Effect of dietary Fe to Cu ratios on hematological and growth responses of broiler chickens.

A total of 2,640 broiler strain cockerels were used in three experiments to determine the interrelationships between Fe and Cu requirements of 1- to 21-day old broiler chicks. In each experiment, a starch non-fat milk basal diet was fed to chicks maintained in battery brooders beginning at 1 day of age. Maximum hemoglobin levels and packed cell volumes (PCV) of 21-day old chicks were found by feeding 80 parts per million (ppm) of dietary Fe and 8 ppm of dietary Cu from 1 to 21 days of age. The heaviest 21-day old chicks were found by feeding 80 ppm dietary Fe. Variations were found among experiments in the copper requirement based on body weight. The Cu requirement ranged from 8 to 16 ppm as indicated by 21-day old chick weights. A 10:1 dietary Fe to Cu ratio with an Fe requirement of 80 ppm appeared to maximize hemoglobin levels and PCV's of 21-day old broiler chicks; whereas, a 5:1 dietary Fe to Cu ratio, rather than a 10:1, 15:1, or 20:1 ratio, maximized 21-day old chick weights. Iron requirements for hematological and growth responses are essentially the same; however, the copper requirement may be slightly different for the two criteria.