A survey of play behaviour in domestic lambs out on pasture

Sammanfattning: Play has been recorded in a wide variety of animal species and presents itself at different ages in different species. It has been reported that the occurrence of play behaviours can be affected by factors in the animal's environment, such as housing, feeding and management. Thus play might be used as a measure of animal welfare. The purpose of this study was to examine play in lambs in a semi-natural environment out on pasture, by observing the lambs during their first months of life from a qualitative as well as a quantitative perspective. Three different groups of lambs, from two different farms, were observed: Gute sheep, Texel sheep and crossbreeds (Swedish Fine Wool, Dorset and Suffolk). The observations took place over the course of 6 weeks on pastures around Uppsala, Sweden, and no induction or stimulation of play was implemented. One observer was involved and the observations were divided into two sessions- one in the morning (8 to 10 am) and one in the evening (6 to 8 pm). Two types of methods were used: focal sampling and scan sampling. The focal method involved systematic and continuous observations for 10 minutes for 8 focal lambs. Following each focal session, two minutes of scan sampling followed where the entire group was observed instantaneously. It was found that lambs perform several different behavioural patterns that could be interpreted as play. A total of 10 play behaviours were recorded. It was concluded that type and prevalence of play changed over time, and became less frequent as the lambs grew older. At 12 weeks of age play had greatly reduced, and it became rare at 4 months of age. Object play was almost only seen during the first three weeks. Social play, on the other hand, continued throughout the study, perhaps because it is a play category of a more complex nature that needs to be more finely-tuned. The most distinct play peak was identified at 2nd to 4th week of observations, which corresponds to 51-75 days of age. When it comes to their diurnal play cycle, the lamb played substantially more in the morning and evening, and the evening was somewhat preferred over the morning. This play cycle could possibly be connected to the lambs’ evolutionary background and the activity patterns of their predators at that time. There were clear contrasts between genders; ram lambs represented the main part of play occurrence, mainly in the form of social play such as mounting, pushing and butting. Conversely, ewe lambs performed more locomotor play, particularly jumping and pivoting. Lastly there were substantial differences between the breeds, where the Gute lambs displayed the highest amount of play, followed by the crossbreeds and then the Texels. These differences can presumably be a consequence of both age, considering that the breeds varied in age (about 2 months between youngest Gute lamb and oldest Texel lamb), and breeding for specific traits. Hopefully the knowledge from this study can provide material for assessing the level of play in lambs, and hence promote the usage of play as a measure of animal welfare.