Predição da composição química corporal de ovinos Morada Nova utilizando o corte das costelas 9-10-11ª

Abstract

The objective of this work was to develop equation to predict empty body and carcass chemical composition of Morada Nova sheep, using section from 9 to 11th ribs (HH section). Thirty-five morada nova lambs, with initial weight of 14.50 ± 0.89 kg and approximately 2 months of age. Animals were distributed in a completely randomized design, in a 3 x 3 factorial scheme, being three sexual classes (11 whole males, 12 castrated males and 12 females) and three feeding restriction (ad libitum , 30 and 60%). Experimental diet was composed of Tifton-85 hay, corn grain, soybean meal, dicalcium phosphate and premix. For ad libitum treatment animals intake was allowing up to 10% of leftovers. When animals fed ad libitum reached 28 kg of body weight, all were slaughtered. The right half carcass and HH section of left half carcass were analyzed for ethereal extract (EE%), crude protein (CP%), water and energy (EN Mcal/kg). Stepwise procedure was used to determine inclusion of variables in regression models. Variables from HH section used were water (HH%), protein (CPH%), ethereal extract (EEH%) and energy (ENH%), and also we collected carcass yield (CY kg), warm carcass weight body weight (WCBW), empty body weight(EBW), other viscera (OV% EBW) and visceral fat (VF% EBW). The contents of water, EE and EN in the carcass and EBW were satisfactorily estimated by section HH, but there was no precision in the estimation of CP contents. Sex influenced the content of water in carcass and EBW. The equations developed to predict the water content of the carcass (%) were: uncastrated males = 73.86 (± 3.95) - 0.46 (± 0.23) x EEH - 0.29 (± 0.22 ) x VF (R² = 0.84, EQM = 2.55), castrated males = 69.91 (± 1.46) - 0.23 (± 0.10) x EEH - 0.54 (± 0.17 ) ± 0.32 (± 0.31) × EEV - 0.33 (± 0.42) , female = 70.67 (± 4.23) - 0.32 (± 0.31) x GV (R 2 = 0.81, EQM = 8.12). In order to predict content of ethereal extract, protein and energy of the carcass (%) the equations developed were: 6.83 (± 1.20) + 0.37 (± 0.08) x EEH + 0.33 (± 0, 10) VF x (R² = 0.86; NDE = 1.34) 12.35 (± 0.64) + 0.17 (± 0.04) x CPH (R² = 0.30; NDE = 0, 55), 1.59 (± 0.11) + 0.03 (± 0.01) x EEH + 0.03 (± 0.01) x GV (R² = 0.82, EQM = 0.01), respectively. Predicted equations for estimation of the water content, EE and EN in the carcass and EBW can be used with accuracy and precision in Morada Nova sheep growing except for CP in the carcass and EBW.