Equine Research: A Question of Values

by Dr. Joseph Thomas & Crystal Leaman

Printed in: Natural Horse Magazine
Featured Article
Volume 10, Issue 2, 2008

The value of research with horses is in the advancement of our understanding of the diseases they endure so that we can find the most effective means to intervene and assist them. Within the world of research, there is an ethical question about the need to “sacrifice” some horses within the experimental design in order to discover ways to help the larger population. In other words, do the ends justify the means? If that is your horse being sacrificed, the answer is likely no. If that is a horse you don’t know and your horse is suffering from the malady under study, you may well say yes.

horse herbs healthOur intent in writing this article is to demonstrate that this choice does not need to be made. Although, traditionally science has chosen to “sacrifice” animals in the name of research and though that practice is still common, there are actually many other viable means to obtain the information we need to learn how to help our horses. It is not animal research that is the problem but rather the shortsightedness of some research that is so intent on isolating information that the lives of the horses within the design are considered expendable.

To us the core issue is the consideration of life as something that can be reduced to parts and studied solely in that respect. Such a perspective not only makes it seem acceptable to kill horses as subjects in research purporting to help horses, but also limits the value of the results such research can obtain.

Reductionism, Holism, or Both?

Over the last century science has pursued a course of reductionism to explain the complexity of life. In other words, scientists following this course have looked at smaller and smaller parts of problems in order to understand them. There is much to be learned through this approach and it has yielded some amazing information. But there is also a hazard as this approach lends itself to the distorted perception that life can be understood like a complex puzzle made of increasingly smaller pieces that just need to be understood so that the entire puzzle can be solved. The problem with this way of thinking and researching is that it easily loses sight of the complex whole through which the pieces interrelate. Life does not follow the same rules as puzzles. Instead it shifts and balances and compensates in order to sustain itself. So to understand one piece under one circumstance is rather like trying to understand ocean currents through an exact analysis of a drop of water.

This is the heart of the debate between the reductionist approach to research and the holistic approach. The former would decree that an understanding of a complex-life system is best explained by reducing them to their “simplest” units and the latter would pronounce that the whole is more than the sum of its parts. Reductionism alone in research not only can lose sight of the horse as a life but can also lose sight of the “world” that the horse lives in as an essential ingredient to what is being studied. Holism without consideration of the necessary factors involved in the issue being investigated can underestimate the value of key components involved in the underlying health problem.

Clearly a collaborative relationship in which the parts are researched and explored within the context of the whole is the best way to avoid the blinders imposed by either extreme.

In order to illustrate the real world differences that stem from these views, we present two recent research publications dealing with the same health concern in horses, i.e. “insulin resistance” and its relationship to laminitis. The first is a very clear example of pure reductionism and what can result from such an extreme approach to a research question. The second study presents a cooperative effort of reductionism and holism yielding the benefits of such an effort.

“The greatness of a nation and its moral progress can be judged by the way its animals are treated.” - Mahatma Gandhi

Reductionism example

We were disturbed by a recent study in which the design necessitated the killing of nine healthy ponies.[1] This research was conducted by a well respected scientific institution and the methods were appropriate to the information they were seeking. Their intent was to isolate the effects of elevated blood insulin on the laminae tissue of the hoof. Elevated blood insulin has been implicated in laminitis since 1983.[2] But this recent research was designed to isolate that variable from any metabolic dysfunction and demonstrate that elevated blood insulin in and of itself could be causational.

The design of this study involved the careful “removal” of all the influences that would have been present in the “real” life of a pony that does have high blood insulin levels. Hyperinsulinemia (high blood insulin levels) most frequently occurs in ponies as part of a metabolic disease process. Rather than having these metabolic and dietary influences as part of the study, the authors chose nine healthy young ponies so that these influences could not affect their results. Five of these ponies were injected with IV (intravenous) insulin for 72 hours while four other ponies received a placebo. The intent was to determine that this insulin influence could then be the sole explanation of the damage to the ponies’ hooves.

All the variables that might create a laminitic breakdown were methodically reduced to a single factor – externally induced excessive insulin levels in the blood. This control was insured by measuring, at determined time intervals, blood glucose levels and infusing the ponies with glucose to maintain a “normal” glucose concentration. In order to isolate the effects of elevated blood insulin this was necessary as the natural response of the body to increasing insulin levels is to “push” glucose from the blood into cells for energy “demands,” thereby reducing blood glucose levels.

The five ponies that received the insulin treatment endured the extreme pain of laminitis before being killed along with the four ponies that received the placebo. Their deaths were required by the research design so that their hooves could be removed and the hoof tissues could then be microscopically examined for the exactdamage.

This research design did demonstrate that elevated blood insulin in and of itself can cause laminitis. Yet it so effectively isolated the information that it is of little use in the real world for finding a cure or intervention strategy. It also shows the problem with any research that gets so focused on obtaining a result that the experience and lives of the horses used within it are disrespected.

