Method of treating fescue toxicosis with domperidone

A novel method for using domperidone, a dopamine receptor antagonist, for treating fescue toxicosis in animals is provided. Fescue toxicosis is caused by animals grazing on endophyte-infected fescue grass. Treatment of the animal with various dosages of domperidone results in effective management of the toxin. The domperidone treatments do not cause any substantial adverse behavioral or neurological side effects in the animal. Domperidone is a more effective treatment for fescue toxicosis than previously-known agents such a metoclopramide and sulpiride.

FIELD OF THE INVENTION 
A process for treating and preventing fescue toxicosis in animals with 
domperidone is provided. 
Background of the Invention 
Tall fescue grass (Festuca arundinacea) is the pasture grass of choice in 
most humid, warm weather areas of the United States. Tall fescue is also 
used for various other purposes such as ground cover, parks, lawns, along 
waterways, and other areas where a quick-growing and durable grass is 
needed. Fescue is easily established, has a wide range of adaption, allows 
animals to graze for longer periods of time when used as pasture grass, is 
tolerant to abuse, is resistant to most pests, has good seed production, 
and exhibits a generally acceptable overall appearance. 
Animals that feed on fescue, however, often suffer from fescue toxicosis. 
Fescue toxicosis is caused in animals by consuming endophyte-infected tall 
fescue. The particular endophyte is known as Acremonium coenophialum. 
Symptoms of fescue toxicosis in animals include (1) fescue foot, which is 
a gangrenous condition of the feet and/or tails, (2) summer syndrome, 
which is characterized by poor animal weight gains, intolerance to heat, 
excessive salivation, nervousness, dramatically reduced weaning weights, 
lower milk production, and a reduced pregnancy rate, and (3) bovine fat 
necrosis, which is characterized by hard fat masses and abdominal fat 
tissue deposits that cause poor digestion and calving problems. Other 
known symptoms include (4) agalactia, which is nonsecretion of milk 
following childbirth, (5) prolonged gestation, (6) weak or stillborn 
offspring, (7) retained placentas, (8) thickened placental tissue, (9) 
dystocia, and (10) rebreeding difficulties. In animals experiencing such 
symptoms, researches have observed decreased serum prolactin and 
progesterone levels. 
As mentioned above, fungus growing on the fescue is the generally 
documented cause of fescue toxicosis in animals. Studies have shown that 
animal performance is greatly increased if they graze on low endophyte 
fescue as opposed to high endophyte-infected fescue. Generally, fescue 
toxicosis has been avoided in the past by shifting cattle from high to low 
endophyte-containing pastures. 
Various dopamine antagonists have recently been examined as possible 
treatments for fescue toxicosis in both horses and cattle. Metoclopramide, 
a substituted benzamide related to sulpiride, has been shown to increase 
serum prolactin levels in animals consuming endophyte-infected tall fescue 
as shown in U.S. Pat. No. 4,880,632 to Lipham et al. Perphenazine, a 
phenothiazine derivative, has been used to treat fescue toxicosis induced 
by injection of bromocriptine. 
Although both drugs offer some promise in treating the symptoms of fescue 
toxicosis, both drugs have the potential to produce various neurological 
side effects because they bind to central dopamine receptors. 
Metoclopramide has been shown to produce nervousness, listlessness, 
restlessness and depression in dogs, and can cause constipation with 
longterm use. Perphenazine is no longer used in quinine veterinary 
practice because it produces excitatory reactions in horses similar to 
those seen with chlorpromazine. Horses treated with chlorpromazine are 
generally sedated for the first few minutes after administration and then 
become unsteady, sinking backward on the hocks. Horses may then stumble 
and fall, followed by lunging and rearing. These types of side effects are 
undesirable for drugs used for longterm therapy in horses due to the high 
risk of injury to the horse and/or handler. 
Additionally, as indicated in U.S. Pat. No. 4,880,632, various research has 
been conducted indicating that these and other D.sub.2 specific dopamine 
antagonists may be employed as active agents for treating or preventing 
fescue toxicosis in animals. As described in U.S. Pat. No. 4,880,632, the 
D.sub.2 specific antagonists that may be used to treat or prevent fescue 
toxicosis are those that cause minimal neurological and psychological 
adverse side affects in the animals. The patent describes and lists the 
above-mentioned substituted benzamides, such as metoclopramide, sulpiride, 
tiapride, and alizapride, as the preferred and available D.sub.2 
antagonists that may be used. Specifically, the U.S. Pat. No. 4,880,632 
patent indicates that dopamine antagonists which exhibit psychotropic, 
neuroleptic or adverse neurological actions in animals must be avoided. 
The patent also touts metoclopramide as being the preferred treatment for 
fescue toxicosis. Among the drugs listed in the U.S. Pat. No. 4,880,632 
patent as being an ineffective treatment for fescue toxicosis due to its 
psychotropic or neuroleptic side effects is domperidone. Specifically, the 
U.S. Pat. No. 4,880,632 patent states that domperidone exhibits 
sufficiently adverse behavioral effects in animals that it would be 
eliminated from use in the prevention or treatment of fescue toxicosis. 
The patent states that this is not surprising because domperidone falls 
within compound groups known to have neuroleptic effects that were 
originally developed for anti-psychosis therapy, including phenothiazines, 
butyrophenones, and thioxanthenes. The U.S. Pat. No. 4,880,632 patent also 
states that domperidone is thought to be specific for D.sub.1 receptors or 
a combination of D.sub.1 and D.sub.2 receptors. The patent fails to recite 
any examples or studies conducted by the Applicants in which domperidone 
was employed to treat fescue toxicosis. 
