Changes

*Failure of mineralisation of osteoid / softening of the bones

*Failure of mineralisation of osteoid / softening of the bones

*Active resorption of bone replaced by excess osteoid on trabeculae, endosteum of cortices and [[Haversian systems|Haversian canals]]

*Active resorption of bone replaced by excess osteoid on trabeculae, endosteum of cortices and [[Bones and Cartilage - Anatomy & Physiology#Bone Remodeling|Haversian canals]]

*Decreased resistance to tension -> osteoid build-up at tendon insertions

*Decreased resistance to tension -> osteoid build-up at tendon insertions

*In advanced disease

*In advanced disease

**Vitamin d is also present in sun-dried hay

**Vitamin d is also present in sun-dried hay

**Mostly seen where there is long grass growing season with poor sunlight

**Mostly seen where there is long grass growing season with poor sunlight

===Hypovitaminosis A===

===Hypovitaminosis A===