246 AJVR • Vol 76 • No. 3 • March 2015 A nimal health and welfare are important consider- ations in the cattle industry. Beef and dairy cattle are most productive when they are free from pain; therefore, development, evaluation, and application of protocols that prevent diseases such as lameness are necessary to produce healthy and productive cattle. Lameness is one of the 2 most costly diseases of dairy cattle in England 1 and is the most costly disease of the US dairy industry, costing producers more than mastitis on a herd basis. 2 On an individual case basis, lameness ($478/case) is only slightly less costly than left displaced abomasum ($489/case) when the preva- lence of lameness within the herd is moderate at an estimated 30%. 2 Results of another study 3 indicate that the prevalence of lameness in dairy herds is approxi- mately 20% for primiparous cows and 50% for multipa- rous cows. Lameness causes substantial negative effects on the production and well-being of dairy cattle; there- fore, it is currently considered one of the most important challenges for the US dairy industry to overcome. 2–5 Results of multiple studies 2–9 indicate that lame- ness predisposes cattle to other conditions that impair Effect of exercise and environmental terrain on development of the digital cushion and bony structures of the bovine foot Julie A. Gard DVM, PhD Debra R.Taylor DVM, MS Dewey R. Wilhite PhD Soren P. Rodning DVM, MS Megan L. Schnuelle BS Richard K. Sanders MD Ronald J. Beyers PhD Misty A. Edmondson DVM, MS Fred J. DeGraves DVM, PhD Edzard van Santen PhD Received June 27, 2014. Accepted October 13, 2014. From the Departments of Clinical Sciences (Gard, Taylor, Schnuelle, Edmondson) and Anatomy, Physiology, and Pharmacology (Wilhite, van Santen), College of Veterinary Medicine; the Department of Agriculture, College of Agriculture (Rodning); and the Department of Engineering, Samuel Ginn College of Engineering (Beyers), Auburn University, Auburn, AL 36849; the Department of Radiology, School of Medicine, University of Utah, Salt Lake City, UT 84132 (Sanders); and the Department of Animal Science, Ogden College of Science and Engineering, Western Kentucky University, Bowling Green, KY 42101 (DeGraves). Address correspondence to Dr. Gard (waldrja@auburn. edu). OBJECTIVE To determine whether exercise on alternative terrain affects the development of the digital cushion and bony structures of the bovine foot. ANIMALS 20 weaned bull calves. PROCEDURES Two-month-old calves were randomly allocated to an exercise or control group. For 4 months, the control group was maintained in grass paddocks, and the exercise group was maintained in a 0.8-km lane with a mixed terrain of dirt, stones (0.32- to 0.95-cm pea gravel and 5-cm crusher run), and grass. Water and food for the exercise group were located at opposite ends of the lane; calves were fed twice daily, which ensured they walked 3.2 km/d. Pedometers were applied to all calves to measure distance traveled. All calves were slaughtered at 6 months of age. The right forefeet and hind feet were harvested for MRI and CT evaluation. RESULTS Control calves walked a mean of 1.1 km daily, whereas the exercised calves walked a mean of 3.2 km daily. Mean digital cushion volume and surface area were 25,335 mm 3 and 15,647 mm 2 , respectively, for the exercised calves and 17,026 mm 3 and 12,745 mm 2 , respectively, for the control calves.When weight was controlled, mean digital cushion volume and surface area for the exercise group were increased by 37.10% and 18.25%, respectively, from those for the control group. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that exercise on alternative terrain increased the volume and surface area of the digital cushion of the feet of dairy calves, which should make them less susceptible to lameness. (Am J Vet Res 2015;76:246–252) production and reproduction. For some dairy herds, the deleterious effects of lameness on reproduction is especially problematic because the mean first-service pregnancy rate is fairly low (18%). 6 Results of another study 10 indicate that fertility was decreased by 50% for dairy cows that had foot rot, compared with the fertility for nonlame cows. Dairy cows that become clinically lame during the first 70 days of lactation are 25% as likely to become pregnant as are nonlame cows. 4 Investigators 2,9,a estimate that each episode of lameness costs producers a mean of $302 to $446, with the cost positively associated with the severity of lameness. In a 1978 study, 7 sole ulcers and white line disease were associated with milk production losses of 574 and 369 kg/cow, respectively, during a 305-day lactation. Investigators of a 2010 study 10 report that each case of sole ulcers, digital dermatitis, and foot rot cost dairy producers $216.07, $132.96, and $120.70, respectively. Most of the economic cost for cows with sole ulcers was associated with a decrease in milk pro- duction while lame. 10 Those investigators 10 concluded that it was economically beneficial to treat 97.3% of Unauthenticated | Downloaded 09/24/22 11:14 PM UTC