Although various D.sub.2 dopamine receptor antagonists have been employed 
to treat or prevent fescue toxicosis, domperidone has been viewed as an 
unacceptable drug for such treatment. Metoclopramide and sulpiride have 
been disclosed as treating fescue toxicosis, but domperidone has been 
considered as causing many behavioral and neurological side effects and, 
thus, has been avoided. The prior art does not suggest that domperidone 
could be employed as an effective agent in the treatment of fescue 
toxicosis. In fact, the prior art teaches that such treatments are 
discouraged and should be avoided. The present invention overcomes the 
shortcomings of the prior art in that a process for using domperidone to 
treat and prevent fescue toxicosis in animals without substantial side 
effects is employed. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a method for preventing 
and/or treating fescue toxicosis with domperidone. 
It is a further object of the present invention to provide a D.sub.2 
dopamine receptor antagonist for treating fescue toxicosis in animals 
while avoiding substantial adverse behavioral and neurological side 
effects. 
It is further another object of the present invention to provide a process 
for employing domperidone to effectively treat and/or prevent fescue 
toxicosis in farm animals grazing on endophyte-infected fescue grass. 
Generally speaking, the present invention is directed to a method for 
treating and/or preventing fescue toxicosis caused by animals grazing on 
endophyte-infected fescue grass. The process employs the D.sub.2 dopamine 
receptor antagonist domperidone in such treatments. Domperidone has 
heretofore been avoided in such fescue toxicosis treatment due to common 
knowledge that domperidone would produce adverse behavioral and 
neurological side effects in the animals. Broadly speaking, the present 
composition may be administered to farm animals, including cattle and 
mares, in varying doses to obtain an effective treatment for fescue 
toxicosis and prevention of the disease without creating the previously 
reported behavioral side effects.

DESCRIPTION OF PREFERRED EMBODIMENTS 
In studies directed to the present invention, the ability of domperidone to 
reverse adverse effects on prolactin treatment as compared to sulpiride 
was determined after attaining the following information: (1) the effects 
of ergovaline or loline on in vitro pituitary prolactin secretion; and (2) 
the activity of these alkaloids at the D.sub.2 dopamine receptor using two 
selective D.sub.2 dopamine receptor antagonists. 
Recently, the ergopeptine (e.g., ergovaline) and loline-derivative (e.g. 
N-formyl loline and N-acetyl loline) alkaloids produced in 
endophyte-infected tall fescue have received much attention as possible 
causative agents of fescue toxicosis. One symptom consistently observed in 
animals consuming endophyte-infected tall fescue is hypoprolactinemea. 
Based on these observations, Examples 1-4 provide exemplary studies 
wherein a bioassay with rat anterior pituitaries was developed to study 
the effect of individual alkaloids produced by the endophyte on prolactin 
secretion in vitro; a cell culture bioassay was used to study the effects 
of ergovaline and loline on pituitary prolactin secretion in vitro; the 
site of action for these alkaloids was investigated indirectly using 
D.sub.2 dopamine receptor antagonists; and, finally, domperidone was 
studied as to its efficacy to reverse the inhibitory effect of 
.alpha.-ergocryptine on prolactin section in vitro and then compared to 
sulpiride's ability to do the same. 
Example 1 
Anterior pituitaries were collected from several 225 to 250 gram male 
Wistar rats. Anterior pituitary cells were dispersed with a trypsin 
enzymatic digestion and counted using a hemocytometer made by CMX of 
Houston. The trypan blue exclusion assay was used to determine pituitary 
cell viability. 
Cells were plated into 24 well Falcon Primaria culture plates made by 
Becton Dickison of Lincoln Park, N.J., at a density of 1.0.times.10.sup.4 
live cells per well for Example 2 below and 1.0.times.10.sup.5 live cells 
per well for Example 3 below. Cell cultures were incubated (37.degree. C., 
5% CO.sub.2, 100% humidity) in culture medium until monolayer formation 
was achieved (approximately 7 days). Culture medium consisted of 90% 
Dulbecco's Modified Eagle's Medium ("DMEM") from Sigma of St. Louis, 
Miss., 7.5% horse serum from Sigma, 2.5% fetal calf serum from Sigma, 25 
mM HEPES from Sigma, 2.5 .mu.g/mL amphotericin B from Sigma, 100 .mu.g/mL 
of penicillin from Sigma, 100 .mu.g/mL of streptomycin from Sigma and 1.0 
.mu.g/mL of insulin. Monolayers were then exposed to their respective 
treatments. 
Example 2 
Treatments for this example included: (1) loline 2HCl supplied by R. G. 
Powell, USDA, ARS of Peoria, Ill.; (2) .alpha.-ergocryptine from Sigma; 
(3) ergovaline from Sandoz Pharmaceuticals of Bezel, Switzerland; and (4) 
dopamine HCl from Sigma at three concentrations each of 10.sup.-4, 
10.sup.-6, and 10.sup.-8 M. Dopamine (a catecholamine) and 
.alpha.-ergocryptine were used to verify that the control mechanisms for 
inhibitions of pituitary cell prolactin section were intact. Additionally, 
cells were exposed to domperidone obtained from Janssen Pharmacueticals of 
Belgium and sulpiride from Sigma at 10.sup.-6 M concentrations each. 
Dopamine HCl and loline 2HCl were solubilized with 70% ethanol. 
