
The equine feed industry is packed with options claiming to optimize equine health and performance. You have products manufactured to meet all types of equine energy and nutrient requirements in forms ranging from textured to pelleted to extruded. Among these, extruded feeds have garnered attention because of their unique processing methods and subsequent impacts on digestibility, nutrient availability, and more. For veterinarians, understanding extruded feeds and the science behind them can allow for informed diet recommendations—particularly for horses with specific nutritional needs or health concerns.
Understanding the Extrusion Process

Extrusion technology uses heat, pressure, and moisture to produce a feed product that is not only highly palatable but also has enhanced nutrient digestibility. Extruded feeds undergo a transformation at the nutrient level, breaking down complex carbohydrates and proteins into simpler, more easily digestible forms.
“Extrusion is the most technologically advanced method of equine feed processing,” says Jeanne van der Veen, MS, Equine and Specialty Nutritionist with Kent Nutrition Group. “During the extrusion process, the ingredients are pressure-cooked, combining high pressure, heat, and moisture to rapidly cook the ingredients and form the feed.”
The ingredients themselves are ground about one-third finer than what they would be in a pelleted feed. “When you grind those ingredients finer, you increase the surface area, and if you increase the surface area of those ingredients, you increase the digestive efficiency of those ingredients,” explains Randy Raub, PhD, director of research and nutrition for the Kent Nutrition Group. “Then those ingredients are going to be cooked, if you will, at a higher temperature and for a little longer duration (than pelleted feeds), and then the extruding process facilitates a little bit more steam and pressure to drive them through the die.”
As a result, the starch and sugar portions of the feed ingredients gelatinize—what Raub refers to as a kind of “pre-digestion” to ensure those elements don’t end up undigested in the horse’s hind gut. The protein fraction also undergoes pre-digestion into the individual amino acids—a key step in protein digestion.
“With about 75% of the immune system located in the gut, anytime you can improve the horse’s digestive system, you’re going to see better health,” adds van der Veen.
The Unique Characteristics of Extruded Feeds
An extruded feed has several physical characteristics that give it digestive advantages:
Breaking strength. Extruded feeds break under just 10-15 pounds of pressure compared to pelleted feeds with average breaking strengths ranging from 23-28 pounds (and some upward of 35 pounds), Raub explains. A lower breaking strength facilitates ease of chewing, which is crucial for senior horses and those with dental issues.
Water dynamics. Extruded particles tend to draw up moisture faster than pelleted particles. If you soak pellets in water for about five minutes, for example, they’ll be wet, fluffy, and sticky on the outside but remain hard on the inside, says Raub. Extruded particles, on the other hand, will maintain their form without adhering to each other, but will have a mushy consistency throughout. Extruded feeds, therefore, can help prevent choke in at-risk horses.
Fewer fines. Fines are the small crumbles and dust-like particles that collect in a feed bag. “Even though those extruded particles are easier to break, pieces don’t break off as easily as with a pelleted feed,” says Raub. Extruded feeds will have fewer fines and might produce less wastage and tiny particulates that could irritate horses’ respiratory systems.
Density. Extruded particles are light, airy, and less dense than pelleted particles, meaning a pound of extruded product is going to have a greater volume for the horse to consume than a pound of pelleted product. “It will take longer for the horse to chew and consume that given pound of feed, and that’s a good thing,” says Raub.
All these elements contribute to increased digestive efficiency, which means you might be able to feed less concentrate while delivering the same amount of nutrients to the horse. “That leaves more room for hay in their diet, and that’s a good thing every day and twice on Sunday,” Raub adds.
Putting Science Behind the Product
While limited research has been conducted on extruded equine feeds specifically, we do have some insight as to how their form and function benefit the horse:
- Saliva flows from the horse’s salivary glands only during mastication, and sodium-bicarbonate-rich saliva acts as a buffering agent against gastric hydrochloric acid.
- Poor mastication and bolting feed can lead to esophageal obstruction.
- Prolonged mealtime can improve nutrient digestibility and gut motility as well as help prevent gastrointestinal disorders such as gastric ulcers and colic.
- Heat-based processing techniques like extrusion improve starch digestibility in the small intestine and might help prevent colic- and laminitis-inducing starch overload in the hindgut.
Raub and his team are adding to our body of knowledge. They’re conducting a study to assess horses’ jaw movements per pound of extruded feed versus pound of pelleted feed.
“Our hypothesis is that a horse is going to utilize more jaw movement per pound of extruded feed than a typical pelleted feed because it’s a greater volume for that horse to consume,” he explains. “They’re also going to take a little longer to consume that same amount of feed. If the horse takes longer to consume that concentrate portion, it may enhance digestive efficiency. And if they have to move their jaw more per pound of feed, it generates more saliva.”
The study horses will wear halters that measure and record jaw movement electronically. Raub’s team will use that data to assess the number of chews or jaw movements each horse makes while consuming an entire meal and also measure the time it takes the horse to consume a meal.
Take-Home Message
The extrusion process enhances digestibility and nutrient availability by breaking down complex carbohydrates and proteins into simpler, more easily absorbed forms. These feeds are particularly advantageous for horses with specific health concerns or needs, such as seniors or those prone to choke and gastric ulcers. As the body of research on extruded feeds grows, veterinarians can devise more informed nutrition strategies for their clients’ horses.
Click here to watch a video about how horses can benefit from extruded feeds.
This article originally appeared in “Feeding for the Future: Nutrition Knowledge for the Modern Equine Practitioner,” brought to you by Sentinel Horse Feeds. You can download the complete issue here.
References
- Alexander F. A study of parotid salivation in the horse. J Physiol. 1966 Jun;184(3):646-56. doi: 10.1113/jphysiol.1966.sp007937. PMID: 5963737; PMCID: PMC1357605.
- Harper, J. M. Food Extrusion. CRC Critical Reviews in Food Science and Nutrition. 1978. 11-2:155-215.
- Hintz, H. F., J. K. Scott, T. Hernandez, L. Shewokis. Extruded Feeds For Horses. Proceedings of the 1985 Cornell Nutrition Conference. 1985. p. 81-85.
- Rosenfeld, I., D. Austbo. Effect Of Type Of Grain And Feed Processing On Gastrointestinal Retention Times In Horses. J. of Animal Sci. 2009.87:3991-3996
- Sanchez LC. Disorders of the Gastrointestinal System. Equine Internal Medicine. 2018:709–842. doi: 10.1016/B978-0-323-44329-6.00012-7. Epub 2017 Nov 17.
- Siciliano PD. Nutrition and feeding of the geriatric horse. Vet Clin North Am Equine Pract. 2002 Dec;18(3):491-508. doi: 10.1016/s0749-0739(02)00028-7.
Related Reading
- Equine Nutrition Breakthroughs
- Managing EMS and ID Horses
- Storage’s Effects on Commercial Equine Grains
Stay in the know! Sign up for EquiManagement’s FREE weekly newsletters to get the latest equine research, disease alerts, and vet practice updates delivered straight to your inbox.