Effect of a screen with flaps and straw on behaviour, stress response, productive performance and meat quality in indoor feedlot lambs

•Screen with flaps and straw were added in indoor pens for feedlot lambs.•We evaluated the effect on behaviour, stress physiology, performance and meat quality.•Enriched lambs showed higher preference for enrichments and fewer stereotypies.•Enriched lambs increased their reactive response and may be difficult for their handling.•Enriched system had no detrimental effects on performance or meat products.

We analysed the effect of a modified pen using a wooden screen with flaps and cereal straw as forage and bedding, on behaviour, stress response, performance and meat quality variables of lambs housed in feedlots. Sixty male lambs were placed in enriched (ESF) or conventional (CO) pens (3 pens/treatment, 10 lambs/pen). The CO environment was barren. The ESF lambs showed a great preference for the provided items, which encouraged more natural and richer behaviour, reducing stereotypies and lamb aggressions, and increasing affiliations (P ≤ 0.05), which improves group cohesion. However, ESF lambs also developed a more natural coping style to the handling, evidenced by the higher cortisol levels (65.4 vs. 43.8 nmol/L) and a higher eye temperature as response to the reactivity test (38.1 vs. 37.8 °C). The ESF lambs had a higher (P ≤ 0.05) slaughter weight (27.2 vs. 26.3 kg), conformation score (7.38 vs. 6.07) and pH 24 (5.63 vs. 5.56) but lower cooking losses (12.9 vs. 14.9%) than CO lambs.