THE EFFECT OF CONFINEMENT HOUSING UPON THE INCIDENCE OF LEG WEAKNESS IN SWINE

Abstract

Live animal evaluation for soundness of foreleg (FL), hindleg (HL), and hip (HP) and postslaughter cartilage condition score (CCS) of the elbow were recorded for 257 Lacombe male castrates (barrows) and gilts, housed either singly or in groups of four in confinement or in groups of 12 in large outside pig lots. Barrows had poorer FL, HL and HP scores than did gilts (P = 0.111, 0.032 and 0.001, respectively). Management system (P = 0.005, 0.001 and 0.001) and its interaction with sex (P = 0.096, 0.016 and 0.023) also affected the scoring of the FL, HL and HP, respectively. Single and group-confinement-housed gilts did not differ in leg weakness or CCS, while singly penned barrows suffered greater cartilage damage (P = 0.037). In general, confinement-housed pigs had greater leg weakness of FL, RL, and HP (P < 0.001), but this effect was attributed almost entirely to barrows (P < 0.001). No meaningful correlations were found between leg weakness and average backfat. The correlations between FL and preweaning (−0.23) and post-weaning ADG (−0.24) suggest that a prerequisite for optimum growth rate is structural soundness. Confinement housing and not growth rate appears to be the primary factor contributing towards the incidence and severity of structural weakness in the pig. Key words: Pig, leg weakness, swine management, confinement housing, growth rate, backfat