Better Understanding, Proper Management can Minimize Risk of Lameness
The single most costly disease of dairy cattle, on a herd basis, is lameness. Nevertheless, many producers ignore this serious problem, or address it only superficially, attributing many cases to dietary causes that are difficult to control. In fact, current research has revealed more influential factors, and with those factors come tactics that dairy farmers can employ to minimize the risk - and cost - of lameness.
According to the 2010 Iowa State University Animal Industry Report, no disease rivals lameness in terms of economic losses to dairy herds.
That’s because it affects so many animals and is often insidious, says Jan K. Shearer, DVM, M.S., author of the report and professor and extension veterinarian at the Iowa State University College of Veterinary Medicine.
“I use statistics compiled by Chuck Guard at Cornell University,” Shearer explained in a recent interview with Bovine Health Watch. “His estimate on economic losses associated with clinical disease indicates that lameness is the single most costly disease of dairy cattle on a herd basis. The loss estimates vary, based on milk prices, but it’s roughly $460 to $480 a case. And, because approximately 30 percent of cows are affected to some degree over a one-year period, that loss becomes a big number—and it doesn’t even take into account subclinical cases.”
Based on this rate of occurrence and cost per case, Iowa dairy farmers alone are losing nearly $103 million annually due to lameness.
Shearer offered that the per-case cost of mastitis and displacement of the abomasum are also high, but these conditions are not nearly as prevalent as lameness, a condition he says is often poorly understood and addressed by producers, and even many veterinarians.
Why lameness is so prevalent—and costly
Lameness often goes undetected and untreated until late in the process, Shearer said, because early symptoms are subtle and because, as animals of prey, cows often disguise their discomfort. Another reason lameness issues aren’t addressed in a timely manner is because producers have become somewhat desensitized to it, as well as a bit daunted by the constant attention it requires.
“Dairy farmers are so used to seeing lameness—and often have no way to deal with it. It’s hard to work on feet, and unless they have someone assigned to that task on a daily basis, animals can go days or weeks before their problems are addressed. Outside trimmers, for example, may only come in every few weeks.”
To make matters worse, Shearer said that most dairy record-keeping systems do not include lameness events. Data provided by trimmers often cannot be conveniently incorporated into the dairy’s system, and hoof-trimming terminology has not been standardized, which makes data entry and interpretation difficult.
As a result of all these things, the conditions causing lameness often become exacerbated, necessitating more extensive treatment and resulting in higher costs.
But the impact of lameness isn’t confined to performance and profit, Shearer offered. It is also important from an animal welfare standpoint.
“Animals really suffer with these conditions. Being forced to walk to and from the feed bunk and the parlor several times a day creates a lot of distress for them. They don’t have a choice; they are required to do these things.”
“For some reason,” Shearer observed, “we treat lameness as if it weren’t a disease. If a case of mastitis were detected today, it would be treated today on any dairy farm anywhere in the country. Lameness IS a disease and animals really do suffer, so it needs to be addressed promptly. People forget that cattle are very stoic animals. They put up with it. In fact, they hide it instinctively because that’s the way their brain is wired as prey animals. In the real world, the ones that show any degree of sickness are the ones who get eaten. So if they are showing symptoms of lameness, you can be sure they have a problem.”
Here are some of the symptoms of lameness you should look for.
• An arch in the back. This can be indicative of other conditions but is a way to detect lameness at an early stage.
• Posture of rear legs. A cow standing cow-hocked may have discomfort or a problem with the outer claws of the rear foot.
• Tracking. Normally when a cow walks forward, the front foot comes up where the back foot goes down. If there is a problem with lameness, they do not track correctly.
The anatomy of lameness
Most cases of lameness involve the outer claw of the rear feet. Here’s how it breaks down, according to Shearer:
• 90 percent of lameness involves the foot
• 90 percent of those cases are of the rear feet
• And, 90 percent of those cases are of the outer claw
The outer claw bears most of the weight, so it overgrows and develops more hoof horn, which means it bears more weight and therefore is more apt to develop problems. It’s a vicious cycle that operates somewhat like calluses on human feet.
As the process progresses, hoof ulcers can also develop. When this occurs, the suspensory system in the hoof breaks down and permits the bone to sink and rotate within the claw capsule, damaging the underlying tissue of the sole and the heel. Usually the point where this occurs is right beneath the backside of P3 at the heel-sole junction of the weight-bearing surface of the foot, Shearer said.
Attitude adjustment
Certainly, it’s important to understand the process by which lameness develops. However, the most important thing about all this, according to Shearer, is understanding the primary cause of lameness. He contends that most dairy farmers are operating under a misconception: that the majority of lameness, laminitis (founder) and hoof ulcers are caused by rumen acidosis.
“In reality,” he explained, “we are learning over the past several years that the effects of enzymes and hormones that relax the muscles and ligaments around the birth canal around the time of calving can also relax the suspensory apparatus areas around the bone and cause the sinking of P3. These things have nothing to do with how you feed cows.”
This discovery indicates that during the peripartum period, maximum cow comfort is of the utmost importance. It’s a time when cows are normally forced to stand for long periods of time at the feed bunk or waiting for vaccinations and other health procedures.
“Poor comfort after calving is one of the single most important factors in causing some lameness disorders later on,” Shearer said. “We think rumen acidosis is related, but in reality it’s looking more and more like there’s more of a relationship to cow comfort during the transition period—approximately 2-4 weeks prior to calving and up to 2-4 weeks after calving. And, that’s exactly the time when the diet is being transitioned and rumen acidosis is more prevalent.”
So, it’s important to maximize cow comfort around the time of calving.
• Make sure the cow has a soft place to rest and lie down
• Be sure the stall is of adequate size
• Don’t force cows to stand for too long, including in the holding pen
• Minimize hard surfaces
All of these efforts will contribute to improved herd health, performance and profit. Furthermore, dairy farmers should consider how lameness issues can influence consumer perceptions—and preferences. Because lameness is a very visible condition, reducing its incidence will likely improve consumer trust about safety and animal welfare—and help shield producers from damaging attacks by animal welfare activists.
Tips for reducing losses due to lameness
• Understand the potential causes of lameness
• Maximize cow comfort, especially during the peripartum period
• Include hoof trimming and lameness events in your dairy record-keeping system
• Treat lameness for what it is—a disease
• Know the signs and symptoms of lameness
• Address lameness issues promptly