It thrives on dirty feet and spreads in dirty conditions. In the past, it was thought to be a problem of indoor systems, but the disease is now being found in pasture-based herds.
A 2014-15 pilot study in Taranaki found that of the 224 herds tested (60,455 cows), 707 cows had lesions.
Taranaki vet Neil Chesterton, who led the study, says before the survey he knew of five farms in the area which had cows with lesions, but he was surprised at the degree of infection.
Sixty-four percent of tested farms had infected animals. Some with as few as two animals; one with 40. Not one farmer knew they had it.
“It typically starts with a very mild infection. If the disease isn’t proactively controlled, the number of cows affected and severity of the disease can increase.
“Cattle with digital dermatitis may show signs of lameness when standing or moving. The most commonly seen presentation is the standing animal that flicks its foot repeatedly for no obvious reason. However, a very high proportion of cattle with digital dermatitis may show no signs of lameness.”
- Digital dermatitis can be treated. If suspicious lesions are detected, then veterinary advice should be sought to confirm it is digital dermatitis.
- Infected cows can be treated with a topical antibiotic spray and antiseptic footbaths can be used to control the spread of disease.
- Check for digital dermatitis at milking time. Clean the rear feet with water and look for any fresh ‘strawberry’ or dried scabby lesions between the claws at the back.
- If you see even a small suspicious lesion, ask your vet to take a sample to check if it is the disease.
- Record the tag of every suspicious cow so that you can follow up with treatment.
- Digital dermatitis is usually introduced by bringing infected animals onto the farm. Don’t graze your animals with animals from an infected herd.
- All introduced animals should be checked and footbathed before mixing with a clean herd.
- Take biosecurity seriously, because once digital dermatitis becomes established it is difficult to get rid of it.
- Install a foot-bath for monthly sanitizing of feet as a precaution.
A bovine digital dermatitis (BDD) working group was established in 2012 to raise awareness and perform research. The cross-sector group received funding from DairyNZ's On-Farm Innovation Fund and includes veterinarians, Massey University, the Ministry for Primary Industries, DairyNZ and AsureQuality.
This article was originally published in Inside Dairy March 2016