Influence of Lighting Regime on Developing Layers Pullets within an Open- Sided Housing System in the Sudan

Abstract

This study was aimed to investigate the capabilities of four applicable lighting regimes in inducing the onset of correct sexual maturity of developer layer pullets. The applied lighting regimes include natural day light (NDΩ 12 hrs light), continuous lighting regime (CLR Ω 24 hrs light), boosted natural day length (BND Ω 16 HL: 8 HD) and 2-stages lighting regimes (2-SLR Ω 12 HL: 4 HD: 8 HL). The four lighting regime and 64 grower layer pullets were randomly and evenly distributed to 16 similar experimental pens within an open – type poultry house. The experimental pens were equipped with all required facilities and prepared with an aid of black curtains to keep them light-tight. The experiment was commenced when the grower pullets were 10 weeks old and continued for a week post the onset of laying. During this period the experimental birds were kept restricted to the planned lighting regimes, got accessible to water and feed and vaccinated against the endemic diseases (New-Castle, Infectious Bronchitis and Fowl Pox). Data collected include: age, body weight, egg size and feed intake at point of lay and a week after in addition to mortality rate throughout the experimental period. The collected data were statistically analyzed to come up with the following results: The developer pullets reflected at point of lay showed significantly (P< 0.05) controversial responses towards the examined lighting regimes; The flock developed under CLR demonstrated the youngest age at point of lay (131 days), the highest rates of feed intake and body weight gain in addition to the smallest first egg size; The flock exposed to the ND responded significantly (P< 0.05) in a complete opposite manner to that of the former group under CLR. In contrast to the response patterns of the former two flocks (CLR and ND), the interaction trends and magnitude of the flocks confined to either the BND (16 hrs light) or the 2- SLR (20 hrs light) were moderate. With the exception of feed intake of the ND group, no other apparent changes in performance pattern of the studied flocks were observed through a week post the onset of production. Further studies are strongly recommended for displaying the complete production features of each experimental lighting regime.