Equine Disease Quarterly | EQUINE
tissues other than the pituitary, including ovarian
tissues and the corpus luteum, but the roles of those
receptors in fescue toxicosis, if any, have not been
fully elucidated. The drug domperidone is frequently
used in broodmares that are exposed to KY31 fescue
and prevents or reverses the adverse reactions of
ergovaline. Domperidone functions by binding to
dopamine receptors, but rather than suppressing
prolactin production, it competes with dopamine and
allows for normal prolactin secretion.
Because of the adverse health effects of common
endophyte infected fescue in grazing animals, varieties
of tall fescue which do not contain the fungal endophyte
have been identified. Even though these endophyte-
free varieties do not produce ergot alkaloids, animal
performance is excellent. However, the plants do not
persist well in pastures or compete well with other
pasture grasses. More recently, endophyte strains that
do not produce the alkaloids that are harmful to animals
but still confer vigor and persistence to the plant, have
been identified and inserted into tall fescue. These are
called novel endophyte varieties of fescue, and some
of these are commercially marketed as “Jesup Max
Q,” “Texoma Max QII,” and “Baroptima Plus E34.”
More recently, “Lacefield Max QII” was released by
Dr. Tim Phillips in the Department of Plant and Soil
Sciences at the University of Kentucky. The Alliance
for Grassland Renewal is an association of seed
companies, universities, and government agencies
that regulate themselves by establishing certain quality
control standards for novel endophyte tall fescues. For
example, all seeds sold under the Alliance tag must be
95% pure, have 70% live (viable) endophyte, and have
independent confirmation that the fescue variety does
not cause fescue toxicosis in animals and will persist
well under conventional grazing conditions.
Although this article emphasizes the effects of ergot
alkaloids on a dopaminergic receptor, it is important to
remember that some of the alkaloids also bind to other
receptor types, including adrenergic and serotonergic
receptors, and thus may affect additional body systems.
CONTACT:
Karen McDowell, PhD
[email protected]
(859) 218-1104
Maxwell H.Gluck Equine Research Center
Tim Phillips, PhD
Department of Plant and Soil Sciences
University of Kentucky
Lexington, KY
Equine Abortion: A Review of the 2016 and
2017 Breeding Seasons in Kentucky
The loss of a developing fetus during pregnancy can be
a frustrating, emotional, and costly experience for horse
owners, farm workers, veterinarians, and the public. A
thorough evaluation of the aborted fetoplacental unit
(fetus and placenta) by a veterinary pathologist can help
determine the cause of abortion, identify new, unusual,
or foreign causes of fetal loss, rule out involvement
by infectious agents, and aid in the epidemiologic
monitoring of abortifacients (factors that can result in
abortion). A two-year review of equine abortions, from
the 2016 and 2017 breeding seasons, was conducted
at the University of Kentucky Veterinary Diagnostic
Laboratory to evaluate current abortion trends.
Dates listed below indicate data for the respective
breeding season, not calendar year.
A total of 898 cases of equine abortion, 570 from 2016
and 328 from 2017, were evaluated. The majority of
cases were considered sporadic and unrelated, except
for one equine herpesvirus 1 abortion storm that was
identified during the 2016 breeding season. Abortions
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