Mineral Bioavailability

In my last post, I talked some about feeding a mineral supplement as a form of “cheap” insurance against a mineral deficiency, and I’d like to expand on that topic tonight.

Feeding additional minerals is usually a reasonable thing to do in my opinion. There are a lot of commercial mineral and vitamin supplements out there that provide a good balance of additional minerals and vitamins and selecting one of these products is an excellent first step. The reason for selecting a pre-balanced supplement is that minerals and vitamins interact with one another and they need to be present at calculated rates in order to do their job optimally. Too often, a megadose of any one mineral or vitamin unbalances the system and winds up being both costly and ineffective, not to mention sometimes dangerous.

When I’m comparing feeds and mineral supplements one of the first things on my mind is the bioavailability of the minerals contained within the feed or supplement. In addition to looking at the feed tag to determine what levels of mineral and vitamins may be contained in the product, I like to flip the bag over and have a gander at the ingredients list as well. As a general rule mineral bioavailability is lowest in mineral oxides, is higher in mineral sulfates, and is highest in mineral chelates or proteinates.

Lets use iron to highlight my point, although one could use nearly any trace mineral and arrive at the same place. Iron oxide is (literally) rust. As you might imagine, an animal could eat quite a bit of iron oxide before it met it’s daily iron requirement. In most cases, iron sulfate is several times more bioavailable than is iron oxide. It wouldn’t take nearly as much iron sulfate to meet an animal’s daily iron requirement as it would iron oxide. Similarly, chelated or proteinated iron is more bioavailable than either iron sulfate or iron oxide. So when a feed tag says it contains 50 ppm iron, my first question is from what source ?

Understanding the basics of equine mineral nutrition isn’t difficult provided one keeps in mind that individual minerals need to be fed at pre-set levels in order to work correctly and that when comparing mineral oxides to mineral chelates there are usually significant differences in bioavailability, so sometimes less is more when it comes to mineral chelates.

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Thor and Lightening

MyLight and Norman on the run

Cinnamon and Silky and finally a picture with a bit of fall color. Jason and I were discussing our lack of fall color this morning. The leaves mostly seem to be staying green and just falling off. It doesn’t make for any striking fall photos so I had to take this picture.