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Tibial Dyschondroplasia

Osteochondrodystrophy, Focal Osteodystrophy, Cartilage Plug

Tibial dyschondroplasia (TD) is a common skeletal bone deformity that occurs in modern rapid growing, heavy chicken breeds (usually broilers).
Tibial dyschondroplasia
In 1995, it was estimated 30-40% of male broiler birds suffered from TD. TD involves the development of an abnormal mass of cartilage at the growth plate of the long bones of the leg, usually the tibia bone. Instead of calcifying, the cartilage remains soft and will often bend backwards under pressure or heavy body weight. As a result, chickens with TD often suffer from spontaneous leg fractures, necrosis, and severe lameness. Birds with severe lameness are often unable to stand due to the pain, and often die from starvation from being unable to reach food or water, or trampled to death by other flock members. TD is thought to be similar to osteochondrosis which occurs in rapidly growing horses.

TD has been shown to have multiple possible causes, which include:
  • Ingestion of commercial feed contaminated with fusarochromanone, a mycotoxin produced by Fusarium equiseti has been associated with the development of TD in chickens.
  • Vascular endothelial growth factor (VEGF) deficiency in the growth plates.
  • Diet with excess vitamin A have been linked with chickens developing TD, since excess vitamin A depresses absorption of vitamin D.
  • An imbalanced calcium to phosphorus ratio, with too low of calcium levels and too high of phosphorus.
  • Improper incubation conditions
  • Genetics
  • Limited exercise and/or restricted movement
  • Poor sanitary conditions
  • Large meat-type chicken breeds, such as modern day commercial broilers

Symptoms

Swelling
Lameness
Bowing of legs
Reluctance to stand

Diagnosis

  • History
  • Clinical signs
  • Physical exam
  • Radiography

Treatment

MethodDetails
Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
Exogenous chicken vascular endothelial growth factor (chVEGF) proteins from Pichia pastorisAdministered at a dosage of 10 or 30 μg/kg through intramuscular injectionZhang et al. 2013

Prevention

  • Ensure proper calcium and phosphorus ratio in diet
  • Provide vitamin D3 supplementation
  • Supplement diet with yeast extract

Scientific References

Age Range

is most common in young, rapidly growing male broiler chicks between 3 and 8 weeks of age.

Risk Factors

  • Mycotoxin-contaminated feed
  • Fast-growing chicken breeds
  • Unbalanced diet consisting of too little calcium and too much phosphorus

Also Consider