Influence of housing type and age in female pigs. 1. Effects on growth performance and fat deposition and distribution in the carcasses of female Large White × Landrace pigs grown from 5.5 to 120 kg liveweight

Abstract

One hundred and sixty female Large White × Landrace pigs were obtained at 3 weeks of age, average liveweight (LW) 5.5 ± 0.08 kg, stratified on LW and allocated to four treatments in a factorial design that consisted of two housing treatments, conventional (C) or deep-litter (D), across two growth periods: early (3–13 weeks of age) and late (13–24 weeks of age). At 13 weeks of age eight pigs per treatment (n = 32) were slaughtered, and the remaining pigs (n = 128) moved to new pens where they remained until slaughter at 24 weeks of age. Moving pigs into a new housing system caused a growth reduction, as indicated by significantly lower LW (P = 0.003), compared with pigs that remained within the same housing system, regardless of whether the new system was C or D. Carcass composition results indicated that pigs finished in the D system (24 weeks of age) were not fatter than pigs raised in C housing, with pigs raised entirely in C housing tending to be the fattest (P = 0.090). There was an effect of housing on fat distribution within the carcass where pigs finished in D housing had significantly less fat in the belly primal compared with pigs finished in the C facilities (35.3 versus 31.2%, P = 0.030). These findings suggest that the strategy of moving pigs from D housing to C housing for finishing, to reduce carcass fatness and improve pig growth performance, was not successful as pigs were fatter, lighter and less efficient than pigs of the same age housed in D from wean to finish.