Putting in Legwork to Help Cow Health
Lameness is one of the most important animal welfare concerns in the dairy industry and is the subject of more than 100 scholarly papers a year.
But despite all that work on improving cow mobility, the problem isn’t going away.
“In fact, in some research we find that lameness actually has shown increases over the years,” said Kathryn Proudfoot, an Ohio State University Extension specialist in animal welfare and behavior.
Proudfoot spoke in one of two recent webinars presented by DAIReXNET, a national dairy Extension group.
One reason lameness’ persistence might be that farmers don’t recognize the scale of the problem.
Studies in the United States, Britain and Canada have all found that dairy farmers underestimate how many lame cows they have in their herds.
Farmers may be defining lameness more narrowly than researchers, or they may be missing some of the subtle indicators.
“Pretty much anyone can pick out a cow that’s showing very obvious signs of a limp,” but stiffness and awkward movements can be harder to spot, Proudfoot said.
For example, when cows move, they normally keep their heads steady or bob rhythmically.
“Cows that are lame show more jerky head movements,” she said.
Researchers have found that a horse that bobs its head up likely has lameness in its front legs.
If it jerks its head down, it probably has lameness in the back legs.
That behavior seems to apply with cows as well, Proudfoot said.
When a cow is walking, its back foot should hit the same place its front foot stepped. If the back foot doesn’t come forward far enough, the cow could be lame.
An arched back is another indicator, though it’s not associated strictly with lameness.
“Typically you’re not looking at just one behavior” for a diagnosis anyway, Proudfoot said.
Lameness is typically scored on a three-, four- or five-point scale, and it takes some training to identify the symptoms and score cows correctly.
Farmers should watch cows on a straight, flat, nonslip surface where the cows make at least three strides and can be evaluated one at a time.
“One of the most ideal places to watch cows (is) as they’re coming out of the milking parlor,” Proudfoot said.
Watching the cows go into milking isn’t as helpful because healthy cows sometimes have to adjust their gait to accommodate their full udders.
It’s best to check all the cows daily for lameness, though that can be tough to do.
Especially in large herds, electronic trackers like pedometers could be a useful way to monitor the herd.
Motion sensors are often associated with heat detection, but they can also record movements that indicate lameness.
Lying down for long or inconsistent periods of time are suggestive of lameness.
Cows that spend little time lying down could also have problems, especially if they are perching — standing with just their front feet in the stall.
Lame cows go to the bunk at feeding time along with the healthy cows but return to their stalls sooner than the rest, Proudfoot said.
Housing design can influence a cow’s activity as well.
Cows on a bedded pack tend to spend more time lying down than those on mattresses or uncomfortable surfaces, she said.
Nutritional problems can also contribute to lameness, said Robert Van Saun, a Penn State Extension veterinarian.
Low rumen pH, which is a particular risk with grain-heavy diets, can kill bacteria in the digestive tract, causing chemical changes that produce inflammation.
When this happens in the hindgut, a part of the digestive tract with a sensitive lining, the cells release histamine, a compound associated with hoof blood flow problems in horses.
A similar hoof-harming process might be happening in cows, Van Saun said.
Body condition score correlates with the thickness of the cushion that protects the bone from rubbing against the hoof.
Lameness is prevalent in cows with a body condition of 2 or less.
A higher body condition correlates to a thicker cushion and lowers the risk of lameness, he said.