41 Effect of space allocation on feeding behavior in grow-finish pigs

The objective of this study was to evaluate the feeding behavior of grow-finish pigs in pens with two different floor space allowances. A total of 159 commercial crossbred barrows (n = 90; 25.87 ± 7.43 kg) and gilts (n = 69; 28.74 ± 4.08 kg) were housed in single gender pens and fed a common diet for approximately 14 weeks. At the start of the trial pigs were randomly assigned to pens providing one of two space allocations: 3.05m2/pig or 2.29m2/pig with 3 replicate pens per treatment. At allotment each pig was tagged in the ear with a unique colored ear tag for individual identification. Feed was delivered in standard 3-hole box feeders and water was delivered via nipple waterers. Pigs had ad libitum access to feed and water throughout the trial. Final body weight averaged 119.15 ± 31.54 kg (barrows) and 122.84 ± 12.55 kg (gilts). Video monitoring of trial pens was accomplished with cameras mounted to the barn ceiling and 12 h recordings were taken during week 1 (first week on trial following a 7 d acclimation period) and week 14 (last week before marketing at 97 d) to evaluate feeding behavior and activity at both the beginning and end of the grow-finish period. Behaviors of interest included activity (walking, standing, moving, drinking), the number of times each pig entered the feeder, total time spent eating and eating type (nibbler vs. gorger). Data were analyzed as a completely randomized design using the MIXED procedure in SAS. In week 1, increased floor space tended to increase the number of times pigs entered the feeder (P = 0.07) and significantly increased (P = 0.008) the total time spent eating by ~14%. However, these trends were not present at week 14. Floor space allocation did not influence eating type or alter activity level (P > 0.05) in either week 1 or week 14. No significant differences in feeding behavior resulted from an interaction between space allocation and gender. In week 1, gender did not influence the number of times pigs entered the feeder. However, barrows spent more time eating than gilts (84 vs. 63 min) (P < 0.0001). At week 14 these differences were not present (P > 0.05). As space allocation in swine production becomes increasingly scrutinized it will be important to evaluate behavior changes in the context of performance. In this study, increasing floor space impacted grow-finish pig feeding behavior early in the finishing period, but those behaviors were not observed at the end of finishing. Future research in this direction will attempt to identify at which point in production those behaviors change.