EARLY DIETARY-PROTEIN RESTRICTION AND INTERMITTENT LIGHTING .1. EFFECTS ON LAMENESS AND PERFORMANCE OF MALE TURKEYS

A trial was conducted to determine the effects of dietary protein restriction at an early age and intermittent lighting, designed for curtain-sided houses, on lameness and performance of Nicholas commercial male turkeys sired by male Line 88. Four isocaloric diets containing different levels of protein (100, 90,80, or 70% of control value) were consumed ad libitum from 8 to 56 days. All birds were provided control diets from 1 to 7 days of age and from 57 to 124 days of age. Two lighting regimens, control [15 h light (L):9 h dark (D)] and intermittent (15L:2D:1.5L:2D:1.5L:2D), were each assigned randomly to two rooms from Day 8 until the end of the study. Light intensity was maintained at 20 Ix throughout the study for both lighting regimens. When compared with the control (15L:9D) photoperiod, intermittent lighting improved market body weight and feed efficiency and increased the incidence of leg abnormalities but did not affect overall mortality. The incidence of leg abnormalities among toms decreased linearly with decreasing levels of dietary protein at 85 days of age. However, the dietary effect on lameness was transient in that no differences were apparent at market age of 123 days. Mortality was not affected by dietary treatment. Testes weight increased and shank length decreased linearly with increasing levels of dietary protein. Toms fed the 90% protein diet in both lighting regimens had market body weights and feed efficiency values similar to those of controls. It is concluded that Nicholas commercial male turkeys have improved performance in intermittent lighting and can be fed dietary protein at 90% of control levels from 8 to 56 days of age to reduce feed cost.