.alpha.-Ergocryptine was solubilized in absolute ethanol and ergovaline 
was solubilized in acidified absolute ethanol (0.02N HCl). Domperidone and 
sulpiride were solubilized in 0.9% saline. The concentration of D.sub.2 
dopamine receptor antagonist (domperidone and sulpiride) or alkaloid 
carrier in treatment medium was 0.3%. All treatments were initially 
replicated four times. Controls consisted of four replicates each with no 
D.sub.2 dopamine receptor antagonist/no alkaloid, domperidone/no alkaloid 
and sulpiride/no alkaloid. No carrier controls were performed because 
preliminary experiments had established that ethanol at 0.3% of the 
culture medium had no effect on prolactin secretion in vitro. 
For one hour preceding treatment, exposure cells were incubated in 1 mL of 
DMEM to determine baseline pituitary prolactin secretion. After the 
pretreatment period, the medium was removed from the wells, spun (300 
grams .times.15 min), and placed into individual 12.times.75 mm glass 
tubes for storage at -20.degree. C. until a prolactin (PRL) 
radioimmunoassay (RIA) could be performed. 
Cells were then incubated for 3.5 hours in 1 mL of DMEM containing the 
particular D.sub.2 dopamine receptor antagonist and alkaloid treatments. 
D.sub.2 dopamine receptor antagonist treatments were placed into the 
appropriate wells at the beginning of the treatment period and incubated 
for 30 minutes. Immediately following incubation, the alkaloid treatments 
were added and the cells were again incubated for another 3 hours. 
Subsequently, the treatment medium was removed, spun (300 grams .times.15 
min) and placed into individually labeled 12.times.75 mm glass tubes for 
storage at -20.degree. C. until assayed for prolactin. 
Both baseline and treatment cell prolactin secretion were adjusted for 
milligrams of total cell protein in a well. Eight untreated wells were 
used to determine total cell protein in a well. Total cell protein per 
well was determined before and after the treatment period using a 
Coomassie dye binding assay bovine serum albumin as a standard obtained 
from a protein assay kit of Biorad of Richmond, Calif. 
Example 3 
Experimental procedures for Example 3 were performed as described above 
with respect to Example 2. Cells were pre-exposed to domperidone and 
sulpiride at concentrations of 10.sup.-5, 10.sup.-7, 10.sup.-8, 10.sup.-9 
and 10.sup.-10 M for 30 minutes prior to the addition of 
.alpha.-ergocryptine at 10.sup.-8 M. Cells were then incubated an 
additional 3 hours. Treatments were made with domperidone and sulpiride at 
10.sup.-5, 10.sup.-7, 10.sup.-8, 10.sup.-9, and 10.sup.-10 M 
concentrations in competition with .alpha.-ergocryptine at 10.sup.-8 M. 
Controls consisted of no carrier, drug carriers and .alpha.-ergocryptine, 
with and without drug carriers. .alpha.-Ergocryptine was solubilized in 
absolute ethanol; domperidone was solubilized in absolute ethanol; and 
sulpiride was solubilized in 5% glacial acetic acid. Carrier solutions for 
domperidone and sulpiride were altered in this example to facilitate the 
higher drug concentrations needed. Treatments were added as in Example 2 
to restrict the carrier solution of each treatment to 0.3% of the medium. 
Example 4 
Prolactin radioimmunoassay was performed using materials and methods 
supplied by the National Hormone and Pituitary Program and the National 
Institute of Diabetes and Digestive and Kidney Diseases. Iodination of 
prolactin was performed by a lactoperoxidase method. 
The results from Examples 2 and 3 were arranged as randomized block designs 
and analyzed by Analysis of Covariance. Blocks of the treatment replicates 
were fitted to remove variation due to location within a culture plate and 
each block represented one of four columns on a plate. The covariate, 
baseline prolactin secretion was fitted to remove well to well variation 
in prolactin secretion. 
The analysis was performed in two stages. Initially, the model was run and 
the square root of the mean square error was used to identify outliers. 
Those data that were plus or minus two standard deviations away from the 
mean of the treatment were removed. The model was rerun to analyze for the 
main effects of D.sub.2 dopamine receptor antagonists, alkaloid and 
D.sub.2 dopamine receptor antagonist/ alkaloid interaction (D.sub.2 
dopamine receptor antagonist/alkaloid interaction only, for experiment 2). 
Least square means were calculated for each D.sub.2 dopamine receptor 
antagonist/alkaloid treatment and expressed as a percent of the control. 
Orthoganol polynomial contrasts were used to fit the dose response curves 
of Example 3 and means separation was performed with a series of linear 
contrasts using Student's test. All analyses were performed using the GLM 
procedure of SAS. 
Controls for Example 2 containing either domperidone (10.sup.-6 M) or 
sulpiride (10.sup.-6 M) stimulated prolactin secretion over that of the no 
D.sub.2 dopamine receptor antagonist control. Prolactin values for 
controls were 853.9, plus or minus 75.0, 1267.4, plus or minus 73.0, and 
1387.1, plus or minus 62.8 ng PRL/mL/mg protein for the no D2 dopamine 
receptor antagonist control, domperidone control, and sulpiride control, 
respectively. 
The main effects of the D.sub.2 dopamine receptor antagonist/alkaloid 
interaction were significant. Those means were used to present the data 
shown in FIGS. 1-4. The designations and description of the data for each 
Figure are described above. In each run, domperidone and sulpiride were 
delivered at doses of 10.sup.-6 M concentrations. 
As expected, both dopamine and .alpha.-ergocryptine suppressed prolactin 
secretion below that of the control across all three dosage levels, 
10.sup.-4, 10.sup.-6 and 10.sup.-8 M, as shown in FIGS. 1 and 2. No dose 
response effect of dopamine or .alpha.-ergocryptine on prolactin secretion 
was exhibited. It is possible that lower dosages or more pituitary cells 
were needed to create a dose response (i.e. receptors may have been 
saturated by the 10.sup.-8 M concentration). 
