A recent study on the effects of pen density on pig welfare and growth showed that lower pen densities improved average daily gain, lesion scores and behavior activities in the weaner phase, but once pigs entered the finishing phase in standardized pens, these benefits disappeared.
Conducted at the University of Leuven, the study used two weaning density rates: high density of 0.24 m2/animal and low density of 0.29 m2/animal, with pigs remaining in the weaner until they reached 20 kg. Pigs were weighed entering and leaving the weaner unit and at the end of the finishing phase.
During the weaner phase, pigs in the lower density pens had better welfare scores and average daily gain, but no improvement in feed conversion was shown. During the finishing phase under uniform pen conditions, all benefits originating in the weaner unit disappeared, with pen densities remaining constant at 0.69 m2/animal.
While maximal pen densities are required across Europe, variations in these laws exist between countries. Producers must balance growth and welfare benefits associated with lower pen density with the economics of fewer pigs produced per pen, the researchers concluded.