Small ruminant bone and muscle disorders

Bone disorders

Osteomyelitis can occur due to trauma or hematogenous spread. Signs include lameness, pain on palpation, and focal swelling. Animals may be recumbent. Radiographic changes may not be visible for up to two weeks. Prognosis is guarded.

Rickets and osteomalacia can occur in young animals due to deficiencies in Vitamin D, phosphorus and/or calcium. Corriedale sheep can develop inherited rickets. Signs may include stiff gait, shifting legs, lameness, and recumbency due to bone fragility and pathological trauma. Joints and bones of the distal aspects of the limbs may be enlarged along with enlargements of the ribs at the costochondral junctions (rachitic rosary). Limbs may be bowed (angular limb deformities). Teeth may be mottled and their eruption delayed. Treatment is based on Vitamin D3 injections.

Fibrous osteodystrophy (nutritional hyperparathyroidism) may be seen in animals on a high phosphorus diet. Animals have a big head/rubbery jaw due to replacement of bone by fibrous tissue.

Fractures and other injuries can be treated fairly effectively due to the ruminant healing potential and small size. Amputations are a possible option, as are limb slings. Schroeder-Thomas splints can be effective at fracture stabilization when a cast is not appropriate.

See orthopedic emergencies chapter

Muscle disorders

• Blackleg– Clostridium myositis
• Sarcocystis– intracellular protozoan parasite; typically asymptomatic in animals but issues in people
• Nutritional muscular dystrophy– deficiency of selenium, Vitamin E or both; white muscle disease

Congenital disorders

• Spider lamb syndrome/ Hereditary chondrodysplasia
  • Suffolk and Hampshire breeds are at greatest risk for this inherited condition that leads to stunted crooked legs
  • Chondrodysplasia may be seen at birth or develop within the first 6 weeks of life
  • Caused by a mutation in the fibroblast growth factor receptor 3; testing is now available
  • UC Davis spider lamb information and testing
  • A similar condition is found in beef cattle with hypomagnesemia

Kaltura version w/ captions: Spider Lamb Syndrome

• Polydactyly
  • likely inherited
• Spastic paresis
  • constant contraction of gastrocnemius muscle -> leg extended behind and back arched
  • considered inherited

Kaltura version w/ captions: Annabelle the tiny goat with Spastic Paresis

• Myotonia congenita / Fainting goats
  • tetanic contraction when startled
  • autosomal dominant trait

Kaltura version w/ captions: Fainting Goats | National Geographic

Resources

Sheep, goat and cervid medicine. 3rd ed. Elsevier, 2021, Ch 11. Diseases of the musculoskeletal system.

Musculoskeletal Disease including Foot Disorders. In Goat Medicine and Surgery. 1st ed. 2017