Research

Updates on research funded by the Animal Health Foundation

Dr. Chris Pollitt
Dr. Chris Pollitt continues to build on his work with laminin-5, the key molecule responsible for attaching the inner hoof wall to the coffin bone. In 2005, Pollitt reported on how laminin-5 affects the normal enzymatic remodeling of the hoof wall that allows it to grown down past the stationary coffin bone; laminitis occurs when these enzymes go out of control. Pollitt said that, during the development phase of laminitis, laminin-5 is cleaved into fragments, and these fragments are extremely potent activators of key enzymes.

In 2006, Pollitt and his team of scientists continued to investigate this process and how the findings can be used practically in the field. While their research can’t be released before it is presented, Pollitt says it may lead to a long-awaited breakthrough: “We are on the threshold of developing preventive and treatment strategies for laminitis.” For more on Pollitt's research, go to http://www.laminitisresearch.org/.

Dr. Philip Johnson
Dr. Philip J. Johnson of the University of Missouri-Columbia is studying how external forces on a hoof, such as excessive weight bearing, affect the functions of specific cells. His research topic has become more high profile in light of Barbaro's development of laminitis in his "good" hind foot. Johnson's study, similar to Pollitt's, examines the enzymes responsible for the detachment of the hoof from the coffin bone during laminitis.

Johnson continues to explore methods to study laminitis without working on live horses and, to that end, has developed the cultivation of equine skin cells from healthy horses and investigated their response to bacterial toxins implicated as one of the causes of laminitis. These results were presented at the 2005 veterinary internal medicine meeting and stimulated a great discussion.
Johnson also has continued to investigate the biochemical processes that go on in the horse's fat and liver tissues. These processes play an incredibly important role in the regulation of blood sugar. Dysregulation of blood sugar control in obese horses is regarded as an important risk factor for laminitis. It appears, from Johnson's preliminary resuts, that there are clear differences between laminitic horses, obese horses and normal (lean) horses.

Johnson's goal is to develop and describe simple diagnostic tests that may be useful to veterinarians in making a distinction between horses at risk of laminitis and those less at risk, expecially among the obese group.

Johnson also has been studying the brain of obese horses versus fat horses to better understand how obesity affects fat composition and appetite.

Kathryn Watts
Kathryn Watts has continued to study how various elements affect the sugar content of hay and grass, as well as the most accurate way to test that sugar content. Proper sample selection and handling make test results more trustworthy, she says. After sending several grass samples to a lab under different shipping conditions, Watts found the less ideal the shipping, the lower the sugar content appeared to be, thus giving horse owners a false sense of security in their forage. Watts emphasizes that sugar content of grass hay is not related to color, texture, amount of stem or age of the haystack. The only reliable gauge is to get hay tested.
Kathryn Watts, an agricultural researcher and crop consultant in Center, Colo., has continued to study how many elements affect the sugar content of hay and grass and the most accurate way to test that sugar content.

She says proper sample selection and handling go a long way to make test results more trustworthy.

Suggestions include: freezing fresh grass samples immediately and shipping them fast and frozen; and sampling 15 to 20 bales of hay with a hay probe to get a better reading of the whole load.

With grass, Watts says that gathering grass from the area that's most enticing to one's horse is important, rather than a random sample from a pasture. Watts tested how temperature and amount of time shipping can affect results, with the answer being significantly. The less ideal the shipping conditions, the lower the sugar content appeared to be, thus giving horse owners a false sense of security in their grass.

She also debunks the myth that hay high in fiber is low in sugar. Hay high in fiber also can be high in sugar.

Lastly, she emphasizes that sugar content of grass hay is not related to color, texture, amount of stem or age of the haystack. Also, the nonstructural carbohydrate content of well cured, properly stored hay will not change over time. The only reliable way to choose appropriate hay for your horse is to get it tested.

Hay likely to be higher in nonstructural carbohydrates includes:
  • Hay cut after drought or cold nights, especially under a sunny sky.
  • Thin sparse stands of grass that have more sunshine on every leaf.
  • Hay grown under growth-limiting levels or nitrogen, phosphorous or potassium, as in hay that was not fertilized.
  • Hay made from cereal grains, such as oat, wheat, rye or barley, even if the grain is not developed yet. The stems collect sugar in preparation for seed development.
Watts' results were published in The Horse magazine.

For more information, visit Kathryn's website: http://www.safergrass.org/