Testing Lameness in bulls
As you are well aware, your bull or bulls are especially valuable to the productivity of any well-operated ranch. By quickly and accurately identifying lameness issues within the herd, one can diagnose and treat those animals most efficiently in order to avoid significant loss of profit in the long run.
How does a bull become lame? Other than obvious injury from aggression, fighting, or other types of trauma—the bull’s hind legs and spinal canal are put under a large amount of stress during the breeding season. Sprains and ligament tears can result from overactive bulls either acutely or with progressing time. Pasture bulls who are traveling long distances to reach cows also can be affected by less than adequate footing conditions. Moist ground often breeds bacteria while very dry pastured areas can predispose the hoof wall to cracks and chips.
Clinicians from Kansas State University report that approximately 90 percent of lameness cases are typically isolated to issues within the foot. Out of this proportion, animals are most likely to be affected in the hind feet and lateral (outer) claws. A big reason for this presentation is due to how the animal carries its weight normally.
Each animal’s body condition status must be taken into consideration during a lameness evaluation. Young, overweight bulls may demonstrate a degree of development disease due to over nutrition and too rapid of weight gain. In addition, excess weight adds to the strain on developing and recovering bones, muscles, and joints—and serves as a detriment to resolving lameness problems.
Evaluating a lameness case involves analyzing the animal in the chute as well as during natural movement. It is important to watch the bull move in a small round pen in order to rule out concurrent lameness conditions and to look for muscle loss and symmetry (or lack thereof) in movement patterns. Once gait has been examined, the bull can be moved to a restraint chute for a closer look.
Because the foot is a leading cause for lameness, palpation begins here. The leg may be tied up for closer examination of the toe and sole, but a quick palpation of the entire limb is recommended in order to prevent further tearing injury to ligaments or bones—as a bull will inevitably struggle with the leg tying procedure.
Any swelling is palpated for heat or coolness in the region, as well as determining whether the swelling is soft and fluid-filled or hard and possibly related to bony growth and proliferation. An area of swelling located over a joint is often a sign of some septic infection process taking place. All limbs are palpated and assessed for bilateral abnormalities.
The most common cause for lameness in herds is called ‘footrot,’ caused in part by bacteria living in moist or filthy soils. Many cattle present with painful abscesses in the toe and sole of one or more claws. These lesions are many times detected when the claw is cleaned and roughened hoof wall is removed with a knife and nippers. Often these animals will be treated on the farm with oxytetracycline—but veterinarians urge that chronic cases that do not adequately respond to treatment have further evaluation, as a ‘simple’ footrot scenario should always show a degree of response to antibiotics. It is also important that adequate drainage is allowed by paring away necrotic hoof wall from the abscessed region. Any questionable scenarios may be further evaluated with joint fluid aspirations, ultrasound or radiographs.
Some orthopedic issues, such as ‘spastic paresis’ and ‘corkscrew claw,’ are caused by developmental disease, nutritional imbalances, environment factors and heritable traits. Producers should always keep orthopedic and lameness problems in mind when selecting candidates for their breeding programs.
Overall, treatments indicated for lameness issues can demonstrate a broad range of low cost therapy to the desirable gold standard care. The economic value of each particular bull will play a significant role in what type of care may be recommended and utilized in the end. Consult with your regular veterinarian for a lameness examination before turning out bulls to ‘full work’—whether that may be in artificial insemination or pasture breeding. A strong skeleton is always a critical factor to success! — Dr. Genevieve Grammer
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