[Energy and protein concentration of broiler rations in Cuba. 2. Female broilers in winter]

Four energy concentrations (10.5, 11.5, 12.6 and 13.6 MJ ME) and four protein concentrations (15.0, 17.5, 20.0 and 22.5% CP) were tested with a total of 1,900 female broilers of the breed White Plymouth Rock in their first 56 days of life in 16 experiment groups. The animals were kept in cages and were directly exposed to the natural Cuban winter temperatures from their 15th day of life. As six repetitions were carried out in every test group, the results could be variance-analytically calculated. In winter the female broilers of the breed White Plymouth showed a lower intake of feed, metabolic energy and crude protein than male animals. They achieved a lower live weight, lower amount of body protein and fat and worse feed, protein and energy utilisation. Possibilities are shown to meet the crude protein and energy requirement in monophase feeding systems with 11.5 MJ ME and 20% CP or with 12.6 MJ ME and 17.5 or 20% CP.