The Thai Journal of Veterinary Medicine


The aim of this study was to investigate the reproductive performance of lactating sows in Thailand kept in farrowing housing using an evaporative cooling system (EVAP) in comparison with conventional farrowing system (CONV). The study was based on data from one commercial sow herd, with four farrowing houses (one EVAP and three CONV) with sows of different parities, randomly circulating between these farrowing systems. In the herd, continuous farrowing and cross-fostering was practiced, and the litters were weaned at 18.7 ± 1.3 days of age. The data from 11,000 farrowings (between May 1999 to April 2002) were statistically analysed (ANOVA), to study the effect of present, as well as previous farrowing housing systems, on reproductive and production results. No significant effect of previous or present farrowing housing systems on litter size at birth were found. A significant effect of present farrowing housing systems was found on the average piglet weight at weaning (WPWT) and on the weaning-to-first-service interval (WSI). The WPWT (P≤0.001) in the EVAP system was higher than in the CONV system (5.8 vs. 5.6 kg) and the WSI (P≤0.01) in the EVAP system was shorter than in the CONV system (5.4 vs. 5.6 days). For both these traits, a significant interaction was found between the farrowing housing system and the two-monthly periods of results. The WPWT in the EVAP system was significantly higher than in the CONV systems in four out of six two-month periods (0.2-0.4 kg difference). These results suggest that keeping sows in the EVAP system during lactation might be beneficial for piglet production under tropical conditions.

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