Cows and calves from a 1,600-cow drylot dairy were screened for IgG antibodies to Salmonella dublin lipopolysaccharide (LPS), using an indirect ELISA. The ELISA was performed on milk samples from lactating cows and on sera from nonlactating cows and calves. Fecal samples were collected from calves and nonlactating cows for culture of Salmonella spp. All seropositive cattle were retested by culture and ELISA 5 times at monthly intervals or until antibody concentration decreased. None of the cattle remained culture-positive and seronegative. Prior to and during the sample collection period, approximately 30% of calves < 8 weeks old died of S dublin infection. Vaccination of cows with a killed S dublin/S typhimurium vaccine at cessation of lactation was a routine management practice. The ELISA-determined Igg response to vaccination had decreased by 50 days after vaccination. Eight cows and 5 calves that maintained a high serologic response to S dublin were purchased and moved to a research facility for 6 months of intensive monitoring. Lactating cows were milked twice daily, and culture of milk and feces for Salmonella spp was performed 5 times/wk. Serum IgG antibodies to S dublin LPS were measured weekly, using ELISA. At the end of 6 months, all 13 cattle were necropsied and tissues were obtained for culture of Salmonella spp. All 8 cows and 5 calves maintained persistently high ELISA titer for the 6 months of testing, and shed S dublin in the milk and/or feces during the same period. On this basis, they were termed S dublin carriers. Salmonella dublin was isolated from mammary tissue of 2 calves at necropsy, indicating that bacteremia may be a mode of mammary infection by S dublin. Results of the study indicated serologic testing can be used successfully on a large dairy to identify S dublin carrier cattle. Using initial milk screening, 42 of 1,268 lactating cows were identified as suspect, requiring repeated serologic testing. One nonlactating cow, 7 of the 42 suspect lactating cows, and 5 of the 222 calves maintained an Igg response, and were found to be S dublin carriers. Carrier cows shed S dublin in 3.35% of fecal samples and 2.51% of milk samples, and carrier calves shed S dublin in 17.26% of fecal samples.

A suction blister technique was used in 10 healthy dogs to remove the epidermis from the dermis in a standardized way. Collection chambers were attached to these skin windows and filled with autologous serum to attract exudative neutrophils. The chambers were emptied by fine-needle aspiration at 4-hour intervals and were refilled with serum for 24 hours after the Int aspiration. The collected cells were counted, differentiated, and stained, using the trypan blue dye-exclusion method to determine cell viability. Multiple skin biopsy specimens obtained during the procedure were examined histologically. The chamber fluid collected after 24 hours was cultured for bacteria. Increasing numbers of viable neutrophils were collected during the 24-hour period from the induced skin windows. In all but 1 dog, sufficient viable neutrophils could be collected to perform further functional tests in vitro. Our conclusion is that this technique might be useful to study chemotaxis in vivo and to perform functional tests on exudative neutrophils.

Ultrasound-guided brain biopsy of the cingulate gyrus and the head of the caudate nucleus was performed in clinically normal dogs. Dogs survived the surgery, and neurologic deficits were not detected in the 14-day postoperative period. Magnetic resonance imaging detected changes in the brain associated with biopsy in 9 dogs (90%) immediately after surgery and in 6 dogs (60%) 14 days after surgery. Fourteen days after surgery, sonography of the brain, performed through the skin overlying the burr hole, detected changes associated with biopsy in 9 dogs (90%). Histopathologic changes evident in the brain 14 days after surgery consisted of focal malacia and hemorrhage with associated subacute encephalomeningitis. Postmortem examination indicated that the biopsy specimen was accurately obtained from the desired site in 9 dogs (90%). Tissue specimens suitable for histologic examination were obtained from 10 dogs (100%). Accuracy and low morbidity of ultrasound-guided biopsy indicate that this may be a useful technique for diagnosis of focal brain disease in dogs.

One indication for referral of horses to veterinary hospitals is for diagnosis of the microbiologic cause of pneumonia, particularly when the initial treatment fails. Although endoscopic methods have long been available for microbiologic sample collection, accuracy of these methods under these conditions have not been studied in detail. We compared the bacteria isolated from samples obtained by bronchoalveolar lavage (BAL) with those obtained by protected catheter brush (PCB) from foals with unilateral pneumonia induced by inoculation with Klebsiella pneumoniae. As part of previously described clinical trials, foals were administered antimicrobial therapy IM (n = 15) or vehicle IM (n = 7), and collection of distal airway secretion samples was conducted during the treatment period. Sensitivity and specificity of the sample collection methods were assessed by comparison of the isolates from BAL or PCB samples with isolates from tissue of the inoculated lung lobe, which was the most severely affected lung region. Sensitivity and specificity of BAL for recovery of K pneumoniae (challenge strain) and Streptococcus zooepidemicus (common secondary pathogen) was 90 and 69%, respectively, compared with 76 and 85%, respectively, for the PCB method. Sensitivity was significantly (P = 0.03) higher for BAL (100%) than for PCB (69%) for recovery of K pneumoniae (P = 0.03) from lungs. However, difference in the sensitivity of these methods for recovery of S zooepidemicus was not significant. In conclusion, BAL was a more reliable method for recovery of bacteria from the lungs in chronically infected foals that received antimicrobial treatment.

