key: cord-0040230-lg4tytmd
authors: Blowey, Roger W.; Weaver, A. David
title: Alimentary disorders
date: 2011-06-22
journal: Color Atlas of Diseases and Disorders of Cattle
DOI: 10.1016/b978-0-7234-3602-7.00010-8
sha: 804344838d0543ee10a4b51fa08b9ad4b3f5b369
doc_id: 40230
cord_uid: lg4tytmd

nan

Chapter 4 illustrates those conditions with primary alimentary signs. It excludes congenital (e.g., cleft palate) and acquired neonatal conditions (e.g., calfhood enteritis). The first section comprises infectious and contagious diseases: bovine virus diarrhea/mucosal disease (BVD/ MD) complex, vesicular stomatitis, papular stomatitis (all of which have rather similar gross features), and paratuberculosis. The second section covers the alimentary parasitic conditions: ostertagiasis, and small and large intestinal parasitism (for coccidiosis, see 2.31, 2.32). The remaining conditions are listed by anatomical site (oral cavity to anus), irrespective of their traumatic, nutritional, or other etiology.

Three viral diseases present problems clinically in differential diagnosis: bovine virus diarrhea/mucosal disease (BVD/MD), vesicular stomatitis, and bovine papular In utero infection in the second trimester, before the age of immunological competence of the fetus, can lead to the birth of a persistently infected calf which is BVD antigen positive, but antibody negative. Such animals may be either clinically normal or stunted, but they continually excrete virus. Unpredictable nervous signs such as aggression may be seen in some BVD persistent infection (P1) calves. At a later date, usually 3-30 months old, superinfection with a noncytopathic strain of BVD virus leads to a syndrome of mucosal disease, with ulceration throughout the gastrointestinal tract. Clinically these animals present signs of oral, intestinal and respiratory involvement. Erosions and hyperemia around the nares, lips, and gums are seen in 4.3.

The specimen in 4.4 shows numerous erosive and hemorrhagic lesions over the entire hard palate. Secondary bacterial infection of the lesions produces the necrotic ulcers seen in the caudal pharynx and rima glottidis stomatitis. In some regions, further differential diagnosis from foot-and-mouth disease and rinderpest may be necessary (see 12. 2-12.15 ). The pathogenicity and economic importance of these vesicular viral diseases vary greatly. Accurate differentiation is essential and usually depends on laboratory studies.

Bovine virus diarrhea/mucosal disease (BVD/MD) Definition: major infectious disease caused by a pestivirus.

Clinical features: BVD/MD is a major viral disease worldwide. Congenital defects such as cerebellar hypoplasia and cataracts (8.1, 8.4 ) may develop in the progeny of females infected during early pregnancy. BVD/MD causes diarrhea and unthriftiness in young cattle. Erosive stomatitis and rhinitis occur, together with similar lesions on other mucous membranes.

In utero infection in the first trimester can produce early embryonic death and infertility, and in the early to midfetal period congenital abnormalities such as cerebellar hypoplasia or, less commonly, hydranencephaly, as in the Piedmontese calf in 4.1. Though alert, and suckling with difficulty, it was unable to stand. It was relatively normal at rest, but extensor spasm and opisthotonus developed on minimal stimulation, e.g., when attempting to feed. Cerebellar hypoplasia was confirmed at autopsy examination. 4.2 shows a normal brain (left) and the affected brain (following infection of the dam at 150 days' gestation). mucosal changes are so severe as to leave the chronic, persistent infective case emaciated (as in the crossbred animal in 4.10) and a constant source of infection to susceptible contact cattle.

In some herds primary BVD in nonimmune cattle can also produce severe enteric signs and an increased (4.5). Necrosis and abscessation surround the epiglottis. The laryngeal mucosa is also hemorrhagic. Pus lies between the arytenoids, making respiratory efforts difficult and painful. Similar necrotic ulcers may extend over the hard palate, down the esophagus and into the abomasum. The esophagus may have patchy, linear areas of hemorrhage, edema and erosions. Erosions may be seen on the edematous and hyperemic edges of the abomasal rugae (4.6). Small intestinal erosions can lead to mucosal sloughing and the production of casts that pack the intestinal lumen (4.7). A secondary bacterial infection may be responsible for the enlarged nodes. Erosions may also occur around the coronary band and in the interdigital cleft (4.8).

The two cattle in 4.9 are both 18 months old. The nearer heifer, with an abnormal, rust-colored coat, is stunted as a result of chronic, persistent infection (antigen positive, antibody negative) due to maternal infection with BVD virus acquired in early pregnancy. Many of the Clinical features: the Charolais calf shows blanched areas on the rugae of the hard palate, dental pad, and gums (4.11). These pale areas are vesicles that rupture after some days (4.12). Secondary infection is rare. Vesicular stomatitis has only been confirmed in North and South America. Many animals may be simultaneously affected on one farm, showing excessive salivation, together with oral and possibly teat lesions. Teat lesions (11.26) in vesicular stomatitis can cause problems with milking. Secondary lesions may involve the claws.

Differential diagnosis: foot-and-mouth disease (12.2-12.8) and bovine papular stomatitis (4.13, 4.14 Clinical features: Johne's disease causes progressive weight loss, leading to eventual emaciation, although animals may remain alert and continue to eat. This chronic wasting disease is characterized by a profuse, watery diarrhea as seen in an 8-year-old Santa Gertrudis cow (4.16). Clinical signs of wasting and watery diarrhea are evident in a 2-year-old Blonde d'Aquitaine bull (4.17). When compared with normal ileum (4.18), the mucosa in a clinically overt case (A) shows numerous, thick, transverse rugae that cannot be smoothed out by stretching. Local intestinal lymph nodes are usually enlarged and pale, and may contain granulomatous areas. The usual age range is 3-9 years for the onset of clinical signs, which may be insidious, or develop suddenly after calving. Carrier animals excrete for many months prior to this. Infection is introduced into healthy herds by subclinical carriers. Young calves become infected in utero, via colostrum, or by oral ingestion. Age immunity develops by 4-6 months old.

