THE EFFECT OF ENVIRONMENTAL ENRICHMENT ON THE IMMUNE RESPONSE AND MEASURES OF DISEASE RESILIENCE AND WELFARE IN PIGS
Date
2022-09-08
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0002-4937-3487
Type
Thesis
Degree Level
Masters
Abstract
Disease is a considerable threat to swine well-being and economic productivity. Further, standard barren rearing environments are associated with chronic stress, which can suppress immune function and growth, and contribute to negative social behaviour. Environmental enrichment may mitigate harmful effects of stress, but more research is needed on types of enrichment that improve swine well-being while being practical to use in commercial facilities. This thesis aimed to identify whether pigs provided a rotation of inedible point-source enrichments (E) differ in immune cell concentrations and behaviour compared to barren-housed controls (C), and to explore relationships between behaviour and immune response within each treatment. Chapter Three compared behaviour, productivity, complete blood counts (CBC), and mortality of C and E pigs in three phases of the experiment: quarantine (Q), polymicrobial natural disease challenge (NDC), and finisher (F). E pigs were more likely to interact with enrichments than C pigs on most observation days, but use declined within each phase. E pigs were also more likely to perform comfort-related postures and less likely to show illness-related postures early in the Q and F phases. Lastly, E pigs demonstrated a greater increase in total white blood cell concentration from pre- to post- challenge. Chapter Four examined relationships between individual pigs’ social and exploratory behaviours and their growth rate, CBC values, and disease resilience (classified using mortality, growth, and veterinary treatment rate). E treatment altered Q behaviour: enrichment use was positively correlated with pen rooting and both positive and negative social interactions. Pen rooting was also positively correlated with positive social behaviour in Q and NDC, and with concentrations of white and red blood cells, hemoglobin, and lymphocytes. These results suggest that behavioural influences of enrichment were more likely when enrichment use was highest within a phase. In conclusion, pigs provided with inedible point-source enrichments differed in social and exploratory behaviours and posture frequencies, and provision of enrichment influenced relationships between exploratory behaviour, growth, and cellular immune response. More research is needed on providing enrichment that sustains use and satisfies motivational needs, and therefore may have a greater impact on stress reduction and disease response.
Description
Keywords
environmental enrichment, disease resilience, swine behaviour, swine welfare
Citation
Degree
Master of Science (M.Sc.)
Department
Large Animal Clinical Sciences
Program
Large Animal Clinical Sciences