Introduction
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.
Viral diseases
Three viral diseases present problems clinically in differential diagnosis: bovine virus diarrhea/mucosal disease (BVD/MD), vesicular stomatitis, and bovine papular stomatitis. In some regions, further differential diagnosis from foot-and-mouth disease and rinderpest may be necessary (see 12.2–12.1512.212.312.412.512.612.712.812.912.1012.1112.1212.1312.1412.15). 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).
4.1.
Cerebellar hypoplasia in BVD/MD in calf (Piedmontese)
4.2.
Normal (left) and hypoplastic cerebellum in BVD/MD
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 .
4.3.
Bovine virus diarrhea calf with muzzle and oral hyperemic changes
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 (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 ).
4.4.
BVD showing erosive changes in hard palate
4.5.
BVD with severe changes in caudal pharynx and larynx
4.6.
BVD with abomasal hemorrhage and erosions at autopsy
4.7.
Intestinal mucosal casts in BVD
4.8.
Erosions at coronary band in BVD
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 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.
4.9.
BVD/MD: nearer rust-colored stunted calf with chronic persistent infection (18 months old)
4.10.
BVD/MD: chronic emaciated crossbred steer
In some herds primary BVD in nonimmune cattle can also produce severe enteric signs and an increased mortality, especially in dairy cows, although most primary infections in younger animals are subclinical.
Differential diagnosis
salmonellosis, paratuberculosis (4.16), winter dysentery (4.19, 4.20) and other causes of acute enteritis in individuals. Bovine papular stomatitis (4.13), vesicular stomatitis (4.12), FMD (12.2–12.812.212.312.412.512.612.712.8) and other causes of oral ulceration.
4.16.
Johne's disease showing severe diarrhea in cow (Santa Gertrudis, 8 years old)
4.19.
Winter dysentery in cow: watery feces (Jersey)
4.20.
Winter dysentery: specimen showing fresh blood in feces
4.13.
Bovine papular stomatitis: papules on muzzle and around nares
4.12.
Vesicular stomatitis: recently ruptured vesicles on hard palate
Management
long-term program needed for effective control: persistently infected virus-positive cattle should be identified by blood-testing and culled, as they represent the major source of virus. Screen all purchased stock. Double-fence neighboring cattle. Vaccinate prior to service to prevent the development of persistently infected offspring.
Vesicular stomatitis
Definition
caused by a rhabdovirus (two strains: New Jersey and Indiana) causing vesicular formation in various superficial tissues. It is probably spread by insect vectors.
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.
4.11.
Vesicular stomatitis: pale lesions on hard palate, dental pad and gums in calf (Charolais)
Differential diagnosis
foot-and-mouth disease (12.2–12.812.212.312.412.512.612.712.8) and bovine papular stomatitis (4.13, 4.14 ). Diagnosis by ELISA or CF test, and if negative, following passage, virus neutralization tests.
4.14.
Bovine papular stomatitis: vesicles developing on gums
Management
suspect cases should be immediately reported to State authorities. (Transboundary disease of Office International des Épizooties (OIE).)
Bovine papular stomatitis (BPS)
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.
4.15.
Bovine papular stomatitis
Differential diagnosis
foot-and-mouth disease (12.2–12.812.212.312.412.512.612.712.8) and vesicular stomatitis (4.11, 4.12).
Management
specific treatment is rarely necessary.
Johne's disease (paratuberculosis)
Definition
chronic wasting disease caused by Mycobacterium avium paratuberculosis (formerly M. johnei).
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.
4.17.
Johne's disease (paratuberculosis): severe diarrhea (see tail) in bull (Blonde d’Aquitaine, 2 years old)
4.18.
Johne's disease : normal and abnormal ileum (right) with prominent rugae
The disease may be potentially zoonotic (Crohn's disease).
Differential diagnosis
salmonellosis, severe parasitism, BVD.
Management
no effective treatment is known. Suspect cows should be tested (ELISA, CF, AGID), and culled if positive. Biopsy and histopathology of intestinal lymph nodes is an effective method of diagnosis. Vaccines have limited efficacy in control. There is no test to detect accurately subclinical carriers, and heifers from infected dams should be culled. Reduce spread of infection by hygiene at calving and possibly by pasteurization of pooled colostrum. Separate newly–born calves from their potentially infected dams at once.