.alpha.-Ergocryptine, an ergopeptine alkaloid found in very low amounts in 
endophyte-infected tall fescue, was shown to inhibit prolactin secretion 
at the pituitary level. Therefore, the ability of dopamine and 
.alpha.-ergocryptine to suppress prolactin secretion in this in vitro 
system verifies that the cells were intact and responsive. 
Determination of the potential toxicity of ergovaline is important 
considering its concentration of 0.3 to 2.8 .mu.g/g of leaf sheath 
(greater than 80% of the total ergopeptine fraction), in 
endophyte-infected tall fescue. In Examples 1-4, ergovaline suppressed 
prolactin secretion in vitro at all concentrations tested in relation to 
the non-treated control and the magnitude of suppression was very similar 
to that of dopamine and .alpha.-ergocryptine. Ergovaline is a member of 
the same class of compounds, ergopeptines, as .alpha.-ergocryptine, 
ergocornine and ergotamine. All three ergopeptines have been shown to 
suppress pituitary prolactin secretion in vivo or in vitro. 
As with .alpha.-ergocryptine and dopamine, there was no dose response 
effect of ergovaline on in vitro pituitary prolactin secretion. Cell 
numbers were speculated to be insufficient to elicit a dose response as 
described above. The presence of ergovaline in endophyte-infected tall 
fescue and its activity in vitro in suppressing prolactin secretion make a 
strong case for it being a causative agent of fescue toxicosis. 
Additionally, its chemical relationship to ergotamine, an ergopeptine 
known to cause vasoconstriction and dry gangrene of the extremities, as 
well reduced serum prolactin levels, only strengthens its position as a 
major component of the causative mechanism(s) of fescue toxicosis. 
Loline suppressed prolactin secretion only at the highest concentration 
(10.sup.-4 M), thus, exhibiting a dose response effect not observed in the 
other alkaloid treatments. The presence of loline, a pyrrolizidine 
alkaloid and the parent compound of N-formyl and N-acetyl lolines, in 
endophyte-infected tall fescue has been reported. The dose response effect 
of loline seems to indicate that it has a much lower affinity for its 
target site or fewer binding sites than dopamine, .alpha.-ergocryptine or 
ergovaline. Additionally, the ability of the D.sub.2 dopamine receptor 
antagonist domperidone to reverse the effects of loline on prolactin 
secretion seems to indicate that the site of action for loline is the 
D.sub.2 dopamine receptor. 
Across all alkaloid treatments, domperidone was shown to be more efficient 
than sulpiride at antagonizing the prolactin suppressing effect of the 
alkaloids. Domperidone was able to completely reverse the effect of all 
three concentrations of dopamine on prolactin secretion. Sulpiride, 
however, was only able to reverse the effect of the 10.sup.-8 M 
concentration of dopamine on prolactin secretion. 
Both domperidone and sulpiride were able to partially reverse the effects 
of the lowest concentration (10.sup.-8 M) of .alpha.-ergocryptine on 
prolactin secretion, but neither had an effect on prolactin secretion at 
the other treatment concentrations (10.sup.-4, 10.sup.-6 M) of 
.alpha.-ergocryptine. 
Sulpiride had no effect on suppression of prolactin by ergovaline. 
Domperidone, however, was able to completely reverse the suppression of 
prolactin secretion induced by the lowest concentration (10.sup.-8 M) of 
ergovaline. The ability of domperidone to antagonize the effect of 
ergovaline indirectly indicates that ergovaline is eliciting its effect on 
prolactin secretion through a D.sub.2 dopamine receptor. Both domperidone 
and sulpiride were equally efficacious at reversing the effect of loline 
on prolactin section. 
FIG. 6 shows the dose response relationships of domperidone and sulpiride 
on in vitro pituitary prolactin secretion in the presence of a 10.sup.-8 M 
concentration of .alpha.-ergocryptine. The dose response curve of 
domperidone had a significant cubit fit indicating that there was no added 
benefit to increasing doses of domperidone past 10.sup.-7 M concentration. 
In contrast, the dose response curve of sulpiride had a significant 
quadratic fit and the dosages were not sufficiently concentrated to reach 
a plateau as was observed with domperidone. In fact, sulpiride was unable, 
even at the highest dose (10.sup.-5 M), to completely reverse the 
suppression of prolactin secretion caused by .alpha.-ergocryptine 
(10.sup.-8 M) back to the control level. Domperidone, on the other hand, 
increased prolactin secretion above that of the .alpha.-ergocryptine 
(10.sup.-8 M) control at doses of 10.sup.-8, 10.sup.-7, and 10.sup.-5 M. 
Sulpiride was only able to increase prolactin secretion when given at 
10.sup.-5 M concentration. Accordingly, domperidone is a more potent 
D.sub.2 receptor antagonist than sulpiride. 
In summary, the results from the above Examples show that ergovaline 
reduced in vitro pituitary prolactin secretion by 40% or greater at 
10.sup.-4, 10.sup.-6 and 10.sup.-8 M concentrations. In contrast, loline 
reduced prolactin secretion only at the highest dosage given, 10.sup.-4 M. 
Two standard dopamine agonists, dopamine and A-ergocryptine, were used to 
verify that the inhibitory control mechanisms of pituitary cell prolactin 
secretion were intact. Both reduced prolactin secretion by at least 40% 
for 10.sup.-4, 10.sup.-6 or 10.sup.-8 M concentrations. The D.sub.2 
dopamine receptor antagonist domperidone at 10.sup.-6 M was able to 
reverse the effect of loline on in vitro pituitary prolactin secretion and 
domperidone of 10.sup.-6 M was able to reverse the effect of ergovaline at 
the lowest dosage (10.sup.-8 M). Domperidone was more effective in 
reversing the prolactin suppressing effect of the alkaloids than 
sulpiride. The dose response curve for domperidone indicated a threshold 
concentration, 10.sup.-7 M, for reversal of .alpha.-ergocryptine's effect 
on prolactin secretion. However, at similar concentrations of sulpiride, a 
threshold level was not obtained. These data indicate that both ergovaline 
and loline alkaloids are D.sub.2 dopamine receptor agonists and that 
domperidone is a more potent drug for reversal of the alkaloids' 
hypoprolactinemic effects than sulpiride. 
