# Effects of Housing and Environmental Enrichment on Performance, Welfare, and Air Quality in Fattening Pigs

## TL;DR

This study compares different environmental enrichment materials for fattening pigs, finding that sling belts offer better long-term welfare and performance than traditional bedding materials.

## Contribution

The study introduces sling belts as a viable alternative to conventional bedding materials in intensive pig housing systems.

## Key findings

- Conventional bedding materials like rice-straw silage and sawdust improved early behavior but worsened hygiene and air quality over time.
- Sling belts provided stable welfare and production outcomes without the negative effects of bedding materials.
- Prolonged use of bedding materials without proper management reduced growth performance and cleanliness.

## Abstract

Insufficient space and limited access to appropriate environmental enrichment materials (EMs) restrict the expression of natural behaviors, increase stress, and compromise the welfare of pigs in intensive production systems. In some countries, however, the practical use of conventional bedding-based EMs is constrained by difficulties in manure management and environmental control, making their long-term application challenging. This study compared different EMs to evaluate their effects on growth performance, behavior, body lesions, and pen-level air quality in growing-finishing pigs. Conventional bedding materials provided short-term benefits by stimulating positive behaviors and reducing skin lesions during the early growing period. However, these benefits were not sustained and were accompanied by negative consequences over time, including deteriorated hygiene, elevated concentrations of noxious gases, and reduced growth performance when material management was inadequate. As an alternative approach, the present study demonstrated that the use of sling belts (SBs) in pens with slatted flooring was associated with improved welfare-related outcomes and stable production performance. These findings provide practical insights into the selection and management of EMs that can be feasibly applied in intensive pig housing systems where the use of bedding materials is limited.

In intensive pig production systems, limited space and lack of enrichment materials (EMs) restrict natural behaviors, inducing chronic stress and impairing welfare and health. Conventional EMs such as straw and sawdust improve comfort but increase NH3 and particulate emissions and hinder manure management on slatted floors. This study compared rice-straw silage (RS), sawdust (SD), and sling belt (SB) as EMs for growing-finishing pigs to evaluate their effects on growth performance, behavior, body lesions, cleanliness score of body, and pen air quality. A total of 344 crossbred pigs ([Landrace × Yorkshire] × Duroc, 30.5 ± 3.10 kg) were randomly allocated to four treatments: Control, 50% slatted and 50% solid flooring; RS, 100% solid flooring with a 7-cm layer of RS; SD, 100% solid flooring with a 7-cm layer of SD; SB, 50% slatted and 50% solid flooring with 10 SBs (1.5 m long and 75 mm wide). At week 10, the RS pigs had the lowest body weight. At week 0, the RS and SD pigs exhibited more positive behaviors, although the SD pigs also showed the highest number of injurious interactions at week 3. Between weeks 0 and 5, the SD pigs spent less time lateral lying and more time sternal lying, while during weeks 8–11, sitting was more prevalent. Both RS and SD groups exhibited lower cleanliness scores at week 6 and higher NH3 and CO2 levels at week 10. In conclusion, bedding materials such as RS and SD promoted positive behaviors during the early phase; however, prolonged use without adequate management impaired hygiene, air quality, resting behavior, and growth performance. These findings highlight the importance of the appropriate selection and management of EMs in intensive pig production systems.