Search Results

Abstract

Objective—To evaluate the clinical and endocrine responses of ferrets with adrenocortical disease (ACD) to treatment with a slow-release implant of deslorelin acetate.

Animals—15 ferrets with ACD.

Procedure—Ferrets were treated SC with a single slow-release, 3-mg implant of deslorelin acetate. Plasma estradiol, androstenedione, and 17-hydroxyprogesterone concentrations were measured before and after treatment and at relapse of clinical signs; at that time, the adrenal glands were grossly or ultrasonographically measured and affected glands that were surgically removed were examined histologically.

Results—Compared with findings before deslorelin treatment, vulvar swelling, pruritus, sexual behaviors, and aggression were significantly decreased or eliminated within 14 days of implantation; hair regrowth was evident 4 to 6 weeks after treatment. Within 1 month of treatment, plasma hormone concentrations significantly decreased and remained decreased until clinical relapse. Mean time to recurrence of clinical signs was 13.7 ± 3.5 months (range, 8.5 to 20.5 months). In 5 ferrets, large palpable tumors developed within 2 months of clinical relapse; 3 of these ferrets were euthanatized because of adrenal gland tumor metastasis to the liver or tumor necrosis.

Conclusions and Clinical Relevance—In ferrets with ACD, a slow-release deslorelin implant appears promising as a treatment to temporarily eliminate clinical signs and decrease plasma steroid hormone concentrations. Deslorelin may not decrease adrenal tumor growth in some treated ferrets. Deslorelin implants may be useful in the long-term management of hormone-induced sequelae in ferrets with ACD and in treatment of animals that are considered at surgical or anesthetic risk. (Am J Vet Res 2005;66:910–914)

Abstract

Objective—To evaluate the effects of administration of recombinant human (rh) thyroid-stimulating hormone (TSH) for evaluation of thyroid function in euthyroid guinea pigs (Cavia porcellus).

Design—Prospective, experimental study.

Animals—10 healthy, sexually intact, pet guinea pigs (approx 1 year of age).

Procedures—Guinea pigs were given rhTSH (100 μg, IM); plasma thyroxine concentrations were determined prior to and 3 and 4 hours after rhTSH injection. The animals were housed in 2 groups on the basis of sex and fed different commercial maintenance diets according to their husbandry.

Results—There was no significant difference in thyroxine concentrations between males and females before or after rhTSH injection. There was also no difference between thyroxine concentrations at 3 versus 4 hours after rhTSH injection. There was a significant difference between thyroxine concentrations before (median, 9.05 nmol/L [0.70 μg/dL]; 10% to 90% range, 7.39 to 16.99 nmol/L [0.57 to 1.32 μg/dL]) and after (mean ± SD, 23.95 ± 4.2 nmol/L) rhTSH injection. Euthyroid guinea pigs had plasma thyroxine concentrations of at least 7.30 nmol/L (0.57 μg/dL) and an increase of at least 2.6 times prestimulation thyroxine concentrations at 3 or 4 hours after stimulation.

Conclusions and Clinical Relevance—The results suggested that rhTSH administered IM can be used for the TSH stimulation testing in guinea pigs. We suggest thyroxine concentration in a euthyroid guinea pig should at least double 3 to 4 hours after rhTSH injection.

Abstract

Objective—To evaluate the effects of IM administration of recombinant human thyroid-stimulating hormone (rhTSH) on plasma total thyroxine (T₄) concentrations in euthyroid ferrets.

Design—Evaluation study.

Animals—25 healthy neutered ferrets (14 female and 11 male) of various ages from 2 populations (laboratory ferrets from Georgia and pet ferrets from Pennsylvania).

Procedures—Each ferret underwent a physical examination and standard hematologic testing to ensure it was healthy and had clinically normal thyroid function. Once determined to be euthyroid, ferrets received a single IM injection of 100 μg of rhTSH. Blood samples were collected into plasma-separator tubes immediately before the rhTSH injection (time 0) and 4 hours after injection to measure T₄ concentrations.