The greater efficacy of domperidone versus sulpiride to reverse the 
suppressing effect of a .alpha.-ergocryptine on in vitro pituitary cell 
prolactin secretion may be explained by differences in chemical structure. 
Additionally, the different physiological distributions of sulpiride and 
domperidone in the animals' body may be useful in localizing the target 
tissues of tall fescue toxins in the animal. Domperidone, an 
investigational antiemetic distributed as Motilium in Europe, but not 
currently cleared for clinical use in the United States, is chemically 
unrelated to other antiemetics, such as butyrophenones, phenothiazines, 
and metoclopramide. Unlike other antiemetics (e.g., metaclopramide, 
haloperidol), domperidone does not cross the blood brain barrier. 
Therefore, central neurological side effects are not a concern when using 
domperidone as a treatment for fescue toxicosis. In contrast, sulpiride is 
a D.sub.2 dopamine receptor antagonist of the same chemical class as 
metoclopramide, a drug that has been shown to be effective in reversing 
the hypoprolactinemea of fescue toxicosis in cattle. Both sulpiride and 
metoclopramide, however, cross the blood brain barrier. 
The results from Examples 1-4 indicate that ergovaline and loline suppress 
prolactin secretion in a manner similar to that of dopamine and 
.alpha.-ergocryptine, implicating these alkaloids as possible causative 
agents of fescue toxicosis. Further, the prolactin suppressing effect of 
these alkaloids was partially or totally reversed by the D.sub.2 dopamine 
receptor antagonist domperidone. Therefore, treatment of the 
hypoprolactinemia of fescue toxicosis is possible using domperidone. 
Domperidone was shown to be a more potent antagonist than sulpiride, 
indicating that lower dosages of domperidone are required for treatment or 
prevention of fescue toxicosis. Further, the inability of domperidone to 
cross the blood brain barrier makes it a valuable tool for localizing the 
mechanisms of fescue toxicity to peripheral tissues, i.e., those outside 
the blood brain barrier. This inability to cross the blood brain barrier 
significantly reduces the chance of central neurological and adverse 
behavioral side effects when using domperidone. 
Example 5 
The effectiveness of domperidone was also evaluated as a treatment for 
equine fescue toxicosis comparative to sulpiride. As indicated above, 
gravid mares grazing on endophyte-infected tall fescue frequently exhibit 
one or more symptom of equine fescue toxicosis, including agalactia, 
prolonged gestation, weak or stillborn foals, retained placentas, 
thickened placental tissue, mild to severe dystocia and febfeeding 
difficulties. In addition, a failure of the foal to rotate into the proper 
position for delivery has been observed. Infected mares also exhibit 
decreased serum prolactin and progesterone levels. 
In this Example, sixteen gravid mares (6 Quarter Horses and 10 Arabians) 
were assigned to one of three treatments by breed, expected foaling date 
and whether a maiden mare or having previously foaled. The treatments 
included: (1) control (no drugs); (2) 2.2 mg domperidone/kg body 
weight/day; and (3) 3.3 mg sulpiride/kg. Each treatment group contained at 
least one maiden mare. The control treatment group (C) contained one 
Quarter Horse and three Arabians, the domperidone treatment group (D) 
contained two Quarter Horses and four Arabians, and the sulpiride 
treatment group (S) contained three Quarter Horses and three Arabians. 
Mares were pastured as a group on one of eight 1.0 hectare 
endophyte-infected tall fescue pastures with free access to complete 
vitamin and mineral salt blocks and fresh water throughout the study. The 
average infection level for endophyte-infected pastures was 95.0%, plus or 
minus 4.41%. Mares were rotated to a fresh pasture when canopy height in 
the pasture being grazed reached approximately 7.6 cm. Mares were 
vaccinated and dewormed according to normal herd health management 
practices for the Clemson University equine herd. 
Weights and body condition scores were obtained on each mare at 28-day 
intervals until foaling. Mares and foals were weighed on the day of 
foaling. Prepartum weights were used to determine mare weight gain during 
gestation. Postpartum mare weights were used to determine foal weight as a 
percentage of mare weight. A subjective udder scoring system was developed 
and udder scores were assigned every five days, starting 30 days prior to 
each mare's expected foaling date and continuing until withdrawal from the 
infected pasture, then every two days until parturition if parturition had 
not already occurred. Blood samples were taken every five days, with the 
first sample taken one to two days prior to the start of treatment (30 
days prior to expected foaling date). Samples were taken in the form of 
what is commonly called a "window", where one 20-ml sample is obtained by 
jugular venipuncture at the start of the window, then other samples are 
obtained every hour for four hours for a total of five samples per window. 
Samples were allowed to clot for 30 minutes at room temperature and then 
refrigerated at 4.degree. C.. Samples were centrifuged within one hour 
after the last sample was drawn. Serum was drawn off and the five samples 
per window were combined into one sample. Aliquots were subsequently 
frozen at -10.degree. C. until assayed for prolactin, progesterone and 
estradiol-17.beta. content. 