Winter dysentery (winter diarrhea)
Definition
etiology uncertain, although coronavirus has recently been implicated.
Clinical features
a watery diarrhea (4.19 ) lasting about 3 days, winter dysentery causes a sporadic problem in adult dairy cattle. Spontaneous recovery usually takes place after a few days. Some animals show profuse intestinal hemorrhage, passing large quantities of fresh blood in feces (4.20 ), and suffer a severe production drop, though deaths are rare. Seroconversion to coronavirus can be used for diagnosis, although many animals in a herd are already seropositive.
Repeated outbreaks are possibly due to the presence of carrier animals.
Differential diagnosis
Johne's disease (4.16), rumenitis or overeating (4.56), BVD, salmonellosis, bovine influenza A (diarrhea with respiratory signs), PPH (9.39).
4.56.
Rumen acidosis with severe yellowish diarrhea
Management
fresh water and palatable feed should be available. The value of intestinal astringents and protectants is disputed. No vaccine is available.
Gastrointestinal parasitism
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.
Ostertagiasis
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 L3 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 L4), and then emerge en masse in late winter or early spring to produce a profuse scour and weight loss in housed cattle. Note the weight loss, chronic diarrhea, and tenesmus in an older Charolais heifer (4.24 ).
4.21.
Ostertagiasis with multiple abomasal nodules
4.22.
Ostertagiasis with “Morocco leather” appearance of abomasal mucosa
4.23.
Ostertagiasis showing thickened abomasal rugae and many white worms
4.24.
Ostertagiasis type II: chronic stage in wasted heifer showing tenesmus (Charolais)
Oesophagostomum infection
Clinical features
clinical signs tend to be much less severe than with Ostertagia. Heavy worm burdens in 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.
4.25.
Oesophagostomum infection: numerous caseated and calcified nodules on distal intestinal serosa (USA)
Management of Ostertagiasis and 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.
Dental problems
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.
4.26.
Temporary incisors being replaced by permanent teeth
4.27.
Grossly excessive wear of incisors, worn down to stumps
4.28.
Shedding incisors
Management
heifers should ideally be milked as a separate group during their first lactation and be given easy-access feed.
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 13.3213.3113.32.
4.29.
Fluorosis with mottling of temporary teeth (USA)
4.30.
Severe fluorosis-induced discoloration of teeth (USA)
Irregular molar wear
Irregular molar wear can sometimes cause masticatory problems. When eating or ruminating, this 8-year-old 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.
4.31.
Locked jaw position (chronic, intermittent) in bull (Charolais, 8 years old)
Mandibular fracture
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 was unknown, and full recovery occurred without treatment.
4.32.
Symphysial fracture in cow, which recovered without surgery (Friesian)
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.
4.33.
Habitual tongue-playing in cow. Note saliva on ground (Guernsey)
Actinobacillosis (“wooden tongue”)
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.
4.34.
Actinobacillosis with severe submandibular swelling
4.35.
Actinobacillosis in thickened dorsum of tongue (D)
4.36.
Actinobacillosis causing tongue protrusion in cow (Highland)
4.37.
Actinobacillosis of several limbs in Angus steer (Canada)
4.38.
Actinobacillosis on mandible
Differential diagnosis
tooth abscess, actinomycosis, foot-and-mouth disease, snakebite (4.39 , showing thickening and ulceration 4 days later).
4.39.
Snake bite causing severe slough of ventral surface of tongue epithelium
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.
Actinomycosis (“lumpy jaw”)
Clinical features
actinomycosis (Actinomyces bovis) 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, fist-sized, 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).
4.40.
Actinomycosis with several granulomata on maxillary region of cow (Guernsey)
4.41.
Actinomycosis with large granulomatous mass on jaw of cow (Hereford cross)
4.42.
Lateral radiograph of mandible with actinomycosis showing bone destruction and proliferation
Differential diagnosis
mandibular abscess (4.48), actinobacillosis (4.34, 4.35, 4.36, 4.37, 4.38).
4.48.
Submandibular abscess in cow (Guernsey)
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).
Ameloblastoma
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.
4.43.
