Abnormal gait in goats is a nonspecific sign common to many diseases and conditions. A thorough history is important for diagnosis and should include incidence and duration in the individual or herd, nutrition, feed changes, method of rearing, and recent introductions to the herd. (Also see Preventative Health Care and Husbandry of Goats.)
Some causes of lameness may be associated with systemic disease. Therefore, a thorough physical examination should always be performed, followed by a detailed examination of all four limbs, with a specific assessment of gait and mobility in an attempt to localize locomotor problems. In goats, as in other species, locomotor difficulties usually involve the musculoskeletal system directly; however, conditions of the nervous system can mimic musculoskeletal disease.
The hoof of the affected legs should be examined, and excess horn material removed to leave a level weight-bearing surface. If the feet have not been trimmed recently or the goats have been on soft ground or bedding, excess horn commonly overgrows from the walls, toes, and heels and folds over the sole. With severe neglect, deformed hooves with elongated toes (ie, sled-runner or Turkish slipper) may cause the goat to walk on its heels. During foot trimming, note any abnormally thickened portion of the horn, underrunning of the heel or sole, abnormal wear of one claw, or abnormal smell.
After trimming, the feet should be scrubbed clean and inspected for puncture wounds, foreign bodies such as stones or clover burrs caught in the interdigital space, or pus from an abscess. Inspection should also include the coronary band or coronet.
The rest of the leg should be palpated carefully, including the bones, tendons, and muscles. Any muscle atrophy or restriction of movement should be noted, and contralateral limb structures should be compared for asymmetry.
The joints also should be checked for heat, swelling, or signs of pain. If the clinical examination suggests joint involvement, it may be necessary to aseptically sample fluid from an affected joint via arthrocentesis.
A blood or serum sample may also be useful to establish the underlying cause of lameness. In septic arthritis, WBC count may be elevated. Serum calcium, phosphorus, and vitamin D concentrations may help diagnose epiphysitis or rickets, although concentrations often return to normal before the affected goat is examined. If caprine arthritis and encephalitis (CAE) is suspected, the presence of antibody can be checked via serum ELISA; however, false-negative and false-positive results may occur. Neonatal animals may have interference from colostral antibody.
Radiography is often a helpful diagnostic for lameness, especially in cases of fracture, epiphysitis, and septic arthritis. In epiphysitis, the growth plates should be checked; there is often lateral deviation of the radii and occasionally thinness of the bone. In CAE virus infection, the initial swelling of the soft tissue surrounding the affected joint may be followed by calcium deposits in the swollen periarticular tissue, joint capsule, ligaments, tendons, and tendon sheaths. Later changes may include mild periarticular osteophyte production, intra-articular loose bodies (ie, joint mice), and rough extensions of the periarticular bone proximally and distally.
The differential diagnosis in any case of lameness is influenced by geographic location, herd history, management practices, and other relevant factors.
