Dr. Darrell Emmick shared his experience with animal foraging behavior and explained how to train livestock to eat weeds.
Animals learn what to eat through the interactions of two interrelated systems: affective and cognitive. The affective system operates without any conscious thought using feedback from osmotic, chemical, and mechanical receptors within the gut to evaluate the chemical and nutritional composition of foods eaten. This is ‘Post ingestive feedback.’ If they feel good or energized after eating a certain food, they will eat it again. If they feel uncomfortable, bloated or sick afterwards, they are not likely to eat that food or plant again.
The cognitive system uses information gained through the senses of sight, smell, touch, and taste, as well as social learning. Generally, babies eat what they see their moms eat. Animals also learn from other adventurous animals in their herd or group. [Read more here]