Objective—To investigate glucose tolerance and
insulin sensitivity in llama crias.
Animals—7 llamas (age range, 14 to 30 days).
Procedure—On each of 2 sequential days, crias were
administered glucose (0.5 g/kg) via rapid IV injection.
On 1 day (randomly determined for each cria), regular
insulin (0.2 U/kg) or 0.9% NaCl solution (0.002 mL/kg)
was administered IV 15 minutes after glucose administration.
Blood samples were collected before (baseline)
and at 5, 15, 30, 45, 60, 90, 120, 180, and 240
minutes after glucose administration for determination
of plasma glucose and insulin concentrations;
fractional turnover rates and plasma half-life of glucose
were calculated. The data were compared over
time and between days (ie, between glucose treatments
with and without insulin administration).
Results—A peak plasma glucose concentration of
342 ± 47 mg/dL was detected at 5 minutes after glucose
administration and llamas cleared glucose from
plasma within 60 minutes; at 15 minutes, plasma
insulin concentration attained a peak value of 33 ± 13
µU/mL (ie, triple the baseline value). During the 15- to
45-minute interval, fractional turnover rate of glucose
was 1.10 ± 0.24%/min and plasma half-life was
65.7 ± 13.4 minutes. Insulin significantly increased
glucose turnover and resulted in hypoglycemia within
75 minutes of administration.
Conclusions and Clinical Relevance—Healthy
immature llamas have glucose tolerance and insulin
sensitivity superior to that of adults. However,
whether sick crias retain the pancreatic sufficiency
and tissue responsiveness that are likely responsible
for the rapid glucose clearance in healthy individuals
is not known. (Am J Vet Res 2005;66:1013–1017)
Objective—To describe the metabolic effects of epinephrine
administration in New World camelids and
investigate whether these effects are influenced by
administration of insulin.
Animals—6 llamas and 8 alpacas (all adult castrated
Procedure—Prior to each experiment, food was withheld
from camelids for 8 hours. On each of 2 consecutive
days, alpacas were administered epinephrine
(10 mg/kg, IM; time 0); alpacas were randomly
assigned to receive regular insulin (0.2 U/kg, IV)
immediately after epinephrine administration on one
of those days. In llamas, the experiment was performed
once after administration of epinephrine only.
At 0, 30, 60, 90, 120, 150, 180, 210, and 240 minutes
after treatment, blood samples were collected and
several serum or plasma biochemical variables were
assessed; in addition, plasma samples from llamas
were assessed for insulin concentrations. Data were
compared between days (alpacas only) and between
Results—Administration of epinephrine induced
mobilization of glucose, triglycerides, nonesterified
fatty acids, and β-hydroxybutyrate. A small increase in
endogenous insulin concentration was detected in
epinephrine-treated llamas, compared with baseline
values. Overall, insulin administration decreased,
negated, or delayed the epinephrine-associated
increases in serum or plasma concentrations of circulating
energy substrates, except that it augmented
the epinephrine-associated increase in concentration
Conclusions and Clinical Relevance—Epinephrine
appeared to mobilize energy substrates in camelids
and hence may be involved in the pathogenesis of disorders
of glucose and fat metabolism. Insulin
appeared to antagonize most of these effects, and its
administration may have therapeutic value in
camelids. (Am J Vet Res 2004;65:1692–1696)
Objective—To evaluate the effects of exogenous
insulin on clearance of exogenous glucose in alpacas.
Animals—7 adult castrated male alpacas.
Procedure—Prior to each of 2 trials, food was withheld
for 8 hours. Glucose (0.5 g/kg of body weight)
was then administered by rapid IV infusion. During 1
of the trials, regular insulin (0.2 U/kg, IV) was also
administered 15 minutes later. Blood was collected
immediately before (0 minutes) and 15, 20, 25, 30,
45, 60, 90, 120, 180, and 240 minutes after glucose
administration. Plasma concentrations of glucose and
lactate were determined, and glucose fractional
turnover rate and plasma half-life were calculated.