Ameloblastoma proliferating from mandible in heifer (Saler, 11 weeks old)
Differential diagnosis
Malignant edema (necrotic cellulitis)
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.
4.44.
Malignant edema in right masseteric region of cow (Holstein)
4.45.
Malignant edema with massive enlargement of brisket in cow (Holstein)
Differential diagnosis
cutaneous urticaria (blaine) (3.1), abscessation (4.48).
Management
prolonged and aggressive parenteral penicillin plus NSAIDs may cure some early cases. Some benefit from drainage of foci. Although clostridial vaccines are available, most cases are sporadic and herd vaccination is rarely indicated.
Alveolar periostitis (Cara inchada, “swollen face”)
Definition
severe periodontal disease associated with secondary bacterial infection in young cattle of unknown etiology.
Clinical features
alveolar periostitis is a major problem in some parts of South America, such as Brazil. Periodontal disease affects the sockets of the upper 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.
4.46.
Alveolar periostitis (cara inchada): specimen with tooth loss and maxillary changes in steer (Zebu) (Brazil)
4.47.
Alveolar periostitis: bone specimen with severe periostitis (Brazil)
Submandibular abscess
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).
Management
surgical drainage and flushing. Systemic antibiotics may be unnecessary.
Pharyngeal and retropharyngeal swelling
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).
Drenching gun injury
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.
4.49.
Septic cellulitis following drenching gun injury in (Angus) steer
4.50.
Drenching gun injury (autopsy) with massive septic pharyngeal cellulitis (USA)
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.
Management
aggressive and prolonged antibiotics 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.
Retropharyngeal abscess
Clinical features
a discrete and relatively painless fluctuating, tennis ball-sized mass lies in the retropharyngeal region (4.51 ). The spread of infection (compare 4.49) was limited by the development of a fibrous capsule. Abscessation in this region is commonly caused by ingestion of sticks and thorns, although it may be the result of accidental pharyngeal damage from drenching or balling guns, probangs, or other rigid instruments (see above).
4.51.
Discrete retropharyngeal abscess
Management
most abscesses eventually develop superficial softer areas for drainage, though deep-seated abscesses can be hazardous due to the proximity of other structures, e.g., carotid artery, jugular vein, or parotid salivary gland.
Esophageal disorders
Esophageal obstruction (choke)
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.
4.52.
Esophageal obstruction by potato in heifer
Differential diagnosis
acute rumenitis (4.56, 4.57, 4.58, 4.59, 4.60), traumatic reticulitis, oral lesions, rabies (9.33–9.359.339.349.35).
4.57.
Fatal rumen acidosis with (pink) sloughed ruminal epithelium (autopsy) in bull (Simmental, 10 months old)
4.58.
Mycotic or fusobacterial rumenitis (autopsy) (USA)
4.59.
Chronic rumen acidosis showing necrotic rumen papillae (A) at autopsy
4.60.
Omasitis due to fungal infection (USA)
Management
some foreign bodies can be pushed towards the pharynx by external manipulation and, using a gag, removed manually. Any severe ruminal tympany should be promptly relieved by trocarization. Other conservative therapy (spasmolytics, e.g., acepromazine, or sedative and muscle relaxants, e.g., xylazine) is preferable to hazardous attempts to push the object downwards with a probang.
Megaesophagus
Definition
chronic dilatation and atony of the esophagus.
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.
4.53.
Chronic megaesophagus in heifer (Charolais, 15 months old)
Differential diagnosis
esophageal obstruction.
Management
diet.
Rumen and reticulum
Rumen acidosis (rumenitis)
Definition
ruminal inflammation resulting from excessively rapid fermentation following overeating of grain (corn), or other high-starch/low-fiber diets. SARA (subacute ruminal acidosis) is an increasing problem in high-yielding dairy herds.
