Is there a possibility that a low NSC (10-12%) could cause lack of energy or lower energy? I've mentioned putting him on a diet... hes at a good weight now I dont really want him to lose anymore. Hes in great condition but I just noticed hes kinda more lazy than normal and I got to thinking maybe it's the feed... I call it diet grain .... bluebonnets ex factor. I'm starting to mix in the sr therapy but that's also considered low NSC, 12% I think. Anyway it's nothing alarming it's just something I'm aware of. He gets unlimited hay in his stall and gets pasture a few hours a day... I've gotten the "danger" weight off him.. (cresty neck, fatty pockets) he looks fantastic (imo) I just kinda wish he had a little more energy! Hes never been a hot head so it's not like a huge difference in him.. I just want to make sure im not short changing him. Hes getting pretty close to the recommended amount also is on platinum metabolic support and platinum. I'm cutting down the metabolic support to one serving a day and haven't decided if I want to keep that longterm or not now that hes at the body condition I and his vet wanted. 

I have my horse on a low starch feed as well, although yours is 10-12% you said and mine is 13.5%. I compared the nutrition labels and they are around the same. How many lbs a day do you feed? I feed around 6-7lbs a day. 

I'm around 5lb per day I'm also feeding soaked beet pulp with added alfalfa to it called fibre beet. I'm feeding about 1 3/4 cup (dry) it expands like crazy when soaked. I'm still on the fence if I'm keeping that.. I'm just trying to finish the bag I bought. He really likes it and I like that its extra moisture going in especially when it's this cold and the water drinking decreases. I've been reading that not ALL horses neccesarily need that low of an NSC unless they have certain health issues. I dont believe mine does. 

NSC levels fed to horses is one of the most misunderstood nutritional issues. NSC, non-structural carbohydrates is the combination of starch and sugars in the horses diet.  Horses with metabolic issues like Cushings, laminitis or PSSM, can benefit from limiting NSC levels in the total diet. In a properly functioning digestive system NSC can provide usable energy if digested where nature intended it to be processed, in the small intestine. Here it is broken down by enzymes produced for exactly that purpose. A horse makes those enzymes constantly, but in fairly small amounts since during the evolution of the horse, high amounts of NSC were not available in its normal diet, therefore high amounts of that specific enzyme were not needed. Once that enzyme is consumed, any remaining undigested NSC travels on into parts of the digestive system where it was never intended to be. As this happens, digestive effeciency related to the roughage portion of the diet becomes negativley impacted to one degree or another. In the worst case, the result is colic, founder, laminitis, death. We have all heard of horses that got into the grain bag, consumed an extreme amount and died as a result. While extreme reactions are less likely with very low NSC feeds, many people still overload the system by feeding high amounts thinking that the low NSC numbers means it is safe and effecient at any amount. The digestive upset caused by excess NSC getting into the hind gut, from mild colic to the extreme reaction, death, are all the same issue, just a different degree of that issue. 

So, understanding the above, a lot of people look at feeding low NSC feeds as a safeguard against colic in generally healthy horses, and metabolic issues in horses that are more sensitive because of those problems. But, is a 10% NSC in your horses diet safer than a 20% NSC feed, a 30% feed? Here is how to tell. 

First, while the percentage of NSC in a feed may be informative, the total contribution to the diet is the more critical point. One pound = 454 grams. Since very low NSC feeds are also low in calories, they tend to be fed at higher amounts. Lets look at how much a 10% NSC feed contributes to the diet if you feed five pounds per day. 454 grams x 10% = 45 grams of NSC x five pounds = 225 grams of NSC contributed to your horses diet per day. Most 20% NSC higher fat feeds are fed at a much lower rate per day, closer to 2 pounds or less because they are more calorie dense. So 454 grams x 20% = 90 grams of NSC x two pounds = 180 grams of NSC contributed to the diet per day, or 16% less total NSC contributed to the diet than the 10% NSC feed it would replace. 

In addition to actually contributing less total NSC to the diet per day, two pounds of that 20% NSC feed does not have excess volume to overwhelm the digestive enzyme in the small intestine and is utilized where the horses system is designed to digest it. There is no chance of the smaller feeding rate disrupting the effeciency of the hind gut. As a result the roughage is effeciently digested, something that does not happen if larger feed concentrate inclusions are in the diet.

This is a lot to digest (no pun intended) but the end take away is how much total NSC per day is contributed to the diet, not what percent a certain feed is. 

Thank you Win for the detailed post! I know I sometimes forget to count TOTAL NSC in the diet. 

It's so nice to have someone explain what to me can be complicated stuff and do it in a way that isn't snide and condescending--thank you Mr Win.