Effect of time of year, weather, and the pattern of auction market sales on fatal fibrinous pneumonia (shipping fever) in calves in a large feedlot in Alberta (1985-1988).

A total of 58,885 spring-born calves entering a large commercial feedlot in southwestern Alberta were studied to examine the associations between shipping fever mortality and the pattern of calf sales at the auction markets, time of year, and weather. The observational study followed calves purchased from 42 auction markets in the 4 western provinces between September 1 and December 31 in each of the years from 1985 to 1988. Calf sales at the auction markets consistently peaked during the last week of October and the first week of November. Calves entering the feedlot in November had a risk of fatal shipping fever 2 to 8 times greater than calves entering in September or December. The pattern was the same for all 4 years, with maximum risk occurring 2 to 4 weeks after the peak time for calf sales at the markets. A number of factors could have contributed to this pattern, including changes in transport truck availability, changes in the density of calves at the markets, changes in population dynamics at the feedlot that affected feedlot crew efficiency, and weather. The finding that the risk of fatal shipping fever appears to increase significantly as the feedlot fills with calves in the fall deserves the attention of feedlot owners, so they can design their treatment strategies appropriately, and of researchers, who may gain useful knowledge about the natural history of the disease by investigating why this change in risk occurs.     

Effect of enrofloxacin therapy on shipping fever pneumonia in feedlot cattle

The effect of enrofloxacin therapy was investigated in 110 male double-muscled cattle weighing 275 +/- 3 kg, during a spontaneous outbreak of shipping fever occurring 11 +/- 2 days after they arrived in the feedlot. Forty-six diseased animals were divided randomly into three groups A, B and C, containing 17, 19 and 10 animals, respectively; the animals in group A were injected intramuscularly once daily for three consecutive days with 2.5 mg/kg of enrofloxacin, those in group B with 5 mg/kg of enrofloxacin and those in group C with 10 mg/kg of oxytetracycline. Clinical, serological, production and respiratory functional observations were recorded. The animals were clinically cured after the three day treatment except for three in group A and two in group C. These five animals made a clinical recovery after a three day booster treatment with a dose of 5 mg/kg enrofloxacin. The changes in respiratory gas exchange values induced by shipping fever were completely reversed 15 days later, suggesting that there had been no irreversible lung damage. The daily weight gains and the arterial blood gas values of the three groups of treated cattle were not significantly different. The high efficacy of the low dosage of enrofloxacin in this clinical syndrome may be explained by its antibacterial activity against Pasteurella species and Mycoplasma species. This field trial supports the in vitro studies which suggested than enrofloxacin is an appropriate therapy in cases of shipping fever.     

Intestinal atresia in calves: 22 cases (1978-1988)

A retrospective study of 22 calves afflicted with intestinal atresia was performed to determine typical signs of disease, treatment, and survival rate. All 22 calves, except 2 heifers with atresia ani and rectovaginal fistula, were examined when they were between 1 and 10 days old because of depression, anorexia, abdominal distention, and lack of feces. All calves had been observed to stand and suckle shortly after birth. Survival rate was influenced by the atretic segment affected: 0% (0/2 surgically treated) for atresia jejunal; 42% (5/12 examined) or 71% (5/7 recovering from general anesthesia) for atresia coli; and 63% (5/8 examined) or 71% (5/7 surgically treated) for atresia ani. Survival appeared to depend principally on early recognition, anatomic site affected, and successful surgical establishment of a patent intestinal tract.     

Malignant catarrhal fever in a bison (Bison bison) feedlot, 1993-2000.

