Search Results

You are looking at 1 - 7 of 7 items for

  • Author or Editor: Scott Austin x
  • Refine by Access: All Content x
Clear All Modify Search
in Journal of the American Veterinary Medical Association

Summary

Risk factors for development of pleuropneumonia were determined by reviewing medical records of 45 horses with pleuropneumonia and 180 control horses examined between Jan 1, 1980 and Jan 1, 1990. Factors considered included age, breed, sex, occupation, transport farther than 500 miles within the previous week, racing within the previous 48 hours, viral respiratory tract infection or exposure to horses with viral respiratory tract disease within the previous 2 weeks, and vaccination against influenza or rhinopneumonitis within the previous 6 months. Results indicated that Thoroughbreds were at a greater risk of developing pleuropneumonia than were other horses, and Standardbreds were at a reduced risk. Transport farther than 500 miles and viral respiratory tract disease or exposure to horses with respiratory tract disease were determined to be risk factors for the development of pleuropneumonia.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the effect of intrauterine administration of ceftiofur sodium on fertility and the risk of culling in postparturient cows with retained fetal membranes (RFM), twins, or both.

Design—Single-blind randomized clinical trial and prospective cohort study.

Animals—2,442 cows that calved from January 1, 2000, to May 31, 2001.

Procedure—Cows with RFM, twins, or both were randomly allocated to control or treatment (ceftiofur) groups. Ceftiofur-group cows received 1 g of ceftiofur sodium sterile powder reconstituted with 20 mL of sterile water as a single intrauterine infusion once between 14 and 20 days after parturition. Controlgroup cows received no treatment. Cows that calved but did not have RFM or twins were considered the referent group. Reproductive, culling, and health data were recorded.

Results—There was no significant difference in the overall proportion of ceftiofur-group cows confirmed pregnant, compared with cows in the control group. Ceftiofur-group cows were significantly less likely to be culled and were culled at a later time in lactation than control-group cows. In the cohort study, the risk of pregnancy and the risk of being culled in ceftiofurgroup cows were not significantly different from cows in the referent group.

Conclusions and Clinical Relevance—Intrauterine treatment of cows with RFM, twins, or both with ceftiofur sodium increased longevity of cows in the herd as measured by the risk of culling and the time to culling. Intrauterine administration of ceftiofur in cattle is considered extralabel drug use, and the attending veterinarian must follow the AMDUCA guidelines for extralabel drug use. (J Am Vet Med Assoc 2005:226:2044–2052)

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To describe ascorbic acid (AA) concentrations, plasma antioxidant capacity (PAC) and markers of oxidative stress, as measured by derivatives of reactive oxygen metabolites (dROMs), in healthy foals at birth and during the first month of life.

SAMPLES

Venous blood samples were collected from healthy Standardbred (n = 13) and Quarter Horse (n = 10) foals. Plasma AA, PAC, and dROMs were assessed at 3 to 12 hours, 3 days, and 1, 2, and 4 weeks of age.

PROCEDURES

AA was measured via high-performance liquid chromatography. PAC and dROMs were measured with a free radical analytical system. Comparisons of AA, PAC, and dROMs at different time points were assessed.

RESULTS

Mean ± standard deviation AA concentrations at 3 to 12 hours (44.7 ± 19.6 μmol/L; P ≤ .01), 1 (48.6 ± 22.5 μmol/L; P ≤ .001), and 2 weeks (41.8 ± 15.8 μmol/L; P ≤ .001) were higher than at 4 weeks of age (28.5 ± 12.7 μmol/L). Both PAC and dROMs significantly increased at different time points compared to 3 to 12 hours of age.

CLINICAL RELEVANCE

Healthy foals have higher plasma AA concentrations shortly after birth, which then gradually decrease throughout the first month of life, suggesting that AA may represent a key antioxidant in the postnatal period. The concurrent increase in PAC and dROMs suggests that dynamic development of oxidative balance occurs after birth in foals. Development of AA, PAC, and dROM reference ranges in healthy foals could be used to guide therapeutic interventions and monitor during disease states characterized by increased oxidative stress.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To determine pharmacokinetics and pulmonary disposition of minocycline in horses after IV and intragastric administration.

ANIMALS 7 healthy adult horses.

