Epsilon Archive for Student Projects

Abstract

Commercial fattening pigs are commonly housed in barren environments, limiting their opportunities to perform highly motivated behaviours. This is an animal welfare concern as pigs may develop unwanted behaviours in response to stress and frustration stemming from the limited ability to perform exploratory behaviours. In addition to this, various aspects in the environment can lead to compounded stress, influencing resilience to changes. This not only has a negative impact on welfare, but on production as well as pigs may be less adaptive and fearful, potentially limiting growth rates. Because of this, research is required to develop a solution to alter existing housing systems to improve quality of life. Provision of environmental enrichment is beneficial for pigs to direct exploratory behaviour towards; however, pigs can rapidly habituate to these materials, potentially leading to a regression in welfare. In an on-going research project examining improving enrichment materials with odours for commercial fattening pigs, this study examined the relationship between olfactory enrichment and pigs’ behaviour to a novel item (carrots). The aim of this study is to develop a novel feed test for use to determine whether olfactory enrichment had an impact on how pigs react to a novel feed item by analysing latency, reaction, and play behaviour. The overall experiment was conducted from April 2023 through November 2023 and experimental pens (n=69) were allocated to one of four treatments: O1 – odour altered weekly straw in a rack (n=20), O2 – odour altered daily straw in a rack (n=15), C1 – non-odourised straw on the floor (n=20), and C2 – non-odourised straw in a rack (n=14). The novel feed test was conducted only once per pen near the end of the fattening period for a total of 5 minutes. The latency to approach the novel feed item, reaction upon approaching the novel feed item, and play behaviour was collected from video footage. The results demonstrated that there was no significant effect of treatment on the latency and reaction scores collected from the novel feed test. There was a significant effect of treatment on the frequency of play behaviours, specifically, lifting the carrot and nosing the carrot. O2 treatment group pigs lifted a carrot more in comparison to treatment O1 groups (P < 0.001) and treatment C2 groups (P < 0.01). In addition to this, pigs in treatment O2 groups demonstrated a higher frequency of carrot nosing then pigs in treatment O1 groups (P < 0.01). Treatment group C1 pigs lifted carrots more frequently (P < 0.01) and had a higher frequency of nosing carrots (P< 0.01) than in treatment O1 groups. In addition to this, there was a significant effect of treatment on the duration pigs spent nosing carrots. Treatment C1 groups nosed carrots for a longer duration compared to treatment O1 groups (P < 0.001) and treatment O2 groups nosed carrots for longer durations when compared to the O1 (P < 0.001) treatment groups and the C2 (P < 0.01) treatment groups. It was found that pigs in the O1 treatment groups had a marginally significant result of nosing carrots for a longer duration when compared to pigs in treatment C2 groups (P < 0.1). However, other noted play behaviours were not significantly impacted by the chosen treatments. These results indicate that the provision of olfactory enrichment for commercial fattening pigs has the potential to positively influence behaviours towards novel feed items, and these behaviours could provide insight on animal welfare through neophobia and curiosity. Future research should further develop the novel feed test and the form of olfactory enrichment to improve existing knowledge on improving commercial pig welfare.