Experiments were conducted to evaluate the effect of protein, metabolizable energy, and sulfur amino acid content of five diets upon growth and development of captive Florida Sandhill Crane (Grus canadensis pratensis) and Greater Sandhill Crane (G. c. tabida) chicks raised under controlled conditions. A high protein (32%) diet resulted in faster growth than that obtained when a lower protein (24%) ration was supplied. Florida Sandhill Crane chicks fed a diet containing 2,160 kcal/kg grew significantly slower than chicks fed a ration containing 2,830 kcal/kg. Reducing the sulfur amino acid content of a ration containing 24% protein from 0.88% to 0.73% significantly slowed the growth of young cranes. A 17% incidence of leg disorders and a 25% incidence of wing abnormalities occurred between 7 and 28 days of age among Greater Sandhill Cranes fed a high protein diet. Florida Sandhill Cranes grew slower than Greater Sandhill Cranes irrespective of the type of ration they were provided and did not develop leg or wing abnormalities. Abnormalities invariably developed only in the most rapidly growing Greater Sandhill Cranes. Diets that promoted slower growth reduced the incidence of abnormalities. A ration formulated to contain a low (0.73%) sulfur amino acid level appeared to be the most suitable for slowing growth rates of captive-reared Sandhill Cranes and reducing the risk of abnormaiwing or leg development.
