Body weight and ultrasound measurements over the finishing period in Iberian and F1 Large White x Landrace pigs raised intensively or in free-range conditions

Abstract Iberian (IB) pigs are often finished on grass and acorns, and they are known for their ability to deposit high amounts of fat. Live weight, body dimensions and backfat depth measured by ultrasounds in various layers and backfat depots, were collected in an experimental group (n=117) of IB and crossbred Large White x Landrace pigs (F1), finished either intensively or in oak-tree forests in a factorial experiment. Weight and ultrasounds data were collected at the beginning, midpoint and end of the finishing period, which occurred at a mean live weight of approximately 85, 125 and 160 kg, respectively. Changes in live weight and fat depth over the finishing period were assessed and body dimensions and backfat depth measured by ultrasounds were used to predict carcass traits. Genetic groups differed considerably in growth rate (P 0.05). At the end of the finishing period, total backfat was about twice thicker in IB than in F1 pigs in the dorsal and P2 depots (P