Microbiologic findings in feedlot cattle with acute interstitial pneumonia

OBJECTIVE: To test the hypothesis that feedlot cattle with acute interstitial pneumonia (AIP) have bacterial infection of the lung or liver and concurrent bovine respiratory syncytial virus (BRSV) infection significantly more often than pen mates without AIP ANIMALS: 39 feedlot cattle with signs consistent with AIP and no history of treatment with antimicrobials and 32 healthy control cattle from the same pens. PROCEDURES: Lung and liver specimens were obtained postmortem for bacterial or mycoplasmal culture and histologic examination; lung tissue was assessed for BRSV infection immunohistochemically. RESULTS: Among affected cattle, 26 had AIP confirmed histologically. Lung tissue from 11 cattle with AIP yielded microbial respiratory tract pathogens on culture; tissues from control animals yielded no microbial growth. In 4 cattle with AIP and 2 control animals, liver abscesses were detected; bacteria were isolated from abscessed tissue in 3 and 1 of those animals, respectively. Immunohistochemically, 9 cattle with AIP and no control animals were BRSV-positive. Histologically, 9 AIP-affected cattle had only acute alveolar damage with exudation, and the other 17 had acute exudation with type II pneumocyte hyperplasia. No lesions of AIP were detected in control animals. Only 4 AIP-affected cattle had bacterial infection of the lung with concurrent BRSV infection. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that microbial respiratory tract pathogens are more common in cattle with AIP than in healthy pen mates. Control of bacterial pneumonia late in the feeding period may reduce the incidence of AIP at feedlots where AIP is a problem.     

Technique of mandibular salivary gland biopsy in river otters (Lutra canadensis).

A Franklin-Silverman biopsy needle was used to obtain 2-5- x 1-2-mm mandibular salivary gland tissue samples percutaneously from nine North American river otters (Lutra canadensis). The samples were suitable for fluorescent antibody or polymerase chain reaction rabies testing. Ninety-two percent (11/12) of the biopsy procedures yielded histologically confirmed salivary gland tissue, and the remaining biopsy yielded adipose tissue. No complications were noted after 5-21 days.     

Effect of dietary melengestrol acetate on the incidence of acute interstitial pneumonia in feedlot heifers

Over a 3-y period, 906,000 cattle were monitored in 23 feedlots in southern Alberta for symptoms of acute interstitial pneumonia (AIP). Plasma, urine, and lung tissue were collected at slaughter from 299 animals clinically diagnosed with AIP and from 156 healthy penmates and analyzed for 3-methylindole (3MI) derivatives and reduced glutathione concentration. From each animal, the left lung was subsampled for histologic examination. Concentrations of glutathione in lung tissue were reduced (P < 0.001) in animals showing clinical symptoms of AIP as compared with their asymptomatic penmates. Animals histologically confirmed as having AIP had higher levels of 3MI protein adducts in blood and lung tissue (P < 0.05) than did emergency-slaughtered animals without AIP. Within feedlots, where pens of heifers were fed either a standard dosage of melengestrol acetate (MGA) or none, the rate of death attributable to AIP was similar between treatment groups, but emergency slaughter after clinical diagnosis of AIP was done 3.2 times more often (P < 0.001) in the MGA-fed heifers than in the group not fed MGA. Use of MGA did not influence glutathione concentration. As growth performance of heifers given steroidal implants may not be improved by feeding MGA, the most cost-effective method of reducing the incidence of AIP-related emergency slaughter in feedlot heifers may be to eliminate MGA from the diet.     

Diagnosis of malignant catarrhal fever by PCR using formalin-fixed, paraffin-embedded tissues.

