*Dr. Joe D. Pagan is president and founder of Kentucky Equine Research Inc., which, through consultation and research, aims to bridge the gap that may exist between basic research and horse production.
IN 2013, Kentucky Equine Research (KER) will celebrate its 25th anniversary as an equine nutrition research and consultation company.
During the past quarter-century, several advances have been made in the field of equine nutrition and feed manufacturing.
To kick off this important milestone year, I would like to review what I feel are five of the most important advancements that have been made in the field of equine nutrition and predict what's ahead for the industry.
In the mid-1980s, a landmark study was published by researchers at The Ohio State University in which a correlation was found between the level of copper in a breeding farm's ration and the incidence of metabolic bone disease in the farm's foals.
Metabolic bone disease (later renamed developmental orthopedic disease) is a major problem for many horse breeders that causes huge economic losses due to lameness in performance horses.
Following this study, researchers around the world concentrated on finding the link between trace minerals -- particularly copper and zinc -- and bone development.
One important study from New Zealand demonstrated that trace mineral nutrition of the pregnant mare also affected subsequent bone health in her foal.
Since then, the feed industry has universally embraced the importance of trace mineral fortification for broodmare and foal feeds, and high levels of copper and zinc have become standard.
Although carbohydrates make up the majority of most horse feeds, historically little was known about their chemical composition or metabolic effects in horses.
For more than 100 years, the feed industry depended on the proximate, or Weende, system of feed analysis to estimate the carbohydrate content in horse feed. This system did a poor job of measuring the types and amounts of sugar and starch present.
Along with advancements in carbohydrate chemistry came a huge amount of research that studied the effect of starch type and processing effects on the digestibility and utilization of starches and sugars from different sources. This research proved that starch from various cereals was very different and that grain processing greatly affected starch digestibility.
In addition, it was discovered that the glycemic nature of a feed had profound effects on bone metabolism, behavior and exercise performance.
The time of feeding in relation to exercise was also determined to be important. Today, the glycemic index of various feedstuffs is known, and this information is used in feed formulation.
Alternative energy sources
The last 25 years have seen a large shift away from starch and sugar as the only energy sources in horse feeds.
Adding fat to horse feeds became popular in the 1980s, and there have been dozens of studies since then that have focused on feeding fat to performance horses. Several of these studies showed that horse muscle can be trained to burn fat instead of carbohydrates, resulting in a glycogen sparing effect and improved endurance capacity.
The early work with fat supplementation used a variety of different vegetable oils and animal fat without paying much attention to the fatty acid composition of the fat source.
This has changed recently with the recognition of the importance of omega-3 polyunsaturated fatty acids (PUFAs) in horse diets. Optimal levels of omega-3 PUFAs have been shown to reduce inflammatory responses, support immune function and enhance fertility.
Continuing research is revealing more information about the benefits of supplementing horses with omega-3 fatty acids to achieve a more nutritionally sound balance.
In addition to fat, fermentable fiber has become an important component of performance horse feeds. Fermentable fiber includes galactans, fructans, gums, mucilages and pectin. They are not degraded by digestive enzymes but are rapidly and completely fermented by gastrointestinal microflora, yielding volatile fatty acids, which are versatile energy substrates for performance horses.
The most common sources of fermentable fiber are sugar beet pulp and soy hulls. These raw materials are now common ingredients in most performance horse feeds.
Nutrition and disease
Several metabolic disorders have become common in modern breeds of horses. Recent research has demonstrated that many of these disorders -- such as equine Cushing's disease, equine metabolic syndrome, osteochondritis dissecans, recurrent equine rhabdomyolysis (RER) and polysaccharide storage myopathy -- can be managed nutritionally by careful regulation of caloric intake while paying particular attention to the source of energy provided.
Although these disorders have very different etiologies, they are all either triggered or aggravated by excessive starch and sugar intake.
RER is a specific form of tying-up seen in Thoroughbreds, Standardbreds and Arabians. It is an inherited trait caused by abnormal intracellular calcium regulation during muscle contraction. Excitement and stress seem to be triggers.
Studies conducted at the University of Minnesota in conjunction with KER showed that replacing much of the grain in the diet with a low-starch, high-fat feed will significantly decrease the amount of muscle damage in RER horses. This research lead to the development of Re-Leve, the first commercial horse feed produced to manage a specific metabolic disorder. Since then, a number of reduced-carbohydrate feeds have been developed for a variety of special needs.
The past quarter-century has seen a great increase in demand for well-fortified horse feeds in both the performance and breeding sectors of the horse industry. Much of this increase has resulted from technological advances that have allowed feed manufacturers to illustrate the importance of including fortified feeds in a horse's ration.
Rather than relying on feed tags or brochures with limited nutrition information, horse feed companies now have access to sophisticated software that graphically illustrates how each feedstuff in a ration meets a specific horse's nutrition requirements.
KER released the first version of its computer-based equine nutrition evaluation software called MicroSteed in the early 1990s. Since then, MicroSteed has migrated onto the internet, where horse managers can use their smartphones to evaluate their horses' rations and receive detailed technical support without leaving the barn aisle.
What does the future hold for the equine nutrition field?
Certainly at the top of the list is nutrigenomics, the study of the effects of feeds and feed constituents on gene expression. By understanding how nutrients interact with the genome, better dietary regimens may be designed, or novel treatment of important diseases may be addressed.
The emergence and development of nutrigenomics have been possible due to powerful developments in genetic research. These tools are already being used in horses, and they will certainly become a major tool for equine nutrition research in the future.
Finally, I believe that there will be a great demand for alternative ingredients for horse feeds in the future. As human population growth continues to increase, demand for cereal grains and oilseeds for human consumption will place added pressure on the livestock industry to look at alternative feedstuffs. Co-products from human food production will become attractive future ingredients for horse feed.