PREDICTION OF MEATINESS OF PIG DRESSED CA RCASSES ON THE BASIS OF EYE-MUSCLE AREA AND OR BACKFAT AREA AND THEIR RELATIONS/

Carcass value parameters (percentage of valuable lean cuts - VLC and/o r percentage of lean meat content in vivo, average backfat thickness) were determined in 172 hybrid pigs. The evaluated groups comprised fou r cross combinations SLOVHYB 2 hybrid (type I, n = 62) and three forei gn types of hybrids (types II, III and IV; n = 40; 40; 30) while the p arity proportions of males and females were used (gilts : barrows). Th e percentage of lean meat was determined in the pigs by in vivo method using a PIGLOG 105 instrument a day before slaughter. The day after s laughter, carcass value parameters were determined in accordance to th e standard CSN 46 6164: backfat thickness was measured above the cente r of the second and/or last thoracic vertebra and above the center of the first lumbar vertebra (measures HS 1, 2, 3 in mm) as well as avera ge backfat thickness calculates from the above measures. The eye-muscl e area (m.l.d.) and backfat area above m.l.d. were determined at the l evel of the last rib (eye-muscle area(1) and/or backfat area(1)), at t he 3rd to 4th lumbar vertebra (eye-muscle area(2) and/or backfat area( 2)) as well as at the 3rd to 4th last rib of halving section (eye-musc le area(3) and/or backfat area(3)). Relations between the eye-muscle a rea and backfat area above m.l.d. and vice versa were calculated at th e particular spots of measurement. Tab. I shows the basic data on the carcass value of four hybrid combinations of pigs. The values for the proportions of valuable lean cuts were 50.68; 45.48; 48.26 and 49.30% in the final hybrids of average slaughter weight about 105 kg. Tab. II shows relations between the carcass value parameters examined. The co rrelations between eye-muscle area at the different spots of halving s ection and VLC proportion and/or total meat proportion in vivo were at the level r = 0.29 to 0.52 while the values of correlation coefficien ts between backfat area above m.l.d. at the same spots of measurements and VLC proportions and/or total meat proportion ranged from r = -0.7 5 to -0.82. The differences in the values of correlation coefficients between the backfat area and eye-muscle area on the one hand and meati ness parameters (VLC % and/or meat proportion in vivo by PIGLOG instru ment) on the other were clearer for the estimate of lean meat content in vivo than for VLC proportions. The correlations between meatiness p arameters (VLC % and/or lean meat content in vivo) on the one hand and the ratios of backfat area and eye-muscle area had the value r = -0.8 1 to -0.90. Significant relations between the ratios of eye-muscle are a and/or backfat area above m.l.d. and carcass value parameters can be used to predict meatiness using instruments in breeding pigs (eg. in boars of sire populations to be used for A. I.). It is also possible t o make use of the correlations between backfat area above m.l.d. and/o r the ratio of backfat area and eye-muscle area to determine the VLC p roportion and/or meat proportion by means of instruments for regressio n equation design. The level of correlations suggests that backfat are a and/or the ratio between backfat area and eye-muscle area could be m ore reliable parameters of carcass meatiness than the eye-muscle area and/or backfat thickness proper and m.l.d. thickness proper at the par ticular spots of halving section of pig carcass. We believe on the bas is of our experiment that the ratio between the backfat area above m.l .d. and eye-muscle area at the spot of the last rib having the value l ess than or equal to 0.45 is a trait of good meatiness in the hybrids with slaughter weight about 105 kg.