A previously described polymerase chain reaction (PCR) assay (amplification of a 238-bp fragment of ovine herpesvirus 2 [OHV-2] genomic DNA) for diagnosis of sheep-associated malignant catarrhal fever (MCF) was adapted for use on formalin-fixed, paraffin-embedded tissues. Variables affecting its use were examined. Archived tissues from cattle, white-tailed deer (Odocoileus virginianus), and bison (Bison bison) diagnosed with MCF by clinical signs or histologic lesions were obtained from 2 veterinary diagnostic laboratories. Tissues from healthy animals and from animals diagnosed with other common bovine viral diseases were examined as controls. A total of 86 blocks from 37 suspect MCF cases were examined. Forty-one blocks from healthy animals and animals with unrelated viral diseases were examined as controls. The assay was specific for sheep-associated MCF and did not yield false-positive signals from healthy animals or from cases of infectious bovine rhinotracheitis, bovine virus diarrhea, mucosal disease, or parainfluenza-3 virus infection. A wide variety of tissues were suitable substrates, including spleen, lymph node, intestine, brain, lung, and kidney. Extracted DNA provided a more suitable target than did unextracted tissue lysate. The highest levels of viral DNA were present in lymphoid organs and intestine, but the data indicate that in acute clinical cases, most organs contain sufficient viral DNA to serve as a suitable diagnostic specimen. Fixation of 0.5-cm3 blocks of tissue in 10% neutral buffered formalin was deleterious to the target DNA, and PCR signals progressively diminished after fixation for >45 days. Detection of genomic DNA of OHV-2 by PCR was successful for archived tissues that were 15 years old.     

Percutaneous lung biopsy in cattle.

OBJECTIVE: To determine safety of lung biopsy in healthy cattle and compare 3 biopsy instruments for suitability of use. DESIGN: Prospective study. ANIMALS: 60 healthy cows. PROCEDURE: Bilateral lung biopsy through the ninth intercostal space was attempted in all cows. The procedure was performed with cows standing and restrained by an assistant. To study the short-term effects of lung biopsy, 50 cows were slaughtered 1 day after the procedure and examined. To study the long-term effects of lung biopsy, the remaining 10 cows were examined daily for 10 days and then slaughtered. Three biopsy instruments--the Autovac biopsy cannula, the Tru-Cut needle, and the Bard Biopty-System--were evaluated. RESULTS: 2 cows collapsed momentarily during the procedure but recovered quickly. The remaining cows did not develop adverse effects, and general attitude and condition were not affected. Postmortem examination of the 50 cows slaughtered 1 day after the procedure revealed lesions < or = 5.0 mm long and with a surface area < or = 4.0 mm2 at 108 of 154 (71%) biopsy sites involving the pulmonary pleura. Biopsy specimens were obtained during 48 of 50 (96%) procedures in which the Tru-Cut needle was used, during 38 of 39 (97%) procedures in which the Bard Biopty-System was used, and during only 1 of 11 biopsy procedures in which the Autovac cannula was used. At postmortem examination of the 10 cows slaughtered 10 days after the procedure, lesions were seen as small scars; adhesions were not observed. CONCLUSIONS AND CLINICAL RELEVANCE: Percutaneous lung biopsy is a safe procedure in healthy cows.     

Hepatic failure and hemochromatosis of Salers and Salers-cross cattle

Hemochromatosis is rare in domestic mammals. Five clinical cases and one preclinical case of hemochromatosis were diagnosed in Salers and Salers-cross cattle. Clinical disease developed between 9 and 22 months of age. Animals were healthy until weaning but then lost weight, developed rough hair coats, and lost incisor teeth. In two animals, hemochromatosis was identified by liver biopsy, biochemical evidence of hepatic injury, and/or elevated transferrin saturation values. At necropsy, carcasses were thin, with firm dark brown livers and lymph nodes, soft bones, and brown-colored small bowel. The principal histologic changes were hepatocellular siderosis and periportal, bridging, and perivenular fibrosis. Siderocalcinosis involved collagen, elastin, reticulin, and basement membrane components in liver, lymph nodes, spleen, duodenum, and kidney. Hepatic iron concentrations in clinically affected cattle were 1,500-10,500 microg/g wet weight (reference range for cattle = <300 microg/ g). Ultrastructurally, the heaviest intrahepatic deposition was in hepatocytes, which contained large intracytoplasmic siderosomes. Iron deposition in bone was associated with osteopenia. Genetic analysis indicated a common ancestral bull in the pedigrees of five of six affected cattle; no pedigree was available for the remaining animal. Four dams of five affected animals were phenotypically normal and had histologically normal livers. Test mating of four cows to the ancestral bull resulted in a female calf that developed clinicopathologic and histologic evidence of preclinical hemochromatosis by 40 days of age. It was not possible to establish the pattern of inheritance because of the small number of pedigrees from affected cattle.     

