Doctoral Dissertations

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Animal Science

Major Professor

Kelly R. Robbins

Committee Members

K.M. Barth, J.K. Miller, D.S. Sachan, M.O. Smith


The effects of sex, light treatment (16L:8D versus constant light), and dietary energy and their interactions on growth performance of broiler chickens were evaluated. The diets used were isonitrogenous (23% CP); the dietary energy concentration was either 3300 kcal ME/kg diet or 2475 kcal ME/kg diet. The results indicated that light treatment had significant effects on weight gain, feed consumption, and gain/feed ratio. Constant light depressed growth after the third week of age in each trial. Birds reared under a 16L:8D photoperiod and fed a high energy diet performed best. Within light treatment, males gained more, consumed more feed, and had a higher feed efficiency than females. The light treatment x dietary energy concentration interaction was found to be significant for feed consumption and gain/feed ratio. It was concluded that combining a photoperiod of 16L:8D with high dietary energy under either an ad-libitum or restricted feeding regime resulted in a substantial and significant improvement in overall performance of broiler chickens.

Files over 3MB may be slow to open. For best results, right-click and select "save as..."