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SUMMARY

Restriction endonuclease analysis and seroagglutination were used to characterize strains of Mycobacterium avium and Mycobacterium intracellular (collectively, mai) recovered from 1 local herd and 2 imported shipments of red deer (Cervus elaphus) that developed sensitization to bovine tuberculin during skin testing. A total of 31 mai strains were isolated from lymph node pools (head, thorax, abdomen, and peripheral regions) of 21 of 29 local deer. Similarly, 15 mai strains were isolated from the lymph node pools of 12 deer from the 2 imported shipments. Mycobacterial strains were isolated from more than 1 of the lymph node pools of 9 local and 2 imported deer. Most of the strains (59% from local deer, 46% from imported deer) were recovered from the lymph nodes of the head region. After restriction endonuclease analysis of these isolates using the enzymes Bcl I, BstEII, and Pvu II, 26 of the strains from the local herd were separated into 3 groups, each consisting of strains with indistinguishable or closely related patterns. Seroagglutination results indicated that the first of these groups contained strains belonging to serotype 1, the second group contained strains belonging to serotype 8; and the third group of strains belonged to serotypes 3 and 9. The 5 remaining strains from the local herd had unrelated restriction patterns. One of these belonged to serotype 3, whereas the remaining 4 could not be serotyped. Restriction analysis of the 15 strains from the imported deer identified 2 groups. Seroagglutination results indicated that 1 group contained strains belonging to serotype 2 and the other group contained strains belonging to serotype 8. Some deer were infected with 2 or more strains that differed in serotype and/or restriction pattern. Results indicate that a single source of infection was not apparent for either herd and that a number of mai strains may possibly have contributed to tuberculin sensitization.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effect of hydroxyethyl starch (HES) on colloid oncotic pressure (π) during fluid resuscitation of hypoproteinemic horses and to evaluate the clinical usefulness of direct and indirect methods for determination of π before and after infusion of a synthetic colloid.

Design—Prospective clinical study.

Animals—11 hypoproteinemic horses.

Procedure—Horses received IV infusions of 8 to 10 ml of a 6% solution of HES/kg (3.6 to 4.5 ml/lb) of body weight during fluid resuscitation. Blood samples were obtained for determination of plasma measured colloid oncotic pressure (πmeas) and plasma total protein and albumin (A) concentrations. Plasma globulin concentration (G) was calculated as the difference between plasma total protein and albumin concentrations. Calculated values for colloid oncotic pressure (πA + G) were determined by use of a predictive nomogram previously developed for horses.

Results—There was no significant difference between the means of πmeas and πA + G at the beginning of HES infusion. After HES infusion, the mean of πmeas was increased significantly from baseline for 6 hours. Mean plasma total protein and albumin concentrations and πA + G were decreased significantly from baseline for 24 hours. Differences between mean πmeas and πA + G after HES infusion were significant for 24 hours.

Conclusions and Clinical Relevance—There was good agreement between plasma πmeas and πA + G in blood samples obtained from hypoproteinemic horses immediately before infusion of HES. Use of a predictive nomogram did not, however, account for the oncotic effect of HES. Results of comparison of πmeas to πA + G after HES infusion suggest that a significant oncotic effect was maintained for 24 hours in the study horses. (J Am Vet Med Assoc 2001;218: 1130–1135)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify factors associated with excessive proportions of early fetal losses associated with mare reproductive loss syndrome in central Kentucky during 2001.

Design—Case-control study.

Procedure—Questionnaires were used to collect information on farm-, pasture-, and individual animallevel factors purportedly associated with mare reproductive loss syndrome. Data were collected for 133 farms (97 with excessive proportions of early fetal losses and 36 control farms) representing 6,576 mares.

Results—Factors significantly associated with an increased risk of excessive early fetal losses were exposure to moderate to high concentrations of Eastern tent caterpillars, exposure to cherry trees, farm size ≥ 50 broodmares, being bred during February 2001, and frequent exposure to waterfowl. Feeding hay to mares outside was associated with a decreased risk of excessive proportions of early fetal losses. Pasture composition and management factors were not significantly different between affected and control pastures. Individual animal-level factors were investigated on 6 farms representing 340 mares, and age, parity, and pre- and postbreeding treatments were not significantly associated with risk of early fetal loss.

