Epsilon Open Archive

Abstract

The major part of the life of laboratory animals is spent in their home cages/pens. Both dogs and rats are social, active, exploratory animals. Keeping them on a restricted area leads to limitations in activity. The aim of this thesis was to evaluate if increased physical and social activity in the home environment improves animal welfare. In study I, it was shown that male Beagle dogs increased their activity (steps/hour) and frequency of active behaviours when they had access to an outdoor kennel compared to when they were kept only indoors. Male Sprague Dawley rats were kept in several alternative housing systems for 4-10 weeks; a furnished pen (study II), two or four connected Makrolon type IV cages (study III), Enriched Rat Cage System and Scantainer NOVO cages (study IV), in groups of four (study III) or eight (studies II-IV) with control rats either housed individually (study II) or in pairs (studies III, IV) in standard cages. In study III half of the number of rats from each cage was given moderate treadmill exercise. The cage types in study IV were also tested in Spontaneously Hypertensive rats. Compared to controls, pen-housed rats had lower body weight, increased muscle oxidative capacity and strength and a more diverse behavioural pattern. The treadmill-trained rats had lower exercise blood lactate levels and greater endurance, lower body weight and plasma insulin levels and a greater relative heart weight compared to controls. Rats living in groups of four or eight performed better in an exercise test, had more social interactions and showed more activity in the Elevated Plus Maze compared to controls (study III). In study IV, rats of both strains showed a higher home cage activity with a greater variety of active behaviours in the alternative cages. This resulted in a lower lactate response and a greater endurance in an exercise test in both strains. The hypertensive rat model was not affected by the increased activity. In conclusion, the outdoor housing in dogs and all alternative housing systems tested in rats has lead to higher physical and social activity with positive implications for animal welfare.