Asilent epidemic which has nothing to do with disease is injuring Canadian dairy cattle and costing milk producers millions of dollars annually.
Chronic lameness is widespread in dairy herds throughout Canada and damage from it is far greater than realized, according to a British Columbia dairy scientist.
“It’s a serious, serious problem,” Jeffrey Rushen told producers at the recent Manitoba Dairy Conference in Winnipeg.
Research suggests lameness costs the Canadian dairy industry over $100 million a year in lost production, treatment, reproductive problems and culling, he said. One study puts the annual loss per cow at $308. Other studies range as high as $800 for each animal.
A B.C. study earlier this year found lameness in 28.5 per cent of dairy cows surveyed; 7.3 per cent were severely lame. In a 2007 Ontario study, 28.4 per cent of cows showed signs of lameness with 4.7 per cent of them severely lame.
Most dairy farmers underestimate the extent of the problem, Rushen said during an hour-long presentation.
U.S. and British studies show average dairy producers have three to five times as many lame cows as they think they do. As a result, they underestimate how much money they are losing to lameness, said Rushen an Agriculture and Agri-Food Canada dairy cattle welfare researcher at Agassiz, B.C.
Lameness can be difficult to detect because early symptoms are sometimes subtle, he said.
Rushen encouraged producers to “gait score” cows by spending time watching how cows walk to spot physical signs of lameness.
Cows that walk with an arched back, show reluctance to bear weight and favour one leg over another may have ulcerated hooves.
Cows standing half in and half out of stalls is another sign. The more they do that, the more hoof problems they may have. Most cases of lameness are due to hoof lesions.
However, only direct examination of an animal can confirm sore feet, Rushen said.
Dairy experts suggest poor nutrition, genetics and infectious diseases are causes of lameness. But Rushen said he considered housing the main root cause.
Cows’ hooves were made to walk on soft, well-drained surfaces such as pasture. These days, however, dairy herds spend much of their time indoors on concrete floors often wet with slurry.
Prolonged standing on wet concrete is the main risk factor for lameness. Wet flooring makes the horn of the hoof soft and increases the risk of infection, according to Rushen.
He suggested several steps to deal with lameness. Those include:
Try to reduce wetness by cleaning alleyways daily. Drier floors reduce the incidence of infectious causes of lameness, such as digital dermatitis.
Ensure stalls are comfortable so that cows lie down in them. One reason cows stand up in stalls is that they are too small for the animals to lie.
Minimize exposure to bare concrete floors. Rushen recommended installing rubber flooring in areas where cows spend a lot of time standing or walking. But he emphasized it should be soft rubber with high traction, not slippery hard rubber mats.
Make sure there’s enough bedding in stalls. Rushen said people sometimes think they can use rubber mattresses without any bedding at all. But that’s not the case. Cows like to lie on a soft surface. Straw is best but even wood shavings or sand will help. Rushen said producers should make sure bedding is dry because one of the biggest things that stops cows from lying down is wet bedding.
Reduce stocking densities to improve stall conditions. Stalls that are uncomfortable or too small increase the time cows spend standing up. The more time a cow spends lying down, the more comfortable she is.
One way to treat lameness is a walk outdoors. Rushen said lame cows put on pasture show improvement because the soft surface is better for their hooves.
But because it’s not always possible to range milking cows outdoors or to build a new barn suited to their comfort, the above methods should be followed, he said.
Rushen recommended producers follow the new dairy industry code of practice which outlines procedures for cow comfort. [email protected]
– JEFFREY RUSHEN, AAFC