A solid phase I.sup.125 radioimmunoassay kit from Coat-a-Count, Diagnostic 
Products Corporation, Los Angeles, Calif., was used to measure serum 
progesterone. Serum estradiol-17.beta. was measured by the procedure of 
Henricks et al. 57 J. Anim. Science 247 (1983) with the modifications 
specified by Breuel et al. 30 Theriogenology 613 (1988). The procedure was 
further modified by using two 0.2 ml aliquots of HPLC grade methanol to 
remove the steroid from the columns as opposed to the two 0.5 ml aliquots 
used by Breuel. This change resulted in a decreased evaporation time of 
the methanol without affecting the amount of estradiol-17.beta. recovered 
from the columns. A heterologous equine-canine radioimmunoassay was used 
to measure serum prolactin. 
The foaling date for each mare was calculated using the breed averages over 
a period of several years for the Clemson University herd. Due dates for 
Arabian mares were calculated using an average gestation length of 338 
days. Quarter Horse due dates were based on an average gestation length of 
342 days. 
Administration of the treatments began 30 days prior to the expected 
foaling date for each mare. A corn and dried molasses mix was utilized as 
the carrier for the drug treatments. The mix contained 20% molasses to 
increase palatability of the treatments. Control mares received 454 
gm/head/day of the carrier, with 20 ml of cider vinegar mixed into the 
grain. Domperidone mares received 454 gm/head/day of the carrier to which 
domperidone had been added at a level of 0.55 mg/kg body weight. During 
preliminary experimentation, it was determined that cider vinegar needed 
to be added to the mix to induce consumption by the mares of the 
apparently bitter-tasting sulpiride. Domperidone was dissolved in 5 ml of 
cider vinegar and mixed into the grain to facilitate even distribution of 
the compound. An additional 15 ml of cider vinegar was then added to 
encourage complete consumption of the ration. 
Sulpiride administration was accomplished in the same manner as that of 
domperidone, but was administered at a level of 1.65 mg/kg body weight. 
Each mare was restrained by means of a halter and fed individually to 
insure consumption of the correct ration. Treatment continued until 
parturition occurred. Dose levels were increased to 2.2 mg domperidone/kg 
body weight and 3.3 mg sulpiride/kg body weight after the first mare on 
each drug foaled without adequate mammary development. Mares that had not 
foaled within seven days after their expected due date were moved to 1.0 
hectare endophyte-free fescue pastures to minimize chances of death due to 
severe dystocia. 
Data were analyzed by one-way ANOVA in a completely random design. 
Treatments served as main effects and individual mares served as 
experimental units. Within-mean square was used as the error term, and 
differences between means were tested using least significant difference. 
The General Linear Model of the Statistical Analysis System was used to 
perform all statistical analyses. The results are listed in Table 1 below. 
TABLE 1 
__________________________________________________________________________ 
Treatment.sup.a 
Item Control Domperidone 
Sulpiride 
__________________________________________________________________________ 
Number of mares 
4 6 6 
Condition score 
6.31 .+-. .24 
6.10 .+-. .20 
6.27 .+-. .20 
Mare weight, kg 
Initial weight 
474.11 .+-. 35.00 
478.73 .+-. 28.57 
506.06 .+-. 28.57 
Final weight.sup.b 
460.26 .+-. 32.68 
480.02 .+-. 26.69 
506.51 .+-. 26.69 
Weight gain -13.85 .+-. 6.07 
1.28 .+-. 4.95 
.45 .+-. 4.95 
Number of live foals 
3 6 6 
Foal weight, kg 
41.32 .+-. 3.54 
40.55 .+-. 2.89 
42.45 .+-. 2.89 
As a percentage of 
10.08 .+-. .67 
9.28 .+-. .55 
9.50 .+-. .55 
mare weight, % 
Gestation length, days 
350.25 .+-. 4.17.sup.c 
338.67 .+-. 3.41.sup.d 
343.00 .+-. 3.41 
Number of days past 
11.25 .+-. 3.87.sup.c 
-.67 .+-. 3.16.sup.d 
3.00 .+-. 3.16 
expected foaling date 
Retained piacentas 
0 1 3 
Number of mares with milk 
3 5 4 
at foaling 
Number of mares rebred 
2 5 4 
__________________________________________________________________________ 
.sup.a Mean .+-. standard error. 
.sup.b Last weight before parturition. 
.sup.c,d Means within a row lacking a common superscript letter differ (P 
&lt; .05). 
Mare weights and body condition scores did not vary according to treatment. 
A trend, however, was observed towards weight loss in control mares as 
seen in Table 1. Mares consuming endophyte-infected fescue have been found 
to gain less than mares consuming endophyte-free fescue prior to 
parturition. Previous studies have shown that sheep and cattle gain less 
weight when grazing infected fescue when compared to their counterparts 
consuming endophyte-free fescue. There was no effect due to treatment on 
foal birth weights as seen in Table 1. 
Domperidone-treated mares had shorter gestation lengths than control mares. 
No mare, however, was allowed to graze on infected fescue more than 7 days 
beyond her projected foaling date. The gestation lengths for the 
domperidone mares are comparable to those found for mares consuming 
fungus-free fescue that had an average gestation length of 333, plus or 
minus 5, days. Average gestation length is known to vary widely between 
horse breeds, and a slight difference between Arabians and Quarter Horses 
has been observed within the Clemson University herd (338 and 343 days, 
respectively). Domperidone-treated mares foaled much nearer to their 
expected foaling date than did control mares. While the gestation length 
for control mares was not as long as the gestation lengths observed when 
mares were allowed to go to term on infected fescue, it is comparable to 
the gestation length observed when mares were removed from infected 
pasture 10 days after their expected foaling dates. In addition, mares 
which foaled after removal from infected fescue required an average 10 
days recovery time on fungus-free fescue before foaling. 
