Idiopathic megaesophagus in a calf: clinical and pathologic features

A 4-month-old female Gelbvieh calf regurgitated 3 to 9 minutes after eating hay but not after eating grain or drinking water. A fiberoptic endoscopic examination and positive-contrast radiography revealed megaesophagus. The calf was euthanatized, and necropsy revealed a dilated esophagus (12 cm long) proximal to the thoracic inlet. Histologically, the major portion of the muscular layers of the esophagus was replaced by fat cells.     

The role of antibody in protection against African swine fever virus

Intraperitoneal immunization of pigs with anti-African swine fever virus (ASFV) antibody protected them against the effects of challenge with ASFV. This protection, which was exemplified by a reduction in pyrexia and viraemia plus an increased survival time, appeared to be mediated through the effects of complement-dependent antibody-mediated cytotoxicity (CDAC) or antibody dependent cell mediated cytotoxicity (ADCC). Experiments suggested that the reduction in viraemia was associated with complement lysis whereas protection was conferred by ADCC.     

Pemphigus foliaceus of the footpads in three dogs

Severe hyperkeratinization and villous hypertrophy of the footpads were seen in 3 middle-aged dogs. Peeling, fissuring, swelling, and ulcerations were noted on the margins of severely affected pads. Pain was evident in palpation and ambulation. Lesions were compatible with the traditional diagnosis of "hard pad disease". Histopathologic findings were diagnostic for canine pemphigus foliaceus in all 3 dogs, and direct immunofluorescence in an intercellular pattern was seen in both dogs that were tested. All 3 dogs responded to immunosuppressive dosages of corticosteroids.     

Comparisons of the genomic RNA of Arkansas DPI embryonic passages 10 and 100, Australian T, and Massachusetts 41 strains of infectious bronchitis virus

The genomic ribonucleic acid (RNA) of Arkansas DPI at embryonic passages 10 and 100, Australian T, and Massachusetts 41 strains of infectious bronchitis virus (IBV) were compared using two-dimensional, 32PpCp-labeled oligonucleotide fingerprinting. The Arkansas DPI strain embryonic passage 10 was pathogenic for chickens and had one oligonucleotide not present in the attenuated passage 100. The remaining Arkansas DPI oligonucleotides had identical electrophoretic mobility. The fingerprint patterns of the Australian T, Massachusetts 41, and Arkansas DPI IBV genomes were dissimilar, thus indicating they were genetically distinct. The distinctive fingerprint patterns of these virus strains, all identified as IBV by other criteria, indicate considerable genomic variation. Fingerprinting is reliable and sensitive, and should be used in combination with other characterization methods for identifying and differentiating IBV strains.     

Persistence of avian influenza viruses in water

Persistence of five avian influenza viruses (AIVs) derived from four waterfowl species in Louisiana and representing five hemagglutinin and neuraminidase subtypes was determined in distilled water at 17 C and 28 C. Infectivity was determined over 60 days by microtiter endpoint titration. One AIV was tested over 91 days at 4 C. Linear regression models for these viruses predicted that an initial concentration of 1 x 10(6) TCID50/ml water could remain infective for up to 207 days at 17 C and up to 102 days at 28 C. Significant differences in slopes for AIV persistence models were detected between treatment temperatures and among viruses. Results suggest that these viruses are adapted to transmission on waterfowl wintering habitats. Results also suggest a potential risk associated with waterfowl and domestic poultry sharing a common water source.     

Effects of gonadotropin treatment on ovarian follicle growth and granulosal cell aromatase activity in prepuberal gilts

This experiment was conducted to compare the ability of USDA porcine FSH-B-1 (pFSH), USDA porcine LH-B-1 (pLH), and pregnant mare's serum gonadotropin (PMSG) to grow large follicles and induce granulosal cell aromatase activity in prepuberal gilts. Twenty-four gilts (164 d old) received one of four treatments by i.m. injection: 1) saline once, n = 8; 2) pFSH (8 micrograms/kg BW, nine times at 8-h intervals), n = 5; 3) pLH (2 micrograms/kg BW, nine times at 8-h intervals), n = 6; or 4) PMSG (15 IU/kg BW, once), n = 5. At slaughter, 72 h after the first injection, the ovaries to saline-treated gilts contained an average of 104 surface antral follicles 1 to 3 mm in diameter. compared to treatment with saline, pFSH increased (P less than .05) the number of follicles 46%, whereas pLH or PMSG decreased (P less than .05) the number by 70 and 84%, respectively. Compared with saline, treatment with PMSG or pLH induced growth of large follicles (7 to 9 mm) (10.8 and 4.8 follicles/gilt, respectively), increased plasma estrogen, increased granulosal cell aromatase activity, and decreased plasma FSH by 51 and 69%; treatment with pFSH had no significant effect on these traits. Results indicate that injected pFSH did not cause growth of large follicles or induce granulosal cell aromatase activity in prepuberal gilts. In contrast, LH initiated growth and increased granulosal cell aromatase activity in a small number of follicles and accelerated atresia among the remaining follicles.     

Use of ELISA for detection of immunoglobulins G and M that recognize Salmonella dublin lipopolysaccharide for prediction of carrier status in cattle

Immunoglobulin reactions to Salmonella dublin in serum and milk from 4 groups of lactating cows were measured by an indirect ELISA. The groups consisted of (1) cows that were natural carriers of S dublin in the mammary gland, (2) experimentally infected cows that did not become carriers, (3) cows inoculated with a commercial S dublin bacterin, and (4) cows used as S dublin-negative controls. Milk and serum samples were obtained at monthly intervals. Models for predicting carrier status were developed by use of stepwise logistic regression. Independent variables consisted of serum and milk IgG and IgM titers to S dublin lipopolysaccharide and a ratio of IgG to IgM. The utility of a single sample vs multiple samples obtained at 1-month or 2-month intervals was tested by comparison of goodness-of-fit chi 2 P values for 8 models predicting carrier status. Immunoglobulin reactions specific to S dublin were a significant predictor of carrier status (P less than 0.001). Serum IgG titers specific for S dublin were the most important variable for predicting carrier status. Two serum IgG titers to S dublin obtained 2 months apart was a better predictor of carrier status than measurement of the IgG:IgM ratio from a single serum sample. Immunoglobulin recognizing S dublin epitopes also were detected in milk samples. In milk, performing 2 ELISA 60 days apart to determine IgG and IgM reactions to S dublin appeared to be useful for the prediction of carrier status, but was not as accurate as models for serum immunoglobulin reactions.     

Effect of creep feeding on the incidence, duration and severity of post-weaning diarrhoea in pigs

The effect of creep feeding on the response of pigs weaned at two or three weeks old to infection with an enteropathogenic strain of Escherichia coli (O149; K91[B], K88 a, c [L]) was studied in two separate experiments. Gastric intubation was adopted to regulate the intake of creep feed during the sucking period. Animals were given the enteropathogenic strain either before weaning or at weaning and the course and outcome of the infection followed bacteriologically and clinically. The response of the animals to the infection varied considerably in accord with recent reports of multiple phenotypes (to K88 +ve organisms) among pigs but consumption of creep feed before weaning did not significantly affect the prevalence, duration or severity of the diarrhoea induced experimentally by the organism. Hence reputed immunological responses mounted against dietary antigens did not predispose to or protect against this infection.