A 3-year-old 817-kg (1,797-lb) Angus bull was evaluated at the J.T. Vaughan Large Animal Teaching Hospital at Auburn University because of an inability to copulate. According to the owners, the bull had successfully sired calves the previous breeding season but had not been observed successfully breeding females during the current season. The owners indicated that the bull displayed acceptable libido and would mount cows normally, but he failed to extend the penis or to achieve intromission. There was no history of previous injury or penile trauma.
The bull had no evidence of muscle atrophy. No genital abnormalities were identified
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 mm3 and 15,647 mm2, respectively, for the exercised calves and 17,026 mm3 and 12,745 mm2, 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.