Osteopetrosis

(Marble bone disease)

• Occurs in sheep, dogs, cattle, horses
• Failure of resorption by osteoclasts -> failure of remodelling of cancellous bone
• Bones become thickened and dense but brittle
• Marrow cavites are full of unresorbed primary spongiosa
• Thickened intramembranous bones of skull -> altered shape of brain
• Associated with severe viral infections, e.g. FeLV, BVD
• Hereditary in Angus cattle