Effects Of Group Size And Toys On Growing Pigs' Welfare And Performance

The experiment was conducted to determine the effects of group size and toys on growing pigs'welfare and performance.In first trial, six hundreds and forty-eight White×Landrace female growers of similar initial weight (26.32±0.98kg ) and age were randomly allocated to investigate the effect of group size (18 and 54 pigs/pen) and toys (no provided and provided) on welfare and performance for 35 days. For all the trial pigs, space allowance was 0.96m2/pig, with one drinker per 9 pigs and 7.8cm feeder allowance per pig. The result showed that average daily feed intake (ADFI), average daily gain (ADG) and feed/gain ration (F:G) were not different among all the treatments (p>0.05). Over the entire period of the trial, large groups had less pollution proportion of the pens than small groups (p<0.05).Toys decreased saliva cortisol concentration at day 3 of the trial (p<0.01). Neutrophil: lymphocyte ratios (N/L) also differed and the pigs with large-group or toys had low N/L value (p<0.01, p<0.05). Large groups and toys both made pigs less lying posture and more standing posture (p<0.05). Large groups decreased aggression behavior (p<0.05), while toy were not (p>0.05). Group size significantly decreased the growing ing pigs'skin lesion score in the latter phase of the trial (P<0.05).After regrouping aggression were not different among all the treatments (p>0.05). Group size and toys had not reduced aggression behavior in the"aggression behavior test"(p>0.05).It was concluded that large group or toys could reduce stress and improve welfare with no difference of performance in the pigs, and that large group also decreased the polluted proportion of the pens and growing pig'aggression behavior.