QUALITY TRAITS OF SLAUGHTER PIGS OF DIFFE RENT SEX

Long-range programs aimed at rationalization of meat production on a w orldwide scale create conditions for nontraditional systems of lean po rk production. One of the ways of increasing production without any fu rther inputs only on the basis of biological potential utilization is fattening of uncastrated young boars. Besides the positive effects lea ding to improvement of basic commercial traits the qualitative aspects of produced pigs, that means the characteristics of the carcass and n utritive value of the final product, play a key role in this system. P ost mortem characteristics of carcass value and chemical composition o f muscular and adipose tissues were evaluated in the conditions of a s tandard plane of nutrition and idential fattening period in a performa nce test carried out with three separate groups of gilts, barrows and young boars of the breed cross Large White x Landrace (n = 8). The hig hest proportion of valuable lean cuts in carcass (Tab. I) was found ou t in young boars, (50.04 %) while the gilts had the value of 49.12 %. Barrows had the clearly lowest value of this characteristic (44.53 %). The rank of the proportion of fatty parts was quite opposite: the low est values were determined in young boars (17.47 %), followed by gilts (18.93 %) and finally by barrows (21.69 %). Statistical data on detai led carcass characteristics (Tab. II) confirm a significant difference (P < 0.05) between the fatty part proportions in barrows and gilts. T he proportion of ham in the weight of side of pork was in fact identic al in gilts (18.30 %) and in young boars (18.46 %), while the lowest p roportion of ham was found out in barrows (16.60 %). There were no sig nificant differences in belly proportions between the gilts (16.36 %), barrows (15.98 %) and young boars (16.21 %). The gilts had the lowest backfat thickness (2.86 cm), followed by young boars (3.04 cm) and ba rrows (3.39 cm). These differences may be due to various slaughter wei ght. The best meat to fat ratio (1 : 0.35) was determined in young boa rs, the gilts had a very similar value (1 : 0.38) while the worst rati o was observed in barrows (1 : 0.48). Analytical determinations of the nutritive value of muscular and adipose tissues (Tab. III) show compa rable values of meat dry matter contents in gilts (295.7 g/kg), barrow s (299.2 g/kg) or young boars (300.7 g/kg). The differences in crude p rotein contents in the group of gilts (224.9 g/kg), barrows (226.6 g/k g) and young boars (227.8 g/kg) did not either correspond to the value s which could be taken as significant. Fat content in the muscular tis sue is an exception as its value for the meat of barrows (78.7 g/kg) w as significantly different from the values for the meat of gilts (57.5 g/kg) and young boars (64.3 g/kg). An evaluation of adipose tissues i ndicated the highest dry matter value in boars (927.5 g/kg), the two o ther groups (gilts - 889.9 g/kg, barrows - 885. 5 g/kg) had practicall y the same data. Dripping content and proportion of extracted fat in b arrows (903.4 g/kg) am in correspondence with the above-mentioned data while mutual differences from the other groups (gilts - 874.4 g/kg, b arrows - 841.6 g/kg) can be described as significant (P < 0.05).