Recurrent outbreaks of a cutaneous form of Pasteurella multocida infection in turkeys.

Cutaneous infection caused by Pasteurella multocida was diagnosed in a flock of seven thousand 17-to-22-week old male turkeys. The affected grow-out facility had an annual outbreak of fowl cholera, in which a cutaneous infection ventral and lateral to the tail was the predominant lesion. P. multocida serotypes 1 and 14 were the predominant isolates. The exact source of the infection was not determined.

English yew poisoning in 43 cattle.

Thirty-five privately owned 1- to 2-year-old mixed-breed steers and heifers, weighing 340 to 454 kg, died from accidental ingestion of English yew (Taxus baccata). Estimated dosages ranged from 0.36 to 0.70 g of fresh plant/kg of body weight. Clinical signs of poisoning and death began 2 to 3 hours after first exposure, and cattle continued to have clinical signs, which ended in death 6 to 8 hours later. Most cattle had died by 4 hours after first ingestion. Necropsy of 4 cattle revealed substantial amounts of English yew leaves and small stems in the rumen contents. Grossly, there were areas of hyperemia in the abomasum and small intestine. Histologically, lesions were limited to the lungs and included moderate congestion and interlobular edema. Chemical analysis by thin-layer chromatography of suspected yew plant material from the rumen contents of the 4 necropsied cattle was compared to authentic taxol, and confirmed the presence of taxol in rumen samples.

Bovine myocardial epithelial inclusions.

Light microscopic, histochemical, immunohistochemical, and ultrastructural methods were used to examine myocardial epithelial masses in the hearts of ten cattle. The tissues consisted of paraffin-embedded or formalin-fixed samples from eight hearts that were being inspected in slaughter houses and from two hearts from calves that died of septicemia. The ages of the cattle ranged from 4 days to 12 years; the breeds were unspecified for all but one Hereford female and the two Holstein calves; and there were three males, four females, and three steers. The masses in these cases were compared with similar appearing lesions found in other animal species. The lesions in the bovine hearts were single to multiple, well circumscribed, found in the left ventricle wall, and composed of squamous to cuboidal epithelial cells that formed tubular, ductular, and acinar structures with lumens that were void or filled with amorphous protein globules. Electron microscopic examination revealed epithelial cells that had sparse apical microvilli, tight apical intercellular junctions, perinuclear bundles of filaments, and rare cilia. Almost half of the bovine epithelial masses (4/9) had occasional diastase-resistant periodic acid-Schiff-positive granules in their cytoplasm, and few had hyaluronidase-resistant alcian blue-positive granules (2/9) or colloidal iron-positive granules (1/9). All myocardial masses had abundant collagen surrounding the tubular and acinar structures, and 2/9 had elastin fibers as well. None of the myocardial masses had Churukian-Schenk or Fontana Masson's silver staining granules in epithelial cells. Immunohistochemically, all bovine myocardial tumors stained positively for cytokeratin (8/8), and occasional masses stained positively for vimentin (3/8) or carcinoembryonic antigen (3/8). None of the masses stained positively for desmin. The myocardial epithelial tumors most likely represent endodermal rests of tissue misplaced during organogenesis.

Relationship of the hypothalamic-pituitary-adrenal axis with chemically induced immunomodulation. I. Stress-like response after exposure to T-2 toxin.

T-2 toxin (T-2), a trichothecene mycotoxin, produced by several members of the genus Fusarium is a cytotoxic feed contaminant and has been shown to by immunomodulatory. It is suspected that T-2 associated immunomodulation is mediated partly through the hypothalamic-pituitary-adrenal (HPA) axis. T-2, prepared in 4% ethanol/corn oil, was administered orally to male CD-1 mice. Endotoxemia was evident 24 h after a single, oral exposure to T-2. Blood levels of corticosterone, indicative of the stress-response, increased 24 h after T-2 exposure. Hypothalamic norepinephrine and serum corticosterone levels increased in a dose-related manner after 2 weeks of T-2 exposure. Endotoxin, detected in the serum of animals exposed to 2.5 mg/kg T-2 for 1 week, was not associated with bacteremia. Neither endotoxin nor bacteremia were detectable after 2 or 4 weeks of T-2 exposure. Exposure to 2.5 mg/kg T-2 also affected several organs. The forestomach was ulcerated, with lymphocytic infiltration, epithelial proliferation, and hyperkeratinization. Increased spleen weight was associated with a proliferative red pulp. No histological changes were observed in the enlarged liver. Gastritis has been associated with increased corticosteroid production; cortical depletion and reduced mass of the thymus are phenomena attributable to increased corticosteroid levels. An increased corticosteroid level has been associated with thymic involution leading potentially to decreased T-dependent antibody response, a known effect of T-2.

