284 Roundworm Parasites of the Digestive Tract of Cattle

DALE A. PORTER, HARRY HERLICH, AND HALSEY H. VEGORS

APPROXIMATELY 25 species of tilization occurs, and 18 to 23 days roundworms can live in the digestive after the larvae have been swallowed, tract of cattle. About 10 of them are of eggs from the female are passed with economic importance. Natural para- the droppings of the host. sitism usually is a mixture of several or We used to think that a bovine and all of them in one animal, and each an ovine strain of the common stomach type of worm produces a specific effect worm existed, but F. H. S. Roberts in on the infected animal. Australia stated in 1954 that the com- Three species of roundworms are mon stomach worms from sheep and commonly to be found in the stomach cattle were two distinct species. He (abomasum) of cattle. proposed that the name H. contortus be continued for the sheep species. He THE COMMON STOMACH WORM, Hae- proposed the name H, placei for the monchus contortus, occurs throughout the cattle species. Cattle are more suscep- United States in cattle and sheep. It is tible to H. placei than are sheep, and three-fourths inch to one and one-half sheep acquire greater numbers of H, inches long and about as thick as a contortus than cattle do. common pin. The adult females are larger than the males. The red spiral THE COMMON STOMACH WORM ap- effect often seen in the living worms pears to affect sheep and cattle in the gives rise to such common names as same way and is one of the most harm- wireworm, barberpole worm, and the ful species to both. twisted stomach worm. The most common symptoms are The free-living part of its life cycle is anemia, which is shown in paleness of much the same as that of all the round- the mouth and eyes, and emaciation worm species in cattle (except two despite continued good appetite. In- species of intestinal worms). Eggs are fected cattle may have a rough hair passed with the feces of the infected coat and "bottle-jaw," a fluid accu- animal. In 5 to 8 days, depending on mulation in the lower jaw. They may temperature and humidity, the eggs be stunted. Diarrhea is rare. The most have produced infective larvae (imma- acute stage of infection is usually dur- ture worms), which are capable of ing the first 2 to 3 weeks after larvae further development if swallowed by have been swallowed. Symptoms often susceptible grazing stock. disappear when the worms have The larvae do not feed and are en- reached maturity. Severe cases may re- closed within the cuticle (skin) of the sult in death. preceding stage of development. They also have an inner cuticle. The two THE MEDIUM STOMACH WORM, Oster- cuticles make the larvae able to survive tagia ostertagi, is hard to detect with the unfavorable conditions. naked eye. In clear water against a The infective larvae are eaten with black background, however, it can be the grass. They pass down to the stom- seen readily as a worm slightly less than ach, where they cast off their sheaths one-half inch long and about half as and undergo further growth until they thick as a pin. Living worms are often become mature males and females. Fer- reddish. Roundworm Parasites of the Digestive Tract of Cattle 285 Its infective larvae are susceptible to their developmental cycle within the heat and resistant to cold, so that they stomach lining of cattle and produce often become a problem during the ringwormlike lesions similar to those colder months. The larvae shed their produced by this parasite in horses. sheaths 3 days after they have been About 4 weeks after cattle have swal- swallowed and penetrate the lining of lowed infective larvae, eggs are passed the stomach. There they undergo fur- in their feces. ther development for about 7 days. The worms then return to the stomach THE SMALL HAIRV^^ORM does not seem lumen (cavity) and develop to matu- to affect the health of calves very rity. Many worms remain in the stom- much unless the level of exposure is ach lining for months. Eggs are passed high. Experimental findings, however, with the feces about 25 days after cattle have borne out clinical evidence that swallow the larvae. the small hairworm has been the main The worms damage the stomach lin- cause of many cases of severe illness ing severely as they bore into it. This and death. action stimulates a host reaction, which The detrimental effect of the small produces small nodules—raised, hem- hairworms on calves is notably marked orrhagic (bleeding) spots—in an at- in cases of parasitism involving both tempt to overcome the invading larvae. the small hairworms and the medium Eventually the worms leave the nodules, stomach worms. Postmortem examina- or die within them. Thereupon the tion of stomachs of these cases shows a nodules degenerate and leave patchy, diffuse reddish-gray or slate-gray color, eroded areas. with evidence of edema. As many as Animals infected with the medium 400,000 small hairworms have been stomach worm show general symptoms recovered after death—the animal of parasitism, including scouring, weak- must have