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The effects of environmental enrichments on behavior and performance of weanling pigs
Newly weaned pigs are exposed to multiple stressors which could cause a decrease in performance. To reduce the stress associated with weaning, this study evaluated the effects of adding environmental enrichments to the nursery pens. Weanling pigs (n=193), that were either socialized for 7 d prior to weaning or not, were randomly assigned to nursery pens (2.5 x 1.25 m) that contained either environmental enrichments or no environmental enrichments. All nursery pens were located in an environmentally controlled room and all pigs received the same diets, which met or exceeded NRC requirements. Each pig was weighed daily from d 21 to d 35 after birth and activity continually recorded using surveillance video from d 21 to d 35 after birth. The behavior of pigs (lying, active, feeding, agonistic) was recorded by 10 observers using digital video playback. The duration of a behavior was timed and recorded when 75% or more of the pigs were engaging in a specific behavior during the elapsed time period. The ADG of pigs with environmental enrichments was not different than the pigs without environmental enrichments. The ADG of pigs that were socialized prior to weaning (0.48 ± 0.02 kg) was significantly higher (P < 0.05) compared to those that were not socialized prior to weaning (0.39 ± 0.03 kg). There were no differences in ADG between the treatments from weaning to d 3 after weaning. Pens with environmental enrichments contained significantly fewer (P < 0.05) pigs displaying aggressive behavior (50.0 ± 4.5%) compared to pens without environmental enrichments (60.0 ± 4.5%) during 6 h after weaning. Similarly, pens with environmental enrichments contained significantly fewer (P < 0.05) pigs displaying aggressive behavior (20.0 ± 4.5%) compared to pens without environmental enrichments (30.0 ± 4.5%) from 6 h to 12 h after weaning. There were no differences in the rate of aggressive behavior between pens at any other times during the study. The results of this study suggest that environmental enrichments can be effective in reducing unwanted agonistic behavior, as well as increasing ADG of pigs that were socialized prior to weaning.
Keywords: environmental enrichment, behavior, performance