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