Definition: mild disease caused by a parapox virus classified as a "paravaccinia virus" which generally has no adverse effect on the calf.

Clinical features: shallow papules and vesicles are seen on the muzzle, hard palate and gums of these young cattle (4.13, 4.14). Papules develop a distinct roughened center that sometimes expands to merge with adjacent vesicles. A Hereford crossbred calf (4.15) also shows muzzle and nares with ruptured vesicles. Teats are not affected. Immature cattle, sometimes an entire group, are usually involved and recovery is rapid. Systemic effects are rare.

Differential diagnosis: foot-and-mouth disease (12.2-12.8) and vesicular stomatitis (4.11, 4.12 

Clinical features: clinical signs tend to be much less severe than with Ostertagia. Heavy worm burdens in

The major gastrointestinal parasites of cattle are the stomach (abomasal) worms Haemonchus placei (barber's pole worm or large stomach worm, 3-18 mm long male), Ostertagia ostertagi (medium or brown stomach worm, 6-9 mm long), and Trichostrongylus axei (small stomach worm, 5 mm long). In tropical regions, other species, e.g., Mecistocirrus digitatus (up to 4 mm long), are significant. Severe infestations of Haemonchus can cause marked anemia, while the major effect of Ostertagia and Trichostrongylus is a severe, protein-losing gastroenteropathy, characterized by a profuse, watery diarrhea. All three species have the facility for their embryonated eggs or infective larvae to survive in feces for weeks or months at lower temperatures (e.g., over winter) or in drought conditions, until a favorable environment returns.

Of the three species, Ostertagia ostertagi is overall the most pathogenic and economically important in most temperate regions of the world, including the UK and much of the USA. As with most gastrointestinal parasites, the most severe effects are seen in growing animals. Nevertheless, it can be a devastatingly debilitating disease in susceptible adults.

Clinical features: cattle are most commonly affected with a chronic, persistent diarrhea and weight loss during their first season at pasture. Type I disease caused by Ostertagia ostertagi results from the ingestion of large numbers of L 3 larvae from herbage, starting 3-6 weeks before the onset of clinical signs. Small nodules that are 1-2 mm in diameter are present on and between the abomasal folds on the mucosal surface (4.21). In severe cases a "Morocco leather" or "cobblestone" appearance is evident (4.22). Higher magnification of a severe case shows the thickened rugae (ridges) and the white worms (4.23). Marked edema of the gastrointestinal wall is often present. Type II disease occurs when larvae ingested in the autumn lie dormant in the abomasal glands (as L 4 ), and then emerge en masse in late winter or early spring to produce a profuse scour and weight loss in housed 

Fluorosis Fluorosis (4.29) leads to mottling and excessive wear of temporary teeth during their development. The more severe fluorine-induced discoloration (4.30) should be differentiated from the staining caused by ingestion of some forms of grass silage. Other signs of fluorosis are seen in 13.31 and 13.32.

Irregular molar wear can sometimes cause masticatory problems. When eating or ruminating, this 8-year-old calves cause anorexia, severe, dark diarrhea, and weight loss. In older animals the nodules affect gut motility. These nodules may be palpated per rectum. The worms measure 12-15 mm and the head is angled to the body.

4.25 shows the serosal surface of the distal small intestine. Numerous caseated and calcified nodules indicate the presence of Oesophagostomum radiatum (nodular worm 12-15 mm long) in an older, resistant animal.

Oesophagostomum infection: in a clinical outbreak, all animals in the group should be treated with an appropriate broad-spectrum anthelmintic. The group should be moved to a "clean" pasture, and adequate nutrition should be ensured. Strategic management techniques have been developed as preventative measures, varying with worm types, climate, management systems, and economic considerations. In the UK the most common control is anthelmintic therapy of first-season calves from turn-out to late June, by which time all over-wintered larvae will have died.

Clinical features: dental problems are not a common cause of clinical disease in cattle. Occasionally, when the temporary incisors are being replaced by the permanent dentition, 2-3-year-old heifers show difficulty in prehension (4.26) leading to excessive salivation and weight loss. Diets such as heavily impacted self-feed silage leading to excessive incisor wear (4.27) may cause progressive weight loss. The crowns have almost disappeared, resulting in impairment of the animal's foraging ability. Shedding teeth (4.28) can lead to temporary dysphagia and impaired weight gain.

Management: heifers should ideally be milked as a separate group during their first lactation and be given easy-access feed. Management: a recent mandibular symphysial fracture may be stabilized by figure-of-eight wiring or use of a resin block across the incisor teeth. Milk-fed calves commonly continue to suckle and recover without treatment.

Discrete swellings of the head Actinobacillosis, actinomycosis, and local abscessation related to Arcanobacterium pyogenes can present similar clinical features in some cattle. Typically, however, actinobacillosis affects the soft tissues, especially the tongue, while actinomycosis involves bone. Abscessation related to tooth root infection is rare in cattle. A curious disorder or vice of habitual tongue playing, not involving any oral pathology, is shown in 4.33. This Guernsey cow lost a considerable volume of saliva through drooling.

