LAMENESS IN cattle can occur at any time of the year but extremely wet conditions are associated with higher rates of lameness in dairy cows. This is because prolonged exposure to moisture causes the hoof to soften and increases the risk of bruising, penetrating injuries and white-line disease.
The skin between the claws and around the foot also softens, leaving the skin more prone to infections such as footrot.
Wet muddy environments favour the survival and replication of bacteria which contributes to this problem.
Larger stones and gravel on farm tracks are also more exposed after wet weather.
Strategies to prevent lameness:
1. Low-stress cattle handling
Calm and patient cattle handling reduces wear and injuries to softened hooves.
Allowing the herd to move slowly along tracks will give cows the time to choose where they place their feet.
Consider putting slow walkers and young cows in a separate herd to improve cow flow and reduce the competitive pressure between cows.
Refrain from hurrying cows with quad bikes, dogs and even the backing gate. Soft hooves are easily damaged by twisting, sliding sideways and turning on abrasive surfaces, such as concrete.
Avoid overcrowding in the yard and let the cows move into the shed at their own pace.
2. Repair track surfaces
It may not be possible to re-surface tracks during wet conditions, but some maintenance can reduce further deterioration.
Aim to clear drains and cut drainage paths through mud using a shovel and/or tractor blade. By clearing the mud that builds up on the edge of tracks, excess water is moved more easily off the track surface.
Large and sharp stones should be removed, and potholes filled with fine screenings and compacted well.
Temporary maintenance to tracks includes topping with sawdust, woodchips (at least 300 mm thick) or finely crushed rock/limestone.
Severely damaged track areas should be fenced off until more permanent solutions are possible.
Placing a log or a 125 mm high concrete nib wall (for the cows to step over) at the laneway-yard junction can reduce the number of stones brought onto the concrete.
3. Protect hooves on concrete
As soft hooves are quickly worn down by rough concrete surfaces, it is essential to keep any concrete clean and free from stones. This should be part of a daily routine.
Purpose-made protective yard matting, carpet or rubber tiles can be strategically placed on turning areas and laneway-yard junctions to catch small stones brought into the yard. These mats must be cleaned off daily.
4. Ensure the diet is not contributing
Insufficient effective fibre or a rapid transition to a highly fermentable diet are risk factors for rumen acidosis.
Acidosis (both clinical and sub-clinical) causes inflammation of the sensitive tissues of the hoof. This results in lameness and/or a disruption to the normal growth of horn tissue and poorer quality horn.
Any changes to the diet should be made slowly over seven to 10 days, especially when increasing the level of grain/concentrate feeding by more than 2–3 kg/day.
Adequate fibre is essential to help prevent rumen acidosis. Aim for the diet to contain 35 per cent NDF, half of which has sufficient stalk length (4–5 cm) to stimulate chewing and saliva production.
If dietary fibre is limited, consider including rumen modifiers in the diet. Other supplements such as biotin and zinc can be beneficial to strengthen the hoof but need to be used for at least six months.