Cattle get lame for a lot of reasons, including injury, poor conformation, grain overload, mycotoxins (e.g., ergot) and bacterial infection. Different types of lameness need to be treated differently. Antibiotic treatment only helps if a bacterial infection is involved.
Lameness is the second leading reason (behind bovine respiratory disease) that feedlot cattle are pulled and given antibiotics. Lame cattle eat less, grow more slowly and less efficiently, may be shipped early and often don’t grade as well. These add up to a significant economic cost. When cattle get lame late in the feeding period, pre-slaughter withdrawal times limit the number of antibiotic treatment options.
A team of Canadian researchers led by Agriculture and Agri-Food Canada’s Karen Schwartzkopf-Genswein recently published a review of large-scale studies of foot-related lameness in feedlot cattle (A Review of Foot Related Lameness in Feedlot Cattle;
What They Did
These researchers reviewed studies of infectious foot-related lameness (i.e., not including chronic arthritis related to mycoplasma or histophilus) in feedlot cattle. These included several multi-year studies conducted in Canadian feedlots with treatment records on between 10,000 to over 1,000,000 cattle. Important hard-to-find details can appear when researchers have data sets that large.
What They Learned
Footrot is the most common cause of infectious foot-related lameness in feedlots. It can occur at any point in the feeding period (as well as in cow-calf operations). Footrot causes swelling between the claws of the hoof (often on the hind limb) that may extend into the lower leg. If the front of the foot is clean, a footrot lesion often looks dark and is surrounded by jagged edges with sloughing skin. Early detection and treatment are key to preventing a worse infection. Footrot typically responds to any long-acting antibiotic, so if the initial treatment doesn’t work, it’s probably not footrot. Several different bacteria appear to be involved, which may be why available footrot vaccines aren’t effective. Footrot is most common in poor pen conditions; good drainage and a good bedding mound help reduce the risk.
Digital dermatitis (also known as DD, strawberry foot rot, hairy heel wart) is generally much less common than footrot in feedlot cattle. Digital dermatitis is more commonly associated with dairy cattle. DD is rarely diagnosed in cow-calf operations but is becoming increasingly common in feedlot cattle. It doesn’t usually appear until cattle have been on feed for three months or more and can occur in combination with footrot. Affected cattle may not be lame and the affected foot may not be swollen, so these cattle may be harder to find in the pen (and may help explain why it isn’t often seen or diagnosed on cow-calf operations). Digital dermatitis starts as a circular or oval strawberry-red lesion where the skin and the heel bulbs meet at the back of the foot. In more advanced or chronic lesions, the infected skin can become rough, scaly and develop long hair-like projections. DD generally responds to topical antibiotics such as tetracycline. Copper sulfate footbaths are less effective for treatment, particularly once they’re contaminated by dirty hooves. Properly disposing of used copper sulfate is also a problem. Digital dermatitis is caused by multiple bacteria, but different bacteria than footrot. There is no vaccine. Clean, well-drained, well-bedded pen conditions help reduce the risk. Digital dermatitis bacteria can survive in the soil to infect new cattle, so once a feedlot is contaminated it probably becomes a fact of life.
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