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R. J. Komarek
Designed Cannulas and a Cannula Insertion Instrument
Rumen and Abomasal Cannulation of Sheep with Specially
1981, 53:790-795.J ANIM SCI
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RUMEN AND ABOMASAL CANNULATION OF SHEEP WITH SPECIALLY
DESIGNED CANNULAS AND A CANNULA INSERTION INSTRUMENT
R. J. Komarek 1,2
Research Laboratories, Tennessee Eastman Company,
Eastman Chemicals Division, Eastman Kodak Company,
Rocbester, NY 14603
Summary
Rumen and abomasal cannulas for sheep and
an instrument that facilitates rapid insertion of
the cannulas were developed. The cannulas
were made from epoxy-filled polyurethane and
were supported by outer support rings held in
place by nuts screwed onto the threaded tops
of the cannula barrels. The insertion device
was used to pull the cannula through a separate-
ly made incision in the abdominal wall and to
stretch the skin and other tissues over a cone
and onto the barrel of the cannula, thus en-
suring a tight fit and the formation of a ring of
scar tissue that virtually eliminated digesta
leakage. Expansion plugs, used to seal the
cannulas, were designed to eliminate a twisting
force that could be transferred to the cannula
when the plugs were secured or released. The
plugs were also designed to protrude minimally
from the side of the animal. More than 75
sheep were cannulated, and the preparations
proved to be relatively maintenance free and
resistant to mechanical disturbance by the
animal. The cannulas had a long functional
life and permitted convenient sampling of
digesta and introduction of liquid and solid
materials, including digestion bags.
(Key Words.. Sheep, Rumen Cannula, Abomasal
Cannula, Cannulation.)
Introduction
Our knowledge of the function of the rumen
and abomasum has been greatly enhanced
1 Biochemistry Research Laboratory, Health and
Nutrition Research Division, Tennessee Eastman
Research Laboratories, Box 1911, Rochester, NY
14603.
2The surgical assistance of R. A. Jandzinski and
G. Hume and the art work of P. J. Komarek are
gratefully acknowledged.
through the use of surgically constructed
fistulas. Cannulation is needed to maintain an
open fistula and to minimize its interference
with normal digestive function. A variety of
rumen and abomasal cannulas have been used
and many have been described in reviews and
texts (Dougherty, 1955; Markowitz
et al.,
1964; Johnson, 1966; Willes, 1972; Hecker,
1974). The cannulas have varied from rigid
forms made from metal or plastic (Phillipson
and Innes, 1939; Hill and Gregory, 1951;
Komarek and Leffel, 1961; Markowitz
et al.,
1964; Hecker, 1974) to pliable forms made
from poly(vinylchloride)plastisols, vinyl tubing
and silicone elastomer tubing (Yarns and
Putnam, 1962; Stewart and Nicolai, 1964;
Stewart, 1967; Driedger
et al.,
1970; Alonso
et al.,
1973;Thyfauh
et al.,
1975).
Cannulas made of flexible materials are
generally easy to fabricate and to insert into
the animal. Rigid cannulas, however, can be
inserted tightly into the abdominal wall,
because the skin and other tissues are suffi-
ciently elastic to stretch over the rigid cannula.
Although a tight fit is difficult to accomplish
consistently, when it is achieved, the resultant
formation of a tight ring of scar tissue seals
the cannula in the abdominal wall and produces
an essentially maintenance-free preparation
(Komareket
al.,
1960; Komarek and Leffel,
1961 ; Markowitz
et al.,
1964).
Ideally, a cannulated preparation should
seal the fistula and eliminate leakage. It should
not protrude from the side of the animal or
be vulnerable to mechanical disturbances, and
it should be easily opened and sealed and
avoid any twisting action that may disturb
the cannula. Rigid cannulas designed to satisfy
these criteria were prepared for the rumen and
abomasum of sheep, along with a device for
inserting the cannulas and a cannula closure or
plug. The cannulas described in this report
790
JOURNAL OF ANIMAL SCIENCE, Vol. 53, No. 3, 1981
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RUMEN AND ABOMASAL CANNULATION OF SHEEP 791
were relatively leak-free, did not protrude
from the side of the animal and were easily
sealed with a low profile expansion plug.
