Introduction

Caused by deficiency of manganese, choline, zinc, either singly or in combination (although deficiencies of pyridoxine, biotin, folic acid, niacin may also be involved).

This condition is seen in chickens, ducks and turkeys. In turkeys it may be an inherited deficiency of galactosamine.

Signs

• Short legs.
• Lameness.
• Distortion of hock.
• Slipping of Achilles tendon (or perosis).
• Malposition of leg distal to hock.
• In embryos parrot beak, shortened bones.

Post-mortem lesions

• Shortening and thickening of long bones.
• Tibia and metatarsus bowed.
• Shallow trochlea.
• Lateral slipping of tendon.

Diagnosis

Lesions, analysis of feed.

Differentiate from twisted leg, infectious synovitis, rickets, infectious arthritis, ruptured ligaments.

Treatment

For flock proceed as for prevention, no value to affected bird.

Prevention

Addition of manganese, choline, vitamins, correct mineral balance.