Achromatosis

Introduction

Achromatosis aka the failure to lay down normal feather pigments is caused by a variety of nutritional deficiencies including choline, lysine and riboflavin deficiencies.

Signalment

A lysine deficiency during growth causes achromatosis in dark breeds of chickens, turkeys and quail, but not in rock doves or cockatiels. Achromatosis is caused by a riboflavin deficiency in growing cockatiels. Choline deficiency during growth can also cause achromatosis. In all these cases, birds moult and grow normal feathers some time after the phase of rapid growth is complete.

The major significance of achromatosis is as a serious sign of an underlying nutritional deficiency. Unlike signs of some other deficiencies, it is not dependent on the severity of the deficiency except in extreme cases where the feathers may not grow at all.

Diagnosis

Diagnosis of achromatosis is possible on physical exam, however this should initiate an investigation into potential nutritional deficiencies.

Treatment

The proper course of action is to supply the limiting nutrient and, if the bird is still growing, observe growing feathers for normal pigmentation. When growth is complete, a reduction in nutrient requirements occurs. This reduction in requirements may allow a diet inadequate for growth to serve as an adequate maintenance diet, allowing the bird to produce normal feather colours. In this case no treatment is required.

Prognosis

Prognosis is good if the underlying nutritional deficiency is addressed, or the rapid growth phase ends (reducing the nutritional requirements of the bird). The birds will moult and grow normal feathers.

References

Forbes NA & Altman RB (1998) Self-Assessment Colour Review Avian Medicine Manson Publishing Ltd