Hypervitaminosis A

bones

Hypervitaminosis A (Image sourced from Bristol Biomed Image Archive with permission)

• Main lesions:
  • Injury to growth cartilage -> premature closure of growth plate
  • Osteoporosis
  • Exostoses
  • Osteophyte formation in prolonged exposure
• In cats fed bovine liver for prolonged periods
  • Rich in vitamin A in grazing animals
  • Vertebrae fuse with each other due to bone proliferation - cervical spondylosis (ankylosing exostosis of the vertebral column), especially in the neck
• Can also be teratogenic, especially in pigs (cleft plate and abortions)

joints

• May cause spondylosis of cervical vertebrae
• Mainly on dorsolateral surface
• Also in elbow and shoulder joints -> fixation of joint
• May resolve with changes of diet