When comparing calories in horse feed, there is more to it than just looking at the calorie counts for each. In fact, not all calories are created equal. The ingredients of a horse feed determine several things that will affect caloric value.
In this article, you’ll gain a better understanding of the calorie requirements for horses, and how these calories can turn into different types of energy.
Calorie Requirements for Horses
While there is certainly a minimum calorie requirement for horses, each individual horse will have its own calorie requirement.
A horse should eat a minimum of 1.5% of their body weight in forage per day. This quantity of forage may or may not meet a horse’s caloric demands.
Several factors will affect the number of calories a horse needs. These factors include age, breed, health status, weather, and how much energy they expel daily.
According to the NRC, the daily calorie requirements for a 1,100 lbs. horse can vary from 15,000 to 35,000 kcal, depending on level of work.
Calorie counting for the horse may seem simple at first glance. However, in practice, two horses of similar size, doing the same job, may require significantly different diets to maintain a healthy body condition.
Using the body condition scoring system (BCS) will help you get a better baseline to determine if a horse needs more or less calories in their diet. A healthy BCS ranges between 5-6.
What is Digestible Energy for Horses?
When we discuss “calories” for horses, we are referencing Digestible Energy (DE). Digestible Energy is derived from nutritional energy sources like protein, fiber, starch, and fats found in a horse’s feed.
Digestible Energy is calculated by first determining Gross Energy (GE) and then subtracting the amount of energy lost in feces (Fecal Energy, FE). Gross Energy is the measurement of heat that is released when a substance is burned.
By using DE instead of GE, we are able to account for the largest source of energy loss from feed – fecal energy. Chemical composition will impact how digestible a feedstuff is, and this is illustrated in the comparison of corn and oat straw. Digestibility of oat straw is very low, while corn is highly digestible and yet they contain the same amount of GE (Figure 1).
Figure 1. Comparison of Gross and Digestible Energy of corn grain and oat straw
Feedstuff |
Gross Energy, kcal/lb |
Digestible Energy, kcal/lb |
Corn grain |
2,011 |
1,760 |
Oat straw |
2,011 |
780 |
Digestible Energy, while better than Gross Energy, fails to account for other major sources of energy loss during digestion. Notably, as hindgut fermenters, the energy loss in gas and heat of fermentation is significant in horses (Figure 2).
Figure 2. Flow of feed energy through an animal
In other livestock species, research has been conducted to quantify these losses. This data doesn’t exist in horses. Which is part of the reason why two feeds with identical DE can perform differently in the same horse.
Further complicating direct comparison based on DE alone is the impact of site of digestion as well as the composition of the horse’s total diet.
For example, in a horse who is eating low-quality hay, adding calories from fat may not be as successful in maintaining or adding body weight as adding the same quantity of calories from high quality fiber. The high-quality fiber can help support the microbes that live in the hindgut and help them better digest the low-quality hay, therefore increasing the calorie extraction from the hay portion of the diet.
Tribute® Equine Nutrition’s Approach to Calorie Requirements
At Tribute® Equine Nutrition, we don’t heavily advertise the calorie contents of our products. This is because calories do not represent what is available for digestion, absorption, and the utilization of those calories by the horse.
Instead, Tribute® Equine Nutrition’s approach is to use high quality ingredients and include digestive support for the horse’s entire diet.
Tribute® feeds include Equi-Ferm XL®, a pre- and probiotic, as well as digestive enzymes to support optimal digestion. Enzymes enhance the digestibility of the feed portion of the diet and Equi-Ferm XL® supports fermentation in the hindgut. This maximizes digestibility of the forage portion of the diet, which is the main source of dietary energy for the majority of horses.
Additional fortification using highly available sources of nutrients that are commonly lacking in equine diets, such as amino acids, trace minerals, and vitamins, support horse health and performance.
Since calories alone will not support optimal horse health and performance, Tribute® focuses on being a reliable and affordable source of key nutrients for horses with feeds of varying composition and caloric density. This allows us to meet the needs of every horse, from the easy keeper to hard keeper.
The below information can be helpful in comparing Tribute® feeds, but we encourage you to reach out for a personalized feeding plan to ensure that we match your horse with the best product for their individual needs.
Product |
Digestible Energy |
1,370 |
|
1,200 |
|
1,230 |
|
1,470 |
|
1,410 |
|
1,270 |
|
1,290 |
|
1,420 |
|
1,540 |
|
1,600 |
|
1,510 |
|
1,510 |
|
1,520 |
|
1,510 |
|
1,480 |
|
1,510 |
|
1,540 |
|
1,520 |
|
1,420 |
|
1,470 |
|
1,390 |
|
1,380 |
|
1,890 |
|
1,320 |
|
1,470 |
|
1,520 |