_Characters._ The biliary calculi of cattle are characterized by a faint
odor of musk, which becomes stronger on the addition of potassa and the
consequent disengagement of ammonia.
They are distinguished according to their color as dark green, yellowish
green, and orange, brownish or white. There are also the sedimentary
deposits (biliary sand).
The _dark green calculi_ are the most frequent, and being found in the
gall bladder and larger bile ducts, they attain a larger size than the
others. Those in the gall bladder may be pear-shaped, and those in the
ducts, round, ovoid or cylindroid. They are often rough and uneven on
the surface with deep cracks and holes penetrating deeply into their
substance and often filled with cholesterin. The pigments may change to
a blood red when dried. The consistency of these calculi varies, some
being hard, resistant and heavy, while others are soft and friable. All
are composed of concentric layers around a central nucleus as in those
of the horse. They vary in weight up to seven ounces in exceptional
cases. They contain cholesterin, fat, resin, pigments, and lime and
magnesia salts.
The _yellowish green calculi_ are usually spherical unless moulded into
polygonal shapes by mutual contact. In the last case they have flattened
surfaces. These have a firm consistency and are composed of successive
layers of nearly equal color and density surrounding the central
nucleus. They are on an average smaller than the dark green variety but
individual calculi have been found of three ounces.
The _whitish or orange calculi_ are usually in the form of hollow casts
of the bile ducts having a dull white color externally and a yellowish
brown internally. They are usually thin, fragile and crystalline and
contain relatively more earthy salts than the two first named varieties.
From this cause also they have a higher specific gravity. One specimen
weighed 8 ounces.
The _biliary sand or pulp_, is made up of granules of a yellowish, dark
green or black color, forming with the bile a pultaceous mass but drying
into a consistent mass. It may be firmly adherent to the mucosa of the
gall bladder and require to be scraped off. These granules may be looked
on as the first step in the formation of calculi or encrustations.
The _causes_ of biliary calculi in cattle are mainly close confinement,
dry feeding, abundant rations, the presence of trematodes in the bile
ducts and finally microbian infection.
_Lesions_ vary. With obstruction of the common bile duct or cystic duct,
there are usually dilatation of the bile ducts with fibrous thickening
of their walls so that they stand out as white branching lines on the
back of the liver. In extreme cases the common duct may acquire the
calibre of the small intestine. The gall bladder may participate in this
thickening (Chassaing) or may even rupture (Proger, Shaw).
In connection with obstruction microbian infection extends upward into
the liver, and in rupture of the bladder an acute, diffuse septic
peritonitis follows (Chassaing). This only follows on infective
inflammation of the gall bladder. Aseptic bile causes little or no
irritation.
_Symptoms._ As in the horse, general symptoms of ill health or hepatic
disorder are not pathognomonic. The presence of intermittent attacks of
constipation, and colic, with icterus, tympanies and violent efforts at
expulsion are the diagnostic symptoms of an acute attack. Pulsation and
respiration are accelerated, and the urine dense, high colored, oily and
slightly yellow. Reboul has noticed that symptoms are aggravated on
exposure to cold; there are great prostration and dullness, frequent
moaning and marked indications of tenderness when the right
hypochondrium is percussed. Charlot has observed that the only symptoms
may be persistent jaundice with scanty, high colored urine, containing
some sediment.
_Treatment_ is essentially the same as in the horse. Vanswieten and
Verheyen draw special attention to the fact that whereas biliary calculi
are very common in cattle during winter, they are rarely found in
animals that have been for even a short period on the spring grass.
Spring pasture is therefore the best therapeutic agent. During paroxysms
of colic, Glauber salts, or olive oil, antispasmodics and fomentations
over the liver are to be tried. In the intervals salicylate of soda,
sodium and potassium carbonate, olive oil, chloroform, and ether may be
used. Abundance of water and aqueous rations are essential.