swallowed enormous num- ness, stunted growth, and anemia. bers of larvae, because not all the Severe infections cause death. larvae become adults. Postmortem examination often re- veals a highly edematous—or swol- A CLOSELY RELATED form, T, Colubu- len—stomach wall, in which there are formis, primarily a parasite of sheep many hemorrhagic or eroded spots. and goats, occurs in the small intestines In the West and Southwest, the losses of cattle. It has been found in great that are directly attributed to round- numbers in New York in calves suffer- worm parasites are due mostly to the ing from parasitism. It might become medium stomach worm. a serious menace to cattle as the practice of raising sheep and cattle THE SMALL HAIRW^ORM, Trichostrongy- together becomes more prevalent. lus axei, is the smallest of the round- worms affecting cattle. It is less than SEVERAL SPECIES OF ROUNDWORMS one-fourth inch long and about as exist in the small intestines of cattle. thick as a hair. Laboratory equipment Three species of small worms arc is needed to detect it. The small hair- referred to as cooperids. One of them, worm can establish itself readily in Cooperia punctata^ occurs in all parts of sheep, goats, and horses. In horses it the United States. C. oncophora and C. causes an extremely severe gastritis pectinata are more often found in the (a stomach inflammation). Rabbits, Northern and Southern States, re- hamsters, and guinea pigs have been spectively. (A fourth species, C. curticei, experimentally infected with it. primarily a parasite of sheep, is found The life history of the small hairworm occasionally in cattle.) generally is like that of the common The cooperids arc as thick as a hair stomach worm and the medium stom- and less than one-third inch long. The ach worm. The worms spend part of live worms are yellowish or pinkish 286 Yearbook of Agriculture 1956 brown. They occur most often on (and up and swallowed and complete their occasionally embedded in) the lining development in the intestine. The of the intestines, principally along the time required for this migration and upper half of the small intestines. development is 52 to 79 days. All three species are similar in the The head end of the hookworm has essential details of their development, a large, cup-shaped mouth cavity which resembles that of the common armed with teeth, or cutting plates. stomach worm. The main difference is With them it attaches itself to the the rapidity with which the cooperids intestinal wall. It sucks a part of the complete their development within intestinal lining into its mouth and the animal. Eggs of C. punctata are cuts the finer blood vessels with the in the feces of infected animals ii teeth, and so gets its food from the days after infective larvae have been blood of the animal. When many swallowed. worms are present, the many small The cooperids have been implicated hemorrhages cause anemia. in field cases of severe parasitism in Other symptoms are like those seen cattle, but other parasites usually were in infections of stomach worms. The present and it was hard to determine calf may go off feed and eventually die. the extent of the detrimental effects Diarrhea, weakness, and unthriftiness directly traceable to the cooperids. are apparent about a month after in- C. punctata is potentially harmful to fection while the worms are still im- cattle. It can cause scouring, loss of mature. Thus severe symptoms of a appetite, weakness, and death. Anemia hookworm infection often are present was not evident in any experimentally during a period in which the infection infected animals. The lesions consist cannot be detected by finding eggs in chiefly of hemorrhages, which are the droppings. usually no bigger than a pinhead. The Adult hookworms may live in cattle intestinal wall is thickened. The sur- as long as 10 months. Infected cattle face of the intestinal lining has an acquire an immunity to further infec- unusual grayish-white appearance. tion with this parasite. The entire length of the small intestine may have an accumulation of white or THE INTESTINAL THREADWORM, the yellowish, cheesy material, indicating Strongyloides papillosus, is another skin- irritation of the intestinal lining. penetrating worm. It reaches maturity The hookworm, Bunostomum phleboto- in the small intestine. It is very widely mum, occurs in cattle all over the distributed and is common in young world. It is most prevalent in regions calves, especially in dairy calves and of high rainfall and warm climate, as in the beef calves that are dropped in in the Southeastern States. Normally barnyards. it is found in the upper half of the These roundworms are so tiny that small intestine, chiefly in the first 8 or they often are overlooked at postmor- 10 feet. The male worms are about tem examination. The adult females, one-half inch long. The females are about one-eighth of an inch long, usu- about three-fourths inch long. Both ally are buried in the lining of the up- sexes are much stouter than the com- per two-thirds of the small intestine. mon