EFFECTS OF PHOTOSCHEDULE AND STRAIN CROSS ON BROILER PERFORMANCE AND CARCASS YIELD

The purpose of the present experiment was to examine possible interactions of strain cross and age with photoschedule for broiler performance and carcass yield. Day-old male broiler chicks from strain crosses of either Peterson x Arbor Acres (PA) or Ross x Arbor Acres (RA) were placed in light-controlled chambers (5.6 lx) with either 23 h light (L):1 h dark (D) from 1 to 56 days (Treatment E) or 6L:18D from 1 to 14 days and 1L:3D repeated from 15 to 56 days of age (Treatment BI). There were age by light treatment and age by strain cross interactions for BW; Treatment E had greater BW than Treatment BI from 7 to 42 days, and the PA cross BW was greater than the RA cross BW from 1 to 42 days of age. Cumulative feed efficiency was improved by Treatment BI compared with Treatment E up to 49 days. There were no differences among main effects for mortality, and the incidence of leg problems increased with age. Fillet and tender yields (per lean carcass weight) were higher for Treatment E than BI and opposite responses were seen for drumstick and thigh yields. The RA cross showed higher fillet and tender yields than the PA cross and the opposite relationship was found for drumstick and wing yields.