Materials and Methods
Animals.
Surgery was performed on lambs
that weighed between 27 and 40 kilograms.
Some rumen cannulas were inserted into
larger sheep. The sheep were crossbreds, with
Dorset and Hampshire blood predominating.
Cannulas.
The cannulas were designed with a
bottom flange, a barrel or tubular portion and
a threaded top with matched nuts that secured
the outer rings to the top of cannulas (figure 1).
The rumen and abomasal cannulas were of the
same design, but they were different in size
and proportion (figure 1). The internal diam-
eter of the barrel of the abomasal cannula was
12 mm, and that of the rumen cannula was
33 millimeters. The cannulas were made from a
rigid, epoxy-filled polyurethane 3 , and the
tissue contact areas were coated with a medical-
grade silicone elastomer 4. The cannulas were
sealed with expandable neoprene plugs, or
closures (figure 1), operated by cam action
levers from commercial closures s . An inner
peritoneal support ring, made from a foamed
poly(fluoroformal) material, was used with
the abomasal cannula (figure ld).
Insertion Instrument.
The cannula insertion
instrument was designed to utilize the drawing
action of a Tyding tonsil snare 6. The instru-
ment consisted of a stainless steel cone, which
was attached to the top of the cannula; a rod,
which was attached to the cone and drew the
cone into the instrument, and two floating
foot pads that slid over the cone when the
operator squeezed the handle of the instrument
(figures 2 and 3). A special pair of calipers
was used during this procedure to bridge the
gap between the two foot pads (figure 6d).
Surgery.
The animals were clipped, washed
the day before surgery and fasted for 24
ho0rs. Surgery was performed under general
3850 Adiprene, E. I. Du Pont de Nemours & Co.,
Wilmington, DE.
4 Silastic 382, Dow Corning, Midland, MI.
s Moeller Manuracturing Co., Greenville, MS.
6No. 683 310, Dittmar and Penn Corp., Phila-
delphia.
7Equithesin, Jensen-Salsbery Laboratories, Kansas
City, MO.
s Fluothane, Ayerst Laboratories, Inc., New York.
9 VML-Fraser Sweatman, Inc., Lancaster, NY.
b ~ r~
C ~1///~ r//w/J
40mm~"J
I" 70rnm
IN
~,- 34mm-,-t
I' 67mm =[
T
I" ?Omm "1
Figure 1. Abomasal and rumen cannulas made
from epoxy-filled polyurethane, along with respective
closures or plugs: (a) cam-activated expansion plug for
the abomasal cannula, (b) retaining nut, (c) outer
flange, (d) inner peritoneal support ring, (e) abomasal
cannula, (f) rumen cannula plug, (g) retaining nut,
(h) outer flange, (i) rumen cannula.
anesthesia produced either by IV infusion of
a mixture of chloral hydrate and pentobarbital
sodium 7 or, preferably, with halothane s
administered in a closed circuit inhalation
anesthetic unit 9. Atropine was given to inhibit
salivation and the motility of the rumen and
abomasal musculature, and to increase respira-
tory efficiency. With halothane, anesthesia
could be induced by masking, thus eliminating
the need for an IV anesthetic. After the induc-
tion of anesthesia, the trachea was intubated
with a cuffed endotracheal tube and anesthesia
was maintained with halothane. The animals
were positioned in either a left (abomasal
cannula) or a right (rumen cannula) lateral
recumbency. The operating table was con-
structed so that the thorax was elevated in
relation to the head and abdomen (Komarek
et al.,
1960; Hecker, 1974). In this position, the
saliva and digesta drained away from the
trachea, preventing inhalation of these fluids,
and the viscera were directed caudally to
reduce the pressure on the diaphram and the
operating field. Entrance to the peritoneal
cavity was achieved by a paracostal laparotomy
(see figures 4a and 4b). Standard aseptic
surgical procedures were used (Markowitz
et al.,
1964).