Alternatives are Available

Research designs are limited only by the constraints of the imagination of the investigators and the ethical parameters accepted in the scientific community.

Although at present the sacrifice of horses for research is considered acceptable by the established community, there are major breakthroughs in equine research coming from designs that advance the understanding of horse health concerns and yet do not harm the horses being used as subjects.

Within the field of laminitis and the effects of insulin, there are many such alternative research designs. The following demonstrates a collaborative effort of reductionism and holism in that it both succeeds at studying the “simple” units of glucose and insulin and yet keeps both the information relevant to the real world and the horses under study well tended and well respected.

Collaborative example

This research began with a cooperative effort among the investigators by using an interdisciplinary approach to arrive at a more precise diagnostic measurement of insulin problems in horses.[3] The researchers considered insulin’s role and function by allowing the horses used as subjects to live in a “representative” pasture environment. Forty eight horses were chosen as subjects for this research from a diverse group of breed, sex, and health. The horses “were maintained on mixed grass-legume pasture and supplemented twice daily with feed high in sugar and starch, resembling a typical commercial sweet feed, or high in fat and protein.”[4] Maintaining the horses in a fairly normal environment within the study made the research results applicable to horses’ actual living conditions. None of the horses were harmed as part of this research.

The focus of this study was to determine if specific mathematical models (calculations) would yield accurate, precise, and valid measurements of insulin function and responsiveness before and after a glucose introduction. This procedure was used to mimic a fructan “trigger” such as would be obtained from grass, hay or dietary ingestion. The mathematical calculations were derived from base line blood “draws” taken before and after a single IV glucose infusion.
The mathematical models being studied offered a wealth of diagnostic information. One of these models was able to calculate the “functional” effectiveness of the pancreatic beta-cells (the cells that secrete insulin) in response to glucose. Since a primary role of insulin is to impel glucose into cells for energy this particular model could be used as a “predictive” measure of the relative health and function of beta-cells for a horse at any phase within the metabolic disease progression.

Another mathematical model calculated “insulin sensitivity” or how effectively glucose in the blood “enters” cells in response to a unit of insulin. This model can potentially demonstrate the relative strength and health of cells, including laminae cells.
To be certain that the particular models “tested” were valid, the investigators then performed the necessary statistical analyses to confirm that similar mathematical models currently being used in humans “agreed with” those performed with the horses. The statistics showed statistical significance for agreement between the horse and human mathematical models.

Simply put, this study’s results could eventually allow veterinarians to “track” a horse’s sensitivity and ability to “deal with” a fructan and carbohydrate ingestion over time and follow the horse’s progression with the underlying disease process that, were it continued, would result in laminitis. The development of this simple diagnostic tool could be used as a measurement of risk factor over time.

We feel that this research investigation displays the creativity needed to reap multiple benefits. Its design approach incorporates reductionism and holism, which can eventually benefit a vast number of horses – beginning with the horses used as subjects in the study itself. The only procedures performed on the horses in this study were two blood draws and a glucose infusion of short duration so that no harm was done to them. Yet the results not only demonstrate concurrence with similar models used with people, they may also be key to the development of a good diagnostic tool for horses.

Concluding Remarks - Our View

Rather than considering the “sacrifice” of horses as necessary to further research into equine disease, we believe that it limits both the value and the results of equine research.

By reducing the concept of life into parts, the value of the horses used as subjects and the understanding of the dynamic process of disease are lost. Values in equine research depend on both the quality of the research and the humane treatment of the horses used as subjects. No choice needs to be made between these values. When both of these values are held to the line, researchers develop new designs that respect the life of the horse and provide a wealth of information.


About the authors:

Crystal Leaman and Joseph Thomas, Ph.D., along with their daughter, Allison Thomas, created For Love of the Horse, LLC, aNatural Herbal Horse Health Care Company. Dr. Thomas is the herbalist of precise, sophisticated Chinese herbal solutions as well as being deeply steeped in research and development. Crystal Leaman is the editor and General Manager.

(Acknowledgement: The authors would like to thank Valerie Burgess, graphics arts designer of For Love of the Horse, for her incredible art work, again.)


  • Asplin, K.E., Sillence, M.N., Pollitt, C.C., et.al., Induction of laminitis by prolonged hyperinsulinemia in clinically normal ponies. The Veterinary Journal (2007),doi: 10.1016/j.tvjl.2007.07.003.
  • Coffman, J.R., Colles, C.M., (1983), Can J Comp Med: 47: 347-351.
  • Treiber, K.H., Kromfeld, D. S., Hess, T.M., et.al. Use of proxies and reference quintiles obtained from minimal model analysis for determination of insulin sensitivity and pancreatic beta-cell responsiveness in horses. (2005) Amer J Vet Res, Vol 66, No. 12, 2114-2121.
  • Ibid, p. 2115