stomach worm. Parasitic males have not been found. Cattle become infected when they The eggs contain fully developed lar- swallow infective larvae. Larvae might vae at the time they are passed in the also penetrate their skin when they are feces. Intestinal threadworms have a lying on contaminated bedding or cycle in which there are free-living ground. The larvae that enter through males and females. the skin migrate to the lungs, probably The worms may enter through the through the blood stream, and pene- skin, or the infective larvae may be trate the lung. Then they are coughed swallowed. Immature females are Roundworm Parasites of the Digestive Tract of Cattle 287 found in the small intestine as early as cecum and large intestine. Eggs are 7 days after infection. Eggs are usually passed with the feces 33 to 43 days in the feces lo days after the animal is after infection occurs. exposed. The larvae in the tissue cause a Heavy infections cause severe in- thickening of the intestinal wall and flammation of the intestinal lining. a rupturing of small blood vessels. At Hemorrhages usually are evident in the point of larval entry, small, raised the first two-thirds of the small nodules are formed as a reaction of the intestine. Diarrhea is frequent during host, which is attempting to overcome the first 2 weeks of infection and con- the invading worms. The nodules get tinues intermittently for 2 to 3 months. bigger as the worms grow. A bloody, slimy discharge sometimes A single exposure to nodular worm accompanies the diarrhea. larvae does not cause nodule forma- The calf may go ofí" feed, lose con- tion. Multiple doses of infective larvae dition and grow slowly, or lose weight at different intervals—the normal oc- rapidly, depending on the severity of currence on contaminated pastures— the infection. Calves 4 or 5 months old result, however, in a severe nodular re- can survive heavy infections for a action. Large nodules are formed and longer period than calves a few weeks the intestine is inflamed and hemor- old, but the effects of parasitism may rhagic. Nodules are usually more pro- persist for some time after the infection nounced in the older animals than in is over. calves. The larvae and the nodules, by inter- THE NODULAR WORM, Oesophagosto- fering with the normal digestion and mum radiatum, gets its common name absorption, may produce a diarrhea of from the small, hard nodules that the varying severity. The discharge be- larvae produce in the wall of the lower comes watery, sometimes bloody, and part of the small intestine and cecum, has a disagreeable odor. Diagnosis is the large pouch at the beginning of the difficult in the early stages because large intestine. Nodular worms are worm eggs do not appear until 3 to 5 distributed wddely, but are especially weeks after onset of diarrhea. Calves prevalent in the Southern and Eastern may lose their appetite within 4 or States. Because their eggs and larvae 5 days after infection occurs, and are susceptible to drought and cold, then they may become weak and they occur less often in Northern and anemic. Western States. Symptoms subside and damaged tis- Adult worms are found in the cecum sues heal after the larvae leave the and large intestine. They are one-half intestinal wall and mature, but the to three-fourths inch long. Like hook- animals may be weak and in poor con- worms, they have a cup-shaped mouth, dition for months. The adult nodular which, however, lacks teeth or cutting worm can live 11 to 14 months in an plates. The head end is hook-shaped. infected animal. The females have a dark-colored spot The larva] stages of the nodular near the tail. worm of cattle can maintain them- Eggs pass out in the feces, hatch in selves for short periods in sheep. Al- 20 to 24 hours, and produce infective though they do not develop to the larvae in 5 to 6 days. Cattle become adult form, the larvae penetrate the infected by swallowing the larvae. intestinal tissues and cause damage in When the larvae reach the calf's low- sheep similar to that in cattle. er digestive tract, they burrow about halfway through the wall of the small Two SPECIES OF WORMS, the thread- intestine or cecum and remain there necked strongyles, Nematodirus helveti- about 10 days. Then they return into anus and N. spathiger, occur in the the intestine and reach maturity in the small intestines of cattle, although 288 Yearbook of Agriculture 1956 J\i. spatkiger is found primarily in sheep. Prevention is better than cure. Be- These worms are one-half to one inch cause the free-living stages of the long and about as thick as a pin. roundworms develop on the ground Living worms are usually reddish in and infection occurs primarily when color. cattle swallow infective larvae, preven- The free-living stages of the two tive measures are most effective when species develop differently from the they are aimed at the pasture phase. other roundworms parasitic in the di- Since moisture abeis the develop- gestive tracts of cattle. Eggs arc de- ment of the free-living stages and dry- posited on the