No difference was observed between treatments for retained placentas. 
Control mares had no retained placentas, but this may have been due to the 
precautionary measures taken to minimize chances of mare death. It has 
been well documented that a retained placenta is one of the problems often 
encountered in fescue toxicosis. The domperidone mare that had retained 
her placenta foaled 7 days early. The mare was discovered immediately 
after delivering the foal and showed no signs of having experienced 
dystocia, a common cause of retained placenta in mares. The foal was weak 
and unable to stand unaided. The foal never suckled and died of a 
suspected congenital heart defect within 12 hours after birth. The lack of 
suckling stimulus to the mare may have contributed to the retention of the 
placenta by preventing the additional release of oxytocin which normally 
occurs upon the initiation of suckling. Oxytocin appears to be involved in 
hormonal control of placental expulsion. Mares that undergo 
oxytocin-induced parturition have prompt placental expulsion. 
Three mares in the sulpiride group retained placentas. One of these mares 
foaled prior to the increase in dosage. The second sulpiride mare foaled 6 
days after the dosage was increased. The third mare was on the higher 
dosage for the entire treatment period. 
The numbers of mares with milk at foaling were similar among the 
treatments. The one control mare that foaled on infected pasture grass 
exhibited no signs of mammary development prior to parturition and was 
agalactic at parturition. One domperidone mare and one sulpiride mare had 
udder development that was insufficient to support lactation, and both 
foaled prior to the increase in dosage. The second sulpiride mare foaled 6 
days following the increase in dosage. This mare was agalactic immediately 
following parturition but began secreting milk within 24 hours postpartum. 
All control mares that were relocated to a fungus-free pasture failed to 
show signs of mammary development until after relocation. Visible udder 
development occurred within three days after relocation and all three 
mares had milk at parturition. 
Two control mares failed to conceive following the experiment. One of these 
mares foaled too late to be bred before the end of the breeding season. 
One domperidone-treated mare exhibited estrus but failed to conceive. One 
of the sulpiride mares which did not conceive had a history of lactational 
anestrus under normal (non-endophyte) conditions. The other sulpiride mare 
had a retained placenta and required treatment. Therefore, this mare 
exhibited only one estrus before the end of the breeding season and did 
not conceive during this estrus. Others had found earlier that mares which 
grazed on endophyte-infected fescue during pregnancy tended toward a lower 
rate of conception following removal from the infected fescue than did 
mares which grazed on fungus-free fescue during pregnancy. 
FIG. 7 illustrates the effects of treatment on mammary gland development. 
Control mares showed no signs of udder development until after removal 
from endophyte-infected fescue. In contrast, domperidone and sulpiride 
mares began exhibiting palpable mammary development within 10 days after 
the start of treatment. Mammary gland scores were higher for domperidone 
and sulpiride versus control mares, but no significant difference between 
mammary scores for domperidone and sulpiride mares existed. The lack of 
mammary development in mares consuming endophyte-infected fescue has been 
well documented. FIG. 7 suggests that domperidone is an effective agent 
for ameliorating the effects of the endophytic toxins on mammary 
development. 
The effects of treatments on prolactin secretion are shown in FIG. 8. Serum 
prolactin was higher in domperidone and sulpiride mares than in control 
mares 10 and 15 days after treatment was initiated. Serum prolactin was 
higher in domperidone mares than control mares 20 and 30 days after the 
start of treatment. Prolactin levels for domperidone mares were similar to 
those of control mares 10 days before parturition. Prolactin levels tended 
to be higher for domperidone mares than sulpiride mares 5 days prior to 
parturition. Control mares had higher prolactin levels than sulpiride 
mares 5 days prior to parturition. There was no difference between 
treatments at parturition. 
Serum prolactin levels in pregnant mares generally remained steady 
throughout pregnancy at approximately 7 ng/ml. Also, recent research shows 
that prolactin levels in normal mares begin to increase greatly around 5 
days prior to parturition, corresponding to the increase in production of 
the various milk components in the mare. However, serum prolactin levels 
remained below 5 ng/ml in control mares until their removal from 
endophyte-infected tall fescue 9.33, plus or minus 2.49, days prior to 
parturition. The control mare that foaled on endophyte-infected tall 
fescue had a serum prolactin level of 1.15 ng/ml in the last blood sample 
prior to parturition. The three control mares that were removed from the 
infected tall fescue showed a rapid increase in prolactin levels following 
removal from infected tall fescue. 
FIG. 9 illustrates the effects of treatments on serum progesterone levels. 
Serum progesterone levels were higher in domperidone and sulpiride mares 
than in control mares 10, 15, 20, 25, and 30 days after the start of 
treatment. Serum progesterone levels were higher in domperidone mares than 
sulpiride mares 30 days after initiation of treatment (-10 and -5 days 
from parturition for domperidone and sulpiride mares, respectively). Serum 
progesterone levels were similar among treatments 35 days after the 
initiation of treatment (-5, 0 and -15 days from parturition for 
domperidone, sulpiride and control mares, respectively). Serum 
progesterone levels were similar for all treatments at parturition. 
Progesterone levels in control mares remained steady until removal from 
infected fescue and then began to increase. The increase in serum 
progesterone in control mares beginning at 10 days from parturition was 
probably associated with the removal of these mares from 
endophyte-infected pasture 9.33, plus or minus 2.45, days prepartum. 
Mares consuming endophyte-infected fescue have been shown to have decreased 
serum progesterone levels. Progesterone in pregnant mares is low from 
about day 160 of gestation to about day 280, then gradually increases 
until parturition. The results shown in FIG. 9 suggest that domperidone 
administration creates a more normal progesterone profile for mares 
consuming infected fescue without domperidone therapy. 
