Digital dermatitis — also known as ‘digi’, ‘strawberry footrot’ or ‘hairy heel warts’ — is an increasingly prevalent infectious hoof disease being seen in Australian dairy herds.
It can lead to lameness, reduced milk production and compromised animal welfare.
Commonly considered to be caused by a bacteria of the Treponema species, DD thrives in wet and muddy conditions, making prevention and control essential for dairy farmers as we enter the wetter and cooler winter months
Digital dermatitis is a painful skin infection affecting the heels, particularly the rear feet. It presents as raw, ulcerated lesions, often surrounded by a red or greyish warty growth.
Infected cows exhibit lameness, reluctance to walk and reduced feed intake, impacting overall productivity.
The disease spreads through direct contact with contaminated surfaces, manure and infected cows.
Key risk factors include moisture and hygiene, stocking density, hoof trauma and injury and poor herd biosecurity.
Muddy laneways, wet yards and poorly drained paddocks create an environment conducive to bacterial proliferation, high-density housing and confined milking areas facilitate disease transmission, rough laneways, poor flooring, badly worn or poorly maintained concrete and excessive standing time contribute to hoof abrasions, increasing susceptibility to infection and the movement of infected cows within and between herds spreads the disease.
Preventing and managing DD requires a combination of hygiene management, hoof care and biosecurity measures, not just reaching for a bottle of treatment.
Maintaining clean and dry conditions is critical in reducing bacterial load so things like regular grading and proper drainage of laneways prevent excessive mud and manure accumulation and also reduces the risk of hoof injury.
Daily removal of manure and use of dry bedding materials lower infection risks in sheds, yards and on feeding areas. Regular use of antiseptic foot baths (for example, two to five per cent copper sulfate) helps prevent bacterial colonisation of the hoof skin and regular foot bathing is a critical component of digital dermatitis management.
Proactive hoof care minimises the impact. Routine hoof trimming helps prevent over-growth and maintains hoof integrity. Regular inspections allow for early identification and intervention, and affected cows benefit from targeted antibiotic treatment.
Proper herd management reduces stress and disease transmission. Managing the herd to ensure cows are moved quietly and slowly along laneways is a critically important factor that will influence the incidence of all lameness events.
If cows are being pushed too hard and their heads are up in the air and not watching where they are placing their feet, lameness incidence will be significantly increased no matter how good (or bad) the laneways or surfaces. Providing dry, comfortable resting spaces reduces hoof exposure to bacteria.
Strong biosecurity policies limit the spread of DD within and between farms.
Keeping affected cows separate helps to prevent cross-infection, while restricting external cattle introductions without proper screening or quarantine will help to reduce the risk of introduction. Cleaning and disinfecting footwear, equipment (especially hoof trimming equipment), and transport vehicles will reduce the risk of bacterial introduction and spread.
While prevention is the most effective strategy, treatment is necessary for affected cows. A treatment plan for DD should be worked out with your herd health veterinarian, especially if you are unsure or unfamiliar with managing this disease
Oxytetracycline sprays are commonly used under veterinary supervision. For occasional or sporadic cases, use of oxytetracycline aerosols is okay but when significant numbers are affected in the herd, you should consider oxytetracycline medicated foot baths or sprays initially to gain control then use preventative foot bathing with other non-antibiotic methods.
Applying medicated wraps aids healing but requires proper monitoring to make sure they are not left on the foot making the problem worse. Non-steroidal anti-inflammatory drugs (NSAIDs) should be used for pain relief in lame cows, and in severe cases, especially where there is swelling of the interdigital skin or leg, treatment with injectable antibiotics may be required
Digital dermatitis is an emerging disease on Australian dairy farms and poses significant challenges for farmers.
By maintaining clean environments, implementing robust hoof care and foot bathing, optimising herd management and enforcing biosecurity measures, farmers can effectively control and prevent this costly disease.
Early intervention and ongoing monitoring are essential in safeguarding herd health, ensuring sustained milk production and promoting animal welfare.
– Dr Rob Bonanno is a ProDairy regional lead veterinarian based in Gippsland.
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