A fatal enteric syndrome was identified in American bison (Bison bison) at a large feedlot in the American Midwest in early 1998. An estimated 150 bison died of the syndrome between January 1998 and December 1999. The syndrome was identified as malignant catarrhal fever (MCF), primarily the alimentary form. Clinical onset was acute, and most affected bison died within 1-3 days; none recovered. Consistent lesions were hemorrhagic cystitis, ulcerative enterotyphlocolitis, and arteritis-phlebitis. Vasculitis was milder and more localized than that in cattle with MCF, and in contrast to the situation in cattle, lymphadenomegaly was minimal. Virtually all affected bison examined were positive for ovine herpesvirus 2 (OvHV-2) by polymerase chain reaction (PCR) assay. A retrospective study of archived tissues established that MCF occurred in the yard as early as 1993. A prospective study was undertaken to establish the importance of MCF relative to other fatal diseases at the feedlot. The fate of a group of 300 healthy male bison in a consignment of 1,101 animals was followed for up to 7 months to slaughter. At entry, 23% (71/300) of bison were seropositive for MCF viruses, and 11% (8/71) of these seropositive bison were PCR positive for OvHV-2. Forty seronegative bison were selected at random from the group, and all were PCR negative for OvHV-2. There was no change in seroprevalence in the group during the investigation. The minimum infection rate for MCF virus was 36.3% (93/256). Twenty-two (7.3%) of the 300 bison in the feedlot died. Of these, 15 had MCF, 4 had acute or chronic pneumonia, and 3 were unexamined. Losses in the entire consignment were higher (98/1,101; 8.8% death loss); 76% of deaths were attributable to MCF. The study failed to reveal a relationship between subclinical infection and development of clinical disease.     

Hypernatremia in neonatal elk calves: 30 cases (1988-1998)

OBJECTIVE: To characterize hypernatremia in neonatal elk calves, including clinical signs, incidence, physical examination findings, and possible causes. DESIGN: Retrospective case series. ANIMALS: 26 neonatal elk calves were examined; 4 calves were evaluated twice, for a total of 30 examinations. PROCEDURE: Medical records were reviewed for signalment, history, physical examination findings, results of diagnostic tests, and response to treatment. Hypernatremia was defined as serum sodium concentration > 153 mEq/L. RESULTS: Hypernatremia was diagnosed in 14 calves and was significantly associated with diarrhea, high WBC count, high anion gap, and high serum concentrations of albumin, chloride, creatinine, and urea. Hypernatremia was not significantly associated with survival, but high serum albumin concentration and rectal temperature were significantly associated with survival of calves. Animals given antibiotics and electrolyte solutions orally prior to evaluation were significantly more likely to die than those untreated. Dehydration was a common reason for evaluation but was not significantly associated with survival. CONCLUSIONS AND CLINICAL RELEVANCE: Hypernatremia was significantly associated with diarrhea. Treatment of diarrheic elk calves is often the same as that used in bovine calves with diarrhea; however, bovine calves are commonly hypo- or normonatremic. Our experience suggests that treatment protocols used in bovine calves are unsatisfactory for elk calves. The rate at which serum sodium concentration is reduced should be < 1.7 mEq Na/L/h to avoid development of neurologic signs associated with iatrogenically induced cerebral edema.     

Clinical management and surgical repair of atresia coli in calves: 66 cases (1977-1988).

The medical records of 66 calves with atresia coli were reviewed; 64 calves were examined at the New York State College of Veterinary Medicine, and 2 calves were examined at the New Bolton Center. In each case, the site of the atresia was within the spiral loop of the ascending colon. In 1 of these calves, a segment of jejunum was also atretic. Absence of feces, progressive weakness, and abdominal distension were the most common clinical signs observed. Other congenital abnormalities were detected in 12 (18%) of 66 calves. Of the 66 calves examined, 5 were euthanatized or died on admission, and 61 had an exploratory celiotomy performed. Eight calves were euthanatized or died during the surgery. In the remaining 53 calves, surgical treatment consisted of enterotomy followed by meconium evacuation, resection of the proximal blind end (in 30 calves), and restoration of intestinal continuity. Restoration of intestinal continuity was done either by side-to-side anastomosis of the proximal to distal blind ends (5 calves), or by side-to-side or end-to-side anastomosis of the proximal blind end to the descending colon (48 calves). Of the 66 calves seen, 27 (41%) were discharged from the hospital, and 11 of these reached reproductive age (11 calves were lost to follow-up before they were 2 years old). From the 11 calves reaching reproductive age, 33 calves were born, one of which may have had atresia coli. The owners should anticipate that long-term survivors likely will have loose feces and normal offspring, but may not grow as well as otherwise expected.     

