EVALUATION OF THE GROWTH-PERFORMANCE AND CARCASS CHARACTERISTICS OF COMMERCIAL PIGS PRODUCED IN QUEBEC

Data for a total of approximately 2900 commercial pigs tested in 12 tr ials from 1987 to 1990 at the Beaumont test station in Quebec were use d to determine the effect of sex, sire breed, cross type and parity nu mber of the dam on growth performance and carcass characteristics. Pig s were housed four to a pen and were fed commercial diets. Feed intake and growth rate were measured during the test, and carcass measuremen ts were taken at slaughter and at 24 or 72 h following slaughter. Cast rated males ate more per day, had a better gain and reached slaughter weight (96.4 +/- 5.6 kg) at a younger age than gilts. Gilts had a bett er carcass yield and were leaner than castrated males. Commercial pigs sired from Duroc or Duroc-Hampshire boars had a growth performance su perior to that of pigs sired by Landrace, Yorkshire or Hampshire boars . Progeny from Duroc or Duroc-Hampshire boars also produced carcasses with less loin fat, a thicker loin muscle, a higher estimated lean yie ld and a better classification index. Pigs from three-way crosses had a higher average daily gain and a better feed conversion than pigs fro m other types of crosses (single, backcross, four-way, synthetic and p urebred), and they reached market weight at a younger age. Most carcas s characteristics were also affected by the type of cross, but no spec ific type of cross was clearly superior to the others for the various variables studied. An increase in parity number of the dam caused a gr adual decrease in growth performance, except for pigs from parity six, which presented the best results. There was also a linear decrease in loin muscle thickness, estimated lean yield and classification index and a linear increase in loin fat thickness with increase in parity nu mber of the dam.