Erica Larson and Sarah Ralston, VMD, PhD, Dipl. ACVN
Editor's note: This article is part of TheHorse.com's ongoing coverage of topics presented at the 2012 American College of Veterinary Internal Medicine Forum, held May 30- June 2 in New Orleans, La.
With feed and hay prices on the rise in portions of the country, some owners might need a more economical ways to feed their horses without skimping on nutrients. At a recent veterinary convention one researcher introduced a relatively uncommon and cost-effective feeding option.
Sarah Ralston, VMD, PhD, Dipl. ACVN, associate director of teaching at Rutgers University Equine Science Center and associate professor in the Department of Animal Sciences in the School of Environmental and Biological Sciences in New Brunswick, N.J., discussed forage-based total mixed rations (TMRs), their economics, and studies supporting their use in young horses. Her presentation took place at the 2012 American College of Veterinary Internal Medicine Forum, held May 30-June 2 in New Orleans, La.
In the interest of full disclosure, Ralston acknowledged that the producer of the original TMR products, Square Meals, Inc., supported her research program for seven years and that she serves as a consultant for the company.
What are TMRs?
Although TMRs aren't new, not all horse owners are familiar with the product. Ralston described the concept behind this grain-free or nearly grain-free diet. TMRs are already used extensively for food animals, cats, and dogs: "That bag of food you buy at the grocery store is basically a TMR for carnivores," she explained.
"Forage-based total mixed rations are made from mixtures of chopped and/or processed hays with minimal additives," Ralston said, noting that they can be formulated to meet or exceed any class of animal's nutritional needs in addition to free access to water and a salt block.
TMRs differ from "complete" feeds currently on the market in that they are chopped and compressed into loose biscuits or cubes that owners can essentially feed free-choice, Ralston said. She explained that pelleted or textured complete feeds must be fed in limited quantities and, because horses consume them more rapidly than TMRs, leave the horse with long stretches of time without access to feed if provided as the sole source of nutrition.
"This in turn can increase vices such as wood chewing and cribbing and increase the risk of gastric ulceration and colic," she said. "Based on discussions at the European Workshop on Equine Nutrition ... June 19-22, 2012, in Lisbon, Portugal, consensus had it that horses apparently need to chew for a significant portion of a 24-hour period, and they will seek to continue eating activity even after their nutritional needs are met by rations that are totally consumed in less than four to six hours."
Ralston said that if owners feed TMRs as designed--as horses' sole source of nutrition--then horses should consume at least 2% of their body weight daily through two or three feedings; however, many owners opt for free-choice feeding arrangements. This is especially convenient and effective when feeding large groups of horses, she said.
"The only problem noted to date is that initially the adult horses may overeat if fed free choice, resulting in weight gain that might be problematic for easy keepers," Ralston said, noting that horses will generally stabilize their free-choice TMR intake if fed at 2% of body weight for a month or so. "TMRs can also be used as 'hay stretchers' to supplement poor quality hay."
Ralston said advantages to feeding forage-based TMRs include:
- Easy handling (typically this product comes in 20 to 22 kilogram bags [about 44 to 49 pounds);
- Reduced feed waste (TMRs can be fed in a trough or bucket rather than on the ground or in a hay rack);
- Minimizes "peaks and valleys" in nutrient absorption seen with traditional hay/concentrate rations where concentrate meals cause sudden peaks in blood glucose/insulin that might be problematic in some horses; and
- Higher feed efficiency in the growth products (higher gain per calorie consumed).
Ralston has studied TMRs' safety and efficacy in young horses (Draft and Warmblood-cross weanlings and yearlings and mustang yearlings and 2-year-olds) for more than seven years.
"In the initial trials corn and/or oats were added to the TMRs but in the last three years no concentrates other than wheat bran (less than 5%) and a mineral/vitamin supplement were added to the formulation," she said. "Researchers at the University of Illinois have obtained similar results using young Standardbreds."
Overall, she said, results indicating TMRs are safe and effective for use in young horses have been encouraging. Important findings from the studies include:
- All studies found that the forage-based TMRs with or without added grains had a higher feed efficiency when compared to a traditional hay and grain diet;
- Developmental orthopedic disorder incidence was low in all studies and did not appear to be affected by either type of ration;
- No feed-related adverse effects such as wood chewing, choke, colic, or diarrhea were noted when the TMRs were fed free choice;
- The University of Illinois' Standardbred horses experienced reduced gastric ulceration when fed TMRs relative to standard rations; and
- There was no difference in trainability or reactivity to novel stimuli in a study of young mustangs when researchers added grain to the TMR formulation, suggesting that grains could be added as needed for weight maintenance and optimal performance if fed to horses with higher energy requirements, such as upper-level performance or hard keepers.
Feeding a TMR diet in 2009 cost horse owners about $4.26 per day, Ralston said, compared to about $4.18 for a diet consisting of hay and grain-based concentrate.
"However, the hay and concentrate horses also wasted 0.8 to 1 kilogram of hay per day, incurring an average loss of about $0.30 per day in wasted hay that should be added to the daily cost; there was virtually no waste with the TMR," she said.
Those responsible for handing the feed on a daily basis observed that it took less time to feed horses the TMRs than hay and grain, and the bags the rations came in were easier to store than hay bales, Ralston said.
"Depending on region, TMR rations are retailing in 2012 for between $12 to $18 per 20 kg bag," Ralston said. "With hay and grain prices soaring through the roof they are still competitive, especially at the lower prices."
Ralston said that forage-based TMRs are currently available in the Midwest and Western states from SquareMeals Inc., and on the East Coast from Blue Seal.
Ralston closed by saying that while TMR use in adult horses has not yet been studied, anecdotal evidence suggests that the prospect of feeding TMRs formulated for mature horses is equally encouraging.
"The use of bagged TMRs that can easily be transported and stored worldwide may be the most economic and practical answer for horse owners in tough economic and environmental conditions," she concluded. "It will take time for owners to get used to the idea of feeding only one product without hay, but it took over 10 years for people to accept pelleted feeds for horses in the '70s and '80s."
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.