The influence of over feeding sows during gestation on reproductive performance and pig growth to slaughter

feed levels for sows in early to mid gestation has been found to increase muscle fibre number in the semitendinosus muscle of progeny thereby increasing their growth rate and improving food efficiency. Sows (n = 238) blocked at mating on parity and weight were assigned at random to the following gestation feed allowances (1) 30 MJ DE/day throughout gestation, (2) as for 1 but with 60 MJ DE/day from day 25 to 50 of gestation, (3) as for 1 but with 60 MJ DE/day from day 50 to 80 of gestation, (4) as for 1 but with 60 MJ DE/day from day 25 to 80 of gestation and (5) as for 1 but with 45 MJ DE/day from day 80 to 112 of gestation. At weaning, three pigs (heavy, medium and light birth weight) were selected from each of 80 litters and penned individually. Feed intake and pig weight was recorded up to slaughter at c.157 days of age. Treatment had little effect on pig weight (P > 0.05), daily gain (P > 0.05) or feed conversion efficiency (P > 0.05). Carcass back-fat thickness measured at 6cm from the edge of the split back between the 3 rd and 4 th last rib was 10.6, 9.9, 9.2, 11.0 and 10.6 (s.e.d. 0.39mm; P < 0.05) for Treatments 1 through 5 respectively. Birth weight was 1.81, 1.51 and 1.15 (s.e.d. 0.025kg; P < 0.001), slaughter weight was 95.5, 96.0 and 88.0 (s.e.d. 2.09kg; P < 0.01) and carcass weight was 72.2, 72.8 and 66.2 (s.e.d. 1.61kg; P < 0.01) for heavy, medium and light birth weight pigs, respectively. Females and males had similar birth weight, slaughter weight and carcass weight. Kill out yield was 768 and 744 (s.e.d 2.0g/kg; P < 0.01) and lean meat yield was 597 and 584 (s.e.d. 3.4g/kg; P < 0.001) for females and males, respectively. In conclusion, increasing gestation feeding allowance had little effect on pig performance to slaughter but did reduce carcass fatness. Light birth weight pigs had a lighter live-weight at slaughter and lighter carcass weight than medium and heavy birth weight pigs which were similar in this regard.