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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine associations between age, sex, breed, and month and year of admission and the diagnosis of lead toxicosis in cattle.

Design—Retrospective case-control study.

Sample Population—Records of all cattle evaluated at North American veterinary teaching hospitals during the years 1963 to 2002, which were available through the Veterinary Medical Database.

Procedures—Logistic regression was used to evaluate the associations between postulated risk factors and the occurrence of lead toxicosis in cattle and predict the occurrence of the diagnosis of lead toxicosis in cattle.

Results—413 cases of lead intoxication and 202,363 control cattle were identified and met the inclusion criteria. Cattle < 4 years of age were at increased risk for the diagnosis of lead intoxication relative to cattle ≥ 4 years of age. Cattle ≥ 2 months and < 6 months of age had the greatest risk for lead intoxication (odds ratio, 12.3). Angus cattle were at greater risk for toxicosis (odds ratio, 1.95), compared with other breeds. The risk of lead toxicosis was greater before 1985 (odds ratio, 1.94) than the risk thereafter. The risk of lead toxicosis diagnosis was greatest in the months of May, June, July, and August.

Conclusions and Clinical Relevance—Lead toxicosis in cattle was associated with age < 4 years and the Angus breed. A seasonal pattern existed with peak occurrence in the late spring and summer. The occurrence of lead toxicosis has declined over time.

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in Journal of the American Veterinary Medical Association

SUMMARY

Immunoglobulin reactions to Salmonella dublin in serum and milk from 4 groups of lactating cows were measured by an indirect elisa. The groups consisted of (1) cows that were natural carriers of S dublin in the mammary gland, (2) experimentally infected cows that did not become carriers, (3) cows inoculated with a commercial S dublin bacterin, and (4) cows used as S dublin-negative controls. Milk and serum samples were obtained at monthly intervals. Models for predicting carrier status were developed by use of stepwise logistic regression. Independent variables consisted of serum and milk IgG and IgM titers to S dublin lipopolysaccharide and a ratio of IgG to IgM. The utility of a single sample vs multiple samples obtained at 1-month or 2-month intervals was tested by comparison of goodness-of-fit χ2 P values for 8 models predicting carrier status.

Immunoglobulin reactions specific to S dublin were a significant predictor of carrier status (P < 0.001). Serum IgG titers specific for S dublin were the most important variable for predicting carrier status. Two serum IgG titers to S dublin obtained 2 months apart was a better predictor of carrier status than measurement of the IgG:IgM ratio from a single serum sample. Immunoglobulin recognizing S dublin epitopes also were detected in milk samples. In milk, performing 2 ELISA 60 days apart to determine IgG and IgM reactions to S dublin appeared to be useful for the prediction of carrier status, but was not as accurate as models for serum immunoglobulin reactions.

Free access
in American Journal of Veterinary Research

Abstract

Eight Holstein cows, 4 inoculated intracistemally in 1 quarter of the mammary gland with Escherichia coli and 4 noninfected controls, were administered ceftiofur sodium (3 mg/kg of body weight, IV, q 12 hours) for 24 hours, beginning at 14 hours after inoculation of infected cows. All challenge-exposed cows became infected, with mean ± SEM peak log10 bacterial concentration in milk of 5.03 ± 0.69 colonyforming units/ml. The infection resulted in systemic signs (mean peak rectal temperature, 41.5 ± 0.3 C; anorexia; signs of depression) and local inflammation (mean peak albumin concentration in milk, 7.89 ± 1.71 mg/ml). Ceftiofur was detectable in milk from all challenge-exposed cows, compared with only 1 of 4 noninfected cows, and the mean period after inoculation that ceftiofur was detectable in milk was longer (P < 0.05) in infected (147.7 ± 27.5 hours) than noninfected cows (1.3 ± 1.3 hours). However, maximal ceftiofur concentration attained in milk for all cows was 0.28 p.g/ml, and was 0.20 jig/ml or less for all but 2 milk samples collected for 10 days after challenge exposure. Mean serum concentration of ceftiofur peaked at 1.0 ± 0.3 μg/ml and 0.7 ± 0.1 μg/ml for infected and noninfected cows, respectively. After each ceftiofur dose, mean peak and trough concentrations of ceftiofur in serum did not differ between groups; however, concentration of ceftiofur in serum was higher at 7 hours after each dose in noninfected cows, suggesting more rapid clearance of the drug in infected cows. Ceftiofur was not detected in serum (< 0.05 μg/ml) of any cow at or after 120 hours following inoculation of infected cows.

Storage of serum samples at —20 C for 3 weeks resulted in a 98.8% decrease in ceftiofur activity, compared with that in fresh serum samples. Eightyseven percent of this loss occurred 30 minutes after mixing serum and ceftiofur; thus, about 13% of the original activity was lost in storage. Storage of milk samples under similar conditions did not result in loss of ceftiofur activity.

Despite acute inflammation, the dosage of ceftiofur used in this trial would not result in drug concentrations in milk above FDA safe concentrations, or above the reported minimum inhibitory concentration for coliform bacteria.

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in American Journal of Veterinary Research

Summary

Milk production was monitored in 16 cows for 6 milkings after intramammary infusion of 1 mg of endotoxin in a single forequarter. The cows were randomly assigned to 1 of 2 treatment groups; 8 cows were treated with isotonic saline solution and 8 cows were treated with hypertonic saline solution. Saline solutions were administered IV (5 ml/kg of body weight) 4 hours after infusion of endotoxin. Mean cumulative change in milk yield and interval change in milk yield were greater in cows treated with isotonic saline solution than in cows treated with hypertonic saline solution. Significant differences between treatment groups were not detected.

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in Journal of the American Veterinary Medical Association

Summary

The diffusing capacity for carbon monoxide (dl co ) and the functional residual capacity (frc) of the lung were measured in 5 healthy Thoroughbreds before and after instillation of autologous blood into their lungs, in an attempt to develop a method to quantitate extravascular blood in the lungs of horses with exercise-induced pulmonary hemorrhage. Mean (± SD) baseline values of dl co and frc were 333.8 ± 61.9 ml/min/mm of Hg and 21.464 ± 4.156 L, respectively. Blood instillation resulted in decreases in dl co and frc. The paradoxic decrease in dl co (we were expecting to find an increase owing to blood in the airspaces, as has been reported in people) appears to be associated with the bronchoscopic procedure and with presence of blood in the airways. We concluded that rebreathing dl co measurements were not effective for detecting blood introduced bronchoscopically into the lungs of horses.

Free access
in American Journal of Veterinary Research