In an abattoir-based case-control study, histologic, and macroscopic examination of porcine intestines at slaughter and 2 molecular assays were compared for use as diagnostic tests of proliferative enteritis (PE). Fecal samples and intestinal specimens were collected from pigs with grossly thick ileum and from clinically normal pigs at slaughter. Tissue specimens were fixed in neutral buffered 10% formalin, and sectioned. Sections stained with H&E were examined for proliferative lesions by a pathologist unaware of the group to which the pig had been assigned on the basis of results of gross examination. Adjacent tissue sections, stained with Warthin-Starry (silver) stain, were examined for presence of the intracellular bacterium of PE, ileal symbiont (IS)-intracellularis, in the enterocytes of the intestinal crypts by the senior author, who was unaware either of the group to which the pig had been assigned or diagnosis by the pathologist. Bacterial DNA was extracted from the fecal samples and assayed by dot-blot hybridization and polymerase chain reaction (PCR) for presence of IS-intracellularis DNA, without knowledge of results of the other examinations. The PCR assay for IS-intracellularis was a specific and sensitive diagnostic test for PE, and dot-blot hybridization was sensitive, but was less specific. Macroscopic examination of intestines at slaughter was a sensitive, but not specific, test. Association between IS-intracellularis and proliferative lesions was statistically examined in the same study. There was a highly significant (P = 0.0078) association between presence of naturally acquired proliferative lesions and intracellular infection induced by IS-intracellularis. The odds ratio of greater than or equal to 14 and estimated attributable fraction of greater than or equal to 92% indicate that IS-intracellularis may be a necessary cause of PE.

A sensitive and specific DNA probe for detection and identification of bovine herpesvirus 4 (BHV-4) was developed. Cloned fragments from a library of HindIII fragments of the BHV-4 (DN-599) genome were labeled with 32P or digoxigenin and were tested for sentitivity and specificity in detecting viral DNA by dot-blot hybridization. Two probes were identified that detected 10 pg of purified viral DNA, and detected viral DNA in 0.001 microgram of total DNA extracted from BHV-4-infected cells. Both probes labeled with 32P and 1 labeled with digoxigenin detected viral DNA in samples prepared from cells infected with 2 prototype strains (DN-599 and Movar 33/63) and 4 field isolates of BHV-4. The DNA probes did not hybridize to total DNA prepared from uninfected bovine cells or from cells infected with BHV-1, BHV-2, alcelaphine herpesvirus 1, pseudorabies virus, or equine herpesvirus 1. One probe, labeled with digoxigenin, was tested further by dot-blot hybridization with infected cell lysates that were simply treated with sodium dodecyl sulfate and proteinase K prior to application to the membrane, avoiding extensive DNA purification procedures. This simplified procedure also resulted in specific detection of field isolates of BHV-4 and prototype strains of BHV-4.

A protocol was developed for preparation of platelet concentrates (PC) to support thrombocytopenic dogs. Four clinically normal dogs with platelet counts that ranged from 200 to 330 X 10(9) platelets/L were used as donors. One unit (450 ml) of blood was collected by venipuncture into a double blood bag. Whole blood (WB) was centrifuged for 4 minutes at 1,000 X g (braking time = 2 minutes, 30 seconds) to prepare platelet-rich plasma (PRP). The PRP was expressed into the satellite bag and was centrifuged for 10 minutes at 2,000 X g (braking time = 2 minutes, 36 seconds). The platelet-poor plasma was expressed, leaving 40 to 70 ml of plasma and the pelleted platelets in the satellite bag. The resulting PC was left undisturbed for 60 minutes to promote disaggregation, and the platelets were then resuspended by gentle manual agitation. Forty-eight PC were prepared. Mean (+/- SD) platelet yield from WB to PRP was 78 +/- 13)% (range, 35 to 97%); yield from PRP to PC was 94 (+/- 6) % (range, 75 to 100%); and overall yield (PC from WB) was 74 (+/- 13) % (range, 36 to 91%). Mean PC platelet count was 8.0 (+/- 3.0) X 10(10) platelets/PC (range, 2.3 to 13.4 X 10(10) platelets/PC). The WBC content was 0.1 to 2.3 X 10(9) platelets/PC, representing 3 to 74% of WBC in the WB. Hematocrit was 0.1 to 26.2%. Results of bacterial and fungal culturing were negative.

