Applied Animal Behaviour Science 186 (2017) 16–21 Contents lists available at ScienceDirect Applied Animal Behaviour Science j ourna l h o mepa ge : www.elsevier.com/l ocate/applanim The effect of trough space and floor space on feeding and welfare of lambs in an intensive finishing system Ellen C. Jongman a,∗ , Maxine Rice a , Angus J.D. Campbell a , Kym L. Butler a,b , Paul H. Hemsworth a a Animal Welfare Science Centre, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria 3010, Australia b Biometrics Group, Agriculture Research, Department of Economic Development Jobs Transport and Resources, Hamilton, Victoria 3030, Australia a r t i c l e i n f o Article history: Received 3 June 2015 Received in revised form 30 August 2016 Accepted 28 October 2016 Available online 7 November 2016 Keywords: Feedlot Lambs Floor space Feeder space Feeding behaviour Growth a b s t r a c t This study examined the effects of floor space and feeder space on the feeding behaviour, growth and stress physiology of lambs, at different times, over a 6-week period in a finishing feedlot. A total of 640 lambs in four time replicates (160 lambs per replicate) were studied in four 40-lamb intensive finish- ing systems (feedlots) for 6 weeks over a 16-month period. The lambs were Merino wethers with live weight at the commencement of the experiment of 28.3 (s.d. = 2.4) kg. The effects of two factors, pen floor space (2 and 5 m 2 /lamb) and feed trough space (4 and 10 cm/lamb) were examined in a factorial arrangement. Measurements taken on individual lambs during the experimental period included: feed- ing behaviour and displacements at the feeder in the feedlot during weeks 1, 2 and 6, lying behaviour during week 3, weekly live weights and cortisol concentrations in weeks 1 and 6. Weekly feed intake for each group of lambs was also record. Trough space of 4 cm compared to 10 cm per lamb reduced aver- age lamb feed intake in all weeks of the 6-week period (a reduction of 1.2 (s.e. = 0.53) kg/hd in week 1, 1.3 (s.e. = 0.62) kg/hd in week 2, weekly average of 0.9 (s.e. = 0.17) kg/hd over weeks 3–6; P = 0.05, P = 0.06 and P = 0.0004, respectively). However, weight gain only differed significantly during the first week in the feedlot (average of 0.2 vs 1.1 (s.e.d. = 0.35) kg for 4 cm vs 10 cm/lamb of provided trough space, P = 0.03). At all observed times within the 6-week period, lambs with the reduced feed trough space spent less total time feeding (P < 0.05) with less feeding bouts (P < 0.05). There was no effect of feed trough space on lying time or cortisol concentrations. Floor space did not affect feeding and lying behaviour, feed intake, weight gain or cortisol concentrations. In conclusion, increasing feed trough space from 4 to 10 cm/lamb increased feed intake and live weight gain through an increase in the number of feeding bouts and the total time feeding. This indicates that the trough space recommendations in the Australian Model Code of Practice (sheep) of 2 cm/lamb are too low for maximum lamb feed intake and live weight. No effects of increasing floor space from 2 to 5 m 2 /lamb were found, however the growth rates in general were low suggesting that the environment in the feedlot may have been sub-optimal. © 2016 Elsevier B.V. All rights reserved. 1. Introduction In primarily pasture-based sheep production systems, finishing feedlots involve the short-term lot-feeding of young sheep before slaughter. Generally, hay- and grain-based diets off pasture are fed in outdoor pens for a period of 6–8 weeks before slaughter (Ashton and Morbey, 1997; Duddy et al., 2007). Few studies of the welfare of lambs in finishing feedlots have been reported. An estimated 5 to 20% of all sheep that enter a feed- lot do not adapt to the feed and the environment (Kirby et al., 2004; ∗ Corresponding author. E-mail address: ejongman@unimelb.edu.au (E.C. Jongman). Jolly and Wallace, 2007). Inappetence of lambs and adult sheep is generally recognized to be largely a result of neophobia towards feed and the environment (Savage et al., 2008). Many lambs enter finishing feedlots from extensive pasture systems and will not have been previously exposed to the high concentrate pelleted diets commonly fed in feedlots. As a result, lambs entering a finishing feedlot not only have to contend with the unfamiliarity of their sur- rounds, but also the novel feeding systems and feed types. Lambs are more likely to avoid novel feeds and consequently eat less in an unfamiliar environment than in a familiar environment (Burritt and Provenza, 1997). Competition for feeding space can also contribute to an increased incidence of non-feeders. In fact, McDonald et al. (1986) referred to an unpublished report that the percentage of regu- http://dx.doi.org/10.1016/j.applanim.2016.10.015 0168-1591/© 2016 Elsevier B.V. All rights reserved.