Results—Insulin treatment caused a significant
increase in fractional turnover rate of glucose and
plasma lactate concentration. Plasma glucose concentrations
were less in insulin-treated alpacas from
30 minutes after glucose administration (15 minutes
after insulin administration) until the conclusion of
each trial, compared with nontreated alpacas. In addition,
plasma glucose concentration in insulin-treated
alpacas returned to baseline values 1 hour sooner
than in the nontreated group.
Conclusion and Clinical Relevance—Glucose
uptake in alpacas improves after insulin treatment,
suggesting that administration of exogenous insulin
will increase the therapeutic and decrease the pathologic
effects of exogenous glucose administered to
hypoglycemic alpacas. However, alpacas and other
New World camelids should be monitored carefully
during treatment with glucose or insulin, because
these species appear to be partially insulin resistant.
(Am J Vet Res 2001;62:1544–1547)
Objective—To evaluate effects of hydrocortisone
administration, with and without concurrent administration
of insulin, on intermediary metabolism in
Animals—8 adult castrated male alpacas.
Procedure—On each of 2 consecutive days, food
was withheld from alpacas for 8 hours. Alpacas then
were administered 1 mg of hydrocortisone sodium
succinate/kg, IV (time 0). On 1 of the days, randomly
assigned alpacas were also administered regular
insulin (0.2 U/kg, IV) 120 minutes after hydrocortisone
administration. Blood samples were collected at 0,
120, 135, 150, 165, 180, 210, 240, 300, and 360 minutes.
Plasma concentrations of glucose and lactate
and serum concentrations of triglycerides, cholesterol,
nonesterified fatty acids, and β-hydroxybutyrate
were determined. Data were compared between
days. Additionally, serum insulin concentrations
before and after hydrocortisone administration were
determined for selected samples.
Results—Hydrocortisone administration induced
hyperglycemia, hyperinsulinemia, a reduction in concentrations
of triglycerides and cholesterol, and a
reduction in triglyceride-to-cholesterol ratio. Subsequent
insulin administration temporarily negated
the hyperglycemic effects of hydrocortisone, induced
temporary hyperlactemia, and augmented the reduction
in blood triglycerides.
Conclusion and Clinical Relevance—A single dose
of a short-acting corticosteroid does not increase
blood lipid fractions in healthy alpacas, probably
because of a competent endogenous insulin
response. Corticosteroids may induce differing
responses in camelids with depleted glycogen stores
or an ineffective insulin response. Administration of
insulin can effectively negate the hyperglycemic
effects of hydrocortisone and augment lipoprotein
clearance. Hence, insulin administration may be therapeutic
for alpacas with hyperglycemia, hyperlipemia,
or hyperketonemia. (Am J Vet Res 2002;63:1269–1274)
Objective—To evaluate the effects of long-acting
insulin on glucose clearance in alpacas.
Animals—8 adult castrated alpacas.
Procedure—On 2 days, food was withheld from
alpacas for 8 hours. Alpacas were randomly allocated
to receive an SC injection of long-acting insulin
(0.4 U/kg) or saline (0.9% NaCl) solution 1 hour before
the first of 3 administrations of glucose (at 60, 480,
and 1,200 minutes after treatment) on day 1 and the
alternate treatment and procedure on day 2. Plasma
glucose concentration was determined before and 15,
45, 120, and 240 minutes after each glucose administration,
and fractional turnover rates were calculated.
The data were compared between alpacas with and
without insulin administration and among the 3 glucose
administrations for each day.
Results—Compared with sham-treated alpacas,
insulin-treated alpacas had significantly lower blood
glucose concentrations from 180 to 600 minutes after
treatment; they also had glucose concentrations significantly
below baseline values from 120 to 480 minutes,
at which time the mean glucose concentration
was in the hypoglycemic range. Also, mean fractional
turnover of glucose was significantly higher in insulintreated
alpacas from 105 through 300 minutes.
Conclusions and Clinical Relevance—Compared
with known effects of regular insulin in alpacas, the
action of long-acting insulin was of slower onset but
longer lasting; its administration may induce hypoglycemia,
even in alpacas that receive glucose. To
maintain the hypoglycemic effect, long-acting insulin
may have to be administered more than once daily
and blood glucose concentration should be monitored
to avoid hypoglycemic complications in alpacas. (Am
J Vet Res 2004;65:1688–1691)
Objective—To describe a technique for abdominocentesis in camelids and report peritoneal fluid biochemical and cytologic findings from healthy llamas and alpacas.