Clinical features: Actinobacillus lignieresii preferentially colonizes the soft tissues of the head, especially the tongue. External swelling beneath the jaw may be seen (4.34). It typically causes a localized, firm swelling of the dorsum (D), as in this dairy cow (4.35) and firm, easily palpable, subepithelial masses elsewhere. Actinobacillosis with severe swelling of the tongue may result in its chronic protrusion (4.36). Other parts of the head, such as the nares or facial skin, are sometimes alone affected. Infection may pass down the esophagus, and lesions in the esophageal groove typically cause vomiting of rumen contents or bloat. Other areas of the body (e.g., the limbs (4.37) face and head (4.38), or flanks) may develop cutaneous actinobacillosis. Skin infection usually follows trauma and exposure to a concentrated infective dose of organisms, which are part of the normal flora of the upper GI tract. Such massive lesions are particularly liable to bleed and ulcerate. Most cases tend to occur in mature cattle of dairy breeds. bull (4.31) occasionally kept the jaws apart as a result of "locking" the overgrown lingual edge of the upper molars and premolars against the buccal edge of the mandibular cheek teeth. The length of the bilaterally symmetrical overgrowth was about 1 cm. 4.31 shows the typical open "locked" position.

Clinical features: mandibular fractures can occur in calves being kicked by cows or occasionally from iatrogenic trauma, e.g., from farm machinery. In the mature Friesian cow (4.32) with the symphysial fracture, the central incisor was displaced. There was little separation of the two halves of the mandible. A considerable quantity of saliva is being lost. In this case the cause Management: systemic antibiotics are effective, but prolonged therapy (7-10 days) may be needed. Provide clean feed and water, and avoid access to muddy streams. causes a rarefying periostitis of the maxilla and the mandible, with a surrounding soft-tissue reaction. The Guernsey cow in 4.40 has a right maxillary swelling, and several granulomatous masses have typically broken through the skin. The cow experienced no apparent interference with mastication for 18 months after the swelling was first seen. The crossbred Hereford cow with "lumpy jaw" (4.41) had moderate difficulty in chewing. A large, fistsized, proliferating mass lies over the angle of the mandible. Any discharge tends to be honey-like, containing hard yellow-white granules ("sulfur granules"). Despite secondary infection, body condition remained good. Dysphagia is usually due to malalignment of molar teeth. A lateral radiograph (4.42) of a 2-year-old heifer with mandibular actinomycosis (in considerable discomfort and rapidly losing weight) shows massive periosteal new bone formation (A) and cavitation (B). Management: actinomycosis has a poor prognosis despite attempts at debridement and prolonged (7+ days) systemic use of β-lactam antimicrobial drugs (e.g., synthetic penicillins and cephalosporins).

Definition: locally invasive and highly destructive tumor of the jaw.

Clinical features: an 11-week-old Saler heifer presents a mass (4.43) firmly attached to the mandible, which is distorted making prehension very difficult. Euthanasia as surgical removal was impossible. Such soft tissue malignancies are rare.

Differential diagnosis: actinomycosis (4.41), actinobacillosis (4.38).

Etiology: malignant edema is caused by Clostridium septicum and results from contaminated wounds in any superficial part of the body, although the head and neck are most commonly affected.

Clinical features: anorexia, pyrexia, and toxemia develop rapidly along with local lesions. In this cow (4.44), infection entered the masseter area of the right cheek to cause a rapidly enlarging and unilateral soft tissue swelling, especially obvious around the right nostril. There was pronounced salivation. The brisket was enlarged with edematous fluid (4.45). Despite prompt, prolonged antibiotic therapy, infection spread to the forelegs and, as in many cases, was fatal. Gas formation is rare. 

Pharyngeal and retropharyngeal swellings can range from being innocuous to rapidly fatal. Careful external and oral/pharyngeal examination is essential. A swelling may be indicative of systemic disease elsewhere, such as right heart failure manifested as submandibular and retropharyngeal edema (6.2). The swelling may involve retropharyngeal and parotid lymph nodes in a neoplastic reaction (12.74). Severe reactions in the submucosal tissues of the pharynx, with potentially dire consequences to the airway and possibly death, can result from ingestion of neat caustic soda (sodium hydroxide) from improperly mixed caustic wheat, or anthelmintic bolus gun injuries. The introduction of a small amount of irritant material (e.g., poloxalene for bloat control) through an accidental puncture wound, or other forms of extensive lacerations to the pharyngeal wall, cause severe edema, cellulitis, and pose a major problem (see below).

Clinical features: perforation of the pharyngeal wall by a drenching gun caused a septic cellulitis leading to the grossly enlarged submandibular and parotid regions (4.49). One consequence of this cellulitis was a malodorous, purulent nasal and oral discharge. The steer was pyrexic and anorexic. Autopsy examination of another case (4.50) revealed masses of inspissated pus beneath the pharyngeal and laryngeal mucosae, which had caused respiratory embarrassment (inspiratory stridor). Note the congestion of the mucosal surface of the epiglottis.

Incorrect dosing techniques can result in anthelmintic boluses penetrating the pharyngeal mucosa, migrating down the neck, and producing severe respiratory distress due to foreign body reaction and airway obstruction.

premolars and molars in calves following a severe gingivitis and secondary bacterial infection (Arcanobacterium pyogenes and Prevotella melaninogenica). The first sign is uni-or bilateral swelling of the cheek as a result of impaction by pasture grass. Autopsy examination reveals loss or marked displacement of several temporary teeth, particularly premolars two and three, and a massive periosteal and osteolytic reaction in the related maxilla (4.46, 4.47). On pastures of guinea grass (Panicum maximum), which causes traumatic damage to the gingiva, the condition leads to malnutrition and sometimes death. The 18-month-old mixed Zebu steer from the Mato Grosso (4.46) has lost the right second and third upper premolars (A) and the left second premolar (B). Loss of the surrounding cement has led to deep pockets on the labial side of the right arcade (C). The steer was severely emaciated. 4.47 shows a similar type of animal. A striking, chronic, ossifying periostitis affects the region around the roots of P2 and P3, explaining the likelihood of tooth loss.

