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Abstract:

Maximal pen densities are prescribed by law, but laws are not consistent between different European countries although it is known that pen density may have a great impact on production results. The objective of the study was to investigate if pen density has an impact on piglet welfare as well as piglet growth. Different pen densities were tested in the weaner unit where piglets stayed until they reached a weight of 20 kg: high density (0.24 m2/animal) vs low density (0.29 m2/animal). The legally required space for piglets until 20 kg in Belgium is 0.20 m2. When moved to the finishing accommodation, a density of 0.69 m2 per animal was maintained in all pens, while the legally required space for fattening pigs until 110 kg in Belgium is 0.65 m2. Piglets were weighed when entering and leaving the weaner unit and at the end of the fattening phase. Behavioral observations were carried out and lesions were scored. Results show that behavior, growth as well as lesions at the end of the piglet phase were influenced by pen density. The lower pen density gave the best results: less frustration behavior, less lesions and a higher average daily gain. Feed conversion ratio was not affected. In the fattening phase, when all pens had the same density, the differences originated in the weaner unit disappeared. As a conclusion, pig welfare and production results can benefit from lower pen densities. However, it must be investigated if a better growth can compensate for the fewer pigs that are being set up. A balance should be found between optimal pen density and optimal economical results.