Animals—17 adult llamas and 5 adult alpacas.
Procedures—Right paracostal abdominocentesis was performed. Peritoneal fluid was collected by gravity flow into tubes containing potassium-EDTA for cell count and cytologic evaluation and lithium heparin for biochemical analysis. Blood samples were collected via jugular venipuncture into heparinized tubes at the same time. Cytologic components were quantified. Fluid pH and concentrations of total carbon dioxide, sodium, potassium, chloride, lactate, and glucose were compared between peritoneal fluid and venous blood.
Results—All but 3 camelids had peritoneal fluid cell counts of < 3,000 nucleated cells/μL, with < 2,000 neutrophils/μL and < 1,040 large mononuclear cells/μL. All but 1 had peritoneal fluid protein concentrations of ≥ 2.5 g/dL. Peritoneal fluid of camelids generally contained slightly less glucose, lactate, and sodium and roughly equal concentrations of potassium and chloride as venous blood.
Conclusions and Clinical Relevance—Peritoneal fluid was collected safely from healthy camelids. Compared with blood, peritoneal fluid usually had a low cell count and protein concentration, but some individuals had higher values. Electrolyte concentrations resembled those found in blood. High cell counts and protein concentrations found in peritoneal fluid of some healthy camelids may overlap with values found in diseased camelids, complicating interpretation of peritoneal fluid values.
Objective—To develop a PCR assay for Candidatus Mycoplasma haemolamae (CMhl) infection in alpacas and use it to study the efficacy of oxytetracycline treatment and development of a subclinical carrier state.
Animals—8 healthy adult alpacas.
Procedures—Alpacas initially had negative results for CMhl in blood samples via PCR assay and were experimentally infected with CMhl; 4 were treated with oxytetracycline, and 4 were not treated. All were monitored regularly via PCR assay, blood smear examination, PCV, rectal temperature, and physical examination. At 6 months after treatment, all alpacas were immunosuppressed by administration of dexamethasone and tested for CMhl.
Results—7 of 8 alpacas had positive PCR assay results 4 to 6 days after experimental infection. When organisms were detectable on a blood smear, they were seen 2 to 6 days after positive results of PCR assay. Infection was often associated with mild anemia that was usually transient. No alpacas became hypoglycemic. Oxytetracycline treatment was not associated with faster clearance of organisms or resolution of anemia, and 4 of 4 treated alpacas still had positive results of PCR assay when immunosuppressed 6 months later; 0 of 3 nontreated alpacas had positive results of PCR assay following immunosuppression. Transient fever was detected in 3 alpacas during immunosuppression.
Conclusions and Clinical Relevance—The PCR assay was more sensitive than blood smear examination for detection of infection. Clinical signs, anemia, and fever were not necessarily associated with infection. Oxytetracyline administration did not consistently clear CMhl infection. Although treated with oxytetracycline, infected alpacas remained chronic carriers.
OBJECTIVE To evaluate the use of the acute-phase proteins serum amyloid A (SAA) and haptoglobin as prognostic indicators in horses with colic with regard to the need for surgical intervention, development of complications, and hospitalization cost and duration.
DESIGN Prospective observational study.
ANIMALS 20 clinically normal horses and 42 horses with colic.
PROCEDURES Total WBC and neutrophil counts and plasma fibrinogen, SAA, and haptoglobin concentrations were compared between healthy (control) horses and horses admitted to a veterinary teaching hospital for colic. Clinicopathologic values were compared between medical and surgical colic cases to test the ability of acute-phase proteins to predict indication for surgical intervention, development of complications, and duration and cost of hospitalization.
RESULTS Mean SAA concentration was significantly higher in the surgical group, compared with that for both the control and medical groups. Haptoglobin concentration did not differ significantly among groups. Horses with colic and an abnormally increased SAA concentration (> 5 μg/mL) were more likely to be managed surgically than medically (OR, 5.7; 95% confidence interval, 1.4 to 22.8). Horses with small intestinal lesions had significantly higher SAA concentrations than did control horses. Euthanasia due to a poor