After the site of the rumen or abomasal
incision was located and the surgically exposed
tissues and peritoneal cavity were isolated and
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792 KOMAREK
Figure 3. Insertion instrument assembled with
cone and calipers for the abomasal cannula. A larger
endpiece, presser feet, cone and calipers were used
for the rumen cannula.
Figure 2. Parts of the cannula insertion instrument
that must be fabricated to convert the Tydings tonsil
snare into the insertion device: (a)upper segment of
the drawing rod, (b) endpiece assembly with presser
feet and the lower segment of the drawing rod,
(c) cone with attaching neoprene plug, (d) presser
foot, (e) support calipers.
protected with sterile towels, an incision was
made (preferably by electrocautery) in either
the dorsal sack of the rumen between the
terminal left ruminal artery and the dorsal
branch of the right ruminal artery, which
extends around to the left side (figure 4c), or
the pyloric region of the abomasum, 10 to 12
cm from the pyloric sphincter (figure 4d). The
incision was only large enough to allow intro-
duction of the bottom flange of the cannula
into the organ. It was necessary to aspirate
excess rumen or abomasal fluid from the organ
after the incision was made. A Murphy purse-
string suture was used to close the incision
around the barrel or the cannula, and, when
necessary for proper inversion, this suture was
oversewn with a regular purse-string suture
(figure 5a). For added strength in the region of
the abomasal cannula, an inner peritoneal ring
(figure 5b) was slipped over the barrel.
The insertion cone was then slid over the top
of the cannula and the neoprene plug slid into
the barrel. The plug in the cannula was ex-
panded by a clockwise turning of the cone
(figure 5c). The cone served to seal the cannula
and prevent contamination of the operating
field. The cannula and cone were loosely
secured with a long piece of suture before
being returned to the peritoneal cavity (figure
5c), thus allowing easy retrieval after the
second skin incision was made.
Either a stab incision no longer than 12 mm,
for the abomasal cannula, or a circular incision
22 mm in diameter (figure 5d), for the rumen
cannula, was made in the skin adjacent to the
opening incision. A stab incision penetrating
the muscle layers and peritoneum was then
made. With the insertion instrument partially
disassembled, the drawing rod from the instru-
ment was passed down alongside the scalpel
through the abdominal wall (figure 6a) and
a
b
d
Figure 4. (a) Positions of the (1) laparotomy and
(2) rumen cannula in a sheep. (b) Positions of the
(1) laparotomy and (2) abomasal cannula in a sheep.
(c) Position of the (1) ruminal incision. (d) Position of
the (1) abomasal incision.
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RUMEN AND ABOMASAL CANNULATION OF SHEEP 793
C
Figure 5. (a) Introduction of the abomasal cannula
with an Ailis forceps; drawing shows the Murphy
purse-string suture in place. (b) Peritoneal ring is
slipped over the barrel of the cannula and lies on the
serosal surface of the abomasum. (c) Cone is attached
to the cannula: plug portion is inserted into the
barrel and the cone over the barrel, and plug is ex-
panded by turning the cone. The cannula must be
held firmly while the cone is attached. (d) A circular
section of skin is removed with a specially designed
circular scalpel before the larger rumen cannula is
inserted.
C
d
d
/
Figure 6. Insertion of the cannula in the abdominal
wall. (a) Lower segment of the drawing rod is slid
down alongside a small-bladed scalpel that has pene-
trated the muscle layers and peritoneum; (b) rod
is screwed into the top of the cone; (c) body of the
instrument is slid over the lower segment of the rod
and the upper segment is screwed into the lower
segment; (d) after movable portion of the handle is
attached and calipers are set in place, handle of the
instrument is squeezed, forcing the muscle layers
and skin over the cone and onto the barrel.
screwed into the top of the cone (figure 6b).
