Association of physiological parameters with final pH in beef

The objective of this study was to correlate physiological parameters such as cortisol, glucose measured by a glucometer and laboratory methods, creatine kinase (CK), lactate dehydrogenase (LDH), and age with the ultimate pH (pHu) of beef. Two hundred Nellore cattle (n = 200) were evaluated and divided into two groups: 100 whole males and 100 castrated males. Soon after exsanguination, blood was collected, stored in tubes, and sent to the laboratory for measurement of plasma glucose, CK, and LDH. Part of the surplus blood was used to measure blood glucose levels using a portable glucometer. Twenty-four hours after slaughter, the pHu of the carcasses was evaluated, and age was verified using the dental chronology method. The obtained data were tabulated and subjected to descriptive and correlation analyses using Spearman's nonparametric test, with a significance level of p < 0.05. Among the evaluated blood parameters, cortisol showed a weak negative correlation (p < 0.05), while LDH showed a strong negative correlation (p < 0.001) with pHu, both observed exclusively in intact males. Moreover, the animals' age showed a strong positive correlation with pHu (p < 0.001) within this same group. Blood glucose, regardless of the measurement method, did not show a correlation with pHu, and the measurements performed using the portable glucometer differed statistically from those performed using the laboratory method. Therefore, the correlations between physiological factors and pHu varied according to the category evaluated, with significant associations with pHu observed only in entire males.