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Distillers grains (DG), a co-product of ethanol production used as protein and energy supplements in cattle diets, have been shown to increase fecal shedding of Escherichia coli O157:H7, a major foodborne pathogen. The reason for the positive association is not known. Because DG often replaces grain in the diet, decreased starch content and flow to the hindgut may create a favorable environment for E. coli O157:H7. Our objective was to determine whether the addition of starch to a corn DG-supplemented diet negates the effects of DG on fecal shedding of E. coli O157:H7. We conducted a study with 21 steers fed 1 of 3 diets: a corn grain-based basal diet (CON), basal diet supplemented with 25% corn dried DG (DDG), and basal diet supplemented with 25% DDG with corn starch (DDG+S) added at a level intended to increase starch concentration to that of the CON diet. Steers, housed individually in a biosafety level 2 animal facility, were randomly allocated to treatment diets and orally inoculated with a 5-strain mixture (10(9) cfu per steer) of nalidixic acid-resistant (Nal(R)) E. coli O157:H7. Fecal samples were collected for 5 wk, and on d 35, steers were euthanized and necropsied to collect gut content samples. Fecal or gut samples were cultured to determine prevalence and concentrations of Nal(R) E. coli O157:H7. Dietary starch concentrations, based on feed analysis, were 46.3% in the CON compared with 43.3 and 41.3% in the DDG and DDG+S diets, respectively. Steers fed DDG or DDG+S diets shed Nal(R) E. coli O157:H7 more often (P = 0.0027 and 0.0003, respectively) and at greater concentrations (1.9 or 2.0 cfu/g; P = 0.0025 and 0.0006) than those fed CON diet (1.4 cfu/g), but no difference was observed between DDG and DDG+S diets. Cumulative prevalence and concentrations of Nal(R) E. coli O157:H7 were greater in gut samples collected at necropsy in steers fed DDG and DDG+S diets compared with those fed CON diet, but no difference was observed between DDG and DDG+S diets. The lack of effect of starch addition to the DDG diet on fecal shedding of E. coli O157:H7 may be because either the decreased starch content in the DG-supplemented diet is not a factor in the increased shedding of E. coli O157:H7 or inclusion of pure starch in the diet may not have achieved our intended goal to have starch flow into the hindgut similar to that of corn grain. The study confirms our previous finding of the positive association between feeding DG and fecal shedding of E. coli O157:H7.

Twelve ruminally cannulated cattle, adapted to forage or grain diet with or without monensin, were used to investigate the effects of diet and monensin on concentration and duration of ruminal persistence and fecal shedding of E. coli O157:H7. Cattle were ruminally inoculated with a strain of E. coli O157:H7 (10 10 CFU/animal) made resistant to nalidixic acid (Nal r ). Ruminal and fecal samples were collected for 11 weeks, and then cattle were euthanized and necropsied and digesta from different gut locations were collected. Samples were cultured for detection and enumeration of Nal r E. coli O157:H7. Cattle fed forage diets were culture positive for E. coli O157:H7 in the feces for longer duration ( P < 0.05) than cattle fed a grain diet. In forage-fed cattle, the duration they remained culture positive for E. coli O157:H7 was shorter ( P < 0.05) when the diet included monensin. Generally, ruminal persistence of Nal r E. coli O157:H7 was not affected by diet or monensin. At necropsy, E. coli O157:H7 was detected in cecal and colonic digesta but not from the rumen. Our study showed that cattle fed a forage diet were culture positive longer and with higher numbers than cattle on a grain diet. Monensin supplementation decreased the duration of shedding with forage diet, and the cecum and colon were culture positive for E. coli O157:H7 more often than the rumen of cattle.