After the rod was attached to the instrument
(figure 6c), the calipers were set in place
under the foot pads (figure 6d). A steady
squeezing action on the handles of the instru-
ment was then used to pull the cone through
the abdominal wall. The tissues were stretched
over the cone and forced onto the barrel of the
cannula (figure 6d). The cone was removed,
and the outer support ring. was slipped over
the top and secured with the cannula nut
(figure 7). After the cannula was sealed with
an expandable plug, the opening incision
was closed.
The use of IV anesthetic occasionally
required the infusion of a plasma extender'to
treat surgical shock. A 5% glucose solution was
used, postoperatively, to enhance detoxif-
ication of the anesthetic. IV therapy was not
necessary when the animals were anesthetized
with halothane. A mixture of penicillin and
10
dehydrostreptomycin was injected IM at
.06 ml/kg body weight immediately after
surgery and daily at .03 ml/kg for 5 days
thereafter.
to Combiotic, Pfizer Inc., New York.
Results and Discussion
More than 60 sheep were abomasally can-
nulated, and 15 were ruminally cannulated.
Recovery from surgery was rapid, and the
animals consumed feed and water within 12
hours. Except in three Iambs found to have
serious respiratory lesions, all surgical attempts
produced functional cannulated preparations.
No excessive swelling around the cannulas or
infections were encountered. The absence of
swelling and the minimal protrusion of the
cannula from the side of the lamb, a day
after abomasal cannulation, can be seen in
figure 7. All sheep resumed normal levels of
feed consumption within 7 to 10 days after
surgery.
The abomasal cannula was used both to
introduce solid or liquid material and to sample
abomosal fluid. The manipulations were easily
accomplished, and, in addition, the rumen
cannula was large enough to permit convenient
introduction and recovery of rumen digestion
bags.
The low external profile of the cannula
enabled sheep to lie on the cannula or to be
grouped with other sheep, without any danger
of their mechanically disturbing the cannula.
The dimensional stability of the rigid cannula
allowed insertion in a manner whereby the
elastic recoil of the skin and other tissues was
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794 KOMAREK
Figure 7. An abomasally cannulated sheep the day
after surgery; note the lack of swelling and the minimal
protrusion of the external portion of the cannula.
Figure 8. Function of a cannula plug with a bullet-
shaped extension designed to keep the mucosal folds
from closing off the end of the cannula.
used to ensure formation of a tightly sealing
scar ring around the device. The difficulties
associated with this type of insertion prompted
the development of the insertion instrument.
The instrument accomplished the insertion
quickly and easily and consistently produced
a tight fit. The rigid cannulas also allowed the
use of effective expansion plugs for convenient
sealing.
The scar ring that formed around the can-
nula produced a liquid-tight seal, and no digesta
leakage occurred for 3 to 6 months after the
operation. The scar tissue around the neck of
the cannula was flexible, and eventually
stretched away from the device and allowed a
small amount of abomasal or rumen fluid to
seep by during movements of the animal.
The quantity of fluid was not sufficient to
require daily care. No leakage of digesta into
the peritoneal cavity was encountered.
Subsequent experimentation indicated that
the leakage could be eliminated by the insertion
of an inner peritoneal flange into a tightly
fitting groove in the cannula just above the
purse string suture (Komarek, 1981). This
procedure has not yet been used for rumen or
abomasal cannulation.
Collection of abomasal fluid through the
abomasal cannula often became difficult 3 to
6 months after surgery. Autopsy indicated that
the abomasum migrated back toward the
omasum while attached to the abdominal
wall by the cannulation and formed a tubular
passage from the abdominal wall to the aboma-
sal lumen (figure 8). The folded mucosa tended
to act as a valve, and, although test material
could be introduced, abommasal fluid samples
were difficult to collect. The problem was
solved by the design of a cannula plug with a
bullet-shaped endpiece which kept the channel
open and allowed easy collection of fluid
during the life of the preparation (figure 8).
