Relationship of empty body weight with shrunken body weight and carcass weights in adult Pelibuey ewes at different physiological states

Abstract

The data of two experiments were used to assess the relationships among shrunken body weight (SBW), empty body weight (EBW), hot carcass weight (HCW) and cold carcass weight (CCW) to develop equations to estimate EBW in dry and lactating Pelibuey ewes fed tropical rations. In Experiment I, 24 three-year-old, non-pregnant, non-lactating Pelibuey ewes were randomly assigned to four groups of six animals each. One of these groups was slaughtered for baseline measurements. The remaining ewes were individually housed in metabolic crates, and were fed at levels of metabolizable energy intake (MEI): Low (L), Medium (M) and High (H) for 65d. MEI was: 0.247, 0.472 and 0.532MJ/kg BW0.75/d for L, M and H levels, respectively. In Experiment II, 21 three-year-old lactating ewes with twin lambs were distributed to three treatments in a completely randomized design (seven ewes per treatment) and housed individually in pens with concrete floors from the fifth to the fifty-sixth day after lambing. Ewes were fed one of three levels of feeding (DM intake): L: 50g DM/kg, M: 100g DM/kg0.75 and H: 150g DM/kg0.75 for 56 days. Individual intake was adjusted according to BW of each ewe and treatment. The ewes were slaughtered at the end of both experiments. Before slaughter, SBW was recorded after feed and water were withdrawn for 24h. EBW was computed as the difference between SBW and contents of the gastrointestinal tract (GIT). The data recorded at slaughter were weights of internal organs and HCW. After refrigeration at 6°C for 24h, the CCW was recorded. In both experiments, the relationships among the SBW, HCW, CCW and EBW measurements were all significant (P<0.0001) and the R2 ranged from 0.94 for Experiment I to 0.95 and 0.97 for Experiment II. The weight of GIT content was approximately 19% of SBW of ewes. Additionally, SBW could be used to reliably predict EBW of Pelibuey ewes.