Playful behaviour of piglets.

Domestic piglets living in multi-litter groups with their dams and other pigs in a large, socially and ecologically rich outdoor enclosure were observed, to obtain a quantitative description of the frequencies and sequences of behaviour patterns performed during play. Focal animal sampling was used to collect data on the playful behaviour of 14 male and 21 female piglets from birth to 14 weeks of age. The "play markers" hop, scamper, pivot, toss head, shake object and carry object were used to identify playful behaviour sequences. The variety of different behaviour patterns performed in first order transitions with play markers was highest in the first 6 weeks and declined thereafter with increasing age. Behaviour patterns occurring in transitions with play markers significantly more often than expected included stand, walk, trot, gallop, freeze, shove and circle. The overall frequency of play markers was significantly affected by age, with a peak frequency occurring between 2 and 6 weeks of age. Male and female piglets performed play markers at similar rates. Results are discussed with reference to the welfare of piglets kept in housing systems which limit playful behaviour.