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Equine nutritional habits explained

by Wyoming Livestock Roundup

Ward Laboratories presented the last webinar of their educational series, Producing Robust Livestock Through Nutrition, Genetic and Soil Health Management, featuring Hagyard Equine Medical Institute Veterinarian Dr. Jenna Moline. Moline, originally from Sundance, focused on modern horse nutritional habits during the Dec. 14 webinar. 

Equid nutrition evolution

                  “Prehistoric horses were fruit and browse eaters 55 million years ago,” Moline shared. “The jaw started to elongate and deepen as horses became mixed feeders, eating more abrasive grasses.” 

                  The horses we know today entered the scene around 4.5 million years ago, mainly grazing for forage. Domestication of horses occurred roughly 4,000 years ago. 

                  “Back then, humans supplemented their horses with corn and barley,” she noted. “But, our knowledge of horse nutrition has really only evolved within the last 150 years.”

                  Moline explained the first horse supplement, called Black Drink, was marketed in 1834. In the early 1900s, vitamins and probiotics were introduced for human use, and by 1929, the first equine vitamin and mineral supplement was produced. 

                  “In the 1970s there was a huge boom in bagged equine feeds. The 1990s was another big boom for supplements, especially for various diseases and disorders, such as hoof, skin and joint supplements,” she added. 

                  Moline shared a study published in 2015 which surveyed horse owners around the country on equine nutrition knowledge. The study showed 87 percent of horse owners fed concentrate or grain supplements, but only 29 percent weighed the feed or used the scoop designed for the specific feed. 

                  All horse owners surveyed fed the appropriate amount of fiber, and 80 percent supplemented with salt, fats and oils. Of those supplementing their horses, 24 percent did so on the recommendation from their veterinarians, while the rest of the supplementation came from trainer advice or someone else. 

                  “A lot of people have really great knowledge on the basics of equine nutrition, but when it came to knowing things about disease processes or working through different nutrition-related problems, there was a lack of knowledge or decisions were based on tradition, folklore and misinformation,” said Moline regarding the study. 

Fundamentals of nutrition

                  Important factors adding into total nutritional plane of the horses’ diet include energy, fats and fatty acids, vitamins, minerals, protein, carbohydrates and water. During the webinar, Moline focused on carbohydrates. 

                  “Simple carbohydrates and starch are very easily digested by the stomach and small intestine. Structural carbohydrates will be broken down in the hindgut, opposite a ruminant,” she explained.  “As great as the horse is at absorbing nutrients in their large colon, they are not quite as good at breaking down cellulose and hemicellulose as cattle are.” 

                  Moline shared pasture and hay access is crucial, as those are the main sources of fiber and cellulose in the horse diet. Forage analysis is important for pastures and hay, as grasses can differ in nutritional value between species and season. 

                  “In hays for horses, we want moisture to be less than 50 percent on a dry matter basis,” she explained, stating the possibility of mold. “Ideally, crude protein should be over 12 percent, acid detergent fiber less than 45 percent and neutral detergent fiber less than 65 percent.” 

Weight and endocrine dysfunction

                  Referring to the study, just as Moline noted many horse owners also did not weigh bagged feed or concentrates, they did not consistently weigh their horses or keep records of body condition score, which is important in monitoring weight loss and gain for overall health. 

                  “We should be weighing our horses approximately every two to four weeks, as horse owners and trainers routinely underestimate bodyweight. Weight tapes are highly variable, but beneficial if the same person uses them in the exact same place every time. As veterinarians, we use the Henneke Body Condition Scoring System,” she explained. 

                  Weighing horses has many benefits, especially in watching for symptoms of nutrition-related endocrine dysfunctions, including Cushing’s disease and Equine Metabolic Syndrome (EMS). 

                  “Cushing’s or Pituitary Pars Intermedia Dysfunction (PPID) is a pituitary disorder that doesn’t release hormones correctly,” said Moline. “Horses with hypoertrichosis, or abnormally long hair, are symptomatic, with other clinical signs including loss of muscle mass and tone, laminitis and abnormal subcutaneous fat deposition. However, these symptoms can also be a sign of insulin resistance.” 

                  Moline stated the importance of diagnostic testing, as many endocrine disorders in horses have previously been lumped together because of similar symptoms. 

                  “EMS could involve insulin disregulation, or hyperinsulinemia-associated laminitis,” she shared. “Basically, for almost any reason a horse seems ‘off’ they should be tested for EMS.” 

                  Fortunately, both endocrine-related disorders can be treated with some level of medication, but nutritional habits are the best bet in fighting against weight loss or gain and laminitis associated with the disorders. 

                  Averi Hales is the editor of the Wyoming Livestock Roundup. Send comments on this article to

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