Hound's-tongue (Cynoglossum officinale) poisoning in a calf.

Cynoglossum officinale was believed to be responsible for the death of one calf and possibly 5 other calves in a group of 9 calves being fed chopped hay contaminated by this plant. The plant, commonly known as hound's tongue, contains pyrrolizidine alkaloids and has been determined to be toxic to horses fed contaminated hay, but was fed to cattle at the same time with no effect.

Fixative evaluation and histologic appearance of embryonic rodent tissue.

Histopathologic study of early hamster embryos was carried out after fixation in Zenker's solution, alcoholic formalin, Bouin's fluid, 10% neutral buffered formalin, or 3% glutaraldehyde and staining with hematoxylin and eosin. Fixation in Zenker's fluid followed by postfixation in neutral buffered formalin provided superior preservation of normal embryonic subcellular detail as compared to the other candidate processing techniques.

Death camas poisoning in sheep: a case report.

Approximately 250 sheep were poisoned and died from ingesting death camas (Zygadenus paniculatus) within a 2-day period on a foothill range in southeastern Idaho. Sixty to 70% of the poisoned sheep were 80-90 lb lambs and the rest were mature ewes. Poisonings were confirmed by field investigation, microhistological analysis of plant fragments from rumen contents of dead sheep, clinical signs, gross and microscopic analysis of tissues, and by experimentally feeding death camas collected on the poisoning site to 3 ewes at the Poisonous Plant Research Laboratory at Logan, UT. Clinical signs and gross and microscopic analysis of tissues were similar in ewes from the field investigation to those in ewes experimentally fed death camas. Ataxia, muscular weakness, trembling, incoordination, discharge of frothy saliva from the mouth and nose, vomition, dyspnea, collapse and death were the most common clinical signs. Gross changes included severe pulmonary congestion and subcutaneous hemorrhage. Microscopic lesions were those of severe pulmonary congestion.

Effects on cattle and their calves of tansy ragwort (Senecio jacobaea) fed in early gestation.

Tansy ragwort (Senecio jacobaea) fed to pregnant cows on gestation days 15 through 30 in lethal and near-lethal doses did not cause detectable damage to 100-day-old or to full-term fetuses as determined by gross examinations, serum enzyme tests chosen to detect hepatic changes, and by histopathologic examinations. Some cows that appeared normal during gestation expired soon after parturition from typical seneciosis apparently triggered by parturition stress. Pregnant cows fed 12% smaller tansy ragwort doses on gestation days 30 through 45 had only minimal serum enzyme changes and gave birth to normal calves that had normal serum enzymes up to 64 days after parturition.

Immunoprophylaxis of an ocular solid malignant tumor in cattle.

Individual Hereford cows bearing benign precursor lesions of ocular squamous cell carcinoma were treated by intralesional injection of mycobacterial cell walls in an oil-in-water emulsion in an attempt to interrupt neoplastic progression. Thirty-one months after treatment, statistical analysis of data indicated that intralesional BCG cell wall vaccine can interrupt this process and provides effective immunoprophylactic prevention of malignant disease.

Parainfluenza-3 virus exposure of beef heifers prior to natural breeding.