The objective of this study was to compare the concentration and duration of fecal shedding of Escherichia coli O157:H7 between calves fed milk replacer with or without antibiotic (oxytetracycline and neomycin) supplementation. Eighteen 1-wk-old Holstein calves were orally inoculated with a strain of E. coli O157:H7 (3.6 x 10(8) cfu/calf) made resistant to nalidixic acid (NA). Rectal samples were obtained three times weekly for 8 wk following oral inoculation. Fecal shedding of NA-resistant E. coli O157:H7 was quantified by direct plating or detected by selective enrichment procedure. Eight weeks after inoculation, calves were killed, necropsied, and tissues (tonsils, retropharyngeal and mesenteric lymph nodes, and Peyer's patches) and gut contents (rumen, omasum, abomasum, ileum, cecum, colon, and rectum) were sampled to quantify or detect NA-resistant E. coli O157:H7. The percentage of calves shedding NA-resistant E. coli O157:H7 in the feces in the antibiotic-fed group was higher (P < 0.001) early in the study period (d 6 and 10) compared with the control group fed no antibiotics. There was no difference between treatment and control groups in the concentration of E. coli O157 in feces that were positive at quantifiable concentrations. A comparison of the duration of fecal shedding between treated and untreated calves showed no significant difference between groups. At necropsy, E. coli O157:H7 was recovered from the rumen and omasum of one calf in the control group and from retropharyngeal lymph node and Peyer's patch of two calves in the antibiotic group. Supplementation of milk replacer with antibiotics may increase the probability of E. coli O157:H7 shedding in dairy calves, but the effect seems to be of low magnitude and short duration.

Ultrasound evaluation was performed on 11 healthy cats to determine wall thickness measurements for the stomach, duodenum, jejunum, ileum, and colon and to characterize the appearance of the ileocolic region. The terminal ileum had a characteristic "wagon wheel" appearance on cross-sectional images. Gastrointestinal wall thickness measurements were as follows: gastric fundus (mean, 2.0 mm; 95% confidence interval [CI], 1.7 to 2.2 mm), pylorus (mean, 2.1 mm; 95% CI, 1.9 to 2.4 mm), duodenum (mean, 2.2 mm; 95% CI, 2.0 to 2.4 mm), jejunum (mean, 2.3 mm; 95% CI, 2.1 to 2.5 mm), ileum (mean, 2.8 mm; 95% CI, 2.5 to 3.2 mm), and colon (mean, 1.5 mm; 95% CI, 1.4 to 1.7 mm).

Summary A total of 81 Pasteurella multocida isolates from healthy and diseased dairy and beef cattle originating from various geographical locations was examined by rRNA gene restriction site polymorphism analysis (ribotyping), restriction endonuclease analysis (REA), SDS-PAGE analysis of whole-cell (WCP) and outer-membrane (OMP) proteins, and capsule and somatic serotyping. Bacterial strains were isolated from nose, lung and in one case testicle, of Holstein and cross-bred beef cattle. The isolates represented for the most part serogroup A3 (88%). Ribotyping was performed on DNA digested with HaeII, electrophoresed and then hybridised with 32P-labelled 16S–23S rRNA from Escherichia coli. Six ribotypes (R1–R6) and 10 REA types were found among the 81 isolates with similar discrimination index (DI) of c. 0.60. Protein profiles revealed reproducibility and high levels of polymorphisms among lung isolates. Isolates were compared according to their geographical habitat, their isolation from dairy or from beef cattle and from nasal cavities or lungs. No correlation was apparent between geographical locations and ribotypes. Overall, isolates obtained from dairy cattle were predominantly R1, whereas those obtained from beef cattle were equally distributed between R1 and R2. R1 was more representative of lung isolates. For some strains, particularly the single isolate ribotypes, good correlation was achieved between WCP analysis, REA types and ribotypes. For others, REA to some extent and WCP profiles were able to discriminate among isolates within ribotypes. The data suggest that a combination of ribotyping, REA and WCP analysis is useful for investigating the epidemiology of bovine P. multocida serogroup A.

A commercially acquired anti-human macrophage antibody (anti-CD68; EBM11) was used in an immunocytochemical technique to detect macrophages in formalin-fixed, paraffin-embedded tissues from cattle, pigs, humans, rats, turkeys, dogs, and cats. In healthy cattle, the antibody labeled alveolar macrophages, pulmonary intravascular cells (presumably intravascular macrophages), and macrophage-like cells in other tissues. In bovine lungs infected with Pasteurella haemolytica, EBM11 antibody labeled 95% of alveolar macrophages and macrophages within alveolar septa but only 0–2% of streaming or “oat” leukocytes. Alveolar macrophages were also stained by EBM11 in pigs but not in rats, turkeys, dogs, and cats. The antibody also stained macrophage aggregates in the mesenteric lymph nodes and intestinal lamina propria of Mycobacterium paratuberculosis-infected cattle. This study shows that the anti-CD68 (EBM11) antibody is a useful marker of macrophages in normal bovine tissues or tissues from areas of acute or chronic inflammation that have been routinely processed. The study also adds strength to the growing evidence suggesting that streaming leukocytes seen in pneumonic pasteurellosis are neutrophils.

