treponemes that cause DD.
Current studies in the laboratory have shown that DD-associated treponemes can survive on hoof knives for at least two hours, which means that they could be passed between cows if knives are not cleaned. Disinfection was most effective in the laboratory using 1:100 FAM30®, 2% Virkon® or 2% sodium hypochlorite. This work informed the development of the hygiene protocol presented here, which is designed for use during foot-trimming to prevent treponemes from being passed between feet. The protocol and further details are also available from AHDB Dairy at https://ahdb.org.uk/reducing-spread-of-DD.
The hygiene protocol is being trialled during foot-trimming to ensure it is effective under farm conditions. Farm trials so far have included 86 cows’ feet with a range of DD lesion M-types and non-healing claw horn lesions (also known to be infected with DD treponemes). In 24/86 cases, it was possible to culture treponemes from hoof-knives after foot-trimming, showing that live treponemes are present. This further suggests it may be possible to pass treponemes between cows if knives are not cleaned. Fortunately, all three disinfectants have so far proved effective during farm trials at removing all treponemes with a short contact time of only 20 seconds. Sampling is continuing to ensure testing of the protocol is robust.
Adoption of these disinfection techniques (https://ahdb.org.uk/reducing-spread-of-DD) should help to mitigate risk of transmitting DD during foot-trimming especially when used in conjunction with other DD management strategies such as regular foot-bathing and good housing hygiene which are also detailed in a resource from AHDB Dairy (https://ahdb.org.uk/knowledge-library/digital-dermatitis-the-three-pronged-approach).