USE OF THE PIETRAIN BREED FOR PRODUCTION OF TERMINAL SLAUGHTER HYBRID

The objective of the paper was to determine some figures of fattening performance, carcass value and meat quality in hybrid pigs (n = 105) w ith 50% blood share of the Pietrain breed. The mothers of the terminal hybrid were crossbred dams of the Large White x White Pork or Large W hite x Landrace breeds. Slaughter pigs received two commercial feed mi xes lower and/or higher in crude protein content (11.4 and/or 14.1%) w hile the mix type and structure did not change during the trial. The s ex ration (young boars: gilts) was approximately equal in the sets. Wh en the hybrids reached slaughter weight, they were slaughtered in the slaughterhouses of Agrokombinat a. s., where stress-free conditions we re actually maintained. A choice of animal for a fattening trial on th e basis of halothane test in a set of 34 pigs demonstrated that approx imately 30% of animals had positive reactions to narcotane inhalation. Some carcass indicators were determined in vivo instrumentally (PIGLO G 105 and ALOKA SSD 210 DX II) in all pigs a day before slaughter. The se traits were determined (Tabs. I-IV): backfat thickness between the 3rd and 4th lumbar vertebrae 7 cm laterally from the central dorsal li ne (ECHO 1, PIGLOG 1 measures) thickness of backfat and/or m.l.d. betw een the 3rd and 4th last but one rib 7 cm laterally from the central d orsal line (ECHO 2, PIGLOG 2 and/or ECHO mld, PIGLOG mld) muscle perce ntage in the carcass instrumentally by PIGLOG 105. Besides usual indic ators (pH1, electrical conductivity and color), meat quality was asses sed by meat quality index (D e m o et al., 1994). Tabs. I-IV show the values of the investigated indicators as depending upon feed mix type, sex, sensitivity to halothane test and slaughter weight; Tab. V conta ins chemical analysis of muscles in the hybrids. In comparison with th e pigs receiving feed mix higher in crude protein content, the hybrids receiving feed mix with the lower content of crude protein had the st atistically significantly lower daily weight gain (602 vs. 621 g), low er percentage of valuable lean cuts (47.9 vs. 50.28%), higher backfat thickness (29.1 vs. 23.2 mm) and higher percentage of fatty parts (18. 1 vs 16.3%). No statistically significant differences were observed in meat quality. As for the differences in the investigated indicators a s depending upon the sex and/or sensitivity to halothane test, statist ically significant differences were determined in most carcass indicat ors in favor of the gilts and/or halothane-positive pigs. These were n o significant differences between the males and females in flesh quali ty while this indicator had undoubtedly worse values in the halothane- positive pigs. The set of experimental pigs was divided into three gro ups according to slaughter weight while significant differences in mos t carcass traits were determined between the evaluated groups. Chemica l analysis of the m.l.d. sample enabled to determine the basic compone nts while the percentage of intramuscular fat was 3.05 and the percent age of total water 73.31. It is possible to summarize on the basis of the results of the indicators of fattening performance and carcass val ue in the hybrid pigs in which a sire of the Pietrain breed was used a s the father of terminal hybrid that the hybrid pigs had the average p ercentage of valuable lean cuts below 48, which does not comply with t he criteria established for slaughter pigs produced in the Slovak Repu blic. The increased content of crude protein and energy (subgroup II) administrated to the hybrid pigs resulted in their better values of fa ttening performance and carcass value. PSE meat occurrence was found t o be 35% in a trial conducted according to the established criteria (m eat quality index).