Studies on the etiology of tibial dyschondroplasia in chickens.

Experiments have been conducted to obtain information on the cause of tibial dyschondroplasia in chickens. All studies were conducted with corn-soybean meal practical-type diets and chicks from 1 day to 3 or 4 weeks of age. A high calcium and low phosphorus content of the diet and a wide calcium:phosphorus ratio in the diet decrease the incidence of tibial dyschondroplasia in broiler chickens. Increasing the chloride level of the diet increased the incidence of tibial dyschondroplasia. Increasing the magnesium content of the diet decreased tibial dyschondroplasia; however, the effect of magnesium was not as strong as that of calcium. The addition of sodium sulfate to the diet had no effect on the incidence of tibial dyschondroplasia. Five broiler strain crosses were all susceptible, although to a variable extent, to the development of tibial dyschondroplasia, whereas Single Comb White Leghorn chickens did not develop the disease. Male chicks developed tibial dyschondroplasia with a higher incidence than did female chicks. Supplementation of the chickens with 20 ng/day of either 1,25-dihydroxycholecalciferol [1,25(OH)2D3] or 24,25-dihydroxycholecalciferol [24,25(OH)2D3] had no effect on the incidence of tibial dyschondroplasia. J. Nutr . 114: 1001-1013, 1984.