Effect of enriched housing on welfare, production performance and meat quality in finishing lambs: The use of feeder ramps L.A. Aguayo-Ulloa a, ⁎, G.C. Miranda-de la Lama b , M. Pascual-Alonso a , J.L. Olleta a , M. Villarroel c , C. Sañudo a , G.A. María a, ⁎ a Department of Animal Production and Food Science, Faculty of Veterinary Science, University of Zaragoza, Spain b Group of Animal Welfare and Sustainable Production, Department of Food Science, Metropolitan Autonomous University, UAM-Lerma, State of Mexico, Mexico c Department of Animal Science, E.T.S.I.A. Polytechnic University of Madrid, Spain abstract article info Article history: Received 7 February 2013 Received in revised form 14 October 2013 Accepted 6 January 2014 Keywords: Full environmental enrichment Finishing lambs Meat quality Animal welfare Productive performance This study analyses the effect of environmental enrichment on the welfare, productive traits and meat quality of lambs housed in feedlots. Sixty lambs were placed in enriched (EE) or conventional (CO) pens (3 pens for each treatment, 10 lambs/pen) where EE had a wooden platform with ramps that provided access to a concentrate hopper, cereal straw as bedding and forage, and one play ramp. The CO pen was barren, similar to commercial feedlots. The physiological adaptation response of EE lambs was more efficient than CO, since the latter mobilised more body reserves (i.e., increased NEFA, P b 0.05), and had lower levels of immunity (i.e., increased N/L, P b 0.05), which indicate chronic stress, probably associated with the barren environment. The EE lambs had a higher (P b 0.05) average daily gain, with heavier carcasses and higher fattening scores, as well as lower pH ult , higher L* and b* values, and lower values of texture (P b 0.05). © 2014 Elsevier Ltd. All rights reserved. 1. Introduction In the future, one of the main challenges of the sheep industry will be to increase production to satisfy the global demand for meat con- sumption, as one more source of protein in the human diet (Montossi et al., 2013). Along those lines, in Mediterranean countries there has been a trend to adjust traditional pastoral sheep production to more intensive schemes (Bernués, Ruiz, Olaizola, Villarba, & Casasús, 2011; de Rancourt, Fois, Lavín, Tchakérian, & Vallenard, 2006). The development of intensive indoor management programmes, such as lamb feed-lotting, externalises the final stage of fattening to off-farm units (Aguayo-Ulloa et al., 2013). That process stratifies the system in two specialised parts, breeding the flock on the farm (under the farmer's responsibility) and fattening on feedlots, also called classification centres (CCs). These changes in lamb meat production simplify the finishing process for the farmer and improve carcass homogeneity (Miranda-de la Lama, Villarroel, Liste, Escós, & María, 2010; Miranda- de la Lama et al., 2010). However, both farmers and animals have to deal with new problems such as external resource dependency, multiple live transports, social mixing, novel and barren environments, and frequent handling (Aguayo-Ulloa et al., 2013; Miranda-de la Lama, Villarroel, & Maria, 2012). The lack of stimulation leads to boredom, which may cause the development of stereotypies, abnormal behaviour, frustration and stress (Fraser, 1980; Lawrence & Rushen, 1993; Wood- Gush & Beilhartz, 1983). The new intensive sheep production described can have negative effects on animal welfare and the quality of products delivered to consumers. The welfare of farm animals is a growing public concern and considered a priority for an increasing number of Europeans (European Commission, 2006; Vanhonacker, Verbeke, Van Poucke, & Tuyttens, 2008). New regulations have been developed to improve the production chain of the intensive livestock industry to satisfy consumer demands (European Commission, 2006; Winter, Fry, & Carruthers, 1998). Adequate environmental enrichment could reduce negative emo- tional states such as fear and stress associated with the adaptation to a novel environment (i.e., the CC). This will reduce the frustration that animals may experience when they are unable to express their behavioural needs (Hughes & Duncan, 1988; Nicol, 1992; Wood-Gush & Vestergaard, 1989). Environmental modifications can also improve physical health by promoting a wide range of movements to promote skeletal muscle and cardiovascular fitness (Chamove, 1989; Fraser, Phillips, & Thompson, 1986; Klont et al., 2001). Many ways to improve animal welfare through environmental enrichment have been explored, mainly in pigs (Bracke et al., 2006; van de Weerd & Day, 2009; Vanheukelom, Driessen, & Geers, 2012). The literature review by de Azevedo, Cipreste, and Young (2007) reports that food and structural enrichment are among the most successful. However, in farm animals Meat Science 97 (2014) 42–48 ⁎ Corresponding authors at: Departamento de Producción Animal y Ciencia de Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, Miguel Servet 177, E- 50013 Zaragoza, Spain. Tel.: +34 976 762490; fax: +34 976761590. E-mail addresses: laguayo@unizar.es (L.A. Aguayo-Ulloa), levrino@unizar.es (G.A. María). 0309-1740/$ – see front matter © 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.meatsci.2014.01.001 Contents lists available at ScienceDirect Meat Science journal homepage: www.elsevier.com/locate/meatsci