Collection was facilitated by the insertion of
a hollow tube through the cannula and past
the mucosal folds.
Abomasal cannulas commonly remained
functional for about 2 years. They were even-
tually rejected by a general weakening and
stretching of the abdominal wall in the region
of insertion. The weight of the viscera seemed
to be an important factor in this hernial pro-
trusion of the cannula. Experience indicated
that positioning the cannula higher on the side
of the animal increased the longevity of the
preparation.
In ruminally cannulated animals, the weight
of the viscera did not bear upon the cannula.
Consequently, these preparations usually lasted
as long as the animals were experimentally
useful.
The rumen and abomasal cannulas ful-
filled the original design objectives. They
effectively sealed the fistula and were essen-
tially maintenance-free. They did not protrude
from the side of the animal and, consequently,
were not vulnerable to mechanical disturbance
by the animal. The cannulas were long
lasting and were easily used for the sam-
piing of digesta or administration of test
materials.
The success of the preparation was due in
large part to the use of the cannula insertion
instrument, which, with relative ease, stretched
the tissues and pulled the cannula through
the abdominal wall, thus ensuring the forma-
tion of a tight scar ring.
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RUMEN AND ABOMASAL CANNULATION OF SHEEP 795
Literature Cited
Alonso, F. R., W. J. Donawick and E. P. Hammel.
1973. Cannulation of bovine abomasum: A
surgical technique. Amer. J. Vet. Res. 34:447.
Dougherty, R. W. 1955. Permanent stomach and
intestinal fistulas in ruminants: Some modifi-
cations and simplifications. Cornell Vet. 45:331.
Driedger, A., R. J. Condon, K. O. Nimerick and E.
E. Hatfield. 1970. A modified technique for
abomasal and rumen cannulation. J. Anim. Sci.
31:772.
Hecker, J. F. 1974. Experimental Surgery on Small
Ruminants. Butterworths and Co. Ltd., London,
England.
Hill, K. J. and R. A. Gregory. 1951. The preparation
of gastric pouches in the ruminant. Vet. Rec.
63:647.
Johnson, R. R. 1966. Techniques and procedures for
in vitro and in vivo rumen studies. J. Anim. Sci.
25:855.
Komarek, R. J. 1981, Intestinal cannulation of cattle
and sheep with a T-shaped cannula designed for
total digests collection without externalizing
digests flow. J. Anim. Sci. 53:796.
Komarek, R. J. and E. C. Leffel. 1961. Gas-tight
cannula for rumen fistula. J. Anita. Sci. 20:782.
Komaxek, R. J., E. C. Leffel. W. H. Brown and K. R.
Mason. 1960, Technique for the establishment of
a rumen pouch. J. Appl. Physiol. 15:161.
Markowitz, J., J. Archibald and H. G. Downie. 1964.
Experimental Surgery Including Surgical Phyiol-
ogy (5th Ed.). Williams and Wilkins Co., Balti-
more, MD.
Phillipson, A. T. and J.R.M. Innes. 1939. Permanent
stomach fistulae in ruminants. Quart. J. Exp.
Physiol. 29:333.
Stewart, W. E. 1967. Gastrointestinal eannulae made
of silastic. J. Dairy Sei. 50:237.
Stewart, W. E. and J. H. Nicolai. 1964. Abomasal
fistula technique for calves. J. Dairy Sci. 47:654.
Thyfault, H. A., E. C. Leffel and Ming Dertluang.
1975. Simplified method for producing perma-
nent ruminal fistulae. J. Dairy Sei. 58:1899.
Willes, R. F. 1972. Permanently installed digestive
cannulae. J. Anim. Sci. 55:1188.
Yarns, D. A. and P. A. Putnam. 1962. An economical
rumen cannula. J. Anita. Sci. 21:744.
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