WHEN Nancy Cato wrote her book “All the Rivers Run” she could not have foreseen the situation of NW Victoria in 2011 nor 2016.
As heavy rain and floods wash away the fine materials in farm tracks or laneways it exposes larger stones and gravel pieces, which have the potential to damage a cow’s hoof.
Prolonged exposure to moisture causes the hoof to soften, making bruising, penetration injuries and white-line disease more prevalent.
The skin between the toes and around the foot also softens and mashes-up leaving it more prone to infections such as footrot.
The overall cost of each case of lameness is estimated at $200-$300 a head – as it decreases the cow’s ability to graze, causes loss of milk production, leads to lowered reproductive performance. It also increases the chance of a cow being culled and causes lost income through the additional cost of treatment.
Dairy Australia says the most common causes of lameness in extremely wet conditions or floods are:
Cows that stand in water for days at a time. They will have their hoof walls and soles softened by the constant contact with moisture.
Inter-digital skin. The usually hard skin between the claws – becomes soft, macerates (mashes up) – and forms cracks after long exposure to wet conditions. This skin is then prone to injury from any sharp object such as buck-shot, gravel or even crop stubble.
Soft hooves. These are more prone to developing fine cracks along the white line, especially if they are turning on abrasive concrete.
Mud coating the feet and lower legs. This can conceal many other problems.
Dairy Australia says there are a number of strategies to help prevent lameness.
Patience in handling stock is critical and the herd should be allowed to move slowly and given as much time as possible to choose where they place their feet. If there are sections of track washed away then allow the cows to work out their preferred alternative route even though this may take longer.
Minimise the use of the backing gate in the yard and let cows move into the shed at their own speed. Cows pushed up tight may result in sole injuries and loss of hoof sole as cows pivot on the concrete surface. Soft hooves are easily worn away by twisting and turning on abrasive concrete.
Protect cows’ hooves from rough surfaces by topping damaged tracks with sawdust, woodchips or limestone as a temporary fix in areas that have deteriorated during wet conditions. This is particularly important for the last 20-30 meters in the lead up to the concrete holding yards.
Similarly, areas of concrete that pose a danger to hooves, including the entry on to the concrete cow turning areas, can be covered with carpet or matting in the short term.
A foot wash at yard entry will wash sand and small stones from the feet before they reach the concrete. Tracks should never be topped with road screenings, rough screed, broken concrete, large river stones or builder’s rubble.
If flooding and debris have created particularly muddy or rough areas, these should be removed or fenced off to prevent stock from accessing these hazards.
Any cow showing lameness should be removed from the herd and placed in a paddock near the milking shed. Farmers should also consider milking affected cows once a day.
Early examination and treatment of lame cows not only improves welfare, but also limits the financial losses from a loss of body condition, milk production and the culling of affected cows.
Using a mix of 5% formalin or 5% copper sulphate foot-baths or treated hoofmats may also be effective in preventing and treating large outbreaks of footrot and bacterial infections. Footbath chemicals can be dangerous and should be handled with care. Footbaths should be at least 2.5m long, only used once-daily and the raceway through them should allow cows to go through in single file. They
Treated hoofmats can be placed on the way into the dairy to increase the time cows are standing on them. They should be recharged regularly and used at every milking.