Free Choice Mineral Supplementation – Self Medication or Lost Opportunity?

As Regenerative Agriculture gains traction, farming practices that are not so commonly used are being explored. One such practice is Free Choice Mineral Supplementation which is based on the concept that if given the opportunity then animals will self-medicate to provide themselves with the required nutrition.

Rather than “instinctively” knowing what they need, the ability of animals to self-medicate is based on post-ingestive feedback (how they feel after eating the substance or food) and learnt behaviours. If a particular food, or in this case mineral supplement provides chemicals that are required by the animal, the animal will associate the flavour of that mineral with a benefit to the body, and the preference for this compound will increase. In this way the animal seeks to maintain homeostasis through a feedback system.

One of the biggest proponents of self-medication is the US based professor, Dr Fred Provenza, who has dedicated his career to understanding foraging behaviour in ruminants and exploring the concept of self-medication. Dr Provenza has led numerous studies in grazing ruminants proving that stock will self-medicate to correct a mineral deficiency. On the other hand, there are also many studies that have concluded that this is not a successful way to supplement production animals.

This idea of free choice supplementation is appealing on a number or levels. Firstly, the notion that animals have choice has been hypothesised to drive wellbeing, which definitely has a feel-good factor. It’s also a whole lot less labour intensive compared to some other methods. Offer a loose lick or individual minerals in a cafeteria style setup and let the animals help themselves.

The complexities of why the free choice method may, or may not work, are beyond the scope of this article but the crux of it comes down to the concept of mineral insufficiency versus clinical deficiency. Many herds we deal with are operating in the insufficient zone rather than at a clinical deficiency, so by all intent and purposes they seem healthy but are not performing as well as they should be.

Marginal mineral status (particularly trace element status) does not typically result in clinical symptoms and the animal will not “feel” sick. Therefore, there will be no post-ingestive feedback (the animal will not “feel better”) to drive correction of this insufficiency through self-selection. Yet this marginal mineral status may be impacting negatively on reproduction (eg. heat expression, conception) and production (eg. growth rates).

Pasture sampling and analysis is a great way of identifying insufficiencies and excesses of minerals in the diet (provided an experienced person can analyse and interpret the results). By calculating what your herd actually requires, you can ensure the supplementation is better matched to requirements, regardless of administration method. Even if you prefer to go down the Free Choice route, it’s still worth your while knowing which minerals are actually required as you can potentially save yourself money in otherwise wasted product.

Before you set down this road it’s worth asking yourself what you are trying to achieve? Are you looking for generally improved animal health and welfare, in which case the free-choice method may be appropriate? Or are you looking for measurable reproductive and production gains? If it’s the latter, in our experience free choice supplementation is unlikely to achieve the outcomes you are expecting.