Conclusions and Clinical Relevance—Results suggest that limiting exposure to Eastern tent caterpillars and cherry trees and feeding hay to mares outside may help decrease the risk of excessive proportions of early fetal losses associated with mare reproductive loss syndrome. (J Am Vet Med Assoc 2003;222: 613–619)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To determine the effects of the 21-amino-steroid, U-74389G, on reperfusion of the equine jejunum, using total (TVO) and partial (PVO) vascular occlusion during the ischemic period.

Design

TVO: 16 healthy horses were randomly allotted to 3 groups—4 horses received the vehicle alone, 6 horses received a low dosage (3 mg/kg of body weight), and 6 horses a high dosage (10 mg/kg) of U-74389G. PVO: 10 healthy horses were randomly allotted to 2 groups—5 horses received the vehicle alone, and 5 horses received the low dosage (3 mg/kg) of U-74389G.

Procedure

TVO was induced for 1 hour followed by 2 hours of reperfusion. During PVO, blood flow was reduced to 20% of baseline for 2 hours, followed by 2 hours of reperfusion.

For both models, either the vehicle alone or the drug was given 15 minutes prior to reperfusion. Samples were obtained before, during, and after ischemia for determination of myeloperoxidase (MPO) activity, malondealdehyde (MDA) concentration, concentration of conjugated dienes (PVO experiment only), and morphometric analysis.

Results

TVO: tissue concentration of MDA and MPO activity were not altered in any group by ischemia or reperfusion. During ischemia, mucosal volume and surface area were reduced. After reperfusion, no further reduction occurred. After initial decrease in submucosal volume during ischemia, there was a significant increase after reperfusion in the vehicle-only group (P < 0.05). PVO: there were no alterations in the concentration of either MDA or conjugated dienes. There was a significant increase in the activity of MPO during ischemia and reperfusion (P< 0.05). These effects were similar for the vehicle-only and drug groups. During ischemia, there was a significant decrease in mucosal surface area and volume (P< 0.05), that was continued during reperfusion for the vehicle-only group (P< 0.05). Submucosal volume increased during reperfusion (P< 0.05). Serosal volume was increased during ischemia and reperfusion.

Conclusions and Clinical Relevance

Reduced blood flow during ischemia (PVO group) caused continued loss in mucosal volume and surface area during reperfusion. At the dosage given, the 21-aminosteroid, U-74389G, was not effective in preventing continued reduction in mucosal volume and surface area after restoration of blood supply in the horses subjected to reduced blood flow. (Am J Vet Res 1996; 57:762–770)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate fecal shedding of Cryptosporidium parvum from California cow-calf herds with respect to age, geographic region, temporal effects, and association with watery feces.

Animals

Cows and calves from 38 beef cow-calf operations.

Procedure

Fecal specimens were collected and examined for C parvum oocysts, using immunofluorescent microscopy. Associations between age, geographic region, month of collection, watery feces, and likelihood of shedding C parvum were evaluated.

Results

3.9% of cattle were shedding C parvum oocysts. Prevalence of shedding among calves ranged from 0 to 13%, and was 0.6% among cattle ≥ 12 months old. The odds of shedding C parvum among 2-month-old calves were 41 times greater than among cattle > 4 months old. The odds of shedding C parvum among cattle tested in May were 8.7 times greater than among cattle tested during June, July, or August. The odds of infected individuals having watery feces were 3 to 4 times greater than for noninfected individuals, but the etiologic fraction was only 8 to 9%.

Conclusions and Clinical Relevance

Substantial fecal shedding of C parvum by cow-calf herds was limited to calves 1 to 4 months old, with low prevalence detected in older animals. Risk of contamination of watersheds with C parvum was limited to those periods when young calves were in the herd. Although the odds of having watery feces were greater for animals infected with C parvum than for noninfected animals, the low etiologic fraction suggests that most calves with watery feces were not infected with C parvum. (Am J Vet Res 1999;60: 420-425)

Free access
in American Journal of Veterinary Research