Clinical features: caused by Arcanobacterium pyogenes, a smooth and localized soft-tissue swelling, discharging pus, lies over the horizontal ramus of the left mandible (4.48). It developed rapidly over 3 weeks and resolved slowly.

Differential diagnosis: actinomycosis (4.40), actinobacillosis (4.34), fracture of the mandible (4.32). 

Clinical features: a potato is lodged two-thirds of the way down the cervical esophagus to the left of the hand (4.52). The animal was uncomfortable and drooling as a result of its inability to swallow saliva. Since eructation was impeded, it also had rumen tympany. Common sites of esophageal obstruction are just dorsal to the larynx and at the thoracic inlet. In cattle, esophageal foreign bodies tend to be solid objects, such as apples, large portions of turnips or beets, or corncobs (maize). Other suspicious signs of esophageal obstruction include extension of the head and neck, dyspnea, occasional coughing, and chewing movements. A cervical esophageal foreign body is readily palpated externally.

Differential diagnosis: acute rumenitis (4.56-4.60), traumatic reticulitis, oral lesions, rabies (9.33-9.35).

and anti-inflammatories are needed, but effective therapy is very difficult in severe cases with extensive septic cellulitis. Respiratory obstruction is possible (emergency tracheotomy) or rumen tympany (trocarization), but most cases fail to respond and culling is the usual economic option.

Clinical features: a discrete and relatively painless fluctuating, tennis ball-sized mass lies in the retropharyngeal region (4.51). Clinical features: the entire cervical esophagus (4.53)

is grossly distended (about 5-6 cm in diameter). Contrast radiography revealed a similar distension of most of the thoracic esophagus. The abnormality had been first observed at 1 year of age. Clinical signs included frequent regurgitation. The 15-month-old Charolais heifer was observed for 1 year and almost completely recovered. Megaesophagus is rare and, although usually congenital, this case was probably secondary to a systemic infection.

Differential diagnosis: esophageal obstruction.

Rumen acidosis (rumenitis) ingestion of moldy feed, e.g., cereals or beans. Changes are most common in the ruminoreticulum (4.58) and omasal involvement is rare.

Differential diagnosis: winter dysentery, bloat, and diarrhea from other causes, e.g., sudden feed change.

Management: cases of mild acidosis will resolve without treatment. More severe cases require oral antibiotics (to reduce rumen fermentation), NSAIDs (to suppress laminitis), and antacids and B vitamins (since ruminal vitamin B synthesis is depressed by acidosis). Advanced cases with a metabolic acidosis benefit from i.v. sodium bicarbonate infusion and even evacuation of rumen contents (rumenotomy or esophageal flushing). Prevention is based on dietary management. Cattle on ad-lib cereals should always have access to palatable fiber (e.g., straw) and never be allowed to be hungry. Highyielding dairy cows need adequate digestible and long fiber to balance a high-starch diet. Ideal concentrate:fiber ratio should never exceed 60 : 40.

Definition: accumulation of gas in a distended rumen.

The gas may be free or present as a foam. (See also bloat in younger calves, 2.38.)

Clinical features: the Holstein heifer in 4.61 has an obvious distension of the left paralumbar fossa. The swelling may extend above the level of the lumbar spine, as seen in the Hereford steer (4.62). Both animals had a gaseous as opposed to a foamy (or frothy) bloat. Extreme cases may die from increased intra-abdominal pressure leading to cardiac and respiratory failure, often with inhalation of rumen contents.

Differential diagnosis: distinguish gas bloat from frothy bloat; esophageal obstruction (4.52), an esophageal groove mass (4.63), traumatic reticulitis (4.67), rumenal atony. (For bloat in a calf, see 2.38.) Management: frothy bloat responds well to oral surfactants such as paloxalene. Gas bloat can usually be are often red or dark. A close-up view of a more chronic rumenitis (4.59) shows a rumen fold separating the disorganized and necrotic rumenal papillae (A) from more normal papillae (B). In rumenitis colonized by Fusobacteria and fungi, healing eventually occurs after sloughing of the necrotic layers, contraction of the ulcer, and peripheral epithelial regeneration, resulting in stellate scar formation. The rumen is then left with a reduced absorptive capacity, and possible secondary hepatic abscessation.

The omasum in 4.60 shows a fungal infection (most likely due to Aspergillus species) following the accidental 4.57. Fatal rumen acidosis with (pink) sloughed ruminal epithelium (autopsy) in bull (Simmental, 10 months old) Differential diagnosis: exploratory rumenotomy may be needed to differentiate benign or malignant (squamous cell carcinoma (SCC)) neoplasia from actinobacillosis of the esophageal groove, chronic reticuloperitonitis or reticular wall abscessation. (See 4.67 for another ruminoreticular neoplasm (fibroma).)

In comparison with the horse, such signs of pain as seen in this heifer (4.64) are uncommon. The forefeet are placed further forward than normal, presumably in an attempt to reduce tension on the abdominal viscera. The head is turned towards the flank. The tail is slightly elevated (indicative of tenesmus) and the heifer is kicking at the belly with a hind foot. The stance suggests an intestinal problem. Posterior abdominal pain can result in tenesmus that may not necessarily reflect an alimentary origin, e.g., babesiosis (12.39-12.43), cystitis (10.14), or urethritis.

