Performance of Male Broilers Changed from Starter to Finisher Diets at Different Ages

Two experiments were conducted, one in the spring and a second in the summer, involving 960 male broiler chicks per experiment. A practical starter diet, containing 23% protein and 3200 kcal/kg metabolizable energy (ME), was fed for different durations (20, 25, 30, and 35 days). Either an 18% or 20% protein finisher diet (isocaloric with 3250 kcal/kg ME) was fed for the remainder of the growing period (49 days). Each of eight treatments was replicated in three floor pens of 40 birds each. The days of diet change and the protein content of the finisher diet had little effect on final body weight (49 days) and total feed consumption. Feed conversion and percent abdominal fat were significantly (P<.05) improved by the protein content of the finisher diet and the days of diet change.