Lameness costs the New Zealand (NZ) dairy industry many millions of dollars every year.
The obvious costs of lameness include labour and vet costs for treatment, drugs and hoof blocks, reduced milk production and lost milk if antibiotics are used. Other costs include reduced overall season production, reduced reproductive performance, increased empties and lates, and increased culls. Important costs to the farmer include the time needed to treat cows, having to run separate herds, emotional stress, concerns about inhibitory substances getting in milk and of course animal welfare concerns.
Spring and mating time are the periods when most lameness occurs. NZ cows, especially heifers entering the herd for the first time, often have to walk long distances. The most common cause of lameness in NZ pastural dairy farming is traumatic injuries (over 70%). Most common are white line disease, bruising and sole injuries, and hoof wall cracks. Footrot accounts for less than 10% of lameness and the vast majority is in the foot rather than higher up the leg (approx. 95%).
Causes of lameness are multifactorial and are a combination of environmental factors, management and hoof health.
Environmental factors include design and maintenance of tracks and the milking shed. Tracks need to be the correct width, well drained, non-abrasive, and as straight as possible with no tight turns or steep slopes. There should be no congestion in gateways or boggy areas. Well designed milking parlours maintain a good quiet flow with no sudden turns, bottlenecks or steep entrance/exits. The entranceway to the shed is a vitally important area and should not provoke fear in the cows so no stray voltage or slippery concrete. Entrance ways should also be kept clear of stones and mud.
Management refers to handling of the cows on the track and in the shed, including the distance walked each day and if cows are held up after milking. On the track, if cows are allowed to set their own pace, then they will walk with their heads down looking for the best pathway. An unhurried cow will put her hind foot in the same place as where the corresponding front foot was and can walk over a moonscape without injury. Problems result if the tail-end cows are pushed by humans on motorbikes or dogs or if poor track design causes cows to bunch up. In the shed problems will occur when backing gates are used to push cows rather than just taking up the space as the cows move forwards. Milkers yahooing or coming out of the pit into the yard will also disrupt flow. Heads poking up in the yard is a sign that the cows are being pushed too hard.
Hoof health is influenced by nutrition (e.g. mineral supplementation such as zinc), genetics (e.g. conformation of legs and feet), hygiene (e.g. walking through boggy, contaminated areas) and diseases such as interdigital dermatitis or metabolic problems that cause grooves in the hooves.
If you are having lameness issues talk to your vet about ways to reduce the problem through treatment and management practices.