Traumatic reticulitis (reticuloperitonitis, "tire wire disease") Definition: perforation of reticular wall and parietal peritoneum (usually diaphragm) with development of localized or generalized peritonitis.

Clinical features: Cattle with acute reticuloperitonitis are pyrexic, slightly bloated, and typically grunt during reticular movements unless there is ruminoreticular stasis. Affected cattle may rapidly become dehydrated, one sign of which is obvious skin "tenting" (4.65): the skin fold remains for 3-10 seconds or more (indicating approximately 6-12% dehydration). They appear dejected, have an arched back, raised tail, sunken eyes as a result of the dehydration, weight loss, and an empty flank and "tucked up" belly due to lack of rumen fill (4.66). They are often reluctant to move due to abdominal pain. relieved by stomach tube, but extreme cases require trocarization. Prevention depends on avoidance of causative agents.

Clinical features: this pedunculated mass (4.63) is a benign papilloma. Lying at the proximal end of the esophageal groove, it caused partial obstruction of the lower esophageal sphincter, resulting in an intermittent this reticulum (4.67) was a discrete pedunculated fibroma (A). Wires contained within fragmenting car tires, originally used to keep grass silage sheets in place or left in a field corner, are a frequent source. An autopsy case (4.68) shows cardiac tamponade due to a tire wire which having perforated initially the diaphragm, has traveled through the epicardium into the myocardium, rupturing a major vessel which has pumped blood into the pericardial sac, resulting a sudden interference with cardiac activity. Herd outbreaks may arise when an entire tire is accidentally chopped up in the feed wagon.

Differential diagnosis: left (4.76) or right (4.78) displaced abomasum, abomasal ulceration with perforation (4.72), cecal dilatation (4.89), bacterial endocarditis (6.3), rumen acidosis (4.58, 4.59), other digestive upsets.

Management: prognosis is good in early acute cases following rumenotomy and removal of penetrating wire in reticulum. Alternative medical management involves antibacterials for several days, elevation of the forequarters, and oral administration of a magnet which is useful both for prophylaxis and treatment. Prognosis is hopeless when penetrating wire has perforated the pericardium (traumatic pericarditis, 6.6) or myocardium leading to cardiac tamponade (4.68) This section (4.67) of the reticular wall illustrates the typical wires that may perforate the wall to cause a localized or generalized peritonitis (4.90, 4.91), hepatic abscessation (4.100), or may travel cranially to produce a septic pericarditis (6.5). An incidental abnormality in Discrete omasal obstruction (as opposed to secondary abomasal obstruction) due to reticuloperitonitis is rare. When compared with 4.69, the abdominal silhouette of the 2-year-old Holstein bull in 4.71 is similarly asymmetrical, showing distension of the upper left (ruminoreticulum) and lower right (omasum, and to a lesser extent ruminoreticulum) flanks. The cause of the omasal obstruction was secondary impaction due to a reticular wall abscess (foreign body: wire) and a localized reticuloperitonitis. Mechanical causes, such as neoplastic infiltration near the pylorus, can lead to similar effects. Diagnosis depends on exploratory laparotomy. Differential diagnosis: chronic traumatic reticulitis, peritonitis, rumen tympany, abomasal impaction, obstruction of the reticulo-omasal orifice.

Management: diagnosis of the specific cause involves an exploratory laparotomy and rumenotomy. Evacuation of rumen contents may improve motility temporarily. Symptomatic treatment is necessary. The prognosis is often poor.

Clinical features: abomasal ulceration occurs in mature dairy and beef cattle and in calves (2.27-2.29). Some cases in adults are the result of primary diseases such as infiltrative lymphosarcoma, and systemic infections such as BVD and malignant bovine catarrh. In highyielding dairy cows, although the cause is unknown, ulcers are usually associated with stress and highconcentrate rations. Multiple abomasal ulcers may occur in calves (2.28). There are four types of ulcer. Type I causes no clinically apparent disease and is common. Type II is a bleeding ulcer that, if persistent, results in progressive anemia. Types III and IV cause an acute localized or generalized peritonitis with signs of pain, and Type IV is almost always fatal. Animals are dull, with a drop in yield, often a subnormal temperature, and general signs of anemia.

The Guernsey cow in 4.72 had abdominal pain due to a Type III (perforating) abomasal ulcer causing a Clinical features: the silhouette of the abdominal wall shows a massive, left-sided swelling due to an accumulation of fluid, primarily in the ruminoreticulum (4.69). After pumping out 90 liters, the flanks became almost symmetrical (4.70). The distension is characteristically in the upper left and lower right flanks, resulting in the so-called "ten-to-four" appearance. 4.71 is a typical example.

Ruminoreticular distension that results from vagal dysfunction due to chronic reticuloperitonitis is the most common manifestation. Severe ruminal distension is most marked in the left sublumbar fossa and low down in the right flank (so-called "papple-shaped", i.e., pear × apple). This specimen from an old Holstein cow shows thickened and irregular abomasal rugae as a result of lymphoma infiltration (4.75). Neoplastic infiltration was widespread. The discrete, dark, punched-out areas are ulcers, indicating that the two conditions can occur together.

Management: diagnosis ultimately requires histological confirmation. Control in a herd is difficult but regular serology may facilitate removal of positive carriers. (See also 12.74-12.81.)

