Ontogeny of Emotion/Cognition
Our focus lies in understanding the basic emotional and cognitive capacities of pigs and poultry, and the effects of farming and management practices in early life on these capacities later in life. We do this both in the stables and in the lab.
Pigs and poultry
We developed and validated a number of behavioural tests to reliably measure emotion and cognition in pigs and poultry, and continue to innovate in this area. In pigs, we showed effects of very low birth weight, housing in a barren environment, and very large litter size on emotional and cognitive capacities; in poultry we see effects on cognition following rearing in high stocking density, (lack of) maternal care, and differences in animals from different genetic backgrounds.
Early life maternal care
In the lab, we use histology and biochemical techniques in poultry and pigs to study effects of early life circumstances on brain development and physiology. We see effects of early life maternal care and of genetic line on the dopaminergic and vasotocin systems in adult layer hen brain. Our studies have also shown effects of management and farming practices on corticosterone in feathers of chickens and cortisol in hair of pigs, sheep and cattle as a long-term record of stress.
The video shows a pig searching for M&M’s® in the holeboard, from the pig’s perspective. We use the holeboard task to test spatial learning in pigs. The holeboard consists of an arena with a 4X4 matrix of “holes”, which are plastic food bowls covered with a red ball. Four of these 16 bowls contain M&M’s®. Because pigs like to eat M&M’s®, they search the holeboard to find the treats. In order to find the hidden M&M’s®, the pig must lift up the ball covering the bowl with its snout. This looks a lot like the natural behaviour of the pig that, in its natural habitat, spends much of its time rooting for food with its snout. If the hole contains M&M’s®, the pigs eat them and search for the M&M’s®. As soon as the pig retracts its nose, the ball falls back onto the food bowl, which means that they can’t see where they have already been. Pigs quite quickly learn which holes contain M&M’s®, and after some training, they only visit the holes that contain M&M’s®. How well and how quickly a pig learns this task can tell us a lot about its long term memory, short term memory, and motivation to find food rewards.
- Dr. F.J. van der Staay