Fatal Clostridium botulinum toxicosis in eleven Holstein cattle fed round bale barley haylage.

Twenty-two lactating Holstein cattle in Tennessee had clinical signs of intoxication with preformed Clostridium botulinum toxin. These signs included weakness, paralysis of the tongue and chest muscles, abdominal breathing, and, in 11 of the 22 cows, death. Differential diagnoses included hypocalcemia, hypomagnesemia, carbohydrate overload, and several toxicoses including mycotoxin, lead, nitrate, organophosphate, atropine or atropine-like alkaloid, and botulism. A diagnosis of botulism by the ingestion of preformed C. botulinum type B toxin was made by eliminating these other diseases, by finding C. botulinum type B spores in 3 bales of round bale barley haylage fed to these cattle, and by isolating preformed type B toxin from 1 of the 3 bales. Confirmation of the toxin type was made by demonstrating mouse lethality by intraperitoneal injection of specimen extracts with neutralization by C. botulinum type B antitoxin. The haylage, harvested green and encased in black plastic bags to facilitate fermentation, was presumably contaminated by the botulinum toxin when fermentation failed to produce enough acid to lower the pH to 4.5, the pH below which C. botulinum growth is inhibited. Farmers and ranchers who use round hay balers to produce haylage should be alert to this potential problem.

Fatal privet (Ligustrum amurease) toxicosis in Tennessee cows.

Five of 24 cows pastured in a 40-acre field in east Tennessee died after they consumed leaves from a privet (Ligustrum amurease) hedge. Clinical findings included ataxia, recumbency with an inability to stand, depression, greenish nasal discharge, cessation of rumination, normal body temperature, and increased heart and respiratory rates. Differential diagnoses included grass tetany, nitrate toxicosis, and plant toxicosis. Privet toxicosis was confirmed by finding privet in ruminal contents, by the presence of a large quantity of privet in the field, by observing places where this privet had been eaten by the cows, by the immediate cessation of the problem when the cows were removed from the field, and by observing no recurrent problems after the privet was destroyed with a herbicide and the cows were returned to the field.

Moving: characteristics of dogs and cats and those relinquishing them to 12 U.S. animal shelters.

The National Council on Pet Population Study and Policy Regional Shelter Survey identified moving as the most often cited of 71 reasons for relinquishing dogs and the 3rd most common reason for relinquishing cats. Most relinquished companion animals were less than 3 years old and female. Dogs were most often intact, whereas cats were most often altered. Friends had given the majority of these companion animals to the relinquishers, who had obtained them at no cost. Most had lived with the relinquishers for less than 2 years. The majority of relinquishers were White and female, and had at least a high school education. Based on the U.S. population age distribution, young adults seem to be using shelters at a significantly higher rate than would be expected. These age groups are also more mobile, according to U.S. Census data. Therefore, educational efforts that target young, potentially mobile adults could decrease the number of animals relinquished.

Pigweed (Amaranthus retroflexus) toxicosis in cattle.

Four of approximately 15 dry cows introduced on a 10-acre fescue-clover-orchard grass-Dallis grass pasture in East Tennessee became recumbent. Clinical findings included depression, muscle tremors, increased heart and respiratory rates, hypocalcemia, hypomagnesemia, hyperkalemia, azotemia, and elevated creatinine phosphokinase. Three cows recovered; 1 died. Differential diagnoses considered were hypocalcemia, hypomagnesemia, rabies and toxicoses from Amaranthus retroflexus (pigweed), Quercus spp (oak), Cassia spp (senna) oxalate (Aspergillus niger or flavus), mycotoxicosis, lead, arsenic or insecticides. Pigweed toxicosis was confirmed based on clinical and postmortem findings, partially ingested pigweed in the pasture, and ruling out other possible causes. Several factors probably contributed to this incident: since the cattle were newly introduced to the pasture, the cattle may have been attracted to the pigweed in the new pasture and became addicted to it; their rumen microflora had little time to acclimate to the pigweed; and dry weather produced poor forage quality thus forcing the cows to eat the pigweed.

Results of a survey to assess knowledge and expectations of veterinarians and their clients regarding heartworm preventives and vaccinations in dogs.

