Understanding the root causes of dairy lameness could save your operation money when it comes time to make culling decisions within your herd. In a webinar conducted by Iowa State University Extension, Phillip Jardon, D.V.M, and Jan Shearer, D.V.M, explained that, “Many years ago, we attributed errors in feeding and nutrition to claw related lameness in dairy cattle. We now understand that if this was the case, all claws and feet would be equally affected.”
Looking at the anatomy of the hoof, the inner claw is less stable compared to the outer claw. Weight is transferred down through the center of the lower limb to the foot, where it is redirected to the outer claw. The digital cushion is the shock-absorbing part of the hoof. Having a small digital cushion means that the cow will be less protected and more apt to hoof issues. The outer claw is where we tend to see the most issues like toe and sole ulcers. Jardon and Shearer explained that 90% of lameness is in the foot, 90% of which involves the rear feet, and of that, roughly 70% to 90% involves the outside claw.
Transition cows are typically more affected by lameness than any other group in the herd. Early lactation cows are going through many changes as they prepare to calve, which can have a direct effect on hoof health. Hormones are rapidly shifting, and there are feed, metabolic, dry matter intake, pen mate, and pecking order changes. Jardon suggests no more than an 80% stocking density for close-up or fresh cows as a precaution to preventing lameness.
Other contributing factors of lameness that were noted were heat stress, fly pressure, overcrowding, and bedding. When cows experience heat stress, breathing becomes more labored, making it uncomfortable to lay down in the stall. Cows resort to perching, which in turn makes breathing easier for the animal, but it also means they spend more time on their feet.
It is also not uncommon to see a group of cows bunching together on a hot summer day. The herd is likely trying to mitigate the number of flies that have access to them. The cows on the outside will get bitten, but the ones in the center of the group will not. If your barn is also overcrowded, there will not be an opportunity for each animal to lay down if no spots are available. Prolonged standing is a contributor to claw conditions and sole ulcers.
When it comes to lameness, it can be attributed to three main factors, said Shearer: the sinking of the P3 bone, followed by toe and sole ulcers; lipid mobilization; and a reduction in the size of the digital cushion. Shearer cited, “We used to think because cows get lame, they get thin. We now know cows become lame because they are thin.”
