Q. Many grains’ and concentrates’ recommended feeding rate is amount is based on the horse’s body weight and how much work he is getting: light, moderate, or heavy. I’ve found online resources for how to calculate body weight but not to determine work level. How do I accurately determine my horse’s work level?
A. Work level can be a hard thing to judge accurately. As a starting point I recommend you consider what a typical week looks like for your horse. This should include both the work your horse does and also how he’s housed. Is your horse at pasture 24 hours a, day 7 days a week, or is he in a stall? Perhaps he’s out part time. A horse that’s stalled at all times but hacked out every day at the walk with little trot or longed for a short period is likely only expending the same amount of energy as a horse that lives out 24 hours a day and without additional work. You should categorize this as “no work” and feed the maintenance requirement.
Once a horse is in more strenuous forced work, he’ll likely considered be in light work or more. While the amount we ride each day can vary quite a lot, I find that over the course of a week a consistent pattern will exist. How many days a week do you get your horse out and what do those outings consist of? Are you getting your horse out and working him solidly for almost an hour each time while staying mostly in the trot and canter? If so, then your horse might be in heavy work. If you only do this two or three times a week, and in between you hack out at the walk or longe for 20 to 30 minutes, then your horse might be closer to moderate work.
Factors That Influence a Horse’s Work Level
These are still inaccurate estimates and many factors can impact how hard your horse is working besides the length of time you ride and the speeds you are going. A rider’s weight combined with that of any tack worn will impact energy expenditure as will the horse’s fitness. Weather conditions also play a role, as can the horse’s age.
The National Research Council (NRC) gives descriptions you can use for estimating work level:
- Light work (recreational riding, beginning training, and horses that occasionally show). One to three hours per week of work composed of 40% walking, 50% trotting, and 10% cantering;
- Moderate work (lessons, recreational riding, polo, and light ranch work). Three to five hours per week composed of 30% walking, 55% trot, 10% canter, and 5% low jumping, cutting, or other skill work;
- Heavy work (ranch work, polo, horses that frequently show in strenuous events, low to medium-level eventing, middles stages of race training). Four to five hours work per week composed of 20% walking, 50% trotting, 15% cantering, and 15% galloping, jumping, or other skill work; and
- Very heavy work (Quarter Horse and Thoroughbred racehorses, endurance horses, and upper-level three-day eventers). Various work durations from one hour per week of speed work to six to 12 hours slow work.
Clearly there are a lot of omissions as far as disciplines in these descriptions with no mention of dressage, show jumping, cutting, reining, combined driving, etc. Plus, the example work schedules are only general descriptions. Horses could still be in heavy work if exercising for significantly longer than five hours per week but at a less intense level than described above.
Tracking Your Horse’s Exercise Level
Keeping a journal of what you do each ride can be a very helpful tool for tracking work intensity and might help you determine an appropriate work level for your horse.
The most accurate way to determine work level is to measure your horse’s heart rate during work. As work intensity goes up so does heart rate. Equine heart rate monitors are relatively inexpensive and can be synced to smartphone apps that collect real-time data.
Heart rate zones have been determined for horses in the same way that they have for humans. The NRC gives an average heart rate of 80 beats per minute (bpm) for light work, 90 bpm for moderate work, 110 bpm for heavy work and 110-150 bpm for very heavy work. Keep in mind that these are averages across the entire exercise bout, which means that your horse might work at higher and lower heart rates than this at points during the ride.
Once you’ve determined you horse’s work level you can more accurately decide how much of a given commercial feed your horse needs. Keep in mind that you might need to adjust amounts depending on the individual horse and whether he’s a hard or easy keeper. If you find yourself feeding less than the recommended amount of a given feed because feeding more would cause weight problems, you should find a feed with a smaller serving size that you can feed at the rates recommended by the manufacturer. This will help ensure that all your horse’s dietary needs are met.