Hoof Nutrition Intelligence is a twice-a-month web segment that is designed to add to the education of footcare professionals when it comes to effectively feeding the hoof. The goal of this web-exclusive feature is to zero in on specific areas of hoof nutrition and avoid broad-based articles that simply look at the overall equine feeding situation.
Below you will find Part 1 of the latest question and answer installment that you can share with your footcare clients.
Q: When's the best time of day to graze horses?
By Kathleen Crandell, Ph.D.
Turned-out horses are typically more fit due to increased exercise, show less anxiety with fewer stereotypes, have healthier, more robust respiratory systems, maintain strong musculoskeletal systems and potentially have fewer gastric ulcers due to a longer, more sustained feeding pattern.
In general, allow horses to graze either in the early morning or evening to minimize the ingestion of fructose-rich leaves.
Nonetheless, not all horses can be managed 24/7 on pasture, and there are some that should not be allowed to graze at will for fear of laminitis. If your horse has signs of insulin resistance (IR) or has been diagnosed with either IR or equine metabolic syndrome, the timing of turnout needs to be optimized to maximize health and minimize ingestion of fructans.
Fructans are short chains of a specific sugar molecule called fructose that cannot be broken down in the stomach or small intestine. Instead, they are fermented in the intestine. Large amounts of fructan aren’t tolerated well by some horses and can result in colic and laminitis.
The level of fructan in forage varies depending on type of grass or legume, time of day, season and even which part of the plant is being grazed (leaves vs. stems). As such, timing of turnout can impact how much fructan is being ingested.
Consider these factors when turning out your horse, especially if it is known to either have or be at risk for IR:
1. Fructan concentrations are higher during periods of fast forage growth. Minimize grazing in spring and after a heavy rain following a heat wave. Grazing muzzles are often used for this purpose.
2. Fructan levels are higher in the stems than the leaves. Therefore, avoid overgrazing pastures so horses do not consume fructose-laden stems close to the ground. Rotating pastures can help achieve this goal.
3. Stressed plants produce more fructan than happy plants. Drought and poor soil conditions (such as high salinity) are examples of stressors. Limit grazing when these conditions exist.
4. Fructans are produced in the leaves during photosynthesis in the daytime. In general, allow horses to graze either in the early morning or evening to minimize the ingestion of fructose-rich leaves. However, those are also the peak feeding times for mosquitoes, which can transmit a multitude of infection-causing organisms, including the West Nile virus. Use protection in the form of insect repellants and sheets.
It is also important to note that starches and sugars, including fructans, aren’t a concern for all horses. In cases of hindgut acidosis, a hindgut buffer might be useful and pasture analysis can benefit IR horses.
Kathleen Crandell is an equine nutritionist for Kentucky Equine Research. Located in Versailles, Ky., the firm is an international research, consulting and product development company working in the areas of equine nutrition and sports nutrition.
Hoof Nutrition Intelligence is brought to you by W.F. Young Co. (Absorbine). 
Like many significant achievements, Absorbine® grew out of humble beginnings—and through the tenacity of someone willing to question the status quo. In this case, it was a young woman in late 19th-century Massachusetts: Mary Ida Young. Her husband, Wilbur Fenelon Young, was an enterprising piano deliveryman who relied on the couple’s team of horses to make deliveries throughout the Northeast. Inspired by Mary Ida and Wilbur’s vision, Absorbine® has continued to add innovative products throughout the years — products used every day by horse owners around the world. Which is why, since 1892, we’ve been The Horse World’s Most Trusted Name®.
Click here to read Part 2 of the June 15, 2017 installment: Should hay be fed before grain, or vice versa?
Click here to read more installments of Hoof Nutrition Intelligence.