Observations at Slaughter
All pigs per pen were slaughtered in the week in
which the average BW of the pigs in that pen was close
to the target weight of 110 kg. In the slaughterhouse,
lungs were collected, examined, and scored by a pathologist
for pleuritis (0 to 2 scale, in which 0 = absence of
pleuritis, 1 = adhesion of lung tissue with film-like tissue,
and 2 = lung tissue completely grown together) and
pneumonia lesions (0 to 3 scale, in which 0 = absence of
pneumonia, 1 = one spot of pneumonia, 2 = a few spots
of pneumonia, and 3 = diffuse deviation of pneumonia
spots). Carcass weight, backfat thickness, and muscle
thickness were measured in the slaughterhouse. Both
fat and muscle thickness were measured at 6 cm from
the back midline between the third and fourth last rib.
Lean meat and dressing percentages were calculated
per pig from the parameters obtained at slaughter using
the following formulas: lean meat (%) = 66.86 − 0.6549
× (fat, mm) + 0.0207 × (muscle, mm) (Engel et al.,
2012) and dressing (%) = (carcass weight/live weight)
× 100% (Watkins et al., 1990).