Wet Weather and Lameness

Dr David Mackey, Greenmount Campus, CAFRE

Lameness is generally more common in winter when around 60 percent of annual lameness cases occur, but the wet weather conditions of the past summer have also been conducive to increased foot problems. To reduce the incidence of lameness due to the wet season and improve foot health this incoming winter, action needs to be taken now.

The bacteria which cause lameness thrive in moist warm conditions. Traditionally foul foot was the only major infectious cause of lameness but since the late 1980s digital dermatitis has become widespread throughout the UK increasing the incidence of summer lameness. This is exacerbated by wet conditions, either in the field or in collecting yards. Digital dermatitis is also associated with stress, particularly around calving when the cow’s immune system is suppressed. Cows that have calved in the last month are therefore at greatest risk of digital dermatitis and measures should be put in place to both treat and control the disease.

Just like mastitis, digital dermatitis is best controlled by a combination of prevention and treatment. Cows with raw open lesions should be treated urgently to reduce the spread of infection. Prevention should focus on keeping a relatively clean dry cow environment both inside the house and out in the field to avoid cows standing in slurry for long periods of time. This allows the area between the cleats of the foot to become drier and limit the spread of infection. Practical things limiting the source of infection include:

Proactive control of digital dermatitis is much more effective than reactive control. Footbathing is effective and practical, and should be increased in winter, wet weather and when the incidence of lameness is high. Where there is a specific lameness problem an intensive footbathing regime is required, for example, seven days on, seven days off. Footbathing once daily for 2 to 4 weeks is generally effective in causing regression of digital dermatitis lesions, even the most chronic ones. Where there is no specific lameness problem it is good practice to footbath on three consecutive days each month.

For autumn and winter calving herds, the winter footbathing regime should begin in early autumn with dry and early lactation cows to prevent mild lesions from developing. For most herds it may be more practical to footbath all cows routinely. Ideally a double footbath should be used providing a pre-wash followed by a treatment bath. This prolongs the effectiveness of the active ingredient which is reduced as the bath gets dirty. If a pre-wash cannot be provided, treatment is much more effective if the cows’ feet are hosed down in the milking parlour prior beforehand.

To allow time for good penetration and bacterial kill, the footbath should be at least three metres long allowing cows to take about three strides. It should be positioned to allow safe disposal of its contents and avoid the risk of milk taint. Common disinfectants include 4 percent formalin, copper sulphate and various proprietary products. The footbath should be filled to a depth of around four inches and be cleaned out regularly, particularly antibiotic footbaths which should be made up fresh every day. Formalin based footbaths which are least affected by contamination also help harden the hoof and control other foot conditions such as foul foot and slurry heel.

With the poor grazing conditions this summer and generally poorer quality silage, higher levels of meal feeding to balance the diet may inadvertently cause some nutritional lameness. High starch, low fibre diets can lead to ruminal acidosis leading to a higher risk of lameness. High protein diets and sudden dietary change, particularly around housing and time of calving can also increase lameness problems. Therefore dry cows should be fed a high fibre forage diet to keep the rumen functioning and be slowly introduced to the milking herd diet in the last few weeks before calving. This will help to maintain intakes and allow the rumen to adapt to dietary change, thereby limiting lameness caused by nutritional stress.

The wet weather and early autumn has caused many headaches but by planning ahead and acting early the impact of potential problems can be minimised. Consult with your vet on the most appropriate methods of lameness prevention and treatment within your herd as action now will give a good payback.