Equine Nutrition Program
The University of Kentucky has been
long known as a leader in equine research. Most equine research
is conducted within the College of Agriculture, either in
the Department of Veterinary Sciences or in the Department
of Animal Sciences. Researchers in the Department of Animal
Sciences have concentrated their efforts in the area of
equine nutrition and feeding management. The equine nutrition
program began more than 25 years ago and continues to be
very active. Most nutrition research is conducted at the
Department of Animal Sciences Horse
Farm on Maine Chance Farm. Laboratory facilities are
available on campus. The horse farm, located on Newtown
Pike, encompasses approximately 100 acres and maintains
a group of about 60 horses. Included in the horse herd are
Thoroughbred and Quarter Horse broodmares, their foals,
three stallions and about a dozen Thoroughbred geldings
used for exercise studies. In addition to being used for
research, the farm is also heavily utilized for teaching
activities within the undergraduate Animal Sciences program
in the College of Agriculture and provides animals for a
number of extension activities as well.
An important component of this program is the training of
graduate students in equine nutrition. Both M.S. and Ph.D.
programs are available. Approximately 4 to 6 students are
enrolled in the equine nutrition program at any one time,
and competition for admittance is fairly competitive. To
be eligible for admission, students must have completed
a B.S. degree in Animal Science or a related field. Once
enrolled, graduate students complete course work in nutrition,
statistics, physiology and biochemistry. All graduate students
in the Department of Animal Sciences complete a research
project and write a thesis. Research topics are designed
to accommodate the student's interests and to be compatible
with available funds and animal resources. Graduate students
are encouraged to present their results at scientific meetings
and to publish their research in scientific journals. The
University of Kentucky has always been successful in attracting
high quality graduate students to the equine nutrition program
and research conducted by graduate students at the University
of Kentucky has received national and international recognition.
UK graduates hold positions at numerous universities and
in companies associated with the feed industry.
PROGRAM OVERVIEW
Nutrition of Mares and Foals
Optimal management of broodmares and growing foals is an
important aspect of producing athletic horses. Our research
investigates the roles that nutrition and feeding management
play in optimal mare and foal management. The weaning period
has been identified as a time of psychological and nutritional
stress for foals. We have documented that many foals experience
a depression in growth rate immediately following weaning.
However, in our studies, age at weaning did not affect the
degree of growth depression observed. Thus far our findings
indicate that waiting to wean at an older age (6 months
vs. 4.5 months) is not an advantage. Current studies are
examining nutritional management techniques that may minimize
disturbances in growth during the post-weaning period.
In the area of broodmare nutrition, our research is addressing
the mineral needs of mares during late gestation and lactation.
We are particularly interested in how nutrition of the mare
in late gestation and during lactation affects the foal.
A recent study found that feeding an organic form of selenium,
an essential trace mineral, increased milk selenium concentrations
and also improved selenium status in foals compared to an
inorganic selenium source, sodium selenite. We are currently
examining whether indicators of selenium status decrease
in foals during severe illness. Another area of interest
is understanding the effects of pregnancy and lactation
on the nutrient requirements of broodmares. In other species
females often mobilize calcium from the skeleton to meet
the needs of gestation and lactation. We are investigating
whether this response occurs in mares, and if so, whether
the diet can impact this process.
Digestive Physiology and Feeding
Management
Little is known about the time-course of the development
of the fiber digesting bacterial population in the large
intestine of the foal. Understanding how well growing foals
digest common feeds, including pasture and forage, is important
to formulating optimal diets. Currently most digestibility
assessments of feeds have been performed using adult horses.
We are using in vitro techniques to assess fiber digesting
capacity in foals, and future research will investigate
in vivo techniques as well. Preliminary studies suggest
that the microbial population of the foal’s gastrointestinal
tract is established within the first few weeks of life.
However, it is not known whether high fiber feeds are retained
long enough in the foal’s gastrointestinal tract to allow
the same level of digestion as in an adult horse’s digestive
tract.
Providing diets that meet nutrient needs
but minimize metabolic and digestive disturbances should
be the goal of any feeding program. Several projects have
investigated how different concentrate feeds affect glucose
and insulin responses in horses. Included in this area are
studies into equine feed preferences and the effects of
processing on mixed grain feeds. Future research will compare
the feeding values of different fiber and protein sources
in horses.
Nutrition of the Performance Horse
This program focuses on dietary interventions
that can help performance horses reach and maintain optimum
form. Several projects have evaluated methods for enhancing
fluid balance in horses exercising for extended periods.
Our findings suggest that high fiber diets help horses consume
and retain more water for use during exercise. Projects
conducted in our program have examined the effects of vitamin
supplementation on exercise metabolism and muscle integrity.
Two vitamins that have been studied so far are niacin and
vitamin E. High levels of niacin supplementation did not
affect metabolic or heart rate response to exercise. Supplementation
of vitamin E at levels beyond the current recommendation
increased vitamin E status in exercising horses but did
not have any detectable effect on indicators of exercise
induced muscle damage. We have also investigated the effects
of omega-3 fatty acids on exercising horses.
Forage Preferences and Grazing Research
Working in cooperation with faculty members in the Department
of Agronomy we are evaluating the tolerance of many pasture
grasses to heavy grazing by horses. This information can
be used by horse farm managers to make choices regarding
the best type of plant to seed into their pastures. We are
also examining the effects of a variety of tall fescue that
is infected with a novel endophyte. The novel endophyte
is believed to convey hardiness to the plant, but not cause
the negative animal effects often observed with common endophyte
infected tall fescue. Our research program is also investigating
the factors that affect the consumption of various hays
by horses. We have studied cool season grasses, some legumes
and a few native warm season grasses. Specifically we would
like to be able to predict daily hay consumption from measurements
of chemical composition or other variables. Understanding
the factors that affect hay consumption by horses will allow
us to more accurately balance rations and also reduce wasted
hay.
More information about specific projects
is available in the section labeled “Equine Nutrition Updates”.
Anyone interested in the equine nutrition
program should contact:
Laurie
Lawrence, Ph.D.
Professor, Department of Animal Sciences
905 W. P. Garrigus Building
University of Kentucky
Lexington, KY 40546
llawrenc@uky.edu