Mycobacterium haemophilum, a nontuberculous mycobacterium, is a pathogen in immunocompromised human patients. We report a case of M haemophilum-induced granuloma in the spinal cord of an American Bison ( Bison bison). M haemophilum infection was diagnosed by sequencing a portion of the 16 S ribosomal DNA and comparing the amplicon sequence with sequences in GenBank.

The objective of this study was to compare the concentration and duration of fecal shedding of Escherichia coli O157:H7 between calves fed milk replacer with or without antibiotic (oxytetracycline and neomycin) supplementation. Eighteen 1-wk-old Holstein calves were orally inoculated with a strain of E. coli O157:H7 (3.6 x 10(8) cfu/calf) made resistant to nalidixic acid (NA). Rectal samples were obtained three times weekly for 8 wk following oral inoculation. Fecal shedding of NA-resistant E. coli O157:H7 was quantified by direct plating or detected by selective enrichment procedure. Eight weeks after inoculation, calves were killed, necropsied, and tissues (tonsils, retropharyngeal and mesenteric lymph nodes, and Peyer's patches) and gut contents (rumen, omasum, abomasum, ileum, cecum, colon, and rectum) were sampled to quantify or detect NA-resistant E. coli O157:H7. The percentage of calves shedding NA-resistant E. coli O157:H7 in the feces in the antibiotic-fed group was higher (P0.001) early in the study period (d 6 and 10) compared with the control group fed no antibiotics. There was no difference between treatment and control groups in the concentration of E. coli O157 in feces that were positive at quantifiable concentrations. A comparison of the duration of fecal shedding between treated and untreated calves showed no significant difference between groups. At necropsy, E. coli O157:H7 was recovered from the rumen and omasum of one calf in the control group and from retropharyngeal lymph node and Peyer's patch of two calves in the antibiotic group. Supplementation of milk replacer with antibiotics may increase the probability of E. coli O157:H7 shedding in dairy calves, but the effect seems to be of low magnitude and short duration.

Hereditary polioencephalomyelopathy was suspected in a young, female Australian Cattle Dog on the basis of clinical signs, including seizures, progressive ataxia, and weakness. Magnetic resonance imaging (MRI) of the brain revealed multiple ovoid, bilaterally symmetric signal abnormalities that were hypointense or isointense on T1-weighted images and hyperintense on T2-weighted images. On necropsy, these areas of signal abnormalities corresponded to areas of malacia in various brain and brain stem nuclei. In addition, poliomalacia was detected at the cervical intumescence of the spinal cord. Histologic examination revealed rarefaction of neuropil and vacuolation of glial cells in these areas, which are lesions consistent with hereditary polioencephalomyelopathy of Australian Cattle Dogs.

To determine the pathogenic potential of an adenovirus isolated from a goat.14 colostrum-deprived, isolation-reared goat kids approximately 3 weeks old.Kids were inoculated with either cell culture fluid containing adenovirus (n = 10) or uninfected cell culture fluid (n = 4): 2 ml transtracheally and 1 ml/nostril. Clinical signs of disease and rectal temperature were recorded daily; nasal secretion and fecal specimens were collected daily. Control kids were necropsied, 2/d, on postinoculation days (PID) 5 and 10. Virus-inoculated kids were necropsied on PID 3, 5, 7, 10, and 28. After necropsy, lung, liver, kidney, and brain specimens were aseptically collected for virus isolation attempts. Tracheal fluid was collected on sterile cotton swabs. Turbinate, trachea, lung, mediastinal lymph node, liver, kidney, duodenum, jejunum, ileum, mesenteric lymph node, colon, and brain specimens were collected for histologic evaluation.Kids developed mild-to-moderate clinical respiratory tract infection. Virus was recovered consistently from nasal secretion and sporadically from fecal specimens. Grossly, there were multiple areas of atelectasis and hyperemia, principally in the cranioventral portion of the lungs. Microscopically, there was detachment and sloughing of foci of epithelial cells of the terminal bronchioles and alveoli. In kids necropsied late in the disease, these changes were accompanied by hyperplasia of type-II epithelial cells. Viral inclusions were not an obvious feature, but a few cells contained probable inclusions.The caprine adenovirus reported here is capable of inducing respiratory tract disease and lesions in the lungs of young kids.

