Objective—To evaluate the clinical and endocrine
responses of ferrets with adrenocortical disease
(ACD) to treatment with a slow-release implant of
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)
Objective—To evaluate the effects of IM administration of recombinant human thyroid-stimulating hormone (rhTSH) on plasma total thyroxine (T4) concentrations in euthyroid ferrets.
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.
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.
Objective—To determine the effects of leuprolide
acetate, a long-acting gonadotropin-releasing hormone
analog, in ferrets with adrenocortical diseases.
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
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)
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)
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.
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.
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.
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)