Summmw Four procedures, one using genetic relationships, were evaluated to rank centrally tested boars from records on 9,093 boars tested in central stations. Breeds with larger numbers of tested boars were found to have more total relationship ties than were breeds with smaller numbers of boars tested. Of the breeds with greater tested numbers, Durocs and Yorkshires were genetically more tied than were the Hampshire or Spotted breeds. Among breeds with fewer observations, Berkshires had the most relationship ties, while Poland Chinas had the fewest. When the number of ties between boars in each season-year with boars in the most recent season-year were evaluated, only the last six or seven-season-year groups were needed to provide sufficient relationship ties with pigs currently tested. The four evaluation procedures were performance value (PV), deviation of the performances value from the station-seasonyear subclass mean (SSYD), mixed model without relationships (MM) and mixed model including relationships (MMR). The MM procedure produced much lower prediction error variances than did the PV or SSYD procedures; whereas the MMR procedure produced the lowest prediction error variances. Although the MM and MMR procedures gave far more precise estimates than did PV and SSYD, they do involve more complex computing procedures. When the cost of these more complex computations is reasonable, the MMR

Thirty-two pigs from seven litters with equal numbers of porcine stress syndrome (PSS) positive and negative pigs within a litter were utilized to assess the effects of PSS on production and carcass traits. Differences between PSS groups for average daily gain and feed efficiency were not significant. Blood creatine phosphokinase (CPK) measured both at 8 to 10 weeks of age and at slaughter was higher (P<.01) for PSS positive pigs, while length of halothane exposure and muscle rigidity scored during halothane exposure were lower. Longissimus muscle pH measured 45 min postmortem was lower (P<.01) for PSS positive pigs, while Photovolt reflectance color and light trans-mittancy of the longissimus muscle were greater than for PSS negative animals. Live backfat probe, carcass backfat and tenth rib fat were not significantly different between PSS groups, although PSS positive pigs were leaner in carcass composition, particularly in the ham and shoulder. Longissimus muscle area was significantly larger for PSS positive pigs and this group also tended to score higher on two indices used to rank breeding stock.