A 5-year-old sexually intact male mixed-breed dog was evaluated because of suspected vena caval syndrome secondary to heartworm disease. On physical examination, the dog was thin, icteric, and weak and had tachycardia and a cardiac murmur. Serum biochemical and hematologic abnormalities included hyperbilirubinemia, high serum alkaline phosphatase and alanine transferase activities, hypoalbuminemia, leukocytosis, and normocytic normochromic anemia. Dirofilaria immitis microfilariae were seen in a blood smear. Echocardiography was used to confirm the diagnosis of vena caval syndrome. Multiple aberrant adult heartworms were evident ultrasonographically in the abdominal aorta and its branches and within hypoechoic nodules in the left caudal lobe of the liver. The dog's condition deteriorated despite supportive treatment and retrieval of 58 adult heartworms from the right side of the heart and vena cava, and the dog was euthanatized. At necropsy, adult heartworms were found in the aorta and inflammatory hepatic nodules. To our knowledge, ultrasonographic identification of heartworms within the systemic arterial system and liver of a dog has not been described previously.

An epizootic of abdominal tympany in goat kids as a result of abomasal bloat associated with a short duration of clinical signs was fatal in over 200 kids. Histologic examination of sections of abomasum revealed high numbers of bacteria that were morphologically identical to Sarcina sp. Sarcina sp are anaerobic, gas-producing organisms that could cause abomasal bloat. Other reports have proposed that abomasal bloat is caused by abnormal abomasal flora; we propose that in the goat kids reported here, Sarcina sp may represent the abnormal flora.

The lipopolysaccharide (LPS)-associated protein (LAP) was extracted from Pasteurella haemolytica serotype A1 strains L101 (bovine origin) and 82-25 (ovine origin). Extracts contained 0.017% total LPS and appeared as only two bands at 14 and 16.6 kDa after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. To determine the extent of pulmonary inflammation induced by LAP and its possible role in the pathogenesis of pneumonic pasteurellosis, LAP (500 micrograms in pyrogen-free saline [PFS]) was deposited by fiber-optic bronchoscopy into the dorsum of the caudal portion of the cranial lobe of the right lung of calves (strain L101 LAP) and sheep (strain 82-25 LAP). LPS (500 micrograms in PFS), 3-h P. haemolytica cultures (1.6 x 10(8) to 1.9 x 10(8) CFU in PFS), and PFS alone were deposited similarly as controls. At necropsy, 24 h after deposition, gross and histologic pulmonary lesions of calves and sheep given LAP, LPS, and P. haemolytica were similar and consisted of various degrees of acute bronchopneumonia (relative severities of lesions induced: LAP < LPS < live organisms). By subjective histologic interpretation and semiquantitative morphometry, animals given LAP had the highest percentage of macrophages per alveolar lumen and the lowest percentage of neutrophils. The lesions from animals given LPS were more severe than those given LAP, but the morphometric cell counts were similar. In contrast, animals inoculated with P. haemolytica had lesions typical of this agent, consisting of many neutrophils, proteinaceous exudate, and a few macrophages. Morphometrically, these lesions had the highest numbers of neutrophils and the lowest numbers of macrophages. These studies show that LAP can induce an inflammatory response in the alveolar lumens and may play a role in the pathogenesis of pneumonic pasteurellosis.

To determine if sheep scrapie agent(s) in the United States would induce a disease in cattle resembling bovine spongiform encephalopathy, 18 newborn calves were inoculated intracerebrally with a pooled suspension of brain from 9 sheep with scrapie. Half of the calves were euthanatized 1 year after inoculation. All calves kept longer than 1 year became severely lethargic and demonstrated clinical signs of motor neuron dysfunction that were manifest as progressive stiffness, posterior paresis, general weakness, and permanent recumbency. The incubation period was 14-18 months, and the clinical course was 1-5 months. The brain from each calf was examined for lesions and for protease-resistant prion protein. Lesions were subtle, but a disease-specific isoform of the prion protein was present in the brain of all calves. Neither signs nor lesions were characteristic of those for bovine spongiform encephalopathy.

A previous report described abomasal bloat with high mortality in kids up to 10 weeks of age at a goat dairy. The kids were found dead within 2 hours of the initial clinical signs of lethargy, reluctancy to stand, distended abdomen, and a hollow sound upon ballottement. Histopathological examination of the abomasum revealed large, spherical cells in packets of 4 to 20, similar to Sarcina ventriculi. Those authors postulated that S. ventriculi may have a role in the development and pathogenesis of abomasal bloat in goat kids. Similar association of Sarcina-like bacteria with abomasal bloat in calves has been reported. Experimental Procedures