Table 3.
Effects of birth weight (BiW) and nursery growth rate on pig performance and carcass characteristics1
| Nursery growth rate | BiW coefficient2 | P-value3 | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Item | Slow | Fast | SE | Slow | Fast | SE | GR | B | GR×B |
| Body weight, kg | |||||||||
| Birth | 1.27 | 1.43 | 0.01 | <0.01 | |||||
| Weaning | 7.2 | 7.2 | 0.07 | 2.84 | 2.76 | 0.11 | 0.490 | <0.01 | 0.447 |
| Nursery exit | 22.7 | 27.4 | 0.20 | 0.26 | 0.01 | 0.28 | <0.01 | 0.975 | 0.359 |
| Finishing exit | 119 | 121 | 0.57 | 3.40 | 1.45 | 1.29 | 0.013 | 0.131 | 0.131 |
| Adjusted finishing (day 167)4 | 118 | 125 | 0.81 | 8.31 | 8.05 | 1.91 | 0.012 | <0.01 | 0.894 |
| Pig age, d | |||||||||
| Weaning | 26.1 | 26.1 | 0.15 | 0.00 | −0.18 | 0.05 | <0.01 | <0.01 | <0.01 |
| Nursery exit | 67.2 | 67.7 | 0.37 | −9.46 | −8.85 | 0.55 | 0.656 | <0.01 | 0.268 |
| Finishing exit | 169 | 164 | 0.72 | −5.94 | −7.31 | 1.59 | 0.190 | <0.01 | 0.392 |
| Slaughter | 177 | 171 | 0.57 | −16.40 | −16.70 | 1.22 | <0.01 | <0.01 | 0.802 |
| Average daily gain, g/d | |||||||||
| Suckling (birth to weaning) | 228 | 227 | 2.52 | 71.82 | 68.00 | 4.04 | 0.484 | <0.01 | 0.345 |
| Nursery (Weaning to d 66) | 375 | 487 | 2.35 | 20.01 | 34.79 | 4.38 | <0.01 | <0.01 | <0.01 |
| Grow-Finish | 920 | 950 | 7.12 | 42.26 | 46.23 | 17.35 | 0.319 | <0.01 | 0.819 |
| Overall (weaning to finish) | 782 | 827 | 5.05 | 37.47 | 36.03 | 12.30 | <0.01 | <0.01 | 0.907 |
| Carcass characteristics | |||||||||
| Hot carcass weight, kg | 91.9 | 92.6 | 0.28 | 1.38 | 1.61 | 0.53 | 0.649 | <0.01 | 0.654 |
| Adjusted HCW (day 174)5, kg | 90.8 | 95.5 | 0.42 | 11.77 | 13.27 | 0.84 | 0.018 | <0.01 | 0.073 |
| Backfat, mm | 13.5 | 13.7 | 0.13 | −0.89 | −0.29 | 0.23 | 0.082 | 0.093 | 0.010 |
| Loin depth, mm | 62.5 | 62.8 | 0.29 | 1.34 | 1.55 | 0.63 | 0.974 | <0.01 | 0.740 |
| Lean percentage6, % | 54.5 | 54.7 | 0.16 | 0.61 | 0.22 | 0.15 | 0.086 | 0.046 | 0.011 |
| Lean growth rate, g/d | 320 | 336 | 1.36 | 35.52 | 24.15 | 2.88 | <0.01 | <0.01 | 0.295 |
1Least squares mean of nursery growth rate categories (slow and fast) were presented with BiW = 1.30 kg and parity =4.6. Pigs with ADG during the nursery period less than 424 g/d were assigned to slow category and equal or above 424 g/d were assigned to fast category.
2Partial regression coefficient for BiW.
3GR = Growth rate effect, B = Birth weight effect, GR×B = interaction between growth rate and birth weight.
4Adjusted finishing (day 167) weight = Average daily gain (ADG, g/d) grow-finish × (167 d – actual age) × 1.16 + finishing BW, kg.
5Adjusted HCW (day 174) = (Hot carcass weight, HCW, kg – weaning weight × 0.7, kg)/ (age at slaughter – age at weaning) × (174 d– age at slaughter) × 1.16 + HCW, kg.
6Lean percentage, % = 66.86 -0.6549 × backfat depth (mm)+ 0.0207 × loin depth (mm).