Toxicosis in cattle from concurrent feeding of monensin and dried distiller's grains contaminated with macrolide antibiotics.

Consumption of monensin-containing feed contaminated with macrolide antibiotic residues resulted in the death of cattle from multiple feedlots in south-central Kansas. Cattle were fed milo dried distiller's grains (DDG) with solubles from a common source in conjunction with the ionophore antibiotic, monensin. Deaths occurred as early as 72-96 hours after feeding and were preceded by either no premonitory signs or 1 or more of the following: anorexia, depression, dyspnea, locomotor deficits, and recumbency. Significant gross lesions were pulmonary and mesenteric edema, hepatomegaly, and generalized myocardial and skeletal muscle pallor that was confirmed histologically as acute myodegeneration and necrosis. Other significant histologic lesions included centrolobular hepatocellular necrosis, congestion, and pulmonary interstitial and alveolar edema with fibrin exudation. Animals that survived beyond 6 weeks had poor weight gain and coalescing foci of myocardial fibrosis with residual myocardial degeneration. Analysis of trace mineral supplements for monensin were within the manufacturer's label range. The DDG samples from affected feedlots had 50-1,500 ppm of erythromycin, clarithromycin, and related macrolide antibiotic analogues, which originated in the alcohol residue. In a preliminary feeding trial, cattle fed this contaminated DDG in combination with monensin had clinical signs and died with gross and histologic findings comparable to those of the field cases. Even though rations supplemented with the contaminated DDG contained approved levels of monensin, the clinical and postmortem findings were consistent with those expected for monensin toxicosis. The presence of macrolide antibiotic residues in the contaminated feed appeared to affect the biotransformation of otherwise nontoxic levels of monensin, leading to clinical ionophore toxicosis.

Gastric perforation associated with administration of ibuprofen in a dog.

A 3-year-old Chow Chow was examined because of a 2-week history of vomiting and anorexia after administration of 200 mg of ibuprofen. Peritoneal effusion and free gas within the peritoneal cavity were observed on radiography of the abdomen. A full-thickness perforation of the pyloric antrum and pylorus were detected during exploratory laparotomy, and a Billroth-I gastroduodenostomy was performed successfully.

Mycobacterium avium abortion in a sow.

A 2-year-old sow aborted her entire near-term litter of 11. Gross and histologic examination of a fetus suggested a tuberculous infection, and a yellow-pigmented Mycobacterium avium serotype 1 was subsequently isolated from the fetal tissue. Efforts to rebreed the sow were unsuccessful. She was anergic to skin tests with purified protein derivative of M. avium on two occasions but had M. avium specific in vitro lymphocyte immunostimulation. Gross granulomatous lesions were found in the liver, kidneys, and endometrium when the sow was necropsied 5 months after the abortion. Histologic examination showed diffuse and focal non-encapsulated granulomas in lymph nodes, tonsils, kidney, liver, spleen, lung, and uterine and vaginal walls. There were a few encapsulated calcified foci in the endometrium. The centers of some granulomas in the tonsils, liver, kidneys, and some lymph nodes were caseated. The yellow-pigmented M. avium was isolated from the reproductive organs and from 11 of 12 other tissues cultured.

Malignant catarrhal fever in bison.

Malignant catarrhal fever was diagnosed in 3 herds of American bison (Bison bison) in South Dakota from 1973 to 1976. Clinical signs included depression, nasal and ocular discharge, conjunctivitis and keratitis, and diarrhea. Herd morbidity ranged from 3 to 53.8%, and mortality was 100%. At necropsy, ulcerative lesions were found throughout the alimentary tract, trachea, and bronchi. Microscopically, necrotizing vasculitis without thrombosis was found in virtually every organ examined.

Effect of supplemental dietary vitamin E on the serologic response of swine to an Escherichia coli bacterin.

Three groups of 10 pigs (6 to 8 weeks old) were fed a nutritionally complete ration (control ration, CR), CR plus 20,000 IU of vitamin E/ton (CR + recommended E), and CR plus 100,000 IU of vitamin E/ton (CR + high E), respectively. Each pig was given an intramuscular injection of an Escherichia coli bacterin at experimental days 0 and 35. Serums were collected 7 days prior to the first injection and at days 7, 14, 21, 35, 42, 49, and 56. Pigs fed the CR + high E ration developed anti-E coli serum antibody titers two- to threefold higher than those of the controls. Pigs fed the CR + recommended E ration developed serum antibody titers intermediate between those of pigs in the other 2 groups.