Submitted to: International Society of Applied Ethology
Publication Type: Abstract only
Publication Acceptance Date: 5/5/2006
Publication Date: 6/8/2006
Citation: Schenck, E.L., Garner, J.P., Toscano, M.J., Kirkden, R.D., Mcmunn, K.A., Pajor, E.A., Lay Jr, D.C. 2006. Utilizing natural rooting behaviors as a means to measure motivation in swine. International Society of Applied Ethology. p. 26. Interpretive Summary:
Technical Abstract: Feed restriction of sows is a common practice in the swine industry. Our objective was to develop a novel method for measuring food motivation in swine by: 1) utilizing natural rooting behaviors; and 2) including force exerted, and hence energy expended as a measure of motivation. Sixteen crossbred barrows, 90.8 ± 2.78 (SD) kg, were assigned to one of four treatments (4 per treatment): 21, 33, 45, or 57 h of food deprivation. Barrows were trained to root up on a bar at varying forces for a food reward. They were then food deprived according to treatment and given access to the rooting bar for a 5-minute test during which they did not receive a reward. In this testing period, the force of each root was recorded and plotted against time to calculate: total number of roots, maximum weight rooted, and area under the curve. Rooting extinguished during the testing period. Mean and SE in extinction curves were calculated by averaging across all barrows in the same treatment and then analyzed using multiple polynomial regression. Extinction curves for mean number of roots (F1,13=51.27; p=0.001) and area under the curve (F1,14=9.41; p=0.008) showed complex treatment effects. In contrast, the variation in the number of roots declined in a linear fashion with increasing deprivation periods (F1,16=11.25; p=0.004). The variation in maximum weight rooted varied with treatment (F1,14=4.95; p=0.043) such that at the beginning and end of the trial, higher deprivation groups showed less variation in maximum weight rooted. These data indicate that as the food deprivation period increased, barrows as a group became more focused on the task. We successfully validated our method, and discovered that it is vital to consider the variation in a population of animals when quantifying motivation rather than only looking at the mean value of the measures.