OBJECTIFICATION OF EVALUATING PIG MEATINE SS BY MEANS OF THE LEAN MEAT CONTENT

The objective of the paper was to evaluate hybrid pig meatiness by usi ng carcass detailed dissection as well as instrumentally (Fat-O-Meater ) in the conditions of packing plants. Hybrids (n = 92) SLOVHYB-1 and SLOVHYB-2 were used to comply with the goals of the first part of expe riments. The former cross combination has been most frequently used in Slovakia until now; it consists of domestic breeds Large White and Wh ite Meaty and of so called synthetic line in the terminal position (Be lgian Landrace x Duroc cross). Newly produced cross combination SLOVHY B-2 is based on a domestic and imported gene pool while the main breed s contributing to its creation are White Meaty, Landrace, Duroc and Yo rkshire. Hybrid pigs were fattened in identical conditions, receiving feed mixture with the content of digestible substances 15.33%, energy 12.73 MJ ME, lysine 0.92% and fiber max. 5.0%. Their slaughter at aver age live weight of 105 kg was followed by detailed dissection of dress ed carcasses while the per cent of lean meat, fat, skin and bones in t he parts of the side of pork were determined. Thirty-five pigs with li ve weight of 100 kg were selected out of the evaluated set in order to determine the observed indicators in this weight category (Tab. I). T he analyzed set was also divided by the sex into gilts - barrows (Tab. III) and by genotype constitution (Tab. IV). In the second part of st udy (Tab. V) the lean meat in slaughter pigs (n = 14 011) with average dead weight of 97.57 kg was estimated instrumentally in operating con ditions of slaughterhouses using the instrument Fat-O-Meater (FOM). Th e per cent of valuable lean cuts and/or lean meat content (LMC) made 5 0.35 and 54.38%, respectively, in the analyzed set while 46.7% of anim als were included in classification grades S and E. The pigs under eva luation were divided into final hybrids SLOVHYB 1 and 2 on the basis o f cross combination (Tab. IV). SLOVHYB-1 has recently represented a ma jor part of carcass pig production in Slovakia. The other cross combin ation has beed bred for increased per cent of LMC in keeping with the prepared grading of slaughter hybrids pursuant to EU regulations. Diff erences in the observed indicators of the cross combinations concerned are statistically significant for all analyzed carcass parts, with be tter values for the newly produced hybrid combination, in which 71.9% of animals against 5.7% were included in grades S and E. In the condit ions of packing plants (Tab. V) the group of 14,011 carcass hybrids sh owed the LMC at the value of 46.51 while about 22% of pigs were includ ed in grades E and U. Increasing dead weight was accompanied by a decr ease in the relative LMC in the specific weight categories. In the lar gest subgroup (95.18 kg, n = 3 933) the LMC determined instrumentally was 46.87% while grades E and U involved 22.2% of animals. The meatine ss of slaughter pigs in operating conditions, estimated instrumentally , did not reach such a level as in the EU countries with advanced bree ding programs. It was also lower in the cross combination SLOVHYB-1. W e believe that besides the worse factors of external environment (low- quality nutrition, level of management and breeding work, lack of long run breeding of produced types for an increased portion of LMC) an un suitable regression equation of the instrument for our hybrids could b e a cause of lower meatiness. One of the producers' tasks will be to d ecrease variability of this trait substantially since the present slau ghter weight ranges from 90 to 150 kg in many cases. It is expected to examine both in theoretical and practical terms the problems of an al l-in all-out system of filling and unloading the fattening facility wi th respect to balanced live weights, separate fattening of gilts and b arrows to various slaughter weights and possible substantial increase in the LMC in dressed carcasses.