The effect of temperature, dietary energy level, and corn particle size on broiler performance.

Experiments were conducted to study the effect on broiler performance of grinding corn with different hammer mill screen openings (HMSO). Corn for Trials 1 and 2 was ground through HMSO of 3.18 or 9.59 mm and broilers were grown at 15.5 and 26.6 C in Trial 1 and at 26.6 C in Trial 2. Dietary energy levels used from 22 to 42 days were 3,050 and 3,230 kcal ME/kg for Trial 1 and 3,230 and 3,330 kcal ME/kg in Trial 2. In all starter and finisher diets, lysine and sulphur amino acid concentrations were similar on a megacalorie basis. In Trials 3 and 4, HMSO were 3.18, 4.76, 6.35, and 7.94 mm. Corn ground through a HMSO of 9.59 mm significantly reduced body weight and feed:gain ratio in Trials 1 and 2 at 21 days as compared with corn ground through an HMSO of 3.18 mm. At 42 days, body weights were reduced when corn was ground through 9.59- and 3.18-mm HMSO for the starter and finisher diets, respectively, as compared with those fed with the corn ground through a 3.18-mm HMSO in the starter diet. In Trials 3 and 4, significant differences in body weight and feed:gain ratios at 21 days were not noted for feed containing corn ground through an HMSO of 3.18, 4.76, 6.35, or 7.94 mm.