A recent study has shown that adding pain relief to lamenesstreatment protocols speeds recovery rates and offers milkyield benefits. We spoke to two vets to find out more.
TEXT HELEN GOLDBERG
Digital dermatitis is a common cause of lameness in UK dairy herds and has a significant impact on health, welfare and productivity. So quick and effective treatment, as well as prevention, are vital.
The use of non-steroidal anti-inflammatories (NSAIDs) in claw horn lesion and other lameness treatment protocols in cows is increasing, with good evidence to support their efficacy. But until recently there has been no specific research to support their use in cows with digital dermatitis (DD).
Now a recent study, conducted at the University of Liverpool, has demonstrated that cows with DD, which were lame at the time of diagnosis, were 20 times less likely to be lame one week later when treated with a zero-milk-withdrawal NSAID, alongside the application of a topical antibiotic spray after cleaning and drying the lesion.
Milk yield was monitored for a week after treatment and freshly-calved cows that were lame and were treated for DD with a NSAID and an antibiotic spray, compared to those treated with antibiotic spray alone, produced an additional 10 litres of milk per day. For early and late lactation cows that were lame initially, the increase in milk yield was in the region of five litres in the NSAID group.
Contagious disease
Digital dermatitis is a contagious cause of lameness that results in a superficial but painful inflammation of the skin surrounding the hoof. Infection usually results in ulcerated and or wart-type lesions around the heel bulbs and/or in the interdigital space. Lesions can vary from ulcerated sores to having the appearance of hairy warts, and affected animals may have more than one lesion type at any time. Infection is caused by the bacterial species treponemes, which can also be found in udder cleft or hock lesions, as well as in necrotic foot lesions. Nantwich Farm Vets’ Steve Crowe is a mobility mentor for AHDB’s Healthy Feet Programme and regularly runs hoof trimming courses. He’s only too aware of the impact that DD can have on dairy herds. “Digital dermatitis, as well as sole ulcers, white line disease and the many other causes of lameness, not only affect cow welfare, but also milk production, fertility and herd longevity. So the study’s findings that administering non-steroidal pain relief not only improves cow productivity but also improves recovery rates is good news for producers.”
Digital dermatitis-causing bacteria are typically found on the skin surrounding the hoof, and thrive in dirty bedding. They can also be isolated from hoof-trimming equipment, but the main source and reservoir of infection is active DD lesions on cows’ feet. Lesions on he feet can be scored and monitored using the M score (see Table 1).
Prevent infection
Ceva Animal Health’s Kythé Mackenzie says biosecurity, both external and internal, is key to DD control. “External biosecurity aims to prevent infection or new bacterial strains entering the herd. Producers should ensure the feet of all bought-in animals, as well as those returning from other units, are inspected. Any lesions found should be treated and cattle should be run through a footbath before they join the herd. External handling and foot trimming equipment must also be kept clean and disinfected, and all staff in contact with animals should maintain hygiene protocols.”
She says internal biosecurity should aim to prevent spread between animals. “Good hygiene is important as slurry can act as a short-term reservoir and also increase the risk of skin damage, which can facilitate infection. Always consider the whole herd when devising protocols and, if running separate heifer groups, have different scrapers and foot dips for staff so infection is not transferred from the cows to these groups.”
Hoof-trimming equipment, particularly knives, should also be cleaned and disinfected between animals. This requires at least 20 seconds’ contact time in a suitable biocide solution.
Footbathing is a key to controlling and treating DD, as well as other foot lesions. “The footbath should be designed and positioned to ensure good cow flow and foot coverage to the appropriate depth and frequency of contact using the correct concentration of biocide. The herd vet can recommend the most appropriate agent for individual herds.
Hoof lesions: check cows' feet as they pass through the parlour
“All cattle on the unit must be footbathed – including dry cows and heifer groups. It’s also important that cows’ feet are clean before they go through the biocide bath.” Ms Mackenzie says one of the challenges is to identify all cattle with active lesions so they can be treated. “As most lesions are on the hind feet this can be done while cows are in the parlour, but it is important to examine the interdigital space as well as the heel bulbs. Use a head torch and a mirror.”
Once identified she suggests a standard protocol, which includes: lifting and trimming the hoof; cleaning the identified lesion, or lesions; removing any scabs and surface discharge; and drying the infected area and applying topical treatment as advised by the herd’s vet. “Control relies on identifying and managing risk factors, and putting protocols in place to reduce the infection pressure,” she says. “Treatment should be prompt and effective, and the use of a NSAID can enhance welfare as well as productivity. If you have questions or concerns about DD on your unit, seek advice from your vet.”