Behavior of Pigs Reared in Enriched Environment: Alternatives to Extend Pigs Attention

Abstract

Three trials were carried out in a completely randomized design aiming to assess the behavior of pigs in growth phase in enriched environments. Trial 1 evaluated the effects of frequency of availability of environmental enrichment. The animals were assigned to four treatments: 1) control with no enrichment object; 2) objects provided for six consecutive days uninterruptedly; 3) objects provided on alternate days, and 4) objects provided for six consecutive days taken away by the end of the afternoon and replaced at dawn. Trial 2 assessed the effects of scent on animals’ acceptance and maintenance of interest in objects. Animals were assigned to four treatments: 1) unscented object; 2) object with banana scent; 3) object with rum scent; 4) object with scents alternated every other day. Trial 3 aimed to assess the influence of environmental enrichment based on providing rewards at different difficulty levels. Animals were assigned to three treatments: 1) object with no reward; 2) object with a reward at an easy level; 3) object with a reward at a difficult level. Each trial had six days of behavioral observations every ten minutes for eight hours each day using images from video cameras. Enrichment objects stimulated the animals’ natural behavior of nuzzling and exploring the environment. The way the objects were available did not impact the success of their use. Offering enrichment on alternate days or removing the objects by the end of the day was not an effective strategy to extend the animals’ interest. The olfactory stimulus in environmental enrichment objects had no positive effect on extending the animals’ interest on them, nor did alternating the aromas. The tactile stimulus was a key factor for object attractiveness. Providing environmental enrichment objects with rewards stimulated the exploratory behavior of pigs. The level of difficulty to obtain the reward may discourage the animals.

Effects of Environmental Enrichment on Pig Welfare—A Review

“…This way of performing an experiment seems to be very important for the reliable assessment of the impact of different categories of enrichment, especially when the markers of stress are used. However, the impact on the behavior of the environmental improvement was found during only six days of observation in the Machado et al [95] study. One of the trials performed in this research was to evaluate the effect of the availability of hanging toys (made from a polyvinyl chloride—PCV pipes and plastic tubing).…”

“…It could be the same effect as seen in previously presented studies [93,94]; when access to enrichment is limited, competition rises, and consequently, a negative form of behaviour may occur. In the Machado et al [95] study, resting behavior was performed the most frequently in the group with no object, compared with individuals that had access to enrichment constantly or on alternate days. There were no differences, however, between the treatments regarding the time spent on interacting with other pigs, nuzzling, or exploring the environment.…”

Different intervals of behavioral observation in the scanning method and the real behavior of pigs

“…At each observation day, 60 events were recorded at 5-min intervals and 30 events at 10-min intervals. For each event, we considered that the pig exhibited this specific behavior until the next event (5 or 10 min) (Machado et al, 2017).…”

Neonatal and infant immunity for tuberculosis vaccine development: importance of age-matched animal models

“…There are many advantages to using pigs for human studies, such as their availability, size, ease of sampling, large litter size, friendly temperament and ethical acceptance (Table 2) (Meurens et al, 2012). The high cognitive abilities of pigs make them responsive to classical and operant conditioning, and thus they are easy to handle in laboratory studies (Gieling et al, 2011;Machado et al, 2017). Further, outbred and inbred lines of pigs, specifically developed for research purposes, are readily available (Meurens et al, 2012).…”