Behavior and physiology of boars housed in three different environments
Format of work:
Journal Article
Event presented at / Journal Name:
Frontiers in Ethology
Speaker / Contact Author's Name:
Thiago Bernardino
Speaker / Contact Author's E-mail Address:
tbernardino.aw@gmail.com
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Research aim:
The present study aimed to evaluate the impact of three different housing conditions on boars' behavior and salivary cortisol concentration.
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Background:
Commercial boars are often kept in barren crates or pens, harming their natural behaviors and welfare. Unlike sows and piglets, boar behavior is understudied, though heat stress and poor housing are known to reduce semen quality and fertility. Enrichment (e.g., straw bedding) improves sperm health, but research on boar welfare remains scarce. Crates restrict social and exploratory behaviors, while group housing—with proper management—can enhance welfare. Salivary cortisol, a key stress biomarker, is rarely measured in boars despite its reproductive implications. This study highlights the need for better housing to safeguard boar health and breeding performance.
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Approach:
We assessed the behavior and salivary cortisol physiology of breeding boars housed in three different conditions: crates, pens, and enriched pens. In the enriched pens, the boars were brushed, showered, and received hay twice daily. All animals were video recorded, and we collected saliva samples in the morning and afternoon to measure the circadian rhythm of cortisol.
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Key finding:
Commercial boars are often kept in barren crates or pens, harming their natural behaviors and welfare. Little research exists on breeding boars’ behavior, cortisol rhythms, or the benefits of environmental enrichment. This study compared boars in crates, pens, and enriched pens (given showers, brushes, and hay twice daily). Boars in crates showed more abnormal behaviors (5.23 sec) than those in pens (2.47 sec) or enriched pens (2.93 sec). Enriched boars also had healthier cortisol fluctuations, suggesting better welfare. Providing enrichment—like showers and hay—improves boars' well-being and should be adopted in breeding facilities.
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Industry or policy relevance:
The opportunity to discuss and modify policies about the commercial boars' housing conditions to enhance their welfare and improve social perception of the industry.
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Route for practical application:
Introduce enrichment to the current commercial boars' housing conditions.
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Confidence in findings and next steps towards realising impact:
When combining, the behavioral and salivary cortisol concentration results showed how the treatments influenced these parameters. Boars housed in crates showed more abnormal behaviors than penned or enriched penned boars. Boars housed in the enriched pens showed significant differences in salivary cortisol throughout the day (morning and afternoon assessment). Environmental enrichment with brushing, short baths, and hay can affect the behavioral and cortisol circadian rhythm in breeding boars, and should be considered as a protocol to improve their welfare.
Funders:
Brazil: FAPESP; CAPES / PROEX; and CNPq. Italy: Italian Ministry for Education, University and Research.
Links to Open Access Publications or DOI:
Citation:
AUTHORS=Bernardino Thiago , Sabei Leandro , Parada Sarmiento Marisol , Sato Denis , Farias Sharacely de Souza , Paula Tauana Maria Carlos Guimarães de , Marques Gabriela Rezende , Zanella Adroaldo José
TITLE=Behavior and physiology of boars housed in three different environments
JOURNAL=Frontiers in Ethology
VOLUME=4
YEAR=2025
URL=https://www.frontiersin.org/journals/ethology/articles/10.3389/fetho.2025.1540458
DOI=10.3389/fetho.2025.1540458
ISSN=2813-5091
