PURDUE      ,    ,
veterinary medical
npEWj
VOLUME 9, NUMBER 1
WINTER-SPRING 1983
Abomasal Displacement Studied
Dairymen and Veterinarians to Benefit from AD Research
The recognized incidence of abomasal displacement (AD) in cattle has increased
from zero, prior to 1944, to the high incidence of today where it is one of the most
common digestive diseases of the adult
dairy cow, and the incidence is increasing.
Considering an incidence of one percent,
the cost of surgical correction, and an estimated drop of 1,300 pounds of milk pro-
ducation, the loss to the dairy farmers in
the North Central United States, with its
4.7 million dairy cows, is $16 million per
year, or an average of $350 per diseased
cow.
Predisposing implications include nutrition, stress, metabolic deficiencies and
other concurrent problems (metritis, mastitis and ketosis). Observation of spontan-
enous recovery after dietetic treatment
and then relapse when the patient was returned to the original feed seems to indicate that nutrition plays an important role
in the development of AD.
Observations are that the greatest incidence tends to occur in high milk-producing herds. In affected herds, the ratio of
concentrate (grain) to roughage (hay and/
or silage) is often significantly higher than
in unaffected herds. There is also a high
correlation between the incidence of AD
and heavy feeding of grain in the prepar-
tum period. Recent research has suggested that abomasal atony and increased gas
production are the major prerequisites
for AD. Until recently, the genesis of the
abomasal hypomotility was only speculative.
The abomasal hypomotility and subsequent delayed emptying rate that accompanies high concentrate feeding may be related to increased volatile fatty acids
VFA's) in the abomasal ingesta. During
microbial fermentation of carbohydrates
in the rumen, acetic, propionic and butyric acids are formed in a ratio of approximately 65:20:15 molar percent. Diets associated with AD are thought to increase
the production of propionic and butyric
Electrodes and strain gauges are surgically implanted onto the abomasum and proximal
duodenum to measure myoelectrica! activity and strength of muscle contraction cf the
abomasal smooth muscle.
acids and to decrease the production of
acetic acid. Production of VFA's increases after feed consumption, especially on a
diet rich in easily digestible carbohydrates,
and, therefore, ingesta that passes into the
abomasum at this time should contain a
relatively higher concentration of VFA's,
especially propionic and butyric acids.
With decreased abomasal motility and subsequent prolonged abomasal emptying
time, gas may accumulate in the abomasum. Research by European investigators
has revealed a markedly increased production of abomasal gas following concentrate consumption and that the gas production was correlated with the quantity
of concentrate consumed. Abomasal gas
normally escapes through the omasal canal to the rumen where it is eructated with
ruminal gases. With abomasal atony, the
gas can become trapped and lead to dilatation of the abomasum and subsequently
predispose the abomasum to displacement.
Studies underway here with the ultimate
objective being to reduce the incidence of
AD through practical dietary and management means, involve measuring abomasal
motility and VFA concentrations in the
rumen and abomasum. Bipolar electrodes,
capable of measuring the electrical activity of smooth muscle, and electronic
strain gauges, capable of measuring the
strength of contraction, are surgically implanted on the abomasum and proximal
duodenum. Rumen cannulae are also positioned which enable ruminal and abomasal fluid sampling for VFA and other
analyses. Three diets are being evaluated
for their effect on abomasal motility and
VFA production. These diets include one
that has been commonly associated with
AD (corn silage), one that has been less
commonly associated with AD (alfalfa
hay and corn silage), and one rarely associated with AD in cattle (grass hay). Each
includes a concentrate which is specifically mixed to provide the diet with identi
cal amounts of total energy, crude protein, calcium and phosphorus. These diets
differ in fiber and in the forms of energy
which vary in their digestibility, and thus
lead to different ratios of VFA production. Motility is measured twice weekly
during two seven-hour recording sessions.
After several recording sessions for each
cow on a specific diet, the diets are changed to allow the evaluation of each cow
on each ration. Ruminal and abomasal
fluid samples are obtained at hourly intervals during recording sessions to enable
correlation of abomasal motility with
VFA concentrations. Data from these
studies are now being analyzed.
There are indications that a decrease in
dry matter intake precedes the development of AD. Experiments are in progress
to learn if decreased feed intake may be a
predisposing cause of AD rather than an
effect of AD. Cows on the previously
mentioned rations have 50% or 75% of
the ration withheld for 24 hours preceding recording of abomasal motility and
fluid sampling for VFA content.
Past studies have utilized non-lactating
cows, and abomasal motility may uiffei
in the early post-partum cow when AD
has its highest incidence. Two cows now
being studied are pregnant, and recordings will be taken preceding and just after
parturition to assess abomasal function
during these critical periods. Additional
studies are planned to evaluate several
pharmacologic agents frequently used to
increase abomasal motility and thus prevent AD. These include caffeine, neostigmine and d-panthothenyl alcohol. Agents
used in gastric ulcers in man and abomasal ulcers in cattle (cimetidine and propantheline) will also be evaluated for effects on abomasal motility.
It is expected that new knowledge obtained from these studies will help to define a complex problem and provide practicing veterinarians with more definitive
information about recommendations to
the dairyman concerning the ultimate objective, the prevention of abomasal displacement.
James L. Becht, D. V.M.
Stephen B. Adams, D. V.M.
VM Faculty Honored
Five Receive A wards in Spring Ceremonies
Q A$
Dr. Edward Hinsman wins Amoco Award.
Each spring the Amoco Foundation provides awards to three University faculty
who have been identified on a University-
wide basis for outstanding instruction.
The number of nominees from each
school is a function of the number of faculty in the school, and Veterinary Medicine is allowed only one. Dr. Hinsman
consistently surfaces as an outstanding
instructor.
to Dr. Lawrence A. Horstman. This a-
ward is for excellence in teaching, and the
selection stems from students and faculty
casting written evaluations for all instructors in the School who have primary responsibility for a course or courses.
The Norden Distinguished Teacher A ward
was presented to Dr. Daniel C. Richardson, assistant professor of surgery in the
Department of Small Animal Clinics.
Like the other teaching awards, selection
Hinsman
Horstman
Richardson
VanSickle
Meyer
Purdue At
ni Association Award given     for the Norden award follows student ana
faculty evaluations of those faculty members who are responsible for course management.
Dr. David C. VanSickle was again recognized for outstanding teaching in the human
medical education program, conducted
on this campus under contract with the
Indiana University School of Medicine.
The medical class of 1983 so honored Dr.
VanSickle at their graduation banquet on
May in Indianapolis.
Weedon Award winner. . .Dr. K.B. Meyer.
Established in 1981, the Weedon Faculty
Recognition Award is made to the faculty
member who by vote of the graduating
seniors is identified as being the faculty
member most helpful to the class members as they proceeded through the curriculum in pursuit of the D.V.M. degree.
An outstanding array of talent! Our congratulations and best wishes for continuing success to each!