ground. Development ness kills them, practices that tend to to the infective stage occurs entirely reduce the moisture on a pasture les- within the ç^gg. Consequently these sens the parasitic contamination. Pas- species are resistant to the effects of tures should be well drained. Watering climate and can survive long periods troughs should be raised above the of drought and cold. ground. Grazing should be kept to a Eggs containing infective larvae and minimum along the edges of ponds and infective larvae hatched from the eggs streams. Supplemental feeding should may be swallowed by cattle. They be away from wet ground, and the pass down the digestive tract to the feeding site should be changed to a upper 20 feet of the small intestine, new location as often as possible. Cattle where they shed the cuticles of the should never be fed hay and grain on second-stage larvae. The worms lie in the ground. close contact in the intestinal tract Free-living stages of roundworms with the intestinal lining, where they gradually succumb to natural environ- develop and become adult worms. mental factors in the absence of sus- Eggs are passed in the host's feces 2i ceptible grazing stock. Maintaining the to 26 days after infection occurs. proper rate of stocking and rotating Large numbers of N. helvetianus are pastures as often as forage is available detrimental to the health of calves. therefore greatly reduce pasture con- Scouring, loss of appetite, weakness, tamination. The fewer animals to the and severe setbacks in weight result. acre and the longer the pasture is left Experimental infections in which as vacant, the greater is the reduction in many as i million larvae were fed did the level of contamination. not kill calves. In Wyoming, however, Young animals, which generally are the deaths of 32 calves on a pasture more susceptible to parasitism, should were attributed to infections with enor- be isolated as much as possible from mous numbers of N. helvetianus. Post- older stock. Rearing dairy calves in mortem examinations of the experi- portable pens is a successful method of mentally infected calves showed that raising calves free of worm parasites the close contact of the worms with the (except S. papillosus). linings of the intestines cause some de- The nutritional state of cattle is im- struction of tissue, with an accumula- portant, for it affects the numbers of tion of thick, milky colored material in worms acquired and the effects of the upper part of the small intestine. parasitism. The use of temporary pas- The effects of N. spathiger on cattle tures, for which the seedbed is prepared have not been determined. In lambs each year, in conjunction with the ro- it produces symptoms like those de- tation of permanent pastures will help scribed for N* helvetianus in cattle. It is prevent severe parasitism. probable that jV. spathiger in large num- The most dangerous period for the bers would be harmful to cattle. development of parasitism in beef calves is during the few months just CONTROL OF ROUNDWORM PARASIT- before and after weaning. Conse- ISM of cattle requires good husbandry quently creep-feeding before weaning and proper treatment. and adequate pasturage, with or with- Roundworm Parasites of the Digestive Tract of Cattle 289 out supplemental grain after weaning, sloughing of nonpigmented areas. help to control parasitism. Calves pro- Temporary blindness has been report- tected from severe parasitism during ed in a few animals following treat- this period may develop a resistance to ment with phenothiazine in bright later infections. sunlight. Whenever practical, there- When animals that harbor parasites fore, cattle should be kept in barns or are added to a herd, they should be in shaded lots or woods for 24 to 48 treated and kept isolated for 3 or 4 hours after treatment. days. They should be treated again in 3 or 4 weeks. PHENOTHIAZINE is partly absorbed Phenothiazine (offered free-choice to into the blood stream of cattle. Milk cattle in combination with a mineral froiTi treated dairy cows is colored pink. base consisting of i part phenothiazine The drug is eliminated quickly from by weight to 3 parts each of bonemeal, the animal's body, and the milk can limestone, and salt, or incorporated in be used by people as soon as it loses its feed pellets) has given excellent control discoloration, usually 4 to 5 days after of the common stomach worm, H, con- it has been administered to the cows. tortus, and the nodular worm, 0. radia- Phenothiazine is given to cattle at a turn. dosage rate of 0.67 ounce (20 grams) The amount of phenothiazine thus per 100 pounds of body weight. The consumed daily averages only 3 grams maximum is 2 ounces (60 grams). or less per head. Although such small Some parasitologists have used as much amounts of the drug may have little as 4.5 ounces of the drug without toxic actual killing effect on the worms, the effects, but without enough evidence phenothiazine may lower the egg pro- that any greater efficiency of the higher duction of the female worms and have dosage justifies