The evaluation of breeding work in nucleus herds of pigs

The suitability of breeding procedures in 40 nucleus herds of Large White ( White Improved) breed has been evaluated by means of correlation analysis o f relations between utility traits and breeding measures. The level of repr oductive traits in the herds did not significantly influence the levels of fattening and carcass traits (from the field test) in reared breeding anima ls. Herd reproduction traits levels are not fully related to the levels of traits of station test. Correlation coefficients between the traits of fiel d test and traits of station test confirm known physiological relations wit h animals, especially among the traits of carcass value. Surprisingly low a re coefficients of correlations between the gains in reared animals and the gains in descendants of breeding animals (r=-0.08, resp. r=0.15). Coeffici ents of correlations between the average daily gain and the traits of leann ess ranged from r=-0.31 to r=-0.35, between average daily gain and backfat thickness it reached r=0.26, Herds with lower feedstuff consumption manifes ted higher leanness (r=-0.32 to r=-0.42) and lower backfat thickness (r=0.4 3; P less than or equal to0.01). Somewhat higher level of relations confirm s simultaneously practised selection both for fattening traits and for carc ass traits. Correlations between selection intensity in the rearing of youn g breeding animals and reproductive traits, resp. traits observed in field test were low and non significant. Selection intensity was markedly influen ced by the traits of station test, especially by lean meat percentage and h am percentage. From methodology point of view, analysis of correlations is appropriate procedure for evaluation of management practices in nucleus her ds.