The Pig Spatial Maze Task was developed by Siegford, Rucker, and Zanella (2008) to provide pre-weaning piglets with physical and cognitive enrichment. Premature weaning, a common practice in commercial productions, tends to be a stressful event for piglets.  Piglets that undergo premature weaning display disruptive behaviors such as restless activity, low food intake, and aggressive behaviors (Cox & Cooper, 2001; Robert, Weary, & Gonyou, 1999). Environment enrichment has been shown to reduce fear-related and negative behaviors that accompany premature weaning by allowing the animals to indulge in a range of normal activities that also provide behavioral and physiological challenges (Beattie, O’Connell, Kilpatrick, and Moss, 2000; Mkwanazi, Ncobela, Kanengoni, & Chimonyo, 2019).

The Pig Spatial Maze Task is a spatial learning and memory-based navigational task that promotes cognitive abilities when used as an enrichment. The maze is constructed in an open arena using panels that each have three doors with a single path leading to the exit. The maze allows removal or addition of panels to increase or decrease maze complexity. This flexibility in design allows the maze to be used in the assessment of cognitive abilities and flexibilities. The maze can easily be adapted for different investigations and protocols such as drug testing and brain lesions.

Other apparatuses used to test pig behaviors include the Piglet Removable Y-maze, the Piglet T-Maze, the Pig Y-maze, and the Pig Open Field.

The Pig Spatial Maze Task consists of an open arena having three panels measuring 1.8 m in length. Each panel has three flap style doors that can be closed to block entry or positioned to manipulate the entry space. The panels are arranged parallel to each other with adequate choice-space in between. The panels are removable to allow manipulation of task complexity.

Clean the maze thoroughly before starting trials and in between trials to avoid odor cues from previous trails. Appropriately light the maze arena. A tracking and recording system such as the Noldus Ethovision XT can be used to assist with observations.

Pig Spatial Maze Task

Place the subject in the Pig Spatial Maze task without any panels present. Keep the exit door of the maze open and allow the subject to exit the maze. Gradually lower the exit door as trials progress until the door is fully closed. Allow the subject to push the door and exit the maze. Place a panel in the maze with one door of the panel kept open and the others closed. Place the subject in the maze and allow the subject to go through the open door of the panel and exit the maze. Gradually lower the open door until the subject has to push the door to go through it. Place the other two panels in the maze one at a time and follow the same procedure. Change the configurations of the open doors in each panel on succeeding trials. Conduct 4 trials per day for a maximum of 5 minutes each.

Investigation of the effects of enrichment on spatial learning and fear in pre-weaning piglets

Siegford, Rucker, and Zanella (2008) investigated the effects of the Pig Spatial Maze Task on fear-related behaviors in pre-weaning piglets. Twenty-seven piglets of both sexes were used in the study. The piglets were equally assigned to three treatments between prenatal days 5 to 11: maze task (MT), isolation control (IC), or control with sow (SC). The Spatial Maze was set-up adjacent to the farrowing crate while the isolation area was created by sectioning-off an area in the farrowing crate. The subjects were removed from the sow 30 seconds prior to the beginning of the training. Following the separation period, MT subject was placed in the maze arena, and the IC subject was placed in the isolation area. The controls were returned to the sow in the farrowing crate. The MT subjects in the investigation were motivated to solve the maze by rejoining the sow and litter at the end, on successful completion. MT and IC animals were separated from the sow for equal durations during each trial. Both males and females in the MT treatment displayed similar performances in terms of the number of training steps and time to complete the task. Animals were early-weaned on postnatal day 12. Assessment of spatial navigation following treatment (postnatal day 14) in the Morris Water Maze revealed male MT pigs and female IC pigs to display significantly lower escape latencies in comparison to the male IC pigs. Between postnatal days 49 to 51, subjects from each treatment group were assessed for their fear behaviors in an open field test (OFT), novel object test (NOT), and human approach test (HAT). The subjects were observed to spend similar amounts of time in the different areas of the open field regardless of treatment. Further, groups were observed to spend similar amounts of time in proximity to a novel object or person. However, MT treatment had a significant effect on the number of times the animals touched an unfamiliar person in the HAT. In comparison to the other groups, the MT displayed a lower approach latency and a higher tendency to touch the unfamiliar person.

The following can be observed on the Pig Spatial Maze Task:

• Time taken to solve each step
• Number of times subject chose an incorrect panel door
• Number of times subject chose the correct panel door
• Number of training steps repeated
• Time taken to complete the entire trial

Strengths

The Pig Spatial Maze Task allows the assessment of spatial learning and memory in piglets. The removable panels in the maze allow manipulation of task complexity. The flap doors in the panels allow manipulation of the navigation routes as well as the entry space. The Pig Spatial Maze Task is a non-aversive task that is effectively used for enrichment.

Limitations

Training in the Pig Spatial Maze Task takes a substantial amount of time. Factors such as age, gender, or strain of the subjects may affect task performance. The exploratory drive of the subject is highly important in the completion of the task. It is important to thoroughly clean the Pig Spatial Maze between trials to avoid odor cues from previous trails.

• The Pig Spatial Maze Task is a spatial learning and memory task.
• The maze is composed of three removable panels, each with three flap doors. The removal or addition of a panel can be used to manipulate maze complexity.
• Different configurations to the open doors can be made to increase task complexity and test behavioral flexibilities.
• The Pig Spatial Maze Task can be used to provide a form of physical and cognitive enrichment.

1. Beattie, V. E., O’connell, N. E., Kilpatrick, D. J., & Moss, B. W. (2000). Influence of environmental enrichment on welfare-related behavioural and physiological parameters in growing pigs. Animal Science, 70(3), 443-450. https://doi.org/10.1017/S1357729800051791
2. Cox, L. N., & Cooper, J. J. (2001). Observations on the pre-and post-weaning behaviour of piglets reared in commercial indoor and outdoor environments. Animal Science, 72(1), 75-86. https://doi.org/10.1017/S1357729800055570
3. Mkwanazi, M. V., Ncobela, C. N., Kanengoni, A. T., & Chimonyo, M. (2019). Effects of environmental enrichment on behaviour, physiology and performance of pigs—A review. Asian-Australasian journal of animal sciences, 32(1), 1. doi: 10.5713/ajas.17.0138
4. Robert, S., Weary, D. M., & Gonyou, H. (1999). Segregated early weaning and welfare of piglets. Journal of Applied Animal Welfare Science, 2(1), 31-40. doi: 10.1207/s15327604jaws0201_3
5. Siegford, J. M., Rucker, G., & Zanella, A. J. (2008). Effects of pre-weaning exposure to a maze on stress responses in pigs at weaning and on subsequent performance in spatial and fear-related tests. Applied animal behaviour science, 110(1-2), 189-202. doi:10.1016/j.applanim.2007.03.022
6. Souza, A.S., Laughlin, K., Siegford, J.M., Zanella, A.J., 2004. Acute stress impairs spatial learning and social recognition in early-weaned pigs. Journal of Animal Science, 82(Suppl. 1), 276.