OBJECTIVE: To determine the knowledge and expectations of veterinarians and clients regarding heartworm preventives and annual vaccinations for dogs. DESIGN: Practitioner and client survey. SAMPLE POPULATION: 435 veterinarians and 1,805 clients. PROCEDURE: A survey was mailed to veterinarians requesting information from them and their dog-owning clients on expectations and knowledge regarding heartworm preventives and annual vaccinations. Responses of veterinarians were compared with those of clients, and both were compared with label indications. RESULTS: Expectations of veterinarians and clients regarding heartworm preventives were similar and usually were consistent with regulatory interpretation of label terms. Of clients purchasing heartworm preventives, 38% did not know that the medication was effective against intestinal nematodes. Veterinarians and clients would be unsatisfied with a product that reduced, but did not eliminate, all intestinal nematodes. Most clients knew that annual vaccinations included distemper virus, parvovirus, and rabies virus, but about half of them did not know that other antigens were in the vaccines. CLINICAL IMPLICATIONS: Effects of heartworm preventives and diseases for which dogs are annually vaccinated should be explained fully to clients.

Acute toxicosis in cattle sprayed with endosulfan.

Two cattle died acutely after being sprayed for lice control with a cyclodiene organochlorine insecticide, endosulfan, not labelled for use in cattle. Three other cattle became acutely ill, but survived after symptomatic therapy and removal of the insecticide from their skin and prevention of enterohepatic circulation. These cases illustrated the risk of acute toxicosis when organochlorine insecticides are used off-label and the potential for illegal tissue and milk residues.

Suspected buttercup (Ranunculus bulbosus) toxicosis with secondary photosensitization in a Charolais heifer.

A presumptive diagnosis of buttercup toxicosis with photosensitization secondary to hepatotoxicity was made in an 18-mo-old Charolais heifer. The differential diagnosis included salmonellosis, aflatoxicosis, bovine virus diarrhea, internal parasite infestation, and plant toxicosis with either primary or secondary photosensitization. All these possibilities were excluded except buttercup toxicosis with photosensitization secondary to hepatotoxicity. While this diagnosis was not absolutely confirmed, it was the most likely cause of the disease and raised the intriguing possibility that protoanemonin, buttercup's toxic principle, is hepatotoxic.

Antibiotic resistance patterns of gram-negative bacteria isolated from environmental sources.

A total of 2,445 gram-negative bacteria belonging to fecal coliform, Pseudomonas, Moraxella, Acinetobacter, and Flavobacterium-Cytophaga groups were isolated from the rivers and bay of Tillamook, Oregon, and their resistances to chloramphenicol (25 microgram/ml), streptomycin (10 microgram/ml), ampicillin (10 microgram/ml), tetracycline (25 microgram/ml), chlortetracycline (25 microgram/ml), oxytetracycline (25 microgram/ml), neomycin (50 microgram/ml), nitrofurazone (12.5 microgram/ml), nalidixic acid (25 microgram/ml), kanamycin (25 microgram/ml), and penicillin G (10 IU/ml) were determined. Among fecal coliforms the bay isolates showed greater resistance to antibiotics than those from tributaries or surface runoff. No such well-defined difference was found among other bacterial groups. The antibiotic resistance patterns of gram-negative bacteria from different sources correlated well, perhaps indicating their common origin. The antibiotic resistance patterns of gram-negative bacteria of different general also correlated well, perhaps indicating that bacteria which share a common environment also share a common mode for developing antibiotic resistance.

Suspected infectious necrotic hepatitis (black disease) in Oregon cattle.

Suspected infectious necrotic hepatitis (black disease) in a herd of 436 cattle in Douglas County, Oregon, resulted in 79 deaths during a 2-week period. Although Clostridium novyi could not be isolated from hepatic lesions, the clinical course of the disease, gross and histopathologic findings, and fluorescent antibody identification of C novyi in various tissues were suggestive of the disease. The epizootic was preceded by a long drought, during which grazing conditions were sparse. A few days before the 1st dead animal was found, the drought was relieved by about 10 cm (4 in) of rainfall, resulting in the growth of young succulent grass. The cattle, attempting to eat this new grass lying close to the ground, consumed large quantities of soil. It was speculated that the soil contained C novyi and that the proliferation of these ingested organisms in necrotic tissue cuased by Fasciola hepatica resulted in fatal toxemia.