the extra expense. some killing effect on eggs passed in the Phenothiazine at the recommended feces. The drug used in this way seems dosage removes 100 percent of the to have little effect on other species of common stomach worms, the small round worms. hairworms, and the nodular worms. It also removes an average of 80 per- THE TREATMENT OF CATTLE with cent of all medium stomach worms, and drugs has two main aims: To remove 40 to 100 percent of the hookworms. worms from the infected animal and Its efficiency against the other spe- to reduce the number of eggs in the cies of roundworm s is relatively low. pasture. Several drugs are available It is effective only against adult worms; for removing worms from cattle. Phe- treatment consequently should be re- nothiazine, the drug of choice, has a peated in 3 to 4 weeks in order to kill number of advantages over other med- the worms that reach maturity during ications. that interval. Routine treatment of Phenothiazine may be given as a beef cattle in early spring and late drench or in a capsule or bolus and summer and fall helps greatly to reduce the animals can remain on full feed. parasitism. Other drugs require that the animals be fasted for several hours before DALE A. PORTER IS director of the treatment. Regional Animal Disease Research Labora- Phenothiazine is effective against a tory at Auburn^ Ala., of the Department greater range of species of worms than of Agriculture. He has worked as a parasi- any other known drug. Used at recom- tologist in the Department of Agriculture mended levels, it is relatively nontoxic since igjj and is an author of several to cattle. papers on parasites of swine and cattle. Dr. Cattle that are partly white occa- Porter is a graduate of Kalamazoo College^ sionally may become sensitized tem- Kansas State College^ and the Johns Hop- porarily and experience scaling or kins University, 366304°—56- 20 290 Yearbook of Agriculture 1956

HARRY HERLICH, a parasitologist at tory and is stationed at Experiment, Ga., the Regional Animal Disease Research where he conducts investigations on control Laboratory^ Auburn^ Ala., has conducted of cattle parasites by management in coop- research on parasites of cattle since ig4g. eration with the Georgia Agricultural Ex- He is a graduate of Tufts College and periment Station. He is a graduate of the Alabama Polytechnic Institute. University of California and has been asso- HALSEY H. VEGORS, a parasitologist, ciated with cattle parasite research in the also is associated with the Regional Labora^ Department of Agriculture since 1945.

Verminous Pneumonia of Cattle

ROBERT RUBIN

MOST internal parasites of cattle live of Great Britain, but in the United in the stomach or intestine, but the States the infective larvae have not worms known as Dictyocaulus viviparus, been known to survive more than a which live in the lungs, in many re- few months at any time of year. spects are the most injurious. There are many degrees of infection. They are 2 to 3 inches long, white, Even a lightly infected animal may be and threadlike. They live in the medi- quite dangerous—it may show only um and small air passages of the lungs. slight or possibly no effects, but it The females lay eggs, each containing might produce larvae enough to infect a very small worm (first-stage larva). an entire calf crop or a number of The larva usually hatches in the lungs. yearlings or adults. The only way such First-stage larvae are coughed up an animal can be detected is by finding and swallowed and then pass out in larvae in the droppings. That requires the droppings. An infected animal can skill, because the larvae cannot be seen pass 5 million larvae in a day—an without a microscope. important fact, for 5,000 fully de- An animal that ingests a large num- veloped larvae can kill a young calf. ber of infective larvae becomes sick in On the ground the first-stage larvae a short time, usually within 2 weeks. develop but do not grow. When a cer- The first noticeable sign is a cough, tain stage is reached, the small worms which becomes more and more fre- (third-stage infective larvae) are able quent. Breathing is faster and more to reach the lungs and develop into forceful. Often a loud grunt follows mature worms if they are taken into each breath. The sick animal may the body of a susceptible calf, yearling, stand away from the herd with head or adult. lowered and extended. The time required for first-stage As breathing becomes more difficult, larvae passed in the feces to reach the as it does in severe and fatal cases, the infective stage depends on the weather. animal breathes with its mouth open Only a week is needed in a warm, wet and tongue protruding—much as a period. Larvae do not develop in ex- dog pants. At that stage, coughing ap- tremely cold or dry weather. The parently has become too difficult or larvae can survive for weeks or months too much of a discomfort, and is in the infective stage. They reportedly seldom heard. A foamy and sometimes can survive an entire winter in parts bloody material may collect around