A study on the effect of the different levels of energy and protein of diet on performance and carcass characteristics of native sheep of Gilan Province

In this research two levels of ME (2. 3 and 2. 5 Mcal /kg DM) and three levels of CP (12, 14 and 16%) and their interaction were studied. Twenty four male lambs with 7-8 month old and live body weight of 19. 7±1. 84 kg were used in an experimental period of 105 days. In this study a completely randomized design in 2×3 factorial experiment with 6 diets and 4 replications were used. average daily gain (ADG)، daily dry matter intake (DDMI, kg/day) and feed conversion ratio (FCR) was calculated each 15 days interval. At the end of the experiment, carcass cuts and chemical composition of 9, 10 and 11th ribs area were measured. The result of this experiment indicated that experimental diet had significant effect (p<0. 05) on ADG, DDMI, FCR and carcass cuts. Results of urea space (US) showed a high and significant correlation (p<0. 05) between urea space (US) and chemical composition of ribs area. It is recommended that an energy concentration of 2. 5 Mcal ME/kgDM and 14% CP in diet will be appropriate for fattening native male lambs. This experiment was conducted at 2007 in Animal Science Research Center in Gilan Province.