Antimicrobial susceptibility and serotypes of Actinobacillus (Haemophilus) pleuropneumoniae recovered from Missouri swine.

The antimicrobial susceptibility of 73 Actinobacillus (Haemophilus) pleuropneumoniae isolates from swine in Missouri was determined with a microdilution minimal inhibitory concentration test system. Serotyping was accomplished by means of co-agglutination. Serotype 1 (39/73) and serotype 5 (30/73) were commonly found, whereas serotype 7 (4/73) was infrequently encountered. Most isolates (MIC90) were found susceptible to ampicillin (amoxicillin), cephalothin, penicillin, erythromycin, gentamicin, and kanamycin. Marked resistance was found with oxytetracycline, tylosin, and sulfadimethoxine. The data indicate that use of ampicillin (amoxicillin) or penicillin may correlate well with the favorable outcome of treatment.

Investigation of the representativeness of a single endometrial sample and the use of trichrome staining to aid in the detection of endometrial fibrosis in the mare.

The uteri of five mares were removed and endometrial samples were procured from 12 specific locations in the uteri and the samples were processed and duplicate sections were stained with hematoxylin and eosin (H&E) or Masson's trichrome stains. The samples were interpreted in a blind manner by one person, and pathologic changes were classified according to Kenney (1). An assessment of stromal fibrous connective tissue and focal periglandular fibrosis or fibrotic nests was made. There were no significant differences in luminal epithelial cell heights or in the occurrence and severity of stromal fibrous connective tissue, focal periglandular fibrosis, or lymphatic lacunae among locations (P > 0.05). There was an effect of location on the occurrence and severity of inflammation (P < 0.05). If only inflammation was considered in categorization, this would have resulted in changing the category in 9 of 60 samples. There was no increase in tendency for inflammation, fibrosis or lymphatic lacunae to occur in the horns versus the body of the uterus, nor of the dorsal versus the ventral uterus (P > 0.05). There was no effect (P > 0.05) of type of stain on the ability to detect incidence and severity of focal periglandular fibrosis. There was an effect (P < 0.05) of type of stain on the ability to detect the incidence and severity of stromal fibrous connective tissue. The use of the trichrome stain showed slightly increased distribution of stromal fibrous connective tissue.

Antimicrobial resistance among Pasteurella spp recovered from Missouri and Iowa cattle with bovine respiratory disease complex.

A retrospective study was conducted to determine the prevalence of antimicrobial resistance among Pasteurella spp recovered from cattle with bovine respiratory disease complex. The study extended from January 1976 through May 1980, and included a review of the necropsy records of 386 beef cattle. Susceptibility or resistance of the Pasteurella isolants was determined by using the standard disk diffusion susceptibility test. Each isolant was tested for susceptibility with 15 different antimicrobial agents. A high prevalence of resistance (greater than 80%) was found when Pasteurella was tested with triple sulfonamides. For P haemolytica isolants, 57% to 70% were resistant to ampicillin (56/97), penicillin (58/101), and streptomycin (70/100); for unidentified Pasteurella spp isolants, 64% to 91% were resistant to ampicillin (83/129), penicillin (89/129), and streptomycin (118/129). For P haemolytica (21/100) and P multocida (34/146) isolants, 21% to 23% were resistant to tetracycline. Most of the P multocida isolants did not show marked antimicrobial resistance to 9 of the 15 drugs tested. However, 58% of the P multocida isolants (84/145) were resistant to streptomycin and 88% of them were resistant to three combined sulfonamides (126/144).

Chromosome evaluation of Angus calves with unilateral congenital cleft lip and jaw (cheilognathoschisis).

Two purebred Angus calves with unilateral cleft lip and jaw were karyotyped and anatomically described. Both calves, 1 male and 1 female, were from the same farm and were born in March and April 1980. The defect was most pronounced in the female calf. Both calves exhibited an elevated midline of the hard palate. The female calf also manifested characteristics indicative of proportionate dwarfism. Karyotypes were constructed after a 72-hour culture of peripheral blood. The 2N number was 60 with no apparent chromosome abnormality. The coefficient of relationship between the 2 affected calves was calculated to be 0.78%. The cause of the defect could not be ascertained from the limited data available.

Recurrent esophageal obstruction due to squamous cell carcinoma in a horse.

Squamous cell carcinoma involving the pars esophagea of the stomach caused recurrent esophageal obstruction in an 11 year old Pinto gelding. The tumor encircled the esophagus and was attached to the diaphragm, spleen, aorta, left adrenal gland and kidney. Definitive diagnosis was provided by biopsy of the mass via standing left flank laparotomy.

Induction of fescue foot syndrome in cattle by fractionated extracts of toxic fescue hay.

Tall fescue (Festuca arundinacea Shreb) hay from a source known to cause "fescue foot" in grazing cattle was extracted with 80% ethanol. The ethanolic extract was further refined and fractionated into cation,nion, and neutral f fractions by ion-exchange chromatography. The cation fraction was partitioned with alkaline-chloroform to give chloroform-extractable cation and residual cation fractions. All fractions plus the crude ethanolic extract were assayed for toxic activity by intraperitoneal injection into 12 calves (weighting 152.4 to 241.3 kg each) over a 14-day period. Clinical signs of fescue foot were observed on the 5th day in calves given the anion and crude ethanolic extracts. Lameness, swelling, and reddening of the rear coronary bands, discoloration of the tip of the tail, and other signs of fescue foot were seen. Microscopically, coronary bands and tail tips of affected calves had blood vessels with thick walls and small lumens.