Diagnosis of heartwater in the live animal: experiences with goats in Guadeloupe

A presumptive diagnosis of heartwater in the living animal can be based on clinical and epidemiologic observations. In Guadeloupe, heartwater can be confused with haemonchosis in goats or cerebral babesiosis in cattle. Confirmation of the clinical diagnosis by brain biopsy is useful in experimental infections but is hardly applicable in the field. Positive results were obtained from 92% of animals 16 to 18 days after experimental infection. In febrile animals the best results were obtained between the 3rd and 6th days of the thermal response. Diagnosis can also be supported by serological tests. These are useful for monitoring experimental infections and for checking recovered animals in the field. Nineteen goats out of 27 were negative on Day 1 of the febrile reaction but positive a week later. The remaining 8 goats were positive on Day 1 and had greatly increased antibody titres a week later. Confirmation of a diagnosis can also be achieved by subinoculating into susceptible animals either blood or suspensions of ticks collected from suspect animals and then homogenized. Ticks that have engorged on a suspect animal can be allowed to moult and then fed on a susceptible animal to test their infectivity. These methods are time consuming but useful for heartwater surveys.     

Use of thoracoscopy to determine the etiology of pleural effusion in dogs and cats: 18 cases (1998-2001)

OBJECTIVE: To assess use of thoracoscopy to determine causes of pleural effusion in dogs and cats. DESIGN: Retrospective study. ANIMALS: 15 dogs and 3 cats with pleural effusion. PROCEDURE: Medical records were reviewed from 1998 to 2001 for dogs and cats that had exploratory thoracoscopy, biopsy, and histologic analysis to determine the etiology of pleural effusion. Intraoperative and postoperative complications were recorded. Surgical biopsy specimens were evaluated for quantity and quality for providing a histologic diagnosis. RESULTS: Biopsy specimens were deemed adequate in quantity and quality to render a histologic diagnosis in all animals. Etiology of the effusion was neoplasia in 8 animals and non-neoplastic pleuritis in 10 animals. Median survival time of animals with neoplasia was 15 days, whereas those with inflammatory diseases had median survival time of > 785 days. Postoperative pneumothorax was encountered in 2 animals subsequent to pulmonary biopsy. No other major complications were recorded. CONCLUSIONS AND CLINICAL RELEVANCE: Thoracoscopy is a diagnostic option that provides excellent viewing of intrathoracic structures and adequate biopsy specimens with minimal complications. This technique provides a less invasive alternative to thoracotomy for evaluating the etiology of pleural effusion.     

Clinical examination of cattle for BSE in a cattle facility and slaughterhouse

Detection of a case of BSE in slaughtered cattle causes considerable expenses. It seems therefore desirable to screen cattle before slaughtering and exclude suspect animals from slaughter. The object of this study was to determine the practicability of such screening under realistic conditions in a large slaughterhouse and to evaluate the specificity of the tests proposed by BRAUN et al. (1997). 949 cattle over 24 months old were examined in the Munich slaughterhouse. Spontaneous behaviour and the reaction to tactile, acoustic, and optical stimuli only could be tested. The evaluation of locomotion was not possible without interference with the routine processing of cattle before slaughter. The examination took about three minutes per animal. The results were evaluated using a modification of the scheme of BRAUN et al. (1997). The specificity of the classification "BSE very likely" was 97.8%. If all animals that exhibit any signs suggestive of BSE were to be excluded, the specificity would drop to 63.7%. This pre-slaughter clinical screening is not useful.     

