Abstract: Energy retention was estimated in F1 crossbred male lambs from different genotypes: Pelibuey x Pelibuey (PbPb), Black Head Dorper x Pb (BHDPb), White Dorper x Pb (WDPb) and Katahdin x Pb (KdPb). The energy retention was estimated by the amount energy stored in the carcass. Forty eight lambs were used with an average Live Weight (LW)±SD of 19.6±3 kg, which were given a basal diet for 21 days. At the end of this stage, three lambs of each genotype were measured the thickness of subcutaneous fat between 12th and 13th Dorsal Vertebra (DVF) with ultrasound and were weighed and slaughtered to determine the initial energy in the carcass. The rest of the animals (36), were distributed in a complete randomized design with a 4 x3 factorial arrangement: 4 genotypes and 3 dietary Metabolizable Energy (ME) concentrations (2.2, 2.5 and 2.8 Mcal kg-1 DM). At the end of the experiment, all animals were measured the DVF with ultrasound and were weighed and slaughtered to determine the Final Energy in the Carcass (FEC). The KdPb had a higher Weight of Internal Fat (WIF), Energy Retained in Internal Fat (ERIF) and Total Energy Retained (TER) (p<0.01-0.05). The animals fed diet with 2.8 Mcal ME kg-1 DM, had a higher LW, carcass weight, WIF, FEC, Energy Retained in the Carcass (ERC), ERIF and TER (p<0.05). A higher relation was observed between the average daily gain, ME intake and TER (p<0.001). We conclude that higher energy retention of KdPb, is the result of highest accumulation of internal fat that they have.
G.C.J. Canton, Q.R. Bores, R.J. Baeza, F.J. Quintal, R.R. Santos and C.C. Sandoval, 2009. Energy Retention of F1 Pelibuey Lambs Crossed with Breeds for Meat Production. Journal of Animal and Veterinary Advances, 8: 2655-2661.