Ninety-six Hereford heifers (approximately 7 months of age) were randomly divided into 2 equal groups and housed 1.6 km apart (with 2 replications in time, 1 year apart). At 15 months of age, 1 group/replicate was inoculated with parainfluenza-3 virus, and the other group was given virus-free spent culture medium. Twenty-four hours later, 2 virgin bulls (2 years old) were placed with each group (24 cows) for natural breeding. Viral inoculation caused a twofold increase in parainfluenza-3 titer and a 0.3 C body temperature increase. There was no effect recognized from the virus on natural breeding efficiency.

Detection of neonatal calf diarrhea virus, infant reovirus-like diarrhea virus, and a coronavirus using the fluorescent virus precipitin test.

Thirty-four calf and five infant fecal specimens were tested for the neonatal calf diarrhea virus (NCDV) and for the reovirus-like infantile diarrhea agent; respectively. The procedures used were the fluorescent virus precipitin test and immune electron microscopy. Fourteen of the calf stools contained detectable NCDV, and four of the five infant stools contained the reovirus-like human agent. Infectious NCDV was detected in four of the 34 calf fecal specimens when Madin-Darby bovine kidney cell cultures that had been inoculated with supernatant fluids from stool suspensions were stained with fluorescent antibody. The 20 calf stools that did not have detectable virus were examined for the bovine corona diarrhea virus. Coronavirus was found in two of these specimens.

The structure of the sternal bursa of turkeys.

The sternal bursa developed as a microscopically recognizable synovial sac in turkeys at about 4 1/2 to 6 weeks of age. In birds 12 weeks old it was difficult to delineate the bursa grossly although microscopically it was a definite structure. After 12 weeks, the walls of the bursa were thick enough that the limits of the sac could be determined grossly. The synovial membrane was in the subcutis, and microscopically was a vascular band of loose to dense connective tissue of variable thickness. Laterally the membrane was folded so that in cross section it appeared as a tonguelike projection of variable length into the cavity. The lining cells centrally were flat fibroblasts while laterally they were cuboidal, particularly over the lateral folds. In older turkeys the cuboidal lining cells were sometimes stratified.

Tissue changes in enlarged sternal bursas of turkeys.

Enlarged sternal bursas evident in turkeys beyond 12 weeks of age were examined grossly and microscopically in 169 turkeys 3 to 26 weeks old. Grossly, the enlarged sternal bursas were sacs of varied size and wall thickness containing fluid in amounts from a fraction of a milliliter up to 70 ml. The fluid was usually the consistency of serum but was sometimes viscid, and in infected bursas it would be purulent. Its color varied from amber to red to dark brown depending on the amounts of and the changes in the blood pigments. The synovial membranes were smooth and glistening and of variable thicknesses. Strands or cords of the synovial membrane of variable thickness and number extended from side to side of the sac. Microscopically, the synovial membrane was focally thickened in the small bursas and generally thickened in the larger bursas. The thickening was the result of an increase in the very cellular fibrous tissue and in the number and size of blood vessels. The lining cells were flat fibrocytes one cell thick in the smaller bursas, and round stratified cells in the larger bursas. In infected bursas, mononuclear and heterophilic infiltration occurred. Hemorrhaging occurred quite often, the result of trauma to the highly vascular synovial membrane.

Causes of enlarged sternal bursas (breast blisters).

Bursas were taken weekly as normal turkeys developed from 3 to 22 weeks of age, and no specific bacterial or viral infection was found. Bacterial cultures were also made of condemned bursas taken at processing. Of 144 collected, 91% were sterile; the others had staphylococci, streptococci, or coliform organisms. Experiments with turkeys measured the effect of strain, body conformation, completeness of breast-feather cover, protection of the keel with sheepskins, age when put on range, and type of range on the incidence of enlarged sternal bursas. The strain difference of 25.4% breast blisters against 11.5% was highly significant (99% confidence). In one experiment the effect of feather cover was significant at the 95% level of confidence (61.7% breast blisters with no feather cover, versus 40% with complete feather cover). The effect of protecting the breast with sheepskin was significant at the 95% level of confidence in reducing incidence of breast blisters. There was no significant difference in the incidence of breast blisters in relation to body conformation, age, or type of range.