Susceptibility of cattle to infection with Ehrlichia equi and the agent of human granulocytic ehrlichiosis

OBJECTIVE: To determine susceptibility of cattle to infection with Ehrlichia equi and the agent of human granulocytic ehrlichiosis (HGE). DESIGN: Experimental disease and prevalence survey. ANIMALS: 6 cattle, 2 horses, and 2,725 serum samples from healthy cattle. PROCEDURE: 2 cattle and 1 horse were inoculated with E equi, 2 cattle and 1 horse were inoculated with the HGE agent, and 2 cattle served as sham-inoculated controls; inoculated animals were evaluated via clinical, hematologic, serologic, and real-time polymerase chain reaction tests. Prevalence of antibodies against E equi in 2,725 healthy cattle was determined by use of an indirect immunofluorescent technique. RESULTS: No abnormal clinical or hematologic findings or inclusion bodies within granulocytes were observed in the cattle after inoculation, and results of all polymerase chain reaction tests were negative. Seroconversion in inoculated cattle developed 10 to 12 days after inoculation (reciprocal titers, 160). Both horses developed clinical signs of ehrlichiosis. Five of 2,725 (0.18%) cattle were seropositive for E equi, with titers ranging from 20 to 80. All seropositive cattle originated from the same tick-rich region in the Sierra Nevada foothills. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that cattle are not susceptible to infection with E equi or the agent of HGE and that prevalence of exposure to E equi in healthy cattle is low. Therefore, E equi and the agent of HGE are likely of negligible importance for cattle in North America.     

Clinical findings and treatment of 30 cattle with botulism

The clinical signs, the results of haematological and biochemical analyses and the treatment of 30 cattle with botulism are described, and the signs of the 13 cattle that survived are compared with those of the 17 that were euthanased owing to the disease. The cattle originated from 11 farms that had experienced an outbreak of botulism. The most important clinical sign in all the cattle was a reduction in the strength of the tongue; excessive salivation and difficulty in swallowing were observed in 20 of the animals, and the ears of 15 of them drooped. In 21 of the cattle, reaction to pricking of the head and body with a hypodermic needle was either absent or slight. Twelve of the animals had an unsteady, slow, difficult gait, and nine were unable to stand. A significantly higher proportion of the cattle which were euthanased had marked changes in behaviour and condition, anorexia, severely reduced skin turgor, weak tongues, a low rectal temperature, a high heart rate and a low blood pH; 11 were euthanased immediately after a clinical examination and six were euthanased one to five days after the initiation of treatment because their condition had deteriorated. Thirteen of the animals were treated for three to 23 days and were healthy when they were discharged. The treatment consisted of an intravenous infusion of 10 to 20 litres of glucose saline per day and the daily administration of fresh ruminal juice. Follow-up by telephone several months later revealed that all 13 animals had recovered completely.     

Preliminary findings on the experimental transmission of chronic wasting disease agent of mule deer to cattle.

To determine the transmissibility of chronic wasting disease (CWD) to cattle and to provide information about clinical course, lesions, and suitability of currently used diagnostic procedures for detection of CWD in cattle, 13 calves were inoculated intracerebrally with brain suspension from mule deer naturally affected with CWD. Between 24 and 27 months postinoculation, 3 animals became recumbent and were euthanized. Gross necropsies revealed emaciation in 2 animals and a large pulmonary abscess in the third. Brains were examined for protease-resistant prion protein (PrP(res)) by immunohistochemistry and Western blotting and for scrapie-associated fibrils (SAFs) by negative-stain electron microscopy. Microscopic lesions in the brain were subtle in 2 animals and absent in the third case. However, all 3 animals were positive for PrP(res) by immunohistochemistry and Western blot, and SAFs were detected in 2 of the animals. An uninoculated control animal euthanized during the same period did not have PrP(res) in its brain. These are preliminary observations from a currently in-progress experiment. Three years after the CWD challenge, the 10 remaining inoculated cattle are alive and apparently healthy. These preliminary findings demonstrate that diagnostic techniques currently used for bovine spongiform encephalopathy (BSE) surveillance would also detect CWD in cattle should it occur naturally.     

