EFFECT OF MIXING UNIFORMITY ON BROILER CHICK PERFORMANCE

Two experiments were conducted to determine the effects of diet nonuni formity, caused by inadequate mixing, on performance of day-old broile r chicks. In both experiments, a common diet was mixed for different t imes to represent poor, intermediate, and adequate uniformity. Methods of uniformity analysis had quadratic responses (P < .001), with diet variability decreasing as mixing treatment was increased from poor to intermediate, and negligible reductions as mixing treatment was increa sed from intermediate to adequate. In Experiment 1 (a 24-d growth assa y), average daily gain, average daily feed intake, bone strength and a sh, and carcass CP, fat, and ash were not different among treatments ( P > .12). However, a 3.3% increase (linear trend, P < .09) occurred in gain:feed ratio as mixing treatment was increased from poor to adequa te. In Experiment 2 (a 28-d growth assay), quadratic responses were ob served for average daily gain (P < .04), average daily feed intake (P < .10), and gain:feed ratio (P < .07), with improvements as mixing tre atment was increased from poor to intermediate, but no further improve ments as mixing treatment was increased from intermediate to adequate. Mortality was not affected by treatment (P > .21), although the only deaths occurred in birds fed the most nonuniform treatment. Beginning on Day 28, all birds were fed a common finishing diet for 14 d to dete rmine whether compensatory growth occurred. The difference in average BW between the poor and adequate uniformity treatments decreased from 116 to 57 g per bird, with increased (P < .007) gain: feed ratio for b irds that were lighter at the end of the grower phase (i.e., those fed nonuniform diets). These experiments indicate that diet uniformity af fects broiler chick performance.