Effect of an Enriched Elevated Platform Rearing System on the Welfare and Bone Quality of Fattening Pigs

An intensive breeding environment usually sacrifices the biological needs of pigs and will have a negative impact on the welfare and production efficiency of pigs. In this study, a bedding elevated platform rearing system was established and its effect on the welfare of fattening pigs was evaluated. A total of 456 fattening pigs were divided into the elevated platform rearing system group (EP) and control group (CON). The welfare of pigs during the rearing period (57–97 days of age) and the fattening periods (98–168 days of age) was assessed through behavioral observation, physiological indicators, growth performance, and bone quality. Pigs in the EP group showed less manipulating behavior and more playing behavior than pigs in the CON group during the first 48 h of the test. Moreover, EP pigs expressed more standing, play, and exploratory behaviors and less sitting, lying down, manipulating, and fighting behaviors than the CON pigs during the rearing period. More standing and playing behavior and less sitting, manipulating behavior, and fighting behavior were expressed in the EP group than the CON group during the fattening period. In both of the rearing and fattening periods, serum cortisol concentrations were lower in the EP group than the CON group; C-reactive protein concentrations were significantly higher in the EP group than CON group; TNF-α, IFN-γ, IL-1β, IL-2, IL-6, IgA, IgG, and IgM levels were significantly higher in the EP group than the CON group, but IL-10 levels were significantly lower in the EP group than the CON group. The EP group had less skin lesions and a higher final body weight. Our study confirms that the enriched elevated platform rearing system promotes the expression of positive behaviors and reduced skin and limb lesions, which also improve the growth performance of pigs.