Effects of Cymbopogon citratus Essential Oil on Social Interactions and Welfare Indicators in Newly Weaned Piglets

Abstract

Aims: This study investigated a sustainable and innovative alternative to improve animal welfare in swine production through the topical application of Cymbopogon citratus essential oil (CCEO) in newly weaned piglets. Study design: Completely randomized design. Place and Duration of Study: The experiment was conducted at the Swine Teaching and Learning Unit of the Federal Institute of Education, Science and Technology of Santa Catarina (IFC), Araquari Campus, Brazil, between February 2019 and April 2020. Methodology: A total of 124 newly weaned piglets were randomly assigned to four groups: a control group and three treatments with CCEO applied at concentrations of 1.25%, 2.50%, and 5.00%. At each weaning, piglets received 1 mL of the solution on the dorsal region and were observed for 3 hours for behavioral recording through photos and videos, without observer interaction. Skin lesions were mapped 24 h after weaning and classified by anatomical region. The study was structured in three stages: (I) an initial observational survey of the behavioral repertoire, (II) development of an ethogram with zootechnical parameters, and (III) validation of the ethogram with detailed behavioral analysis. Zootechnical performance (body weight, average daily gain, and mortality rate) was assessed in stages II and III. Results: Chemical analysis confirmed citral (87.53%) as the predominant component of the oil. CCEO significantly influenced several non-agonistic behaviors (P < 0.05), increasing calm and exploratory activities—particularly at 2.50% and 5.00%. While aggression frequencies did not differ among treatments, CCEO-treated piglets showed a consistent numerical reduction in skin lesions 24 h after weaning. Zootechnical performance was not negatively affected, with higher concentrations showing a tendency toward improved growth. Conclusion: Overall, topical CCEO promoted more positive social interactions and reduced the severity of agonistic outcomes without compromising productivity. These findings indicate that CCEO is a simple, low-cost, and practical strategy that can be readily implemented to enhance welfare during the critical post-weaning period.