animal care and health

by Kiyomi Ito and Katy Proudfoot
The authors are graduate students with Marina von Keyserlingk and Dan Weary with the University of British Columbia Animal Welfare Program.

Lameness is one of the most serious and costly issues for dairy producers. Studies have estimated that between 25 and 30 percent of lactating cows in Canada and the United States are lame. Lameness is painful, results in decreased feed intake, reduced milk production, impaired reproduction, and early culling.

As a result, lameness has been considered by the North American dairy industry as a major problem that needs attention from producers and members of industry alike. For instance, Canada's newly published "Code of practice for the care and handling of dairy cattle" (www. nfacc.ca/) advises dairy producers to take a proactive approach to the problem of lameness on their farms.
Below are their risk factors:
• High-grain rations that may cause rumen acidosis
• Lack of ration effective fiber
• Standing on concrete, especially when wet or rough
• Infrequent or poor hoof trimming
• Poorly designed or inadequately bedded stalls
• Unsanitary conditions - bacteria in the slurry (such as those that cause digital dermatitis)
• Physical hazards
• Unsuitable management of transition cows
• Unbalanced genetic selection (corkscrew claw)

Cutting the risk
Many of the risk factors for lameness can be reduced with good housing and cow care. Research has discovered that the risk of lameness is closely associated with several features of the housing environment and cow management. For example, prolonged exposure to wet concrete and manure slurry increases the risk of hoof injuries and infectious diseases in the foot, both of which are major causes of lameness.

This risk for lameness goes up further if stalls are uncomfortable due to poor design or insufficient bedding.

Practices that can reduce the risk of lameness include:
1. Not overstocking at the feed bunk or lying stalls, especially during transition, as this can increase the time cows spend standing
2. Providing a comfortable lying surface, such as ample, dry bedding and unrestrictive stalls
3. Providing a comfortable and dry standing surface that reduces exposure to slurry and wet concrete
4. Developing a lameness prevention strategy including input from your veterinarian, nutritionist, and hoof trimmer
Here's what the Canadian code of practice says we do with lame cows:
• Lame cows must be diagnosed early and either treated, culled, or euthanized.
• Feet and claws must be inspected and trimmed as required to minimize lameness.
• Severely lame cows or cows that require hobbling in order to walk must not be transported except for treatment under the advice of a veterinarian.
• The prevalence of moderate and severe lameness (see below) be kept at less than 10 percent.

Catch lame cows early
Detecting lameness on-farm is a challenge for dairy producers, especially in larger herds, and the rate of lameness often is underestimated. Reluctance to bear weight on a hoof (a "limp") is an obvious indicator of lameness, but there also are more subtle signs.

Several methods of scoring gait have been developed using visual observation of how cows walk. The typical system uses a 5-point scale where a score of 1 is given to a sound cow and 5 to a severely lame cow. Behavioral signs of lameness include a back arch, a jerky head bob, short strides, stiff joints, uneven steps, and reluctance to bear weight on one foot (limping). To gait score, observe cows from the side walking in a straight line on a flat, even surface using the indicators found in the table.

Good record keeping of lameness and hoof injuries is critical. Incorporating regular gait scoring as a component of standard farm management practice provides you with a benchmark which can help to track improvements in your herd. Recording the occurrence of lameness also will provide clues to the underlying cause of impaired gait.

Talk to your veterinarian, nutritionist, and hoof trimmer about developing a lameness prevention strategy. A proactive approach to the lameness problem on your farm is key to reducing the incidence of this debilitating and costly disease.

Gait score Description
1 Sound - walks smoothly and fluidly, with a flat back and even steps.
2 Imperfect gait - walks with a slightly uneven gait and slight joint stiffness but no limp.
3 Mildly lame - walks with shortened strides, an arched back, and a slight limp.
4 Moderately lame - walks with an obvious limp, an arched back, and a jerky head bob.
5 Severely lame - reluctance to bear weight on at least one limb and/or must be vigorously encouraged to stand or move; extremely arched back when standing and walking.

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