Personally I am not fond of feeding whole grains to horses as a calorie supplement. I prefer to use a "complete" or pelleted feed such as strategy, safe-choice, Ultium, Complete Advantage, or the LMF products like LMF Performance. Whole grains can be difficult for the horse to digest and utilize the caloric contents of the grain. Most grains need to be rolled to be beneficial to the horse, once rolled they begin to lose nutritional value over a relatively short period of time. If you can see the grains in your horses manure, it means they are getting very little out of it, and as such you are only seeding your manure pile.
Here some information about feeding barley in horses that is useful.
It's considered a good feed for putting condition on a horse, but it's certainly not the perfect feed. It has a poor phosphorous/calcium ratio (Corn and oats aren't great either, but barley is the worst of the three). It also lacks vitamins A and D, so alternative sources will need to be found by horse owners.
The grains of barley are very hard and need to be crushed or rolled, or cooked before feeding. It should never be crushed too finely, and, when cooked, it's generally best to do so without crushing or rolling.
The result can be a gluggy mass of food that runs the risk of packing down in a horse's stomach and triggering a colic attack. Like many grains, it simply does not have the bulk that a forage diet provides - and that is bulk critical to the normal function of a horse's digestive tract.
The answer is to mix the barley with a bulkier feed such as sugar beet pulp, chopped hay or wheat bran, lucerne chaff, ensuring the bulkier feed comprises 15 to 25 per cent of the mix.
Some horses dislike the taste of barley. It will generally be more palatable when cooked, or by adding molasses.
It's important to remember also that each grain of barley locks in its nutritional value. As soon as you crush a grain, the nutritional value will begin to decline.
Crushing your own and then feeding it will result in more nutritional value getting to the horse. A bag of crushed barley fed out over two weeks will have considerably less food value after a few days.
There's a big variation in the quality of barley, too. Quality barley will be a pleasing pale-golden colour. The grains will be of uniform size and undamaged. There should be a minimal amount of fines - dust and other debris - in with the barley.
Source the best possible barley you can. As with most horse feed, you're generally better off to pay more for the best quality, rather than saving money by compromising on quality.
Price will vary, depending upon how far the grain has to be trucked.
Barley's nutritional value
I hope this information answers your question fully. If there is anything I can clarify or other questions I can answer, please do not hesitate to ask.
It is pretty standard information about a common grain fed to horses. You'll find the same information on many sites. (Here) is the link to where this was found. Most people feed it because of cost. However, if it is passing undigested, your horse is receiving very little of the caloric contents, thus it is not as cost effective to feed. The complete or pelleted feeds are much easier for horses to digest and they utilize a significantly higher percentage of the feed making it more cost effective on a per available calorie basis. Most often then pelleted feeds are only marginally more expensive. I am sorry that the answer didn't help in anyway and you are never in anyway obligated to accept the answer, but I feel that it answered the questions you asked in regards XXXXX XXXXX barley. It is always good to try and find the most information you can, and to also have multiple sources confirming similar thought as it only helps to assure you.
Well you see, we farm, and I have unlimited supply to barley, thus it is very cost effective for me. I am just concerned about any harm to the digestive tract of my horse. If there is some waste, I don't mind, I just want my horse to be healthy. I am supplementing with minerals, and feeding beet pulp as well, along with good quality timothy hay. I think the calcium/phosphorus ratio should be ok? I am currently feeding it whole. There is some waste in the manure, but not too bad. I am aware of loosing the nutritional value of rolled grain, so if I roll it every day or other day, would this be a good feed plan?
We are now starting to get somewhere!
Yes rolling it daily would significantly increase the available nutritional value to your horse, in which case you can feed less. As long as it is not fed alone and with a good quality hay you can avoid the complications of the calcium and phosphorous. I also would not recommend feeding it with rice bran as this only exacerbates the phosphorous effects on absorption of calcium.
With the feeding plan you can use I would not expect any complications with feeding barley. And by rolling it daily, it will be a significant caloric supplemement for your horse. Feeding it along with beet pulp will prevent GI upset that can occasionally be seen with feeding any true grain.