Research and anecdotal evidence suggest that many horse owners lack the necessary knowledge and resources to properly balance their horses’ diets. Some find it challenging to assess their horses’ body condition and workload and accurately determine the amount of feed and forage their horses receive. Additionally, they often don’t know where to seek reliable expert advice, said Christine Latham, PhD, equine nutritionist with Mad Barn, during her presentation at the Equine Science Society’s Symposium, held June 6-9 in Grapevine, Texas.

It is important for horse owners to understand what nutritional sufficiency means for their horse and what a balanced diet is, she said. However, because the population of horses and owners is very diverse, it can be challenging for experts to relay information that can be used by all.

Latham and her colleagues used an online nutrition survey to collect data from thousands of horse owners about their horses and feeding programs. They recently analyzed a subsample of 200 diets from owners with horses of varying breeds, sexes, ages, workloads, and body weights.

“Overall, energy was oversupplied,” said Latham, adding that one-third of analyzed horses were overweight. “Overweight horses received an average of 108% of their daily (calorie) requirements.” Prolonged excess energy intake can result in weight gain and metabolic issues, she added.

“Underweight horses were getting an average of 145% of their daily energy needs,” Latham noted, according to their data. This suggests that owners of both overweight and underweight horses likely made unsuccessful attempts to modify their horses’ calorie intake before reaching out to a nutritionist. She observed that if horse owners had taken the ideal body weight into consideration, rather than simply adding or cutting back arbitrarily because the horse appeared fat or thin, calorie intake estimates might be more comparable across horses of different body conditions.

The study results also showed that there was widespread overfeeding of crude protein and the amino acid lysine, with horses consuming twice as much protein and lysine as they need on average. Conversely, 40% of horses were not getting enough vitamin E, while one in four horses did not get enough selenium in their diet.

Interestingly, zinc, copper, and iron intakes were higher among horses with a history of hoof issues, and selenium intake was higher among horses having difficulty building topline muscle, said Latham. This finding is counterintuitive, she added, because zinc and copper play crucial roles in maintaining hoof health, while selenium serves as an important antioxidant that supports muscle health.

Latham emphasized the need for caution when interpreting the relationship between nutrient intake and health concerns. She warned against drawing the conclusion that higher intakes of zinc, copper, iron, and selenium have a detrimental effect on hoof and topline health. Instead, the results likely indicate that owners recognized the significance of these nutrients when addressing some health concerns and incorporated them accordingly. In the future, Latham said she and her colleagues hope to conduct more comprehensive research to investigate the specific effects of dietary adjustments on addressing health concerns.

“There was an overall oversupply of macrominerals,” said Latham, highlighting significant potassium and iron excess in equine diets raising concerns about the potential impact on dietary balance. Consulting a nutritionist can help horse owners determine whether current nutrient intakes pose a concern and address any imbalances if needed.

Finally, she noted that “sodium was undersupplied in 62% of the reported diets,” indicating that simple adjustments such as adding salt can easily improve the dietary balance of the average horse.

Take-Home Message

Equine nutritionists need to identify areas where there is a lack of information regarding equid diets so they can help educate owners on how to feed their horses properly, said Latham. “Many diets oversupply energy and protein, and owners need more guidance in determining their horses’ micronutrient and vitamin needs,” she added.

“Overall, this research has shown us that horse owners need some help balancing their (horses’) diets to ensure nutrient requirements are met and not grossly exceeded,” she said. “But there are some simple things that will benefit most horses, like adding some salt!”