Nutrients in Oats:
On average, oats normally contain around 12% Crude Protein, 49% NSC (non-structural carbohydrates = total sugars and starches), 29% Fibre, 5% Fat and 5% Ash (total minerals and vitamins). To help better understand the role of oats in the equine diet, they are the human dietary equivalent to whole-wheat bread.
In regards to oat quality there are two main factors: bushel weight and contamination issues. The two nutrients that will vary the most with the different bushel weight (ie. 32 lb/bushel or 38 lb/bushel) are starch and fibre. Whereby the higher bushel weight oats will contain more starch and less fibre compared to the lower bushel weight oats which will contain less starch and more fibre. In other words, the nutritional quality of oats is linked to its starch content. Furthermore, the fibre in oats in the form of oat hulls is a very poor fibre source. The 1989 Horse NRC listed a DE (digestible energy) of 1.54 Mcal/kg for oat hulls which is less than wheat straw at 1.62 Mcal/kg. Hence, feeding oats for its fibre content does not make financial or nutritional sense.
The two types of contamination regarding oats are cleanliness and mould growth. Cleanliness pertains to debris contamination during harvesting which are predominantly straw stubbles. That is why we clean oats and the more often the oats are cleaned (ie. “Triple Clean”) the greater the amount of debris removed. The freshness, sweet smell and palatability of oats all related to mould contamination. Mould growth occurs from moisture exposure, either during harvest or storage. Bottom-line, even mildly moldy oats should NEVER be fed to horses. In addition to the mould there is a significant chance of mycotoxins produced by the mould that will have further negative health effects on your horse.
Western vs Ontario:
The major difference between a 38 lb/bushel Ontario oat and a 38 lb/bushel Western Oat is that the Western oats depending on where they were grown may contain selenium. The Ontario Oat will technically be void of any selenium. Unfortunately, this selenium level of the Western Oat will be highly variable depending on where the oats were grown and unless every load is tested it would be impossible to predict the level of selenium.
Affects of Processing Oats:
Processing oats such as rolling or steam crimping does not affect the nutrient content of the oats. Nutrient content can be altered if processing involves the separation of different particles based on weight. For example, the kernel is separated from the husk and you end up with 2 products, oat groats and oat hulls. Processing is implemented to compensate for inefficient chewing behavior by your horse. Rolling mimics normal chewing behavior whereby the husk is cracked and the nutrient rich kernel part of the oat will be exposed to the digestive enzymes of your horse.
Oat starch itself is highly digestible (85%) without the need for heat processing (ie steam flaking), which only increases the digestibility by less than 5%. Even though oat starch is highly digestible, this digestibility is 100% dependent on the hull being broken during the chewing process. If the hull is not broken the oats will go straight through, this won’t cause any harm to your horse, however will harm your wallet.
The table below represents the 2009 statistics of oat samples analyzed by Equi-Analytical Laboratories.
Item Average Range
% Dry Matter 90.173 88.828 - 91.518
% Crude Protein 12.676 10.766 - 14.585
% Neutral Detergent Fiber 27.173 19.805 - 34.541
% WSC (Water Sol. Carbs.) 3.715 1.725 - 5.706
% ESC (Simple Sugars) 1.200 0.596 - 1.804
% Starch 44.681 37.137 - 52.224
% Non Fiber Carbo. (NFC) 52.821 45.024 - 60.619
% Crude Fat 5.420 3.980 - 6.860
% Calcium 0.102 0.018 - 0.186
% Phosphorus 0.399 0.327 - 0.472
% Magnesium 0.143 0.118 - 0.168
% Potassium 0.519 0.411 - 0.627
% Sodium 0.033 0.000 - 0.149
PPM Iron 178.899 0.000 - 712.521
PPM Zinc 33.309 19.299 - 47.319
PPM Manganese 53.320 36.200 - 70.440
% Sulfur 0.209 0.126 - 0.291
PPM Copper 7.396