Clinical features
low-grade rumen acidosis can present clinically as rumen atony, cud regurgitation (4.54 ) and a matted sweaty coat. Passage of loose yellow feces as in this animal (4.55 ) leads to extensive soiling of the tail and hindquarters. Tail swishing often produces fecal soiling along the back. More severe overeating can result in rapid carbohydrate fermentation, severe rumenitis, metabolic acidosis, and a subsequent laminitis (7.72). Affected cattle are very dull, weak, ataxic, or recumbent. A light-colored diarrhea containing grain particles may be seen (4.56 ). Ruminal pH is usually very acidic (pH < 5.5). 4.57 shows areas of sloughed ruminal epithelium and intense serosal hemorrhage in a 10-month-old Simmental bull which died 24 hours after unlimited access to fodder beet. Whole fragments of undigested fodder beet are clearly visible (A). Four to six days after a grain overload, mycotic or fusobacterial rumenitis may be seen (4.58 ), comprising sharply defined, thick oval ulcers that 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.
4.54.
Cud regurgitated in mild rumen acidosis (SARA)
4.55.
Rumen acidosis with loose yellow feces
The omasum in 4.60 shows a fungal infection (most likely due to Aspergillus species) following the accidental 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. High-yielding dairy cows need adequate digestible and long fiber to balance a high-starch diet. Ideal concentrate:fiber ratio should never exceed 60 : 40.
Rumen tympany (“bloat”)
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.
4.61.
Rumen tympany (“bloat”) in heifer (Holstein)
4.62.
Severe rumen tympany in steer (Hereford)
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.)
4.63.
Ruminal papilloma (autopsy) which caused intermittent bloat
4.67.
Reticular wall (autopsy) with several typical wires (foreign bodies) (USA)
Management
frothy bloat responds well to oral surfactants such as paloxalene. Gas bloat can usually be relieved by stomach tube, but extreme cases require trocarization. Prevention depends on avoidance of causative agents.
Ruminal neoplasia
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 ruminal tympany. Esophageal groove obstructions often also lead to vomiting.
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).)
Abdominal pain
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 (12.39–12.4312.3912.4012.4112.4212.43), cystitis (10.14), or urethritis.
4.64.
Posture of heifer in abdominal pain with legs extended and head to flank (Holstein) (USA)
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.
4.65.
Skin tenting indicative of dehydration (10%)
4.66.
“Tucked up” belly resulting from poor rumen fill
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 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.
4.90.
Early generalized peritonitis over greater omentum at autopsy (USA)
4.91.
Advanced chronic peritonitis at autopsy following septic reticuloperitonitis
4.100.
Ruptured hepatic abscess at autopsy (USA)
4.68.
Cardiac tamponade and tire wire (↗). Pericardiac sac filled with frank blood-note wire
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.
4.76.
Left displaced abomasum (LDA) (A), seen through left flank incision in cow (Friesian)
4.78.
Right displaced abomasum (RDA): (A) descending duodenum visible caudal to abomasum (B) through flank incision in cow (Guernsey)
4.72.
Abomasal ulceration: passing of dark tarry feces by cow (Guernsey)
4.89.
Cecal torsion in cow with its apex prolapsed at surgery (Holstein)
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)
Abomasum
Abomasal obstructive syndrome (vagal indigestion, “Hoflund syndrome”)
Definition
the cause of vagal indigestion, or Hoflund syndrome, is a functional disturbance of the normal motility of the forestomachs or the abomasum, or of all compartments.
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.
4.69.
Vagal indigestion (Hoflund syndrome) with severe distension from excessive rumen fluid (Netherlands)
4.70.
Same cow as in 4.69 after removal of 90 liters of fluid from rumen (Netherlands)
4.71.
Vagal indigestion: typical dorsal left flank, ventral right flank distension (USA)
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).
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.
Abomasal ulceration
Clinical features
abomasal ulceration occurs in mature dairy and beef cattle and in calves (2.27–2.292.272.282.29). 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 high-yielding dairy cows, although the cause is unknown, ulcers are usually associated with stress and high-concentrate 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 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 (2.27–2.292.272.282.29), 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.
4.73.
Abomasal ulceration (A) and hemorrhage in cow (autopsy) (Guernsey)
4.74.
Healing abomasal ulcers (autopsy)
Differential diagnosis
traumatic reticulitis, abomasitis, abomasal lymphoma (lymphosarcoma) (4.75 ), jejunal hemorrhagic syndrome (4.83, 4.84, 4.85).
4.75.
Abomasal lymphoma infiltrating rugae (autopsy)
4.83.
