EFFECTS OF PHOTOPERIOD, LIGHT INTENSITY AND FEED RESTRICTION ON THE PERFORMANCE OF DWARF AND NORMAL MATERNAL POULTRY MEAT GENOTYPES

Abstract

Performance of female chickens from a dwarf maternal genotype was compared with that from a normal commercial maternal genotype in a fractorial experiment designed to estimate the combined effects of increasing photoperiod at 112 and 140 days of age, increasing light intensity at 112, 126 and 140 days of age, and restricting adult nutrient intake at conventional and 95% of conventional levels. Dwarf layers matured 1 wk earlier and exhibited better feed conversion than the normal layers, but body weights were lighter at all ages. Eggs produced by dwarf layers were smaller but had stronger shells as measured by specific gravity. Gentoype × feed restriction interactions revealed that productivity of the dwarf layer was adversely affected by the 95% feeding rate; at conventional feeding rates the two gentoypes were similar in performance. Increasing light intensity days had no significant overall effect on the measured traits. Increasing the photoperiod (140 vs. 112 days) resulted in fewer double-yolked eggs and delayed sexual maturity particularly for the dwarf gentoype. Key words: Meat breeders, poultry, dwarf, light, feed restriction