Ultrasound-guided percutaneous lung biopsy in sheep

Lung biopsies were taken through the ninth intercostal space on the two sides of the thorax of 10 clinically healthy sheep, using a Tru-Cut needle on one side and the Bard Biopty-System on the other. Nine of the 10 sheep remained clinically healthy, but one coughed transiently and had a mild bloody discharge from the right nostril immediately after the biopsy. The sheep were slaughtered 10 days later and the lungs and pleura were examined macroscopically; there were either no lesions or only small scars visible at the sites of the biopsies. However, well-developed subpleural nodules due to parasites were observed in some of the lungs. There were no adhesions between the costal and pulmonary pleurae. Of the 20 biopsy specimens, 18 were ideal for histological examination, and none of them was histologically normal. Mild interstitial pneumonia was diagnosed in 15 specimens, chronic bronchiolitis in nine specimens, and hyperplasia of smooth muscle or connective tissue in 17.     

Evaluation of Thoracic Duct Healing After Experimental Laceration and Transection

Healing of the thoracic duct (TD) was evaluated clinically and histologically in six healthy dogs. A 2.5 cm longitudinal laceration of the caudal TD was created in three dogs and the caudal TD was completely transected in three other dogs. The site of the defect was identified by placing one 4-0 stainless steel suture in the tissue adjacent to the TD defect. All dogs developed a chylous effusion confirmed by biochemical analysis. By five days after surgery in dogs with TD lacerations, and by 10 days after surgery in dogs with TD transections, thoracic effusion had ceased. Lymphangiography, performed seven days after resolution of thoracic effusion, showed TD patency only in the dogs with TD lacerations. The TD did not appear to be patent in dogs with TD transections. Histologically, in dogs with TD lacerations, one moderately dilated lymphatic vessel was seen at the surgical site in one animal and the thoracic duct and other lymphatics in the two other dogs appeared normal. Minimal perivascular accumulations of neutrophils, macrophages, and lymphocytes were present adjacent to two lymphatics in one animal. A mild increase in fibrous connective tissue and neovascularization was present in the adjacent subpleura. In dogs with complete transections, three to six dilated lymphatics were present at the transection site. Mild thickening of the tunica media was present in one thoracic duct, associated with a "J"-shaped area of condensed collagen, presumed to be a collapsed thoracic duct in one animal. Mild to moderate accumulations of macrophages, lymphocytes, and moderate neovascularization was present in the surrounding tissue, separating it from the underlying connective tissue. Healed TDs could not be differentiated histologically from normal TDs.     

Prevention and treatment of complications of bovine gastrointestinal surgery

Abdominal surgery is the most common major surgical procedure performed by bovine practitioners. Most cattle, particularly dairy cattle, are sufficiently placid that major abdominal procedures are routinely completed with the animal standing, using local anesthesia and minimal physical and chemical restraint. An experienced bovine surgeon who exercises good judgment will infrequently encounter complications associated with this surgery. The purpose of this article is to describe the potential complications related to bovine abdominal surgery, how to avoid them, and how to treat them when they arise.     

Hypertrophic osteopathy associated with pulmonary Eikenella corrodens infection in a dog

