‘Dairy industry must get on top of digital dermatitis’

UK Veterinarian and cattle lameness specialist Roger Blowey has highlighted the increasing importance of digital dermatitis (DD) related infections that appear to be affecting the hoof rather than just the skin.

Speaking to AgriLand during a recent visit to Ireland, he said: “The first of these conditions, commonly referred to as toe necrosis or seedy toe, is seen as a non-healing, stinking open sore at the toe. No-one is sure how it starts, but once established it is very difficult to treat. Part of the problem seems to be that the infection penetrates deep into the inside of the hoof, producing a honeycomb of soft, substandard and infected horn. Many herdsmen will have seen this condition. A related condition is the challenge of non-healing white line lesions, sometimes referred to as wall ulcers and DD infected sole ulcers.

“Treatment of these non-healing hoof lesions consists of removing all the under-run, dead and black horn, applying a topical dressing of antibiotic or some other antibacterial substance and often also injecting long acting antibiotics. Even then, response to treatment is disappointing and in the more severe cases the affected claw frequently has to be amputated.”

Blowey continued: “There seems to be two changes taking place in these non-healing hoof lesions. In the first instance, the corium, or quick, that produces the hoof is becoming infected with the digital dermatitis organisms. This, possibly, is the reason why the corium is no longer able to produce proper hoof. Moreover, the inflammation created by the DD infection, leads to the production of small, sharp bone spicules on the pedal bone. These then penetrate into the corium, leading to further disruption. With digital dermatitis infection below and sharp spikes of bone above, the corium simply never heals and affected cows either have to have a block applied almost permanently until they are sold barren, or have the claw amputated.”

The renowned veterinarian went on to point out that it is currently unknown how the transmission of digital dermatitis occurs from cow to cow. It can almost always be found in the lesion, but surprisingly not in slurry or anywhere in the environment.

So what can be done to control digital dermatitis? As treatment appears to have a low response rate, prevention is clearly vital. Prevention is based on the control of digital dermatitis, i.e. keeping underfoot conditions for the cows as clean and dry as possible, and by frequent foot-bathing.

He further explained: “An increasing number of herds are now foot-bathing cows daily, often twice daily, and this includes foot-bathing dry cows and transition cows at least once daily. As in teat dipping for the prevention of mastitis, it is clearly much more effective to foot-bath cows to prevent infection from becoming established on the foot than to wait until infection is present and hoping you can do something about it.”

Blowey concluded: “Foot-bathing is no longer optional in herds where these lesions exist, it is now a necessity.”