Prediction equations for Warner-Bratzler shear force using principal component regression analysis in Brahman-influenced Venezuelan cattle

Main altered characteristics in the meat of young cattle of different sexual conditions supplemented in tropical pasture

The aim was to identify the predominant variables in the differentiation of meat quality of cattle submitted to surgical castration, immunocastration, or non-castration and finished in a tropical pasture. Thirty-nine crossbred cattle were used and distributed in three treatments: i) surgical castration; ii) immunocastration; and iii) non-castration, with an initial mean age of 14.06±0.72 months and a mean weight of 284.10±31.40 kg. We used the principal component analysis to differentiate the qualitative meat characteristics between the treatments. Based on that analysis, we found that the first three principal components explained 71.44% of the total variation in the meat quality data, which ensures that the variation found is associated with the effect of the treatments. The characteristics correlated with the first three principal components and responsible for the discrimination between sexual conditions were subcutaneous fat thickness, instrumental meat color, cooking loss and shear force. These characteristics were similar among castrated animals, regardless of the methods. Therefore, immunological castration preserves the attributes of the meat and prevents possible damage to the physical and mental integrity of the animals. Finally, principal component analysis is an important methodology in the objective investigation of beef meat attributes.

Beef Tenderness Prediction by a Combination of Statistical Methods: Chemometrics and Supervised Learning to Manage Integrative Farm-To-Meat Continuum Data

This trial aimed to integrate metadata that spread over farm-to-fork continuum of 110 Protected Designation of Origin (PDO)Maine-Anjou cows and combine two statistical approaches that are chemometrics and supervised learning; to identify the potential predictors of beef tenderness analyzed using the instrumental Warner-Bratzler Shear force (WBSF). Accordingly, 60 variables including WBSF and belonging to 4 levels of the continuum that are farm-slaughterhouse-muscle-meat were analyzed by Partial Least Squares (PLS) and three decision tree methods (C&RT: classification and regression tree; QUEST: quick, unbiased, efficient regression tree and CHAID: Chi-squared Automatic Interaction Detection) to select the driving factors of beef tenderness and propose predictive decision tools. The former method retained 24 variables from 59 to explain 75% of WBSF. Among the 24 variables, six were from farm level, four from slaughterhouse level, 11 were from muscle level which are mostly protein biomarkers, and three were from meat level. The decision trees applied on the variables retained by the PLS model, allowed identifying three WBSF classes (Tender (WBSF ≤ 40 N/cm²), Medium (40 N/cm² < WBSF < 45 N/cm²), and Tough (WBSF ≥ 45 N/cm²)) using CHAID as the best decision tree method. The resultant model yielded an overall predictive accuracy of 69.4% by five splitting variables (total collagen, µ-calpain, fiber area, age of weaning and ultimate pH). Therefore, two decision model rules allow achieving tender meat on PDO Maine-Anjou cows: (i) IF (total collagen < 3.6 μg OH-proline/mg) AND (µ-calpain ≥ 169 arbitrary units (AU)) AND (ultimate pH < 5.55) THEN meat was very tender (mean WBSF values = 36.2 N/cm², n = 12); or (ii) IF (total collagen < 3.6 μg OH-proline/mg) AND (µ-calpain < 169 AU) AND (age of weaning < 7.75 months) AND (fiber area < 3100 µm²) THEN meat was tender (mean WBSF values = 39.4 N/cm², n = 30).