Effect of zearalenone on dairy cows.

Doses of 99% pure zearalenone (0.0, 31.25, 62.5, 125.0, 250.0, or 500.0 mg) in gelatin capsules were given once a day per os to 18 nonpregnant, nonlactating, multiparous dairy cows for 2 consecutive estrous cycles. There was no effect (P less than 0.10) on serum progesterone concentrations, RBC, WBC, PCV, hemoglobin, and estrous cycle length. Differential cell counts, clinical health, and sexual behavior were not affected by the zearalenone. One cow from each of the groups given zearalenone and a control were euthanatized at the end of the study. The zearalenone had no effect on the terminal bone marrow smears and did not induce any gross lesions discernible at necropsy or any microscopic lesions in representative samples of 30 tissues/cow. Rectal palpation of the reproductive tracts once a week indicated that the corpora lutea were small in cows given zearalenone. There was a general trend to increased hemoglobin concentrations in cows given the larger doses of zearalenone. Zearalenone of and by itself does not seem to be an important factor in dairy cow health.

Effect of zearalenone on the fertility of virgin dairy heifers.

Eighteen cycling, virgin, Holstein heifers daily were given 250 mg of 99% purified zearalenone in a gelatin capsule orally, and 18 controls were given an empty gelatin capsule once a day. The study lasted through 1 non-breeding estrous cycle and the next 2 consecutive estrous cycles during which the 36 heifers were bred, using artificial insemination. Serum concentrations of progesterone and complete blood cell counts were determined throughout the study. The treated and control heifers had conception rates of 62% and 87%, respectively. There was no effect (P less than 0.05) on the serum concentration of progesterone or the complete blood cell counts. Three heifers, bred but not pregnant by the end of the study, were euthanatized and necropsied. The treated heifer did not have any zearalenone-attributable lesions, and there was no effect seen in the bone marrow smears. The remaining 33 heifers were sold as a herd, and the 31 pregnant heifers calved normally. There was no effect (P less than 0.05) on the sex ratio of the offspring, which were all clinically healthy. Zearalenone did lower the conception rate of the treated heifers (P less than 0.065).

Diacetoxyscirpenol toxicity in pigs.

Purified diacetoxyscirpenol (DAS) mycotoxin fed to growing pigs at 0, 2, 4, 8, and 9 ppm for as long as nine weeks caused several lesions at all levels. The pigs developed multifocal, proliferative, gingival, buccal and lingual lesions. The small intestine had both glandular and mucosal cell hyperplasia. No other lesions were seen at necropsy or in any of the 19 tissues examined microscopically using haematoxylin and eosin stain. A one-way analysis of variance revealed statistically significant (P less than 0.05) decreased ration consumption and weight gain at all levels of DAS. Total ration refusal occurred at 10 ppm of DAS. There was no effect on the packed cell volume, haemoglobin concentration, total red blood cell count, total white blood cell count, 300 cell differential, terminal bone marrow smears or on the serum levels of aspartate transaminase, serum glutamic pyruvic transaminase and lactic dehydrogenase at any level of DAS. Based on the gross and microscopic lesions, decreased ration consumption and decreased weight gain the no-effect level was less than 2 ppm of DAS in the ration.

The failure of purified T-2 mycotoxin to produce hemorrhaging in dairy cattle.

A Holstein cow was intubated with 182 mg of 97% pure T-2 toxin (0.44 mg/kg of body weight) for 15 days. A dairy ration containing 50 mg/kg (50 ppm) of T-2 toxin was refused. A calf, born four days after onset of maternal treatment, was intubated with 26.2 mg of purified T-2 toxin (0.6 mg/kg of body weight) for seven consecutive days and then on alternate days for a total of 16 days. The calf was severely affected clinically by the T-2 toxin. The T-2 toxin failed to cause bovine hemorrhagic syndrome in either animal. Unspecific gastrointestinal lesions were noted in the cow but none were detected in the calf. In the calf, severe depression, hindquarter ataxia, knuckling of the rear feet, listlessness and anorexia were caused by the T-2 toxin.

Comparison of collection techniques for quantitative urine culture in dogs.

The degree of bacterial contamination of 75 urine samples collected by voluntary voiding, catheterization, and cystocentesis was studied in 25 clinically normal dogs (14 females and 11 males) to evaluate the suitability of quantitative urine culture for diagnosis or urinary tract infection. Significant bacteriuria (greater than 100,000/ml) was not observed. Insignificant bacteriuria presumably caused by urethrogenital contaminants was detected in 44% of the urine samples collected by voluntary voiding, in 20% of the samples collected by catheterization, and in 12% of the samples collected by cystocentesis. The urine was sterile in 40% of the samples collected by voluntary voiding, in 80% of the samples collected by catheterization, and in 84% of the samples collected by cystocentesis. A bacteria count suggestive of bacteriuria (10,000--100,000/ml) was obtained in 1 sample collected by cystocentesis but was attributed to inadvertent penetration of a loop of intestine. Low bacteria counts were obtained in 4 (16%) samples collected by voluntary voiding, presumably as a result of urethrogenital and integumentary bacterial contaminants. It was concluded that urine samples properly collected from dogs by voluntary voiding, catheterization, or cystocentesis are suitable for detection of significant bacteriuria.

Porcine abortion caused by Actinobacillus equuli.

Actinobacillus equuli was isolated from an aborted porcine fetus. Fetal lesions of peracute embolic septicemia were similar to those seen in septicemic actinobacillosis of older swine and other species. This case represented an individual rather than a herd abortion problem.