LACTATE CONCENTRATION, BODY WEIGHT AND MEAT QUALITY IN NELORE CATTLE FEEDLOT FINISHED

The objective of this study was to determine blood lactate concentration during the finishing period and after slaughter and to verify its influence on body weight and meat quality traits of Nellore bulls feedlot finished. Ninety Nellore males were used, with a mean initial body weight of 390 +/- 37 kg and age of 24 months. Lactate concentration in the blood was measured by spectrophotometry on days 1 (Lac01), 14 (Lac14), 27 (Lac27) and 69 (Lac69) of the feedlot period and immediately after slaughter (Lac96). Fresh meat samples were collected from the Longissimus thoracis muscle for determination of luminosity, red (a *) and yellow (b *) intensity, shear force and pH of unaged meat and aged for seven days. Lactate concentrations were analyzed by the PROC MIXED of the SAS program, considering in the model the effects of pen and day of blood samples collection. Simple correlations between the studied variables were estimated using the procedure CORR of the program SAS. The lactate was stable during the confinement period, with mean values equal to 4.83 +/- 0.30 mMol/L; 5.68 +/- 0.29 mMol/L; 5.03 +/- 0.29 mMol/L and 4.15 +/- 0.31 mMol/L for Lac01, Lac14, Lac27 and Lac69, respectively. The highest mean lactate concentration was obtained on the day of slaughter (Lac96: 10.77 +/- 0.27 mMol/L). Significant association was detected between a * and b * color parameters of the unaged meat and the lactate concentration at the day of slaughter (Lac96). There is no association between blood lactate concentration at the day of slaughter and body weight of Nellore animals feedlot finished. Blood lactate concentration on the day of slaughter is associated with the coloring of the meat and is independent of other measures of meat quality in Nellore animals feedlot finished.