Endogenous lipid pneumonia in cats: 24 cases (1985-1998)

OBJECTIVE: To determine clinical signs, radiographic and histologic abnormalities, and concurrent diseases in cats with endogenous lipid pneumonia (EnLP) and to determine the pathologic importance of EnLP in cats. DESIGN: Retrospective study. ANIMALS: 24 cats. PROCEDURE: Medical records of cats in which EnLP was confirmed by histologic examination of necropsy specimens were reviewed. Information collected from the medical records included signalment, body weight, clinical signs, and results of clinicopathologic tests. Thoracic radiographs were reviewed by a radiologist; histologic specimens were reviewed by a pathologist. RESULTS: All cats had nonspecific clinical abnormalities, such as lethargy, anorexia, or weight loss; 16 had signs of respiratory tract disease. All cats had concurrent systemic diseases, and clinicopathologic abnormalities were reflective of these conditions. Nonspecific abnormalities were detected on thoracic radiographs from 9 of 11 cats. Most cats had macroscopic, multifocal, subpleural lesions; inflammatory infiltrates, cholesterol clefts, and multinucleated giant cells were common. Ten cats had an underlying obstructive pulmonary disease that was the likely cause of EnLP. Lesions of EnLP were not considered to be severe enough or extensive enough to be the cause of death in any of these cats. CONCLUSIONS AND CLINICAL RELEVANCE: EnLP is an uncommon respiratory tract disorder of cats with no pathognomonic clinical, laboratory, or radiographic findings. Although EnLP was not the cause of death in any of these cats, results of the present study do suggest that EnLP may be a marker for potentially severe underlying obstructive pulmonary disease.     

Salivary gland disease in dogs and cats: 245 cases (1985-1988)

Diagnostic pathology records spanning 41 months (July 1985 through November 1988) were searched for diagnoses of salivary gland disease in dogs and cats. Review of 87,392 records from that period revealed 245 cases (0.3%) in which salivary gland tissue had been evaluated. During that period, salivary gland tissue was submitted to the laboratory almost twice as often from dogs (160 cases) as from cats (85 cases). On the basis of histologic examination, 89% of salivary gland submissions from small animal practices were allotted to 1 of 5 major categories: malignant neoplasms (30%; 74/245), sialadenitis (26%; 64/245), normal salivary gland (16%; 40/245), sialocele (9%; 21/245), and salivary gland infarction (8%; 20/245). The remaining 11% of submissions included various degenerative or fibrotic lesions, ductal ectasia, sialolithiasis, edema, benign neoplasia, and secondary salivary involvement with systemic or cervical lymphosarcoma or with fibrosarcoma in the head and neck.     

The occurrence of ephemeral fever in Kenya, 1968-1988

Ephemeral fever occurs in Kenya in epidemics which have been associated with periods of unusually heavy and prolonged rainfall. The epidemics persist for 2-3 years and involve most of the country. They occur in the same years as epizootics of Rift Valley fever, which is a mosquito-borne Phlebovirus infection. Sporadic outbreaks of the disease have been associated with local heavy rains; though one outbreak occurred during a dry period. Culicoides spp. were generally present in large numbers at the site of the outbreaks. Seroconversions were detected in sentinel cattle, when there had been no apparent clinical disease.     

Hepatic disease in Alberta horses: A retrospective study of 'alsike clover poisoning' (1973-1988)

Over sixteen years, 49 horses were diagnosed by Alberta Agriculture Animal Health laboratories as having “alsike clover poisoning”. There was a distinct northwestern distribution of cases, the majority coming from the Peace River district. This distribution is opposite to that of the Alberta horse population, but coincides with areas of alsike clover cultivation. Cases could be divided into chronic or nervous clinical presentations, as described by Schofield. Tissues from 45 animals were retrieved and examined microscopically. Significant histological lesions were confined to the liver and consisted of biliary fibrosis and epithelial proliferation.

I conclude that alsike clover poisoning is a specific disease entity, likely due to exposure to an exogenous toxin. The evidence is not strong enough to incriminate alsike clover as the etiology.