In areas of intensive management, left and to a lesser extent right abomasal displacements are common localized peritonitis. She passed black, tarry feces containing much digested blood (4.72). Cows sometimes die following severe blood loss into the abomasal lumen. Autopsy examination (4.73) reveals numerous ulcers, several filled with blood (A), and a diffuse abomasitis. The pathology is similar to that of the calfhood disease (2.27-2.29), with localized or generalized peritonitis as possible sequelae. Healing abomasal ulcers (4.74) show scar tissue causing contraction of the abomasal wall in a stellate pattern. Some bleeding was still occurring.

Differential diagnosis: traumatic reticulitis, abomasitis, abomasal lymphoma (lymphosarcoma) (4.75), jejunal hemorrhagic syndrome (4.83-4.85).

Management: depending on the symptomatology, broad-spectrum antibiotics are indicated in perforating ulcers, whilst fluid therapy including blood may be given to dehydrated animals and cases of bleeding ulcers. Unfortunately fluids increase blood pressure and in many cases will precipitate further hemorrhage from the ulcer. Management: mild cases of RDA may slowly respond to medical therapy (meclofenamic acid, spasmolytics) and dietary management. More advanced cases require surgical drainage and abomasopexy. After removal of the large volumes of gas and fluid, most cases will recover slowly.

conditions in dairy cattle. Right abomasal torsion can be a serious secondary complication of right abomasal displacement. Most cases of mechanical displacement of this type occur in high-yielding cows in early lactation, and are preceded by a period of ruminal and abomasal atony. Many cows will have had periparturient problems such as retained placenta, ketosis, metritis, mastitis, for dietaryinduced rumen acidosis (SARA) in the preceding weeks.

Clinical features: the displaced abomasum is situated almost entirely beneath the rib cage on the left, where it can be detected by percussion and auscultation. The caudal, dorsal portion may extend behind the last rib to form a palpable, soft swelling which may on rectal examination be distinguished from the underlying rumen in the paralumbar fossa. In 4.76 the abomasum (A) may be seen through a left paralumbar vertical incision lying between the cranial edge of the incision and the spleen (B), which is cranial to the visible portion (C) of the rumen wall. LDA presents with variable clinical signs, often a sudden loss of appetite for concentrates and precipitous drop in yield. Other cows have moderate inappetance, weight loss, and a secondary ketosis. With this slow loss of condition due to partial inappetance, the bulge (A) of the abomasum may then become more obvious in the left flank (4.77).

Differential diagnosis: right displaced abomasum (4.78), cecal torsion (4.88), primary ketosis. Management: conservative correction by rolling, confinement to a loose box, and a high roughage intake can cure up to 30% of cases. Surgical abomasopexy by one of several techniques, or a "toggling" procedure are preferred, and the prognosis is then good. Clinical features: seen in younger cattle (e.g. 6-12 months) in certain regions and under specific husbandry conditions trichobezoars (4.82) are comparatively rare in cattle. Signs are nonspecific with inappetance and weight loss, but ballottement in calves can be diagnostic. Frequently an abomasal trichobezoar also causes a secondary abomasitis and associated ulceration.

Management: surgery on individual valuable animals, dietary change, and husbandry management, e.g., treatment for lice to reduce the frequency of licking the haircoat.

Clinical features: abomasal torsion with dilatation is clinically severe, and affected cows are dull, sometimes recumbent, totally anorexic, dehydrated, in shock and have an empty rectum. The dilated abomasum can be percussed on the right flank and may be palpable per rectum. An autopsy specimen (4.79) of the abomasum (A), ruminoreticulum (B) and duodenum (C) shows a complex torsion of both the abomasum and omasum. Typically, the cow was found in extreme shock. The abomasal fluid volume exceeded 90 liters (normal volume: 10-20 liters).

Management: most cases should be culled. Any attempt at treatment involves correction of the fluid imbalance and right-sided abomasal drainage followed by attempted reposition of the abomasum.

Clinical features: herd outbreaks usually result from consumption of large quantities of poor-quality roughage in cold weather by young beef cows (e.g., Canadian prairies, Saskatchewan). Sporadic isolated cases are seen in dairy cows secondary to vagal indigestion (p. 71). Signs include anorexia, reduced feces, and increasing distension of both flanks ("10-to-4" appearance). A 5-year-old Holstein cow, fed maize silage and grass silage (4.80), presented with a massive, firm abdominal distension. At autopsy (4.81) the abomasal volume was 60-70 liters, and included 15-20 kg sand. The abomasal mucosa was very congested and, after emptying, some sand is still evident between the folds. This was the only cow affected within the herd, suggesting the impaction could have been related to a pre-existing vagal indigestion. 12 hours profuse dark, tarry feces may be passed, with early recumbency and death within 36 hours. Right flank exploratory laparotomy discloses multiple jejunal loops distended with bloody fluid (4.84). Autopsy reveals massive whole blood clots in numerous jejunal loops (4.85) and petechiae on the intestinal serosa, as well as early peritonitis (serosal tags evident).

Differential diagnosis: acute abomasal ulceration with perforation and early peritonitis, acute jejunal intussusception, right abomasal torsion.

attempt is to be made to correct the massive fluid and blood loss. Few peracute cases survive. Improved dietary management is indicated.

Jejunal hemorrhagic syndrome (JHS), hemorrhagic bowel syndrome (HBS), hemorrhagic gut syndrome (HGS), "hemorrhagic enteritis" Definition: a relatively recently described acute condition of milking dairy cows, usually fatal, of unknown etiology, but associated with high yields and high feed intakes.

