Description
Features |
Length of start-box: 2m |
Width of start-box: 1.5m |
Length of two short arms: 2m |
Width of two short arms: 1.5m |
Length of long arm: 3m |
Width of long arm: 1.5m |
Introduction
The Pig Y Maze is an adaptation of the rodent Y maze designed to study choice behaviors in pigs. Originated by Hemsworth et al. (2011), it explores how pigs make choices when deprived of specific resources.
This apparatus consists of a “Y” shape with a longitudinal arm and two short arms, facilitating the study of choice behavior in the presence of different cues. It includes a start box acting as an isolation area, separated from the choice area by transparent dividers. Various cues can be placed in both choice arms, allowing subjects to express their preferences by entering one of the arms.
The Pig Y Maze is effective for observing resource preference by depriving access to essentials like feed, bedding, and social contact (Hemsworth et al., 2011). Research indicates that pigs choose resources based on their relative preference values (Matthews & Ladewig, 1994). Additionally, this maze assesses behaviors such as social discrimination and recognition learning (Gieling, Nordquist, & van der Staay, 2011), and evaluates the impact of diseases and disorders on learning, memory, and choice behaviors in pigs.
Other tools for behavioral assessment in pigs include the Pig T maze, the Pig Hebb-Williams Maze, and the Pig Conditioned Place Preference Chamber.
Apparatus and Equipment
The Pig Y maze consists of a start box measuring 2 meters in length and 1.5 meters in width. It is separated from the longitudinal arm of the maze, which measures 3 meters in length and 1.5 meters in depth, by a transparent divider. At the end of the longitudinal arm, there are two short arms, each measuring 2 meters in length and 1.5 meters in width, separated from the longitudinal arm by transparent dividers. The walls of the arms are solid black, while the dividers are transparent, providing clear visibility throughout the maze.
Training Protocol
Clean the apparatus before each trail. Properly lit the apparatus. A tracking and recording system such as the Noldus Ethovision XT can be used to assist with observations.
Introduce the subject into the start box of the empty Pig Y Maze for 5 seconds. Following this, remove the transparent divider and allow the subject to explore the maze freely for 2 minutes. Return the subject to its home pen afterward.
Next, place different cues in each short arm of the maze. Introduce the subject to the start box for 5 seconds, then grant access to one short arm for 2 minutes. After this period, return the subject to the start box for another 5 seconds. Subsequently, allow access to the other short arm for another 2 minutes. Once the trial is complete, return the subject to its pen.
Repeat each trial twice daily over a span of two days for thorough evaluation.
Introduce the subject into the start box for a brief period of 5 seconds. Subsequently, enable the subject to select and enter one of the two short arms containing cues. Close off the divider of the alternate arm to prevent access. After a 2-minute exploration period, remove the subject from the maze and return it to its home pen. Repeat this trial daily over a span of 12 consecutive days.
Introduce the subject into the start box for 5 seconds. Following this brief period, allow the subject to freely choose between two short arms, each offering distinct resources. Upon entry into one arm, close the divider of the other to prevent access. After a 2-minute exploration period, remove the subject from the maze and return it to its home pen. Repeat this daily trial for 12 consecutive days.
Literature Review
Investigation of resource deprivation on choice behavior of domestic pigs
Hemsworth et al. (2011) examined how resource deprivation influenced the choice behavior of Sus scrofa (n=80). The study investigated the effects of food, bedding, and social contact deprivation using the PigY Maze. Three experiments were conducted: Experiment one (n=16) evaluated voluntary food intake versus 70% voluntary food intake, and presence versus absence of bedding. Experiment two (n=16) tested full social contact versus restricted social contact, along with presence versus absence of bedding. Experiment three (n=48) assessed voluntary food intake versus 70% voluntary food intake, and full social contact versus restricted social contact. Each experiment employed a 2 × 2 factorial design to analyze treatment effects.
Prior to testing, pigs underwent a one-week training period. Daily sessions in the Pig Y maze followed, measuring the impact of treatments. Results from experiment one indicated no significant effect of feed (p>0.05) or bedding (p>0.05) on choice behavior, with a preference for feed observed in most trials. The time taken to approach feed within 5 cm was faster for restrictively fed pigs with bedding (0.02 min vs. 0.10 min). Experiment two showed no significant effect of social contact (p>0.05), but a significant effect of bedding (p<0.05) on choice behavior, with a preference for social contact in most trials. Experiment three revealed a significant effect of feed (p<0.05) but no effect of social contact (p>0.05) on choice behavior, indicating a preference for feed in pigs with restricted access.
Deprivation of both feed and social contact notably reduced average daily gain, attributed to stress from social isolation. The study concluded that while pigs generally prefer feed and social contact over bedding, they often prioritize social interaction. Despite these preferences, the study did not find evidence of significant disruption in biological functions due to restricted access to preferred resources.
Data Analysis
- Number of times subject chose cue in the left arm
- Number of times subject chose cue in the right arm
- Time taken to approach within 5 cm of the cue
- Time spent within 5 cm of the cue
Strengths and Limitations
The Pig Y Maze offers a straightforward setup and a user-friendly task structure. Utilizing transparent dividers, it creates isolated areas that effectively control subjects’ interactions with cues. This versatile apparatus facilitates the study of various behaviors including resource preference, social discrimination, and recognition learning.
Subjects necessitate thorough pretraining before commencing experiments. Unexpected auditory, olfactory, or visual stimuli can potentially impact observations. When tasks involve food stimuli, the type and quantity of food presented can significantly influence performance. Task execution often demands considerable time investment. Variables such as age, gender, and the subject’s strain may also influence task outcomes.
References
- Hemsworth, P. H., Smith, K., Karlen, M. G., Arnold, N. A., Moeller, S. J., & Barnett, J. L. (2011). The choice behavior of pigs in a Y maze: effects of deprivation of feed, social contact and bedding. Behavioral processes, 87(2), 210–217. https://doi.org/10.1016/j.beproc.2011.03.007
- Gieling, E. T., Nordquist, R. E., & van der Staay, F. J. (2011). Assessing learning and memory in pigs. Animal cognition, 14(2), 151–173. https://doi.org/10.1007/s10071-010-0364-3
- Matthews, L. R., & Ladewig, J. (1994). Environmental requirements of pigs measured by behavioral demand functions. Animal Behaviour, 47(3), 713–719. https://doi.org/10.1006/anbe.1994.1096