     

Transfixation pinning and casting of tibial fractures in calves: five cases (1985-1989)

Medical records of 5 calves with tibial fractures that were reduced and stabilized by transfixation pinning and casting were reviewed. Multiple Steinmann pins were placed transversely through proximal and distal fracture fragments, and the pin ends were incorporated in fiberglass cast material after fracture reduction. Cast material serves as an external frame to maintain pin position and fracture reduction. Calves were between 2 weeks and 6 months old and weighed between 40 and 180 kg. Three fractures were spiral in configuration and 2 were comminuted. One tibial fracture was open. After surgery, all calves were ambulatory within 24 hours. To improve tarsal flexion and achieve normal stance in 3 calves, cast revision was required on the caudal aspect of the limb. Good radiographic and clinical evidence of stability was observed in 5 to 10 weeks (mean 8 weeks), at which time the pis and cast were removed. Return to normal function was rapid and judged to be excellent at follow-up evaluation 3 to 12 months later. Advantages of transfixation pinning and casting in management of tibial fractures include flexibility in pin positioning, adequate maintenance of reduction, early return to weight-bearing status, joint mobility, and ease of ambulation. The inability to adjust fixation and alignment after cast application is a disadvantage of this technique compared with other external fixators.     

Cardiac arrhythmias identified in horses with duodenitis/proximal jejunitis: six cases (1985-1988)

During a 3 1/2-year period, cardiac arrhythmias were identified in 6 of 67 horses diagnosed with duodenitis/proximal jejunitis (DPJ). Arrhythmias were detected by auscultation of irregular cardiac rhythm and subsequently were characterized by electrocardiographic evaluation. Arrhythmias included frequent second-degree atrioventricular block, ventricular ectopic depolarizations, and atrioventricular conduction disturbance. In 4 horses, arrhythmias resolved with recovery from the primary problem. One horse died suddenly 66 hours after admission, and another was euthanatized at 72 hours after admission. Clinical and laboratory data from horses with DPJ and cardiac arrhythmias (group 1) were compared with findings for horses with DPJ and without arrhythmias (group 2). Group-1 horses had significantly (P less than 0.05) higher serum bicarbonate concentration and serum creatine kinase activity. Normal sinus rhythm returned in all 4 group-1 horses that recovered from DPJ, suggesting a causal relationship between DPJ and the arrhythmias. Two group-1 horses were necropsied, and both had myocarditis. The cause of these lesions was not determined.     

An outbreak of chronic pneumonia and polyarthritis syndrome caused by Mycoplasma bovis in feedlot bison (Bison bison).

Mycoplasma bovis was identified by a specific lesion, conventional bacterial culture, immunohistochemistry, and polymerase chain reaction in 2 feedlot bison found dead with severe, chronic, caseonecrotic pneumonia; polyarthritis; and laryngitis. On microscopic examination, pulmonary lesions were characterized by prominent, well-defined areas of caseous necrosis and bronchiectasis. Immunohistochemical analysis of lung exhibited staining in bronchiolar epithelium and in random areas of caseous necrosis. On gross examination, the laryngeal lesion observed in 1 animal was typical of changes seen in cases of calf diphtheria. Nasal swabs taken from 6 clinically ill bison from the same feedlot revealed 1 animal shedding M. bovis by the nasal route. No other pathogens were recovered from the pulmonary or laryngeal lesions; however, Mannheimia haemolytica was cultured from the nasal swabs of 2 clinically ill bison, although not from the animal found to be shedding M. bovis. Several other affected bison had swollen joints and exhibited lameness and a reluctance to move. Changes observed in dead and clinically ill bison from this feedlot are similar to what has been described in the literature as chronic pneumonia and polyarthritis syndrome in feedlot cattle caused by M. bovis. Based on the severity of the lesions, and the number of dead and affected animals, bison in a feedlot setting appear to exhibit sensitivity to infection with M. bovis.     

