Introduction

Phosphorus deficiency in chickens, turkeys and duck is seen worldwide. Some countries have regulations governing the use of phosphorus in fertiliser with a view to reducing water pollution. This has led feed manufacturers to try various approaches to reduce added phosphorus in diets. Intestinal diseases may reduce absorption. Even subclinical levels of this condition can predispose to Femoral Head Necrosis.

Signs

• Lameness.
• Hock swelling.
• Soft bones and beak.
• Birds go off legs.
• Poor growth.
• Enlarged hocks.
• Birds rest squatting.
• Reduction in bodyweight.

Post-mortem lesions

• Bones soft and rubbery.
• Epiphyses of long bones enlarged.
• Beading and fracture of ribs.
• Growth plates widened and disorganised.
• Beak soft.
• Parathyroids enlarged.

Diagnosis

History, signs, lesions (analyse Vitamin A or manganese as a guide to premix inclusion).

Treatment

Over-correct ration with 3 times vitamin D for 2 weeks, or vitamin D in drinking water.

Prevention

Supplementation of Vitamin D, proper calcium and phosphorus levels and ratio, antioxidants.