PROCEDURES For experiment 1 of the study, minocycline was administered IV (2.2 mg/kg) or intragastrically (4 mg/kg) to 6 horses by use of a randomized crossover design. Plasma samples were obtained before and 16 times within 36 hours after minocycline administration. Bronchoalveolar lavage (BAL) was performed 4 times within 24 hours after minocycline administration for collection of pulmonary epithelial lining fluid (PELF) and BAL cells. For experiment 2, minocycline was administered intragastrically (4 mg/kg, q 12 h, for 5 doses) to 6 horses. Plasma samples were obtained before and 20 times within 96 hours after minocycline administration. A BAL was performed 6 times within 72 hours after minocycline administration for collection of PELF samples and BAL cells.

RESULTS Mean bioavailability of minocycline was 48% (range, 35% to 75%). At steady state, mean ± SD maximum concentration (Cmax) of minocycline in plasma was 2.3 ± 1.3 μg/mL, and terminal half-life was 11.8 ± 0.5 hours. Median time to Cmax (Tmax) was 1.3 hours (interquartile range [IQR], 1.0 to 1.5 hours). The Cmax and Tmax of minocycline in the PELF were 10.5 ± 12.8 μg/mL and 9.0 hours (IQR, 5.5 to 12.0 hours), respectively. The Cmax and Tmax for BAL cells were 0.24 ± 0.1 μg/mL and 6.0 hours (IQR, 0 to 6.0 hours), respectively.

CONCLUSIONS AND CLINICAL RELEVANCE Minocycline was distributed into the PELF and BAL cells of adult horses.

Full access
in American Journal of Veterinary Research

Summary

Sixteen helminth-free pony foals were inoculated with a mean (±sd) 2,000 (±545.5) infective Parascaris equorum eggs (day 0). Foals were allocated to replicates of 4, and treatments within each replicate were assigned at random. Treatment administered on postinoculation day (pid) 28 included no treatment (control), 0.2 mg of ivermectin/kg of body weight, 10 mg of oxibendazole/kg, or 6.6 mg of pyrantel base (pamoate)/kg. Paste formulations of the anthelmintics were administered orally. The foals were euthanatized 14 days after treatment (pid 42) and examined for P equorum larvae in the small intestine. The mean ± sd (and range) numbers of fourth-stage P equorum larvae recovered from nontreated foals and those treated with ivermectin, pyrantel, or oxibendazole were 1,603.8 ± 1,026.8 (305 to 2,480), 29.3 ± 55.8 (0 to 113), 413.0 ± 568.1 (0 to 1,204), or 889.5 ± 1,123.1 (1 to 2,345), respectively. Compared with the value for control (nontreated) foals, treatment with ivermectin, pyrantel, and oxibendazole was 98.2, 74.2, and 44.5% effective, respectively, when administered 28 days after experimentally induced infection with P equorum. Adverse reactions attributable to treatment were not observed.

Free access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVES

Determine the effect of sample holding time and single sample reuse on viscoelastic coagulation parameters when using fresh equine native whole blood.

ANIMALS

8 healthy adult horses from a university teaching herd.

PROCEDURES

Blood collected by direct jugular venipuncture (18 ga needle, 3 mL syringe) was held at 37 °C for 2, 4, 6, or 8 minutes according to 1 of 2 protocols. Syringes were gently inverted twice, a small amount of blood was expressed, testing cartridges were filled, and placed within the VCM-Vet™ device (Entegrion Inc). Protocol A: samples were processed from a single syringe. Protocol B: 4 syringes were drawn through a single needle. VCM-Vet™ measures assessed included clot time (CT), clot formation time (CFT), alpha angle (AA), amplitude at 10/20 minutes (A10/A20), maximal clot firmness (MCF), and lysis index at 30/45 minutes (LI30/LI45). Differences over time were examined using the Friedman test and post hoc Wilcoxon Rank Sum Test with Bonferroni correction, P ≤ .05.

RESULTS

Following Protocol A, there was a significant effect of holding time for CT (P = .02), CFT (P = .04), and AA (P = .05). CT and AA decreased over time, while CFT increased. Samples handled by Protocol B showed no significant difference over time for any of the VCM-Vet™ parameters.

CLINICAL RELEVANCE

Sample holding time and handling protocol impact VCM-Vet™ testing results of fresh equine native whole blood. Viscoelastic coagulation samples tested using the VCM-Vet™ may be held unagitated for up to 8 minutes after collection while warm, but should not be reused.

Open access
in American Journal of Veterinary Research