Food is usually eaten until an animal is full. It provides energy, aids growth and supports reproduction. Food is not often bitter to taste and is generally made up of primary metabolites which include carbohydrates and proteins. Food may be eaten when it’s not immediately needed since it can be stored as fat, allowing the animal to have an energy source when food is scarce.
Medicinal plants contain secondary metabolites that are bitter to taste when they are not needed. Animals only take secondary compounds for their immediate therapeutic needs. Secondary compounds are not stored as fat and provide no metabolic purpose, so are not eaten as food or because the animal is ‘greedy’. Unlike with food, an animal stops selecting secondary metabolites once the taste or smell changes. Try this for yourself with a favourite herb or nutrients – perhaps with spirulina or liquorice root – it will go from sweet to bitter but if you don’t need it, the taste will just be bitter, whereas we stop with pasta and potatoes when we are full.
Avoid medicinal plants in the feed. The needs of every animal will vary according to their physical and emotional state at any given time. In the wild, animals will naturally select compounds in their diet one at a time, not mixed together, so offer secondary compounds separately from their feed. It may be that they are only require medicinal plant extracts occasionally, or a couple of times a week.
Offering medicinal plant extracts and food separately allows animals to regulate their dose.