Ask that question and most people will answer [Brand] 10% – or whatever the protein percentage is of their bagged feed. Some will answer [Brand] X/Y where X is the protein and Y is percent fat. What does that tell me about your horse’s diet? Basically nothing.
Maybe the emphasis on the bagged feed is because we are so inundated with advertising about which one is superior. Even worse, a lot of this also comes from people ending up thinking that the bagged feed is the most nutritionally important thing they feed their horse. It’s not.
Let’s take the example of a 500 kg (1100 lb) horse in moderate work eating the middle of the recommended feeding range of a 14% protein, 9% fat premium performance horse feed. At best, this provides the following percentages of the daily minimum requirements: Calories 45%, protein 32%, omega-3 fatty acids 0% (not stable even if added), vitamin E 0% (not stable even if added), vitamin A 25%, minerals around 50%.
If feeding the recommended amount of this high calorie, high fat feed makes your horse gain too much weight, which it often will unless you restrict hay, you will have to feed less which means it also then provides a lower percentage of the required protein, vitamins and minerals.
The bottom line is that even a top of the line feed fed in recommended amounts provides less than half the calories, about 1/3 the protein and half the mineral requirements. The rest must come from the most overlooked component of the diet – hay. When feeding large amounts of grain, hay intake often must be restricted. This in turn can lead to vices like wood chewing and increased risk of gastric ulcers.
Feeding nutrient supplemented grains can help support adequate nutrition, especially intake of minerals and some vitamins. However, it falls short of guaranteeing the diet is truly meeting all needs. Your hay must provide the bulk of the protein, over half the calories and at least half of the minerals your horse needs. Additional supplements may be needed for specific issues. A hay analysis and consultation with an independent professional is the best way to guarantee your total diet is adequate and correctly balanced.
Eleanor Kellon, VMD