Clinical features: possibly fleeting signs suggestive of clinical ketosis (recumbent cow unwilling to go to milking parlor). Most cases have sudden onset (4.83) of shock, total inappetance, and severe anemia. Distension of right flank and ballottement reveal extensive fluidfilled intestinal loops ventrally, and gas in paralumbar fossa and beneath rib cage. In cases surviving more than Clinical features: intussusception, though sporadic, is the most common cause of small intestinal obstruction in cattle. Occurring at any age, it initially causes severe abdominal pain. Progressive shock develops. The rectum is totally void of feces. In larger cattle torsion may be detectable on rectal examination as a tight mesenteric band passing obliquely across the abdomen. In 4.86 the darker loop of small intestine (A), showing marked congestion and subserosal hemorrhage, particularly on the mesenteric border, is the segment of bowel through which the intussusception has passed. Dilated proximal intestine is seen at B. The point of invagination of the intussusception, which is not visible in this picture, lies tightly knotted deeply below the position of the fingers.

An autopsy case of massive jejunal torsion is seen in (4.87) with most jejunal loops dilated and discolored, as is the mesenteric suspension with patchy areas of hemorrhage. The abomasum lies adjacent to these loops. Such cases are usually acute and fatal.

Affected animals often have a grossly distended abdomen (4.88) due to fluid accumulation in the prestenotic small intestinal loops, abomasum, and ruminoreticulum.

Differential diagnosis: abomasal torsion (4.79), jejunal hemorrhagic syndrome (4.83, 4.84).

Management: early cases are sometimes amenable to surgical correction (resection and anastomosis). However, most cases should be promptly culled. Logical preventive measures to reduce the alleged initiating factor for intussusception (intestinal irritation) are parasite control and dietary management.

Clinical features: affected cows are dull, partially anorexic and have a depressed yield. Onset may be slow and subtle. The dilated cecum can be percussed in the caudal upper right flank and be palpated per rectum (slightly mobile "loaf of bread" shape). Following cecal displacement and distension, the Holstein cow (4.89) developed an acute (painful) abdomen within 48 hours. The enlarged cecum was appreciable on rectal palpation. The cecal apex has been prolapsed through a dorsal and caudal right flank laparotomy incision (4.89), but most of the cecum still lies within the abdominal cavity. The peritoneal surface is slightly congested. Many cases of simple cecal dilatation are asymptomatic. Some develop into cecal torsion and show more severe pain and depression. Others may even recover spontaneously from dilatation. Clinical features: it may be localized or generalized, acute or chronic. It is commonly secondary to contamination of the abdominal cavity, e.g., secondary to traumatic reticulitis or cesarian section. In active disease, guarding of the abdomen results in a stiff gait (see p. 69). The bovine peritoneum and greater omentum have a remarkable facility to wall off leaks of bowel contents and localized areas of abscessation. This process often results in few or no complications in the cranial part of the abdomen. Adhesions developing in the caudal part can cause progressive bowel obstruction. In 4.90 the visceral and parietal peritoneum (rumen, jejunum, and greater omentum) is covered with a fibrinous and purulent exudate, typical of early generalized peritonitis. The changes are more advanced and chronic in another case (4.91), resulting from septic reticuloperitonitis (see also 4.67).

Typical clinical cases of active peritonitis are dull, pyrexic, often partially anorexic and cows have a reduced milk yield. More chronic cases are in poor bodily condition. Rectal examination reveals an empty rumen, and a typical "doughy" feel to attempts to palpate abdominal viscera.

Other common causes of peritonitis are perforated abomasal ulcers, either in calfhood (2.29) or in adult life (4.73), and rupture of the small intestine following uncorrected intussusception or small intestinal torsion.

Definition: disease caused by infestation with Fasciola, also termed distomatosis.

Clinical features: an increasing problem in many regions, low-grade fluke infestation produces nonspecific clinical signs such as poor condition, reduced performance (growth and milk yield and quality), and anemia. Autopsy reveals the liver becomes fibrotic with enlargement, the bile ducts grossly thickened, and mature Fasciola hepatica flukes occupy the lumen (4.93, 4.94). The walls may eventually become calcified. The from chronic severe fascioliasis. Compare intestinal obstruction (4.88). The abdomen is rarely painful on palpation, unlike peritonitis (p. 77). Diagnosis is confirmed by a midline abdominal tap (sterile needle).

Differential diagnosis: peritonitis, (4.90), hydrops amnii, hydrops allantois (10.54), abomasal impaction (4.80).

Management: most cases are incurable and should be culled.

Clinical signs of liver disease are variable and relate to its wide range of functions. These include bile production, synthesis of specific plasma components, detoxification, storage, and a variety of metabolic processes.

Its large functional reserve results in the signs of disease usually becoming evident only when hepatic damage is extensive. There are few characteristic signs of malfunction, and diagnosis often presents a major challenge to the clinician. Several specific diseases of the liver cause reduced weight gain and slaughterhouse condemnation of the liver (abscessation, fluke infestation). Ancillary diagnostic aids include enzyme estimation (sorbitol dehydrogenase (SDH), glutamate dehydrogenase (GDH), γ-glutamyl transferase (GGT)) and percutaneous hepatic biopsy.

