18
Passage of Fluids through the Stomach of Sheep
capsules remained in the rumen and drugs administered through the stomach
tube also failed to pass through the rumen unless the tube was passed to its
fullest extent.
Sprehn [1931] records tests conducted by him with small (0.2 grm. each)
tablets which he found were able to pass directly into the abomasum, but
Oppermann Th. and Behrens [1932] were not able to confirm this result. In
connection with the passage of fluids through the ruminant stomach, Ross
[1931] has shown that the passage of fluids through various divisions of the
stomach of sheep is determined, rather by the period over which the animal is
deprived of water, than by the nature of the fluid given. He noted that water
or drugs in solution, when administered after withholding water for 40 hours,
passed in bulk into the omasum and abomasum. He failed to establish that
the administration of certain mineral salts per se markedly influenced the
passage of fluids to the abomasum. Further, his observations give no reliable
indication as to whether the strength of the drugs used (sodium bicarb, sodium
chloride and zinc sulphate) or the volume of fluid given influenced their
passage to the various organs. In a later publication [Ross, 1934] the same
author again records that the period of starvation greatly helps the passage
of fluids to the abomasum and that the administration of copper sulphate has
a marked effect in securing the passage of the whole or a considerable part, to
the abomasum.
LeRoux [1932] observed that tabloids or drugs in capsules invariably
remained in the rumen, and bulky powders followed a similar course.
Monnig and Quin [1933], while studying the physiology of deglutition in
merino sheep, noted that without previous stimulation of the reflex act powders
do not pass into the abomasum and the fluid consistence of the ruminal content
had an influence in stimulating the reflex. Later [Monnig and Quin, 1935]
the same authors made further studies and were able to conclude that copper
sulphate solution stimulates the reflex closure of the oesophageal groove and
under favourable conditions 0.25 per cent of the solution is able to induce the
reflex. The unfavourable conditions in the authors' opinion are poor condi-
tion and dryness of the ruminal contents. They further claimed that a 10
per cent solution is necessary to overcome these conditions. The authors do
not consider that preliminary starvation has a favourable influence unless the
sheep are starved for such a long period that the ruminal contents become fluid.
The method of administration was noticed to be of no importance. Copper
salts, other than the sulphate, also produced the reflex, but related metals such
as zinc or silver failed to do so. Drugs in powder form and pills reached the
abomasum within 15 seconds after previous stimulation of the reflex by copper
sulphate solution.
Quin and Vander Wath [1938] were able to observe that small doses (2
to 3 c.c.) of a 10 per cent solution of copper sulphate, as well as silver nitrate
and nicotine when dosed on the back of the tongue, all caused very profound
changes in the ruminal rythm due probably to vagal reflex.
Swales [1939] records that a simple 2 per cent copper sulphate solution in
2 ounce doses is able to stimulate the reflex closure of the oesophageal groove.
In order to study the problem in greater detail, investigations were
started on sheep, at the Government Cattle Farm, Hissar, in 1939. The study
is being made with the help of some drenches under variable conditions and the