Results—Males did not differ from females in regard to prestimulation or poststimulation plasma T₄ concentrations; however, prestimulation and poststimulation T₄ concentrations were significantly different between the 2 groups of ferrets. A significant difference was also identified between prestimulation T₄ concentration (mean ± SD, 21.3 ± 6.1 nmol/L) and poststimulation T₄ concentration (29.9 ± 8.2 nmol/L). All 25 ferrets had high poststimulation T₄ concentrations (median difference, 7. 5 nmol/L; 10% to 90% interval, 3.26 to 17.70 nmol/L [0.25 to 1.38 μg/dL]; range, 2.50 to 20.70 nmol/L [0.19 to 1.61 μg/dL]); this represented a median increase in T₄ concentration of 35% (10% to 90% interval, 18% to 81%; range, 8% to 126%).

Conclusions and Clinical Relevance—Results suggested that rhTSH can be used for thyrotropin stimulation testing in ferrets when administered IM. According to the findings, a euthyroid ferret should have an increase of approximately 30% in plasma T₄ concentration 4 hours after rhTSH injection.

Abstract

Objective—To determine the effects of leuprolide acetate, a long-acting gonadotropin-releasing hormone analog, in ferrets with adrenocortical diseases.

Design—Case series.

Animals—20 ferrets with adrenocortical disease diagnosed on the basis of clinical signs and plasma sex hormone concentrations.

Procedure—Ferrets were treated with leuprolide (100 µg, IM, once), and plasma hormone concentrations were measured before and 3 to 6 weeks after treatment.

Results—Leuprolide treatment resulted in significant reductions in plasma estradiol, 17 α-hydroxyprogesterone, androstenedione, and dehydroepiandrosterone concentrations and eliminated or reduced clinical signs associated with adrenocortical disease. Decreases in vulvar swelling, pruritus, and undesirable sexual behaviors and aggression were evident 14 days after treatment; hair regrowth was evident by 4 weeks after treatment. The response to treatment was transitory, and clinical signs recurred in all ferrets. Mean ± SEM time to recurrence was 3.7 ± 0.4 months (range, 1.5 to 8 months).

Conclusions and Clinical Relevance—Results suggest that leuprolide can be safely used to temporarily eliminate clinical signs and reduce sex hormone concentrations in ferrets with adrenocortical diseases. However, the safety of long-term leuprolide use in ferrets has not been investigated, and the long-term effects of leuprolide in ferrets with nodular adrenal gland hyperplasia or adrenal gland tumors are unknown. (J Am Vet Med Assoc 2001;218:1272–1274)

Abstract

Objective—To assess associations between herd management practices and herd-level rates of bovine respiratory disease complex (BRDC) in preweaned beef calves in US cow-calf operations.

Design—Cross-sectional survey.

Sample—443 herds weighted to represent the US cow-calf population.

Procedures—Producers from 24 states were selected to participate in a 2-phase survey; 443 producers completed both survey phases and had calves born alive during the study period. Data from those respondents underwent multivariable negative binomial regression analyses.

Results—Bred heifer importation was associated with lower BRDC rates (incidence rate ratio [IRR], 0.40; confidence interval [CI], 0.19 to 0.82), whereas weaned steer importation was associated with higher BRDC rates (IRR, 2.62; CI, 1.15 to 5.97). Compared with single-breed herds, operations with calves of 2-breed crosses (IRR, 2.36; CI, 1.30 to 4.29) or 3-breed crosses (IRR, 4.00; CI, 1.93 to 8.31) or composite-herd calves (IRR, 2.27; CI, 1.00 to 5.16) had higher BRDC rates. Operations classified as supplemental sources of income had lower BRDC rates (IRR, 0.48; CI, 0.26 to 0.87) than did operations classified as primary sources of income. Reported feed supplementation with antimicrobials was positively associated with BRDC rates (IRR, 3.46; CI, 1.39 to 8.60). The reported number of visits by outsiders in an average month also was significantly associated with herd-level BRDC rates, but the magnitude and direction of the effects varied.

Conclusions and Clinical Relevance—Management practices associated with preweaning BRDC rates may be potential indicators or predictors of preweaning BRDC rates in cow-calf production systems.

Abstract

Objective—To determine whether lipid particle coalescence develops in veterinary parenteral nutrition (PN) admixture preparations that are kept at room temperature (23°C) for > 48 hours and whether that coalescence is prevented by admixture filtration, refrigeration, or agitation.

Sample Population—15 bags of veterinary PN solutions.

