ONE OF THE PARAMETERS THAT AFFECT THE QUALITY OF BOVINE MEAT IS THE PERCENTAGE OF FATTY INFILTRATION OR MARBLING. THIS COMPONENT PROVIDES THE MAIN MEAT QUALITY FEATURES THAT CONSUMERS DEMAND: TENDERNESS, FLAVOR AND JUICINESS. THIS RESEARCH HAD AS OBJECTIVE TO DEVELOP MODELS TO MEASURE THE DEGREE OF MARBLING IN LIVE CATTLE. THE DATA WERE OBTAINED FROM 80 STEERS """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""WAGYU TYPE"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""", 50 OF THEM WERE USED TO GENERATE THE MODELS, 20 TO EVALUATE AND MAKE ADJUSTMENTS TO THE MODELS AND THE REMAINING 10 FOR VALIDATION OF THE FINALLY SELECTED MODEL. FIVE MODELS OF MULTIPLE LINEAR REGRESSIONS, UNDER THE STEPWISE PROCEDURE AND MINIMIZING THE MEAN SQUARE ERROR, WERE GENERATED. WHEN MODELS WERE COMPARED, THEY DID NOT SHOW STATISTICALLY SIGNIFICANT DIFFERENCES IN THEIR PREDICTIVE ABILITY, SO IT WAS POSSIBLE TO CHOOSE ONE OF THEM, USING THE CRITERION OF SIMPLICITY. THE SCORE PREDICTED BY THE MODEL WAS COMPARED WITH THE QUALIFICATION OF CERTIFIERS, WITH NO STATISTICALLY SIGNIFICANT DIFFERENCES. FINALLY, IN ORDER TO VALIDATE THE SELECTED MODEL, THE METHOD PRESENTED BY FREESE WAS USED. THUS, IT IS POSSIBLE TO CONCLUDE THAT USING MATHEMATICAL MODELING, ULTRASOUND, AND IMAGE PROCESSING MODELS CAN BE FORMULATED THAT ALLOW TO PREDICT IN VIVO THE PERCENTAGE OF FAT INFILTRATION ACCORDING TO THE JAPANESE SCALE OF BEEF MARBLING STANDARS (BMS).