Ultrasonographic evaluation of horses with thrombophlebitis of the jugular vein: 46 cases (1985-1988)

Medical records of 46 horses with jugular vein thrombophlebitis that were evaluated ultrasonographically were reviewed. The ultrasonographic appearance of the thrombus within the jugular vein was classified as noncavitating if it had uniform low to medium amplitude echoes, or as cavitating if it was heterogenous with anechoic to hypoechoic areas representing fluid or necrotic areas within the thrombus, and/or hyperechoic areas representing gas. Signs of pain on palpation of the affected vein (P less than 0.001), heat over the vein (P = 0.001), and swelling of the vein (P less than 0.05) were significantly associated with the ultrasonographic detection of a cavitating lesion. Ultrasonography also was useful for selecting a site for aspiration of a specimen for bacteriologic culturing and susceptibility testing.     

Traumatic luxation of the cubital joint (elbow) in dogs: 44 cases (1978-1988).

The medical records from 44 dogs with traumatic luxation of the cubital joint were reviewed. Closed reduction was performed in 35 dogs, and open reduction in 9 dogs. Excellent or good results were achieved in 31 of 35 dogs (88.6%) treated by closed reduction and in 5 of 9 dogs (55.6%) treated by open reduction. Collateral ligament repair, performed in 5 dogs, did not appear to affect the prognosis. Factors such as body weight and type and duration of external coaptation also did not appear to influence the outcome. Increased dysfunction associated with open reduction most likely was caused by the chronic nature of the dislocation, iatrogenic damage to the articular cartilage during reduction, or both. A good prognosis for return to normal function with minimal gait abnormality can be expected in most cases of traumatic luxation of the cubital joint treated by early closed reduction.     

Hepatotoxicity of phenobarbital in dogs: 18 cases (1985-1989).

The medical records of 18 dogs that had hepatic disease and received phenobarbital as an anticonvulsant for 5 to 82 months were reviewed. Clinical signs included sedation and ataxia in all dogs, 5 dogs were also anorectic, 2 had coagulopathy, 3 were icteric, and 5 had ascites. Serum biochemical analysis revealed serum albumin concentration less than or equal to 2.2. g/dl in 12 dogs, serum alkaline phosphatase activity greater than or equal to 169 U/L in 18 dogs, serum alanine transaminase activity greater than or equal to 57 U/L in 15 dogs, and total bilirubin concentration greater than or equal to 1 mg/dl (in the absence of lipemia) in 7 dogs. Serum phenobarbital concentration was greater than or equal to 40 micrograms/ml in 12 of 17 dogs. Sulfobromophthalein excretion was prolonged in 8 of 10 dogs. Preprandial serum bile acid concentrations were high in 8 of 10 dogs, and 2-hour postprandial serum bile acid concentrations were high in 9 of 10 dogs. Two of 4 dogs tested had resting plasma ammonia concentrations greater than 200 mg/dl. An ammonia tolerance test was performed on 2 other dogs; both had ammonia concentration greater than or equal to 200 mg/dl in the plasma 30 minutes after receiving 100 mg of ammonium chloride/kg of body weight, PO. Nine dogs died, 1 was euthanatized, and necropsies were performed on these 10 dogs. Biopsies and necropsies of 6 dogs revealed chronic hepatic fibrosis with nodular regeneration (cirrhosis). One dog had hepatocellular carcinoma and mild cirrhosis. In 1 dog, after phenobarbital had been withheld, necropsy revealed complete recovery of the previously observed lesions.     

Iatrogenic fractures of ribs and vertebrae during delivery in perinatally dying calves: 235 cases (1978-1988)

To determine the pathogenesis of vertebral fractures in calves during the perinatal period, a retrospective study was done to determine the relationships between clinical factors at dystocia and the findings during necropsy of 235 perinatally dying calves. It was concluded that excessive traction is the most important cause of rib and vertebral fractures in the calf during dystocia. Vertebral fractures in perinatally dying calves may not be simply judged as a sign of asphyxia. The occurrence of vertebral fractures is highly correlated with the type of delivery and the force of traction. The veterinarian as well as the type of calf also are influencing factors. More perinatally dying calves were delivered after hips were locked, when extraction had been forced, or through induction of trauma when the head of the calf had the pelvic canal during the first obstetric examination. Consequently, fetal position at delivery may predispose calves to risky extractions and to the risk of perinatal death secondary to trauma. In light calves, significantly more vertebral fractures occurred during extractions than in other calves. Therefore, the veterinarian should accurately estimate the birth weight of the calf and the force of traction that should be applied.