In the intervals between the colics, sodium salicylate, sodium or potassium carbonate, or olive oil in continuous doses may assist in disintegrating the calculi or passing them on. Chloroform tends to break them up by dissolving the cholesterin. But any such treatment must be accompanied by the abundant ingestion of water, and this is often best secured by a run in a rich green pasture. In the absence of pasturage, succulent fruits, and roots, ensilage, mashes, and gruels may be advantageously substituted, and conjoined with systematic exercise in the open air.
GALL STONES IN CATTLE.
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).