Protein And Equine Ration Balancers: Let's Do The Math

By Clair Thunes,

PhD

Q. I have been reading several of your commentaries and see that you recommend feeding ration balancers to horses on predominantly forage diets. When I looked at ration balancers at my feed store I notice that they tend to be high in protein, often around 30%. Isn’t that too much protein? I thought mature horses only need about 10-12% protein in their diet. What am I missing?

A. This is a question I get asked quite often, and at first glance you are quite right. But if we delve a bit deeper I think you will see why the ration balancer doesn’t, in fact, offer too much protein.

Most ration balancers have a recommended daily intake of 1-2 pounds (0.45 to 0.9 kilograms) per day. Where the crude protein content is 30% this means that 0.3 pounds (136 grams) of protein are supplied when feeding a pound and 0.6 pounds (273 g) of protein if feeding two pounds.

Let’s say that your horse weighs 1,100 pounds (500 kilograms) and that you feed an average grass hay with a crude protein of 11% at a rate of 2% of body weight per day. This equates to 22 pounds (10 kilograms) of hay that provides 2.42 pounds (1.1 kg) of protein (we reach this number by multiplying 22 pounds by 0.11 [which represents 11%] for the protein content). As you can see the hay is providing far more protein than the ration balancer. The ration balancer has a high protein content but a small serving size so its total contribution is small.

If we assume that this horse is in moderate work, per National Research Council guidelines, he needs 768 grams (or 0.768 kilograms) of protein a day. To convert this to pounds we multiply the amount in kilos by 2.2, because there are 2.2 pounds to a kilo. This gives us a daily protein requirement of 1.69 pounds. In this example the hay is meeting the horse’s protein requirement; however, if the horse was fed less than 2% of body weight per day because he’s an easy keeper, his requirement might not be being met. Similarly, if the hay actually had a lower crude protein content or the horse was in heavier work, the same might also be true.

Considering Easy Keepers

Sometimes I see easy keepers being fed lower nutritional quality hays at lower amounts to reduce calorie intake. For example, a stemmy grass hay with a crude protein of 8% fed at 1.5% of this horse’s body weight would yield only 1.32 pounds (0.6 kilograms) of protein, which is not enough to meet requirement. Adding 1.5 pounds (0.68 kilograms) of ration balancer with 0.45 pounds (0.2 kilograms) of protein would bring the ration protein intake to 1.77 pounds (0.8 kilograms) of protein, which meets his requirement.

Beyond just meeting requirement there is the issue of protein quality and even a grass hay that provides adequate crude protein might lack adequate levels of some essential amino acids. Or the protein might not be fully available if bound up with indigestible structural carbohydrates. Ration balancers not only provide crude protein, they tend to provide guaranteed levels of the most limiting essential amino acids, such as lysine and methionine, that are vital for your horse’s health. So, they’re a good insurance policy even if on paper it looks like protein intake from the forage should be adequate.

Ration Balancers vs. Performance Feeds

Another comparison I often see people make is between ration balancers and performance feeds. Most performance feeds have crude protein levels around 12% and a daily recommended intake upwards of 5 pounds per day. At 5 pounds (2.25 kilograms) per day this would provide 0.6 pounds (0.27 kilograms) of protein (5 x 0.12) the same as two pounds of the 30% ration balancer. In fact, performance feeds given at the upper ends of the recommended feeding levels provide far more protein a day than the ration balancer, even though the previous only contain only 12% protein.