Effect of gilt growth rate and backfat thickness on reproductive performance

Objective of this study was to analyze the effect of growth rate and backfat thickness at the end of test on reproductive performance in the first three parities, and association with lifetime productivity and longevity. Data of gilt productive and sow reproductive performance from large Slovenian multiplying farms was used. Altogether 8139 animals of two maternal genotypes were involved: Slovenian Landrace – line 11 (SL11) and hybrid 12 (Slovenian Large White × Slovenian Landrace – line 11). Statistical model included owner and sow genotype as fixed effects. Backfat thickness and growth rate were included as linear regression. Data was analyzed by GLM procedure in SAS/STAT. Average weight of gilts was 129.4 ± 9.6 kg at 206.7 ± 6.8 days of age, indicating average growth rate of 626 g/day. Gilts had 13.26 mm of backfat thickness, in range from 5.5 mm to 31.5 mm. The increase of 100 g of daily gain resulted in increase of 0.54 ± 0.08 liveborn piglets in the 1st, 0.71 ± 0.11 in the 2nd, 0.64 ± 0.11 in the 3rd parity. Sows with higher growth rate were culled earlier (47 days). Gilts with thicker backfat had smaller litter size in the first three parities. Backfat thickness did not influence lifetime productivity, although sows with 10 mm thicker backfat farrowed more litters (0.41 in average) in lifetime and were culled 50 days later. Growth rate and backfat thickness did not affect the cost per liveborn piglet as number of days per liveborn piglet did not change.