The effect of treatment on serum estradiol-17.beta. levels is shown in FIG. 
10. Domperidone- and sulpiride-treated mares had lower serum estradiol 
levels than control mares. Estrogen levels in pregnant mares peak around 
day 200 of gestation then begin to steadily decrease from day 240 to 
parturition. FIG. 10 illustrates that estradiol-17.beta. in control mares 
remained steady until the mares were removed from endophyte-infected 
fescue, then dropped rapidly, possibly in response to the absence of 
toxins in the diet. In contrast, estradiol-17.beta. began to drop in both 
domperidone and sulpiride mares several days after therapy. The current 
data suggests that estradiol-17.beta. is elevated as a result of endophyte 
consumption, and the treatment with domperidone or sulpiride will restore 
the secretion pattern of this hormone to near normal levels. 
In contrast to other dopamine antagonists, such as metoclopramide and 
perphenazine, domperidone does not cross the blood-brain barrier and, 
therefore, does not produce central nervous system side effects. No 
neurological side effects were observed in any of the groups treated with 
domperidone during these studies. 
Example 6 
Twenty gravid mares (10 Quarter Horses and 10 Arabians) were assigned by 
breed and expected foaling date to one of five treatments: (1) 
endophyte-free (E-); (2) 1.10 mg domperidone/kg body weight/day (D1); (3) 
1.65 mg domperidone/kg body weight per day (D2); (4) 2.20 mg 
domperidone/kg body weight per day (D3); and (5) endophyte-infected 
control (E+) in a randomized block design. E- mares grazed on 0.0% 
endophyte-infected pastures while all other mares grazed on 95.0%, plus or 
minus 4.41%, endophyte-infected pastures. All mares were allowed free 
access to complete mineral and vitamin blocks and water throughout the 
study. 
The above-described treatments were administered orally in 454 grams of an 
80% corn/20% dried molasses mixture daily, beginning 30 days prior to 
their expected foaling date. Mares were weighed and assigned body 
condition scores at 20 day intervals. Blood windows were taken at 5 day 
intervals beginning 30 days prior to expected foaling dates to determine 
effects of treatment on serum levels of prolactin, progesterone and 
estradiol-17.beta.. A single postprandial blood sample was taken daily for 
the first five days of treatment to asses the initial effects of treatment 
on serum hormones. D3 mares had a greater incidence of retained placentas 
than E+, E- and D1 mares. Foal weights were higher for D1 mares than D2 
and D3 mares. Gestation lengths were longer for E+ mares than E-, D1, D2 
and D3 mares. The results of this Examples shows that a 1.10 milligram 
dose of domperidone/kg body weight/day is an effective level for treatment 
of equine fescue toxicosis. 
Example 7 
Twenty beef steers averaging approximately 750 pounds were employed to 
determine the effectiveness of domperidone in treating symptoms of fescue 
toxicosis in cattle. All steers were given free access to 
endophyte-infected hay and were also fed one pound/head/day of 
endophyte-infected fescue seed to further increase the intake of toxins. 
Then ten of the steers were injected subcutaneously daily with 75 mg of 
domperidone in a carrier and the other ten steers were injected daily with 
only the carrier. 
Growing cattle consuming endophyte-infected grass, hay or seed were found 
to gain at a slower rate than cattle consuming uninfected grass, hay, or 
seed. The average daily gain of steers for the duration of this Example 
over three months was 1.57 pounds/head/day for control steers and 1.71 
pounds/head/day for domperidone-treated steers. This represents a 9% 
increase in gain performance for domperidone treated steers. 
Domperidone-treated steers appeared more healthy than control steers. 
Control steers created water bogs in the barn area and tried to lay in 
them to cool themselves and, therefore, had mud and manure covering their 
bodies. Domperidone-treated steers did not have this appearance. Control 
steers were sometimes seen coughing, were very slow in walking and 
exhibited some slobbering. The eyes of the control steers appeared more 
dull and the cattle had a general listless appearance. The domperidone 
steers appeared normal and healthy. Feedlot buyers report that steers and 
heifers coming from fescue growing areas of the country appear sick upon 
arrival at the feedlot and frequently require more medication and 
treatment upon arrival. 
Domperidone is an effective treatment for fescue toxicosis and is more 
effective than sulpiride. In vivo, mares treated with domperidone had 
shorter gestation lengths, foaled closer to the expected foaling dates, 
exhibited better mammary development, had higher serum prolactin and 
progesterone levels and had lower serum estradiol-17.beta. levels than 
control mares. Sulpiride was less effective than domperidone at 
ameliorating the effects of the endophytic toxins on hormone secretion. In 
addition, the effects on steers indicate toxicosis control with 
domperidone. 
In delivering the effective dosages of domperidone to the animals, various 
vehicles may be used, including a feed or feed supplement material as the 
carrier, injection with a suitable carrier, administration orally alone or 
encapsulated, and in an implantable matrix. Additionally, domperidone may 
be added to a salt or mineral blocks during casting or mixed directly into 
seed. Various other administration techniques well known in the art may be 
employed. The present invention is not limited to any particular vehicle. 
It will be understood that the invention is not limited to any specific 
parameters, amounts, or processes described herein, and that any method 
employing agents equivalent to those described falls within the scope of 
the present invention. It will be understood that while the form of the 
invention shown and described herein constitutes a preferred embodiment of 
the invention, it is not intended to illustrate all possible forms of the 
invention. The words used are words of description rather than of 
limitation. Various changes and variations may be made to the present 
invention without departing from the spirit and the scope of the following 
claims.