Estratégias de enriquecimento ambiental para leitões desmamados

Abstract

The research was conducted in order to evaluate the effects of different types and strategies of providing environmental enrichment for weanling piglets on their behavior, interest for the provided objects and their reactions to stressful situations. Forty weaned piglets were used, aged between 21 and 28 days, distributed in a completely randomized design in 5 treatments, with animals used as experimental units. The treatments consisted on: 1) Control with no enrichment objects, 2) Continuous cognitive enrichment, 3) Intermittent cognitive enrichment (6 hours per day), 4) Cognitive enrichment and sensory enrichment alternate each 24 hours, 5) Cognitive/feeding enrichment and sensory enrichment alternate each 48 hours. During 15 days, behavioral observations were made daily, in three periods of two hours (six hours a day). At the end of the experimental period, piglets from the control and continuous cognitive/food enrichment treatments were submitted to three different fear tests: approach test, unknown area test and new object test. Concomitantly with the fear tests, eyeball temperature assessments were performed by infrared thermography. The use of enriching objects in the nursery phase piglet environment reduces undesirable behavior. Piglets kept in an unstimulated environment showed a higher frequency (p <0.05) of unwanted behaviors (sucking, agonizing and belly nosing) in relation to the other treatments, regardless of the type or strategy of enrichment chosen. Piglets in the treatments alternating every 24 hours (T4) had a longer interaction time with the enriching object. In the treatments in which there was an alternation of objects, there was an increase in the interaction with them over the days. Piglets kept in enriched environments, when isolated in a new environment, showed a higher frequency of exploration of the environment (p <0.05). The use of enriching objects in the environment for raising piglets in the nursery phase reduces undesirable behaviors and makes them less reactive to unknown situations. Strategies such as alternating the type of enrichment every 24 or 48 hours are effective in maintaining the animals' interest in enrichers.