Procedures—Bags of a PN admixture preparation containing a lipid emulsion were suspended and maintained under different experimental conditions (3 bags/group) for 96 hours while admixtures were dispensed to simulate IV fluid administration (rate, 16 mL/h). Bags were kept static at 4°C (refrigeration); kept at 23°C (room temperature) and continuously agitated; kept at room temperature and agitated for 5 minutes every 4 hours; kept static at room temperature and filtered during delivery; or kept static at room temperature (control conditions). Admixture samples were collected at 0, 24, 48, 72, and 96 hours and examined via transmission electron microscopy to determine lipid particle diameters. At 96 hours, 2 samples were collected at a location distal to the filter from each bag in that group for bacterial culture.

Results—Distribution of lipid particle size in the control preparations and experimentally treated preparations did not differ significantly. A visible oil layer developed in continuously agitated preparations by 72 hours. Bacterial cultures of filtered samples yielded no growth.

Conclusions and Clinical Relevance—Data indicated that the veterinary PN admixtures kept static at 23°C are suitable for use for at least 48 hours. Manipulations of PN admixtures appear unnecessary to prolong lipid particle stability, and continuous agitation may hasten lipid breakdown.

Abstract

Objective—To determine whether systemic immunologic hyperreactivity exists in horses with chronic laminitis, compared with responses for nonlaminitic horses.

Animals—7 nonlaminitic horses and 7 CL horses.

Procedure—In experiment 1, intradermal testing (IDT) was performed on 7 nonlaminitic and 7 CL horses to evaluate the response to a combination of 70 allergens at 15 and 30 minutes and 4 and 24 hours after injection. Three nonlaminitic and 3 CL horses used in experiment 1 were used in experiment 2 to determine whether histologic differences existed between the 2 groups. The H&E-stained tissue sections were evaluated on the basis of 3 criteria. For all analyses, 2-sample t-tests were used to determine significant differences between the groups.

Results—In experiment 1, CL horses had significantly higher total responses to IDT than nonlaminitic horses at the first 3 time periods. Also, CL horses had significantly fewer total scores of 0 than nonlaminitic horses at all time periods, except at 24 hours. In experiment 2, we did not detect significant differences between groups for any criterion.

Conclusions and Clinical Relevance—Results support the hypothesis that CL horses develop hyperreactivity to various antigenic stimuli, compared with responses for nonlaminitic horses. Therefore, the possibility that antigenic challenge may result in exacerbation of clinical signs of laminitis should be discussed with horse owners. Chronic laminitis should also be a consideration when a horse becomes lame following antigenic challenges. (Am J Vet Res 2003;64:279–283)

Abstract

Objective—To evaluate sensitivities at the herd level of test strategies used in the Voluntary Johne's Disease Herd Status Program (VJDHSP) and alternative test strategies for detecting dairy cattle herds infected with Mycobacterium paratuberculosis.

Design—Nonrandom cross-sectional study.

Sample Population—64 dairy herds from Pennsylvania, Minnesota, Colorado, Ohio, and Wisconsin. Fifty-six herds had at least 1 cow shedding M paratuberculosis in feces; the other 8 herds were free from paratuberculosis.

Procedure—For all adult cows in each herd, serum samples were tested for antibodies to M paratuberculosis with an ELISA, and fecal samples were submitted for bacterial culture for M paratuberculosis. Sensitivities at the herd level (probability of detecting infected herd) of various testing strategies were then evaluated.

Results—Sensitivity at the herd level of the testing strategy used in level 1 of the VJDHSP (use of the ELISA to test samples from 30 cows followed by confirmatory bacterial culture of feces from cows with positive ELISA result) ranged from 33 to 84% for infected herds, depending on percentage of cows in the herd with positive bacterial culture results. If follow- up bacterial culture was not used to confirm positive ELISA results, sensitivity ranged from 70 to 93%, but probability of identifying uninfected herds as infected was 89%.

Conclusions and Clinical Relevance—Results suggest that the testing strategy used in the VJDHSP will fail to identify as infected most dairy herds with a low prevalence of paratuberculosis. A higher percentage of infected herds was detected if follow-up bacterial culture was not used, but this test strategy was associated with a high probability of misclassifying uninfected herds. (J Am Vet Med Assoc 2002;220: 1053–1057)