CASE DESCRIPTION: A 4-year-old English Pointer was examined because of chronic, progressive signs of pulmonary disease and failure to respond to medical treatment. CLINICAL FINDINGS: At examination, radiography of the thorax revealed increased pulmonary opacity and air bronchograms in the right caudal lung lobe, and radiography of the forelimbs revealed periosteal bone production typical of hypertrophic osteopathy. Attempts to isolate a causative organism included bacterial culture of bronchoalveolar lavage fluid and a lung tissue specimen obtained via fine-needle aspiration. Despite a cytologic diagnosis of septic suppurative inflammation in the lavage fluid, those specimens did not yield bacterial growth. However, a biopsy specimen obtained during a lung lobectomy procedure yielded growth of Eikenella corrodens. TREATMENT AND OUTCOME: Despite successful surgical removal of the consolidated lung lobe and initiation of antimicrobial treatment, the dog died 6 days after surgery. CLINICAL RELEVANCE: The authors are not aware of reports of pulmonary infection with E. corrodens in animals. Infection with the organism is rare, but it is possible that infections are underreported given that the organism is difficult to culture and biopsy may be necessary to obtain enough tissue to yield a diagnosis.     

Application of timed artificial insemination protocols to grazing Japanese black cattle with long open period

To investigate the viability of timed artificial insemination (TAI) protocols in grazing Japanese Black cattle with long open period, ovarian status and progesterone and estradiol-17 beta profiles of the animals during the protocol were monitored. In 1998, prosta-glandin F(2a) (PG) was administered to 36 animals seven days after GnRH injection. Three out of the 36 animals were inseminated after detection of estrus and did not receive further treatment. The second GnRH was injected to the remaining 33 animals 48 hr after the PG injection and TAI was performed 24 hr later. In 1999, PG was injected to 25 animals six days after GnRH, the second GnRH was injected to 22 animals 48 hr after PG, and TAI was performed 16 hr later (The other three animals were inseminated before the time of TAI). The percentage of the animals with at least one functional corpus luteum and one follicle equal to or greater than 10 mm in diameter at PG injection was similar between the groups in 1998 and 1999. Likewise, the hormonal profiles were similar between the two groups. Pregnancy rates (PR) after the TAI protocols and natural mating in 1998 and 1999 were 75.0% and 88.0%, respectively. These figures were comparable to the PR obtained by conventional estrus synchronization protocols using PG (in 1995; 69.4%) or CIDR (in 1996; 59.1%). In conclusion, the TAI protocol can be applicable into grazing Japanese Black cattle with long open period.     

Paratuberculosis: a surgical method of diagnosis in practice

This article examines the use of the surgical mesenteric lymph node biopsy in cattle under field conditions. The surgical method and the complications which occurred are described. It is better not to give a sedative to an animal in advanced pregnancy. The site of the incision depended on the stage of pregnancy. In animals in advanced pregnancy in incision should be caudo-ventral in the right-hand flank. To prevent complications, the grid incision should be used then.     

Evaluation of renal gentamicin depletion kinetic properties in sheep, using serial percutaneous biopsies

Tissue drug residue research often involves the killing of an animal every time tissue concentrations are determined. To decrease the number of animals required to perform tissue depletion studies and to circumvent the statistical problems associated with determining tissue depletion kinetic properties, using multiple animals, the renal depletion profile of gentamicin from individual sheep was studied, using a bilateral renal translocation technique. Seven ewes were surgically altered, allowed to stabilize, and then allocated into 2 groups; group-1 sheep (n = 4) were given 3 mg of gentamicin/kg, IM, q 12 h for 10 days, and group-2 sheep (n = 3) were not given gentamicin. The kidneys from all ewes were biopsied 9 times over 74 days after the termination of gentamicin treatment. The renal concentrations of gentamicin were measured by use of a validated tissue digestion procedure coupled with a liquid-phase fluorescence polarization immunoassay. On days 75 and 77 after the end of gentamicin treatment, all ewes were euthanatized and necropsied. The concentrations of gentamicin in the biopsy specimens ranged from 71.9 to 183 micrograms/g on days 1 and 2 after dosing, and decreased to concentrations ranging from 3.99 to 7.35 micrograms/g on days 73 and 74 after the end of dosing. The decrease in renal gentamicin concentrations was best described by a biexponential equation. The early phase half-life was 2.8 days, whereas the terminal phase half-life was 59 days (harmonic means). There was no difference in the appearance or histologic features of the kidneys from groups 1 and 2. The only lesions noticed were linear fibroses that were attributed to the biopsy procedure.