in the Sucker and Weaner Phase Altered the Performance of Pigs in Three
Behavioural Tests. By Cameron Ralph, Michelle Hebart and Greg M. Croninm
2018. Animals 8: 74.
We tested the hypothesis that provision of enrichment in the
form of enrichment blocks during the sucker and weaner phases would affect the
behaviour of pigs. We measured the performance of pigs in an open field/novel
object test, a maze test, an executive function test and the cortisol response
of the pigs after exposure to an open field test. The provision of enrichment
blocks altered the behaviour of the pigs in all three tests and these changes
suggest an increased willingness to explore and possibly an increased ability
to learn. The behavioural tests highlighted that young pigs have the capacity
to learn complex tasks. Our findings support the notion that the benefits of
enrichment cannot be evaluated by measuring the interactions the animal has
with the enrichments in the home pen and it may simply be beneficial to live in
a more complex environment. We have highlighted that the early rearing
environment is important and that the management and husbandry at an early age
can have long-term implications for pigs. The enrichment we used in this study
was very simple, an enrichment block, and we provide evidence suggesting the
provision of enrichment effected pig behavioural responses. Even the simplest
of enrichments may have benefits for the welfare and development of young pigs
and there is merit in developing enrichment devices that are suitable for use
in pig production.
Effects of environmental enrichment on decision-making behavior in pigs
by F. Josef van der Staay, Johanna A. van Zutphen, Mirjam M. de Ridder, Rebecca E. Nordquist, 2017. Applied Animal Behaviour Science.
The animal’s emotional state, eventually modulated by environmental conditions, may affect cognitive processes such as interpretation, judgement and decision making behaviour. The Iowa Gambling Task (IGT) is a common method to examine decision making behavior in humans in terms of risk avoidance and risk taking that reflects the underlying emotional state of the subject. In the present study, we investigated the influence of environmental conditions on decision-making in pigs. To assess decision making behavior in pigs, the Pig Gambling task has been developed. In this task, the pig can choose between two alternatives. The pigs can make advantageous or disadvantageous choices, where advantageous, low risk choices deliver smaller, but more frequent rewards, whereas disadvantageous, high risk choices yield larger, but less frequent rewards. In the long run, over a series of successive trials, the advantageous choices will yield more reward and less punishment, where punishment consists of delivering reward into the central food trough, but making it inaccessible. After habituation to testing apparatus and testing methods during the course of approximately 4 weeks, all pigs learned to discriminate between the advantageous and disadvangeous alternatives (acquisition phase) at the age of 9 weeks. After a 14-week retention interval, at the age of 24 weeks, retention performance was tested (retention phase). In both phases, 20 trials per day were given to a total of 120 trials. Saliva and hair samples were collected once at the end of both phases for determining cortisol, and body mass was measured at the end of the retention phase. The pigs increased the number of advantageous choices during the course of training. In in the acquisition phase, barren-housed pigs chose the advantageous options more often compared to environmentally enriched pigs. No differences werer found during the retention phase. All pigs made less advantageous choices at the start of the retention phase than at the end of the acquisition phase. The level of hair cortisol was higher in the barren-housed than in the enriched-housed pigs. This difference was more pronounced after acquisition than after retention testing. No other differences were found for cortisol in saliva and hair. The environments did not differentially affect body mass at the end of the study. Summarizing, housing in a barren environment appears to be more stressful than housing in an enriched environment, as indicated by higher hair cortisol levels in barren-housed pigs, but it also improved acquisition of the PGT.