25-Hydroxycholecalciferol Fails to Prevent Tibial Dyschondroplasia in Broiler Chicks Raised in Battery Brooders

Abstract

Two experiments were conducted to evaluate the effectiveness of high levels of 25-hydroxycholecalciferol (25-(OH)D3) in preventing tibial dyschondroplasia (TD) in broilers obtained from a commercial hatchery and grown in batter-brooder cages to 17 days of age. Levels of 25-(OH)D3 ranging from 0 to 250 μg/kg were added to diets adequate (0.95%) or low (0.65%) in calcium.There was no effect on body weight, feed:gain, plasma calcium or phosphorus, or bone ash. 25-(OH)D3 did not affect the incidence of TD or the number of severe lesions in these experiments. Although there was a decrease in overall severity in Experiment 1 when 46 μg/kg was fed, there was no response to dietary 25-(OH)D3 when higher levels were fed in either experiment. There was no consistent effect of 25-(OH)D3 on phytate phosphorus utilization. The results of these experiments indicate that 25-(OH)D3 did not prevent TD in commercial broiler chicks raised in battery-brooder cages when fed at levels as high as 250 μg/kg.