Eight dogs were determined to be orthopedically normal on the basis of prelavage physical examination, stifle radiography, synovial fluid analysis, and force plate analysis (peak vertical force normalized for body weight, and time on the force plate). Each dog had 1 stifle randomly assigned to be lavaged with 100 ml of a commercially available 0.05% (w/v) chlorhexidine diacetate solution, and the contralateral stifle was lavaged with lactated Ringer's solution. Difference was not detected between the chlorhexidine diacetate and lactated Ringer's solution-treated joints, with regard to results of synovial fluid analysis and clinical lameness evaluations on days 4 and 8 after lavage. Chlorhexidine diacetate caused a more intense synovitis than did lactated Ringer's solution, as determined by histologic evaluation of synovial membrane specimens after necropsy on day 8; however, a difference in the intensity of toluidine blue staining of articular cartilage was not found between treatments. Chlorhexidine diacetate, as a 0.05% (w/v) solution, cannot be recommended as a joint lavage fluid until the duration of inflammatory changes in the synovial membrane are determined or until the chemical constituents of chlorhexidine diacetate causing the synovitis can be identified and removed.

Urethral pressures profiles (UPP) obtained by use of microtransducer catheters were determined in 8 anestrous sexually intact female Beagles during general anesthesia. A UPP study consisted of 3 consecutive recordings, and 4 UPP studies were repeated at an interval of 5 days in each dog. Maximal urethral pressure (cm of H2O), bladder pressure (cm of H2O), and anatomic urethral length (cm) were recorded. Maximal urethral closure pressure (cm of H2O) was calculated. Mean +/- SD (for all measurements) maximal urethral closure pressure was 12.8 +/- 5.6 cm of H2O (range, 2.4 to 25.2 cm of H2O). Maximal urethral closure pressure was significantly (P < 0.05) decreased during the first recording period (11.4 +/- 5.8 cm of H2O), Compared with the second (13.0 +/- 5.2 cm of H2O) or third 14.1 +/- 5.7 cm of H2O) recording periods within a UPP study (3 consecutive recordings). Mean maximal difference in urethral closure pressure during a single UPP study was 4.8 +/- 2.4 cm of H2O. Significant difference in maximal urethral closure pressure was not observed between studies. Mean (for all measurements) anatomic urethral length was 6.2 +/- 0.9 cm (4.1 to 7.8 cm). Anatomic urethral length was significantly (P < 0.05) less during the first recording period (6.1 +/- 0.9 cm), compared with values for the second and third periods (6.3 +/- 0.9 cm, 6.4 0.9 cm respectively). Anatomic urethral length for time 3 was significantly (P < 0.05) less than the value for time 1 (5.8 +/- 0.7 cm vs 6.6 +/- 0.8 cm). We conclude that the microtransducer catheter technique for measurement of UPP was reproducible during a single study and between successive studies. This method is useful in documenting maximal urethral pressure, maximal urethral closure pressure, and anatomic urethral length in clinically normal sexually intact female dogs.

An epidemiologic study of Pasteurella haemolytica serovar 1 (Ph1) in market-stressed feeder calves from 7 farms in eastern Tennessee was conducted. The nasal mucus of each calf was cultured sequentially at the farm of origin (day 0), at an auction market (day 133), and at a feedyard in Texas (days 141, 148, 155, and 169). Of the 103 calves tested, 77 were culture-positive, including 1 on day 0, 1 on day 133, 20 on day 141, 57 on day 148, 50 on day 155, and 14 on day 169. From the 143 Ph1 isolates, 20 enzyme profiles were determined by use of a commercial enzyme system that detects 19 enzymatic reactions; 4 antimicrobial susceptibility profiles were obtained, using the disk-diffusion method, which evaluated susceptibility to 11 antibacterial drugs. All isolates were positive for acid phosphatase and alkaline phosphatase, but were negative for alpha-galactosidase, alpha-mannosidase, beta-glucosidase, beta-glucuronidase, cystine aminopeptidase, N-acetyl-beta-glucosaminidase, and trypsin. Other positive enzyme reactions included: leucine aminopeptidase, 140 Ph1 isolates; phosphohydrolase, 90 isolates; alpha-fucosidase, 63 isolates; esterase (C4), 59 isolates; valine aminopeptidase, 30 isolates; esterase lipase (C8), 24 isolates; beta-galactosidase, 2 isolates; and alpha-glucosidase, chymotrypsin and lipase (C14), 1 isolate each. Thirty-four Ph1 profiles were identified, using combined enzyme and antimicrobial susceptibility profiles. The data indicate that the strains isolated during the feedyard period may have been determined more by farm of origin (P < 0.001) than by habitation with calves from other farms while in the feedyard. The combined enzyme and antimicrobial susceptibility profile method is a rapid and simple epidemiologic technique for tracking Ph1 strains in market-stressed feeder calves.