Common Diseases of Farm Animals

by Robert Alexander Craig

Species Organ
Ascaris inflexa Intestine
Spiroptera hamulosa Gizzard
Heterakis papillosa Caecum
Syngamus trachealis Trachea and bronchi

INTESTINAL WORMS OF SOLIPEDS.—The large round-worms or ascarides and the sclerostomes are the most injurious intestinal parasites of solipeds. The A. megalocephala or large round-worm is from 5 to 15 inches (12 to 35 cm.) long. It may be present in the double colon in such large numbers as to form an entangled mass that completely fills a portion of the loop in which it is lodged. It may interfere with digestion by obstructing the passage of alimentary matter, and irritating the intestine.

The S. equinum and S. tetracanthum are small worms. The former sclerostoma is from 0.6 to 1.5 inches (18 to 35 mm.) long, and the latter is from 0.5 to 0.6 inch (8 to 17 mm.) long. Both sclerostomes attach themselves to the lining membrane of the intestine by their mouth parts, and suck blood. The young S. equinum may live in tumor-like cysts that they cause to form in the lining membrane of the intestine. The young worm may penetrate the wall of a small blood-vessel as well, and drift into a large vessel, where it may become lodged and undergo partial development. The irritation to the blood-vessel results in an inflammation and dilation of the vessel wall. This is termed verminous aneurism. A portion of the fibrin-like lining of the aneurism may flake off and drift along in the blood stream, until finally a vessel that is too small for the floating particle or embolus to pass through is reached. The vessel is then plugged or a thrombus is formed. If the vessel involved by the thrombus happens to be a mesenteric vessel, then a loop of intestine has its blood supply cut off, and colicky pains result. Such colics are dangerous, and may terminate fatally. Intestinal obstruction, thrombo-embolic colics, unthriftiness and a weakened, anaemic condition may be caused by intestinal worms.

The treatment is both preventive and medicinal. The preventive treatment consists in giving young, growing animals the best care possible. Cleanliness about the stable, giving the colt plenty of range when running in a pasture, and feeding a ration that is sufficient to keep the colt in good physical condition are the important preventive measures. Tartar emetic in one-half to one dram doses may be given with the feed daily until five or six doses are given. Turpentine may be given in one to three ounce doses in a pint of linseed oil. This may be repeated daily for two or three days. Worms located in the posterior bowel may be removed by rectal injections of a weak water infusion of quassia chips. The rectum should be first emptied with the hand, and the nozzle of the syringe carried as far forward with the hand as possible. The injections should be repeated daily for several days.

INTESTINAL WORMS OF CATTLE.—Intestinal worms seldom cause serious losses from unthriftiness or death in cattle. It is in calves only that we are called on to treat this class of disease. The symptoms resulting from the invasion of the intestinal tract by the different worms vary in severity according to the number, habits of the parasite and care that the animal receives. The usual symptoms are unthriftiness, indigestion, diarrhoea and a stunted, anaemic condition. Stiles reported extreme anaemia, unthriftiness and many deaths among cattle in a certain section of Texas, due to extensive infection with the Uncinaria radialus.

The treatment is largely preventive. Calves and yearlings should be provided with plenty of feed at all seasons of the year. Good care and careful feeding will keep them in a thrifty, healthy condition and enable them to throw off invasions of intestinal worms. Turpentine is the vermifuge usually administered to calves. The dose is from two to four drams given in a milk or raw linseed oil emulsion.

STOMACH WORM OF SHEEP.—The twisted stomach worm, Haemonchus contortus, is the most injurious internal parasite of sheep. It is a very small, hair-like worm from 0.4 to 1 inch (9 to 25 mm.) in length. In the adult form it attaches itself to the mucous membrane of the fourth stomach or abomasum, and lives by sucking blood. The blood present in the digestive tract of the worm gives it a brown color, and the white oviducts which are wound around the digestive canal cause the body to appear twisted. When the twisted stomach worm is present in large numbers, the worms become mixed with the contents of the stomach and can be readily found on making a post-mortem examination.

Symptoms of stomach worms are first manifest in the lambs (Fig. 76). It is not until early summer that the disease appears in the flock. The symptoms are not characteristic unless we consider an unthrifty, anaemic, weak, emaciated condition accompanied by diarrhoea, during the summer months characteristic of stomach-worm disease. The sick animals are unable to keep up with the flock, and they like to stand about in the shade. They move slowly, the back is arched, the appetite poor, the mucous membranes and skin are pale and the hind parts soiled by the diarrhoeal discharge. More acute symptoms than the above sometimes occur. The disease may last from a few days to several weeks. A large percentage of the affected animals die.

[Illustration: FIG. 76.—Lamb affected with stomach worm disease.]

The treatment is largely preventive. Frequent changing of pastures and dry lot feeding are common preventive measures. Permanent sheep pastures lead to heavy losses from stomach worm disease. A very effective preventive measure, as we may term it, is the practice of administering a vermifuge to the ewes in the late summer and again in early winter. This may be given in a drench, or with the feed. This prevents the reinfection of the pastures every spring, and the young lambs are not exposed to this form of infection. The most effective treatment that the writer has ever used is the following formula recommended by Dr. Law: Arsenous acid one dram, sulfate of iron five drams, powdered areca nut two ounces, common salt four ounces. This is sufficient for one dose for thirty sheep. It may be given with the salt, or in ground feed. If the flock is apparently healthy, four doses given at intervals of three days is sufficient. If symptoms of stomach worms are manifested the animals should be dosed daily until they have received from five to ten doses, depending on the condition of the animal.