Examples of the hepatic diseases illustrated below include fascioliasis resulting from severe parasitism, necrotic hepatitis caused by Clostridium novyi type B (oedematiens), and hepatic abscessation secondary to rumenitis (Fusobacterium necrophorum). Although not specifically involving the liver, other forms of fluke are also included in this section. Fatty liver syndrome produced by illdefined nutritional and metabolic imbalance is described in Chapter 9 (9.9), and photosensitization secondary to hepatic disease in Chapter 3 (3.3-3.9). (A), with the female lying in a longitudinal groove of the male. Flukes may be up to 30 mm long. Pathogenic species are primarily found in mesenteric blood vessels, although one species, S. nasale, inhabits the nasal mucosa. The major clinical signs of hemorrhagic enteritis, anemia, and emaciation are seen when the spiny eggs pass through the gut wall. In the hepatic form, granulomas form around the eggs. Lesions may also be found in the liver, lungs and bladder. S. nasale (4.97) produces a proliferative reaction of granulomatous masses, seen in this median section through the nasal turbinate bones. Abscesses rupture to release pus and eggs into the nasal cavity. The effect is chronic nasal obstruction and dyspnea. The parasite inhabits the veins of the mucosa. S. nasale is a problem in the Indian subcontinent, Malaysia, and the Caribbean. In the human, cercariae cause "swimmer's itch" and "swamp itch". visceral surface becomes irregular and granular in appearance. The associated fat in ligamentous attachments is lost, leaving little but the grayish peritoneal surface as emaciation develops. Clinical cases become hypoproteinemic, developing ventral and submandibular edema. Ascites (4.92) is a common result. Frequently there is liver condemnation at abattoir.

Diagnosis: in subacute and chronic disease, variable numbers of eggs may be detected in feces. An absence of fluke eggs does not eliminate the presence of fluke. Plasma GGT is elevated in cattle with bile duct damage. Serology will detect antibodies to fluke. Autopsy appearance is diagnostic. A fascioliasis, the larvae of Fasciola hepatica are the usual cause of the initial damage. The resulting lesions are then colonized by Clostridia, which produce a toxin causing severe depression and rapid death from toxemia. Gross pathology may also include extensive subserosal hemorrhage, shown involving the perirenal area in 4.99. The inner skin surface is dark, hence the disease pseudonym.

Differential diagnosis: other clostridial diseases (pp. 240-242) , other causes of sudden death.

Management: rarely are clinical cases seen requiring treatment, but they should respond to antibiotics and NSAIDs. Vaccination is indicated if multiple cases are diagnosed.

Clinical features: clinical signs include nonspecific pyrexia, anorexia, abdominal pain, and depressed yield. On autopsy hepatic abscesses are usually multiple and vary in size. In this case (4.100) a large, central abscess has ruptured to release creamy pus. Typical causes are an acute rumenitis (4.57), which is followed by hematogenous spread to the neighboring liver, or as sequelae to navel infection or traumatic reticulitis. Such abscesses usually yield Arcanobacterium pyogenes on culture, although the initial hepatic colonization is generally by Fusobacterium necrophorum. Fattening steers and high-yielding dairy cows are more susceptible owing to their relatively greater intake of concentrate feed. A specific complication of hepatic abscessation is posterior vena cava thrombosis (5.31) or pulmonary thromboembolism (5.32), discussed elsewhere (p. 92).

Differential diagnosis: traumatic reticulitis, abomasal ulceration, peritonitis.

Management: early cases may respond to aggressive antibiotic therapy, but as abscessation tends to become Diagnosis: history and clinical signs are inadequate for diagnosis. Eggs must be demonstrated in feces, rectal scrapings, or nasal mucus.

Management: in problem regions, e.g., China, where zoonotic spread is widespread, large-scale chemotherapeutic campaigns (e.g., praziquantel), molluskicides, and habitat and management changes are effective in control.

Infectious necrotic hepatitis ("Black disease") Definition: an acute toxemia caused by Clostridium novyi type B (oedematiens) which produces a toxin in necrotic hepatic infarcts. Most cases are seen as sudden onset incidents.

Clinical features: discrete, irregular, pale infarcts on the liver surface (4.98) are characteristic of this acute toxemia. Most frequently seen in areas of endemic However, the majority cause no clinical signs and are an incidental finding during rectal examination when they may be confused with a fetus. Although relatively rare, lipomatosis is considered more common in mature or older Channel Island breeds. Although the etiology is unclear, genetic factors, an excessive intake of soya beans, and persistent pyrexia have been suggested.

Differential diagnosis: abdominal lymphosarcoma, chronic peritonitis with adhesions of abdominal viscera.

Management: lipomatosis cannot be treated.

Clinical features: protrusion of the rectal mucosa is obvious. In 4.102 rectal prolapse had started 24 hours previously, primarily involving the mucosa, which is still fresh and almost undamaged. The second case (4.103) had begun 7 days previously and shows severe lacerations and edema. The only undamaged area is close to the skin-mucosal junction. Rectal prolapse occurs mainly, but not exclusively, in young animals with acute severe, or chronic diarrhea resulting in recurrent tenesmus. Occasionally rectal and vaginal prolapse are seen together, as in this Piedmontese heifer with rectal damage and hemorrhage (4.104). The heifer had a maize-induced tenesmus and rectal prolapse, and vaginal prolapse secondary to dystocia the previous month. Recovery followed induction of a sacral nerve block (alcohol), Buhner suture of the vulvar lips, and dietary correction. Other more severe, with an increasing risk of complications, early culling is advised. Clinical features: a vertical section through the pelvic cavity of an old Angus cow (4.101) shows the rectum surrounded and severely constricted by large areas of fat necrosis, which are firm, dry, and caseous. Such areas, which are also called lipomata, may occur in any part of the omental, mesenteric, and retroperitoneal fat. They may cause chronic progressive bowel obstruction. 

31), babesia (12.43), necrotic enteritis (2.35), and occasionally rabies

Management: replace prolapse under epidural analgesia and keep in place with a purse-string suture

Anal edema (4.105) leading to protrusion of the rectoanal mucosa is an occasional iatrogenic result of rectal palpation.Management: spontaneous recovery is seen within 12-24 hours and no treatment is required.