Q. My 7-year-old Thoroughbred has recently started training as an event horse. We’ve found that he does best on a forage-focused diet, but I’m worried that might not be enough as he starts his first year of competition. Should I consider changing his diet? How can I be certain his needs are being met with a forage-focused diet through the competition season? 

A. Forage-focused diets are fantastic choices for many horse owners because horses have evolved to consume a fibrous diet. If a forage-focused diet is best for your Thoroughbred, there is no need to change that simply because he will be competing this year. However, there are a few steps you can take to ensure his diet supports his increased nutritional needs. 

The Base Diet for Horses 

Typically, dry hay comprises most of a horse’s diet throughout the year. Unlike forage products such as hay cubes, hay does not come with a nutritional label. Therefore, getting a hay analysis can help you accurately develop your horse’s diet.  

A hay analysis provides you with nutritional content of the forage including information on the digestible energy, protein, minerals, vitamins, and sugar content. You can then use this information to create a balanced diet for your horse. 

If your horse doesn’t receive a commercial concentrate at the manufacturer’s recommended amount—which sounds like the case, since you said he’s on a forage-focused diet—then he needs a ration balancer to meet his vitamin and mineral requirements that the hay cannot provide. Once you have your hay analyzed, your first consideration will be which ration balancer would be the best choice.  

Depending on the protein content of the hay, you can either choose a ration balancer fortified with additional protein, or a product with a concentrated source of vitamins and minerals (and no additional protein).  

Adding Energy to Your Horse’s Diet 

If your horse has been maintaining his condition well on the current diet but you’re anticipating an increase in workload, it might be worth adding an additional energy source to his diet. The best way to decide whether you need to alter his diet would be to regularly (every 4-6 weeks) check his body condition score and keep track of his workload.  

Body condition scoring your horse regularly is a great way to notice even the smallest changes in condition. If you notice your horse is losing weight, it might be time to adjust his diet. The same tactic can be applied if he is gaining excess condition.  

Authors of the Nutrient Requirements of Horses (2007) outline various work classes for horses. Workload is based on the number of hours of exercise they receive per week as well as the intensity of that exercise. For example, moderate work is three to five hours per week with a mean heart rate of 90 beats per minute (bpm). Familiarizing yourself with the various workload classifications can be beneficial because you will know if the workload increases, his nutritional requirements will also change.  

Forage-Focused Diets for Active Horses  

Oftentimes forage—even high-quality forage—and a ration balancer will not meet the energy requirements of an actively competing horse, so you will want to consider what products you can add to his diet to increase the calories, provided without adding grain-based products. Most feed stores offer a plethora of fiber-based products such as hay cubes, hay pellets, and beet pulp.  

If your horse needs additional energy, incorporating alfalfa into his diet might help meet his energy requirements because it is higher in calories than some other hays. You can achieve this with alfalfa hay, cubes, or pellets. The other tactic that works well for many active horses on a forage-focused diet is incorporating a fat source. Fats are calorically dense and a great option for increasing energy in a horse’s diet. You can add an oil or fat supplement as a top dressing on soaked fiber such as hay cubes, hay pellets, or beet pulp for additional energy.  

Take-Home Message  

Starting with a diet that includes analyzed hay and a high-quality ration balancer is an important first step in managing a competition horse. From there, regularly monitoring your horse’s body condition and workload changes will provide insight on whether you need to change his diet. If his workload increases, try adding a fat source or alfalfa to support his higher energy needs. These products can help add calories, supporting him in his first competition season while you maintain him on his forage-focused ration.