The Amount of Manganese Required to Prevent Perosis in the Chick

Abstract

PEROSIS has recently been recognized as a deficiency disease affecting the development of bone. Up to the present time it has been observed in several species of domesticated and game fowl but has not been observed in other animals. The most characteristic symptoms of the disease are enlargement of the tibio-metatarsal joint, bending of the distal end of the tibia and the proximal end of the metatarsus, and displacement of the Achilles tendon. Locomotion is impaired and in severe cases the animal is unable to stand. These outward manifestations of injury have given rise to the descriptive terms of “slipped tendon” and “enlarged hock” as names for the deformity. Titus (1932) first proposed the name perosis.The disease is prevalent among rapidly growing chicks confined in battery brooders. Diets high in calcium and phosphorus aggravate the condition according to Wilgus (1931). That the disease is distinct from rickets, in sensu .