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 rest riction at an early age and intermittent lighting, designed for curtai n-sided houses, on lameness and performance of Nicholas commercial mal e turkeys sired by male Line 88. Four isocaloric diets containing diff erent levels of protein (100, 90,80, or 70% of control value) were con sumed ad libitum from 8 to 56 days. All birds were provided control di ets from 1 to 7 days of age and from 57 to 124 days of age. Two lighti ng regimens, control [15 h light (L):9 h dark (D)] and intermittent (1 5L: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 wit h the control (15L:9D) photoperiod, intermittent lighting improved mar ket 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. Test es weight increased and shank length decreased linearly with increasin g levels of dietary protein. Toms fed the 90% protein diet in both lig hting regimens had market body weights and feed efficiency values simi lar to those of controls. It is concluded that Nicholas commercial mal e turkeys have improved performance in intermittent lighting and can b e fed dietary protein at 90% of control levels from 8 to 56 days of ag e to reduce feed cost.