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									    A Simple Method for Preserving the Ruminant Stomach
                        D. C. Church

                   J ANIM SCI 1968, 27:1525-1526.

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                            RUMINANT STOMACH
                                             D. C. C~uRcrI
                                    Oregon State University, Corvallis 1

                                                               Evans (personal communication) used a
  H use of                       visual
T orEsamples appropriate models,may be aids,
              in the classroom          very                technique for fetal stomachs which involves
valuable in teaching. With respect to the rumi-             injection with red latex (Ward's Natural Sci-
nant stomach, fresh specimens are quite use-                ence Establishment) by tying a needle into
ful, but those of some species such as goats or             the esophagus of a fresh fetus. Gentle steady
deer may be difficult to obtain or the desired              pressure will fill the stomach. The esophagus
ages may not be available at any given time.                is then tied off and the fetus placed in a 10%
Furthermore, the normal shape is not always                 formalin solution. This allows the latex to set
easy to visualize after fresh specimens have                while the fetus is floating in fluid with the
been partially dissected. Several methods for               result that stomach shape is more natural
preserving the stomach have been developed,                 than with some other methods of preparation.
however, some of the procedures have not                    The formalin treatment is extended to at least
been published in the literature. Consequently,             a week and the specimen is then macerated in
this paper is intended to review the method-                hydrochloric acid. This removes the stomach
ology and to suggest a simple and effective                 wall and leaves a cast corresponding to the
method for preserving the ruminant stomach.                 internal structures. The cast must be stored
   Hix (1954) described a method for prepara-               in 2% formalin, otherwise it dries beyond
tion of fetal stomachs from calves. In this                 recognition. An example of this type of prep-
procedure, the stomach is washed out and                    aration is shown on p. 25 of Dougherty et al.
placed in 5 % formalin solution for hardening.               (1965). It would appear to be very useful to
After several days, it is washed and injected               show the internal structure of small organs,
with paraffin wax (M.P. 50 to 57 ~ C.) pre-                 but is probably of less use for large organs.
heated to 85 to 90 ~ C. The stomach is then                    Kitchell et al. (1961) have published de-
held under tap water to harden the wax which                tails of a method designed to produce very
is forced into all compartments by manipula-                durable specimens for class use. As with other
tion. Air pockets are removed with a needle                 methods, the stomach is cleaned of ingesta and
and paraffin injected to replace the air. The               inflated and the excess fat removed. The
preparation is then dried thoroughly. Exter-                stomach is immersed in 99% isopropyl alcohol
nal fat is then removed and a heavy coat of                 and partially filled with alcohol, being al-
banana oil-cellulose acetate in acetone is ap-              lowed to soak for about two weeks. Following
plied as a preservative. This method has the                this the stomach is dried with air when
advantage of providing a very durable speci-                s~spended with cheese cloth. After it is dried,
men, but one that is rather heavy if the                    fiberglass mats are applied as a covering ma-
stomach of an adult sheep or a large cattle                 terial with the aid of resins, followed by the
stomach is utilized.                                        application of several coats of resin.
   Scott (unpublished data) described a tech-                  Albright et al. (1963) discuss several meth-
nique in which the stomach is washed and                    ods of preserving stomach specimens. One
trimmed and then placed in a 10% formalin                   method suggested provides for preparation of
solution for at least 72 hr. After thoroughly               an inflatable specimen, the procedure essen-
washing in running water for 12 to 24 hr.                   tially resulting in a tanned stomach with at-
the stomach is placed in 45% v./v. glycerin-                tached valves. These authors also ~tiscuss a
water solution which contains crystals of thy-              method for preserving sections of the stomach
tool (2 to 3 gin/1.) which acts as a bacterio-              mounted in plastic and describe a periscope
star. The specimen is then inflated and dried               that can be constructed to view rumen ac-
with a continuous stream of air until dry. The              tivity.
preparation need not be coated, but may be,                    A simplified method for stomach preserva-
with a plastic-type finish (~uch at 12% solu-               tion that has been used in the author's labora-
tion of Saran 120 in methyl ethyl ketone).                  tory is described below. It has the advantage
 i Department of Animal Science.                            of being simple, yet adequate for most pl,r-

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1526                                          CHURCH
poses. The fresh stomach is trimmed, taking           plastic finish such as epoxy resin if extra
care to leave 6 to 10 cm. of esophagus and            durability is required. The labels can easily
3 to 5 cm. of intestine. Fat, lymph and blood         be seen through the finish, and it adds some
vessels are removed from the grooves and most         support. Holes can be cut in various sections
of the fat from the abomasum. The stomach             to allow one to see the internal structure. This
is flushed out repeatedly with water, or failing      method results in a light weight specimen that
that, it is opened and cleaned b y hand. I t is       has no unpleasant odor and which is reason-
recommended to soak the stomach in ethanol            ably resistant to handling. The shape is
to dehydrate the tissues and extract some of          stretched somewhat from its natural form, but
the lipids. Soaking time of a week is usually         this is difficult to prevent, and is not unduly
adequate if the stomach is moved about                objectionable. An example of such a prepara-
periodically. Following this, it is dried by          tion is shown in figure 1.
passing air through the stomach from the
esophageal entrance after tying off the in-
testine. Care should be exercised to maintain                           L i t e r a t u r e Cited
the stomach in approximately its normal                Albright, J. L., C. L. Davis and T. H. Blosser. 1963.
shape. If the stomach was opened or torn in              Teaching aids in rumen physiology. J. Dairy Sci.
any place, these openings must be closed                 46 : 1142.
 reasonably tight to avoid prolonged drying            Dougherty, R. W., R. S. Allen, W. Burroughs, N. L.
                                                         Jacobson and A. D. McGilliard (ed.). 1965. Physi-
time. In thicker parts of the stomach, es-               ology of digestion in the ruminant. Butterworth,
pecially the omasum, pin holes will help speed           Inc. Washington, D. C.
 the drying process. After the stomach is dried,       Hix, E. L. 1954. Preparation of the foetal compound
appropriate parts (sacs, grooves, major blood            stomach as an aid in the teaching of ruminant
                                                         nutritional physiology. J. Animal Sci. 13:49.
vessel paths, etc.) can now be labeled with            Kitchell, R. L., J. Turnbull, R. A. Nordine and S. C.
 india ink. The stomach is then coated several           Edgell. 1961. Fiberglass technique for preparation
 times with dope, lacquer, or some type of               of natural models. J. Am. Vet. Med. Assn. 138:329.

                      Figure 1. Right and left views of a dried goat stomach.

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