Effect of environmental enrichment on performance of piglets during anxiety tests

Studies in rodents suggested that environmental enrichment can improve the ability of animals to cope with stressful situations. In this study, the effect of environmental enrichment was evaluated on the behavioral response of piglets in anxiety tests. The study included 2 experiments, in the first one, 20 piglets from mothers who received enrichment and 20 from control sows were selected. Mothers of animals from the group with enrichment received stimulation during pregnancy and posteriorly piglets for 21 days. On post-natal day 22, animals were exposed to a novel object test and the day after to an elevated plus maze. Results showed that pigs with enrichment showed a lower number of escape attempts, and a greater latency to vocalizations. Likewise, control pigs performed fewer attempts to enter into open arms and risk assessment. In the second experiment, 60 piglets were divided into 4 groups: 1) received enrichment during pregnancy-lactation, 2) enrichment during weaning, 3) enrichment during pregnancy-lactation-weaning and 4) without enrichment. On post-natal day 70, pigs were exposed to an elevated plus maze. Results showed that pigs from group 1 showed less anxiety during the test compared with groups 3 and 4. This suggested that environmental enrichment during pregnancy-lactation positively impacted the ability of piglets to regulate anxiety.