We’ve all experienced a time where reading the back of a feed bag has made our head spin. Maybe it still does! With all the numbers and categories telling you how much to feed, how the heck do you figure it out?
Luckily, I’m here to quell a little bit of the confusion by explaining the different equine energy requirements that are frequently listed on feed chart recommendations. Equine feeding and nutrition doesn’t have to be complicated! I’m here to help!
Maintenance
For the maintenance equine energy requirement, we can divide it into 3 levels: minimum, average, and elevated. In general, we refer to horses that are not in work to be at a maintenance level.
Minimum
For the minimum maintenance requirement, we refer to horses that are either sedentary, super calm, and/or easy keepers. These could be miniature horses, ponies, or injured horses that are out of work. Basically, these horses are the ones that get fat on air.
Average
We refer to horses that are turned out, stabled but active, open broodmare, and/or resting performance for the average maintenance requirement. Again, these are horses that are not working.
Elevated
Elevated maintenance requirements refer to stallions, young adults, nervous horses, and hard keepers. These horses have a high level of voluntary activity.
But what about weather?
Horses (like all mammals) expend energy to maintain their body temperature. As temperatures rise or lower, energy adjustments are made in the horse’s body. The range of temperatures that a horse expends little to no energy to maintain its body temperature is known as the thermoneutral zone.
Lower Critical Temperature
As temperatures lower, energy is expended for heat production (lower critical temperature). At these temperatures, additional energy needs to be provided in the diet to accommodate for heat production. There are three LCTs that we note:
- 59 degrees F if the horse is wet
- 41 degrees if horse has summer coat
- 18 degrees if horse has winter coat
Mathematically, for every 1 degree F below the LCT, the horse’s energy requirements increase by 1%. Rain and wind will also increase these requirements.
Upper Critical Temperature
Conversely, as temperatures increase, the upper critical temperature can be reached where energy is expended for heat dissipation. There are two UCTs that we note:
- 77 degrees F if horse has summer coat
- 50 degrees F if horse has winter coat
Just like the LCT, for every 1 degree the temperature rises above the UCT, energy requirements increase by 1%. Luckily, there is a handy dandy graph we can look at that displays these zones.
regular requirement x (.01) x change in critical temperature = additional Mcal needed
Let’s do a fun example! It is February in Wisconsin and is a cloudy day at -10 degrees F. Your sweet little pony has developed an appropriate hair coat for the time of year and typically requires 10 Mcal of energy per day. How much extra hay should be fed to accommodate the temperature change?
Since the LCT is 18 degrees F for his hair coat, we will do simple subtraction — 18-(-10)= 28 degrees below LCT. We’ll then throw that number into the equation — 10 x .01 x 28 = 2.8 Mcal extra. Since hay is typically 1 Mcal/lb, you’ll have to feed 2.8 more pounds of hay to accommodate the temperature that day.
Working
Working horses can be classified into 4 subclasses: light, moderate, heavy, and intense. When looking at the subclasses, they are differentiated through duration, intensity, and frequency.
Light
Horses that are in the light subclass exercise for 1 to 3 hours a week (based on 40% walk, 50% trot, and 10% canter; heart rate of 80 bpm). Disciplines that fall into this category could be preparation for trail riding or light training for western pleasure, dressage, and trail riding.
Moderate
Horses that are in the moderate subclass exercise for 3 to 5 hours a week (based on 30% walk, 55% trot, 10% canter, and 5% skills or jumping; heart rate of 90 bpm). Disciplines that fall into this category could be preparation for polo, cutting, jumping, low-level eventing, and showing.
Heavy
Horses that are in the heavy subclass exercise for 4 to 5 hours a week (based on 20% walk, 50% trot, 15% canter, and 15% gallop or other skill work; heart rate of 110 bpm). Disciplines that fall into this category could be reining, jumping, upper-level dressage, polo, endurance, rodeo events, and young racehorses undergoing training.
Intense
Horses that are in the heavy subclass train and compete at the peak of their ability (110-150 bpm), including race horses, 3-day event horses, and endurance horses.
The chart below compares different horses’ maintenance and working energy requirements (based on body weight).
| BW (kg) | Maintenance | Light | Moderate | Heavy | Intense |
| 400 | 13.3 Mcal | 16 Mcal | 18.6 Mcal | 21.3 Mcal | 27.6 Mcal |
| 500 | 16.7 Mcal | 20.3 Mcal | 23.3 Mcal | 26.6 Mcal | 34.5 Mcal |
| 600 | 19.4 Mcal | 24 Mcal | 28 Mcal | 32 Mcal | 41.4 Mcal |
| 900 | 30 Mcal | 36 Mcal | 42 Mcal | 48 Mcal | 62.1 Mcal |
| % increase | — | ~20% | ~40% | ~60% | 110% |
Reproduction
Stallions
Stallions are pretty simple to figure out when it comes to energy requirements. If the stallion is nonbreeding, they are just considered elevated maintenance.
When the stallion is breeding, his energy requirements will be comparable to light work with a 20% increase in digestible energy needed in the diet.
Mares
When looking at broodmares, a body condition score greater than 5 is most desirable. During pregnancy, energy is used for a lot of processes, including:
- Maintenance of the dam
- Deposition of fetal and placental tissue
- Hypertrophy of the uterus
- Mammary development
- Maintenance of the fetus, placenta, mammary, and additional uterine tissue
During lactation, more protein, energy, calcium, and phosphorus in the diet is necessary to help recover from foaling stress, to produce milk, and to rebreed when necessary.
| BW (kg) | Maintenance | Mid-Gestation | Late-Gestation | Early Lactation | Late Lactation |
| 400 | 13.3 Mcal | 14.3 Mcal | 17.1 Mcal | 25.4 Mcal | 22.7 Mcal |
| 500 | 16.7 Mcal | 17.9 Mcal | 21.4 Mcal | 31.7 Mcal | 28.3 Mcal |
| 600 | 19.4 Mcal | 21.5 Mcal | 25.7 Mcal | 38.1 Mcal | 34 Mcal |
| 900 | 30.0 Mcal | 32.2 Mcal | 38.5 Mcal | 54.4 Mcal | 48.3 Mcal |
| % Increase | — | 7% | 28% | 90% | 70% |
Growth
When looking at growth, we can simplify it to be the sum of maintenance and gain. Growth curves have been created over the years to estimate weight gain for younger horses. An example of one of these curves is shown below.
Thank you so much for reading about equine energy requirements. Let me know if anything in this post surprised you! I’d love to hear from you.
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