Jejunal hemorrhagic syndrome (JHS): downer cow, Holstein. Note depression, open mouth breathing and raised hackles (hair coat), symptomatic of severe stress, in right paralumbar fossa (USA)
4.84.
Jejunal hemorrhagic syndrome (JHS): right flank standing laparotomy showing typical loop of grossly distended, blood-filled jejunum (Holstein, USA)
4.85.
Jejunal hemorrhagic syndrome (JHS): autopsy with several loops of distended hemorrhagic jejunum, to right of which lie other fluid- and gas-filled loops. Note early fibrin tags indicative of peritonitis (USA)
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.
Abomasal lymphoma (lymphosarcoma)
Etiology and pathogenesis
adult lymphosarcoma is caused by the bovine leukosis virus (BLV). The tumor incidence varies widely. Enzootic leukosis affects mature cattle, and other structures commonly affected include lymph nodes, heart, and retrobulbar tissue (8.42).
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 12.74–12.8112.7412.7512.7612.7712.7812.7912.8012.81.)
Abomasal surgical conditions
In areas of intensive management, left and to a lesser extent right abomasal displacements are common 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 dietary-induced rumen acidosis (SARA) in the preceding weeks.
Left displaced abomasum (LDA)
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 ).
4.77.
LDA with bulge in left flank (A) of cow (Guernsey)
Differential diagnosis
right displaced abomasum (4.78 ), cecal torsion (4.88), primary ketosis.
4.88.
Severe abdominal distension in jejunal obstruction and torsion
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.
Right displaced abomasum (RDA)
Clinical features
clinical signs are similar to left displacement, but a tympanitic abomasum is detectable by percussion on the right side. In this Guernsey cow (4.78) the distended abomasum is seen through a vertical right flank paralumbar incision about 7 cm caudal to the last rib. The remainder of the abomasum is located medial to the costal arch. The greater omentum containing the descending duodenum (A) is seen caudal to the abomasal swelling (B).
Differential diagnosis
left displaced abomasum, abomasal, intestinal or cecal torsion, ketosis, abomasal ulceration.
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.
Abomasal torsion
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).
4.79.
Abomasal torsion at autopsy showing (A) abomasum, (B) ruminoreticulum, and (C) duodenum
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.
Abomasal impaction
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.
4.80.
Cow with abomasal impaction (Holstein, Germany)
4.81.
Cow of 4.80 showing severe abomasal mucosal hyperemia and remains of massive sand accumulation (Germany)
Differential diagnosis
vagal indigestion (4.69, 4.70, 4.71), omasal impaction, intestinal obstruction (lipomatosis, 4.101), diffuse peritonitis (4.90). (See also 4.82 for trichobezoar.)
4.101.
Lipomatosis: vertical section through rectum with constricting lipomata (USA)
4.82.
Trichobezoar in abomasum of calf at surgery (Chianina) (Italy)
Management
salvage slaughter; avoid impaction by adequate good-quality roughage, when available.
Abomasal trichobezoar
Definition
rounded mass of felted hair and plant material distending and partially obstructing abomasum.
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.
Small intestine
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 fluid-filled intestinal loops ventrally, and gas in paralumbar fossa and beneath rib cage. In cases surviving more than 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.
Management
early recognition of JHS is vital if an attempt is to be made to correct the massive fluid and blood loss. Few peracute cases survive. Improved dietary management is indicated.
Jejunal torsion and intussusception (“twisted gut”)
Definition
twisting of jejunum on itself and telescoping of small intestinal segment.
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.
4.86.
Jejunal intussusception (B) at exploratory surgery
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.
4.87.
Complex intussusception and torsion (autopsy)
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.
Large intestine
Cecal dilatation and torsion
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.
Differential diagnosis
right displaced abomasum, ketosis.
Management
many cases respond to spasmolytics and dietary control. Surgical drainage may be needed when viability of the cecal wall should be checked.
Peritonitis
Definition
inflammation of the parietal and visceral peritoneum.
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. Neonatal peritonitis may occur following the rupture of a distended small intestine proximal to an atretic bowel (1.22).
Diagnosis
peritonitis may be suspected from the clinical signs and rectal palpation. Abdominal (ventral) paracentesis may yield suspect fluid for cytological and cultural examination.
Management
fluid therapy, aggressive broad-spectrum antimicrobial therapy, NSAIDs. Most cases are best culled.
Ascites
Definition
abnormal accumulation of serous (edematous) fluid in the abdominal cavity.
Clinical features
As with peritonitis, this fluid eventually leads to a pear-shaped silhouette (4.92 ). Ascitic fluid is serous or edematous in nature and is usually sterile. This old Galloway cow had hepatic cirrhosis resulting 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).
4.92.
Ascites showing typical pear-shaped silhouette in aged cow (Galloway)
Differential diagnosis
peritonitis, (4.90), hydrops amnii, hydrops allantois (10.54), abomasal impaction (4.80).
Management
most cases are incurable and should be culled.
Hepatic diseases
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 ill-defined nutritional and metabolic imbalance is described in Chapter 9 (9.9), and photosensitization secondary to hepatic disease in Chapter 3 (3.3–3.93.33.43.53.63.73.83.9).
Fascioliasis (common liver fluke infection)
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 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.
4.93.
Liver in severe fascioliasis with massive fibrosis of bile ducts
4.94.
Fasciola hepatica flukes and thickened bile ducts
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.
Differential diagnosis
hemonchosis, ostertagiasis.
Management
grazing management and flukicidal drugs. However, some drugs kill only adult flukes, others a wider range of stages of the life cycle. Many are not licensed for use in dairy cattle, so control can be difficult.
Paramphistomiasis (rumen or stomach flukes)
Clinical features
even the relatively large numbers of soft, pink, pear-shaped, adult flukes seen attached to the rumen wall (4.95 ) cause few or no clinical signs, particularly in older cattle. However, proximally migrating immature worms hatching from metacercarial cysts attached to the duodenum may lead to ulceration and clinical signs including unthriftiness, diarrhea, and death in young animals. Several different species of fluke including P. cervi, P. microbothrium, and P. ichikawai are involved. Planorbid snails act as intermediate hosts, the life cycle being similar to Fasciola hepatica. Paramphistomiasis and fascioliasis may occur together, leading to a more severe syndrome.
4.95.
Paramphistomiasis, with adult flukes on rumen wall (South Africa)
Diagnosis and management
see above for fascioliasis. Treat with oxyclozanide for adult paraphistome infections in rumen. Removal of animals from infected pastures, where metacercaria may survive for 2–3 months after pastures have dried out.
Schistosomiasis (blood flukes): Bilharzia
Definition
disease caused by trematode Schistosoma spp. with chronic hemorrhagic enteritis, anemia, and emaciation in a group of cattle, many dying after months.
Clinical features
eight species of Schistosoma have been reported throughout Africa, the Middle East, and Asia. Cercariae, released into water from the intermediate snail host, penetrate the skin or mucous membranes. 4.96 shows a pair of elongated flukes in a blood vessel of the stretched mesentery (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”.
4.96.
Schistosomiasis: adult flukes in mesenteric vessel (South Africa)
4.97.
Schistosoma nasale in nasal turbinate bones (Belgium)
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 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.
4.98.
Infectious necrotic hepatitis (“Black disease”) with discrete hepatic infarcts (USA)
4.99.
Infectious necrotic hepatitis: subserosal perirenal hemorrhage (USA)
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.
Hepatic abscessation
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 more severe, with an increasing risk of complications, early culling is advised.
Miscellaneous
Lipomatosis (abdominal fat necrosis)
Definition
large lipomatous masses in peritoneal cavity.
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. 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.
Rectal prolapse
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 predisposing causes of tenesmus are coccidiosis (2.31), babesia (12.43), necrotic enteritis (2.35), and occasionally rabies (9.34).
4.102.
Rectal prolapse of 24 hours’ duration. Note perineal blood
4.103.
Rectal prolapse at 7 days showing multiple lacerations and edema
4.104.
Rectal and vaginal prolapse (Italy)
Management
replace prolapse under epidural analgesia and keep in place with a purse-string suture. Control causes of tenesmus.
Anal edema
Anal edema (4.105 ) leading to protrusion of the rectoanal mucosa is an occasional iatrogenic result of rectal palpation.
4.105.
Anal edema with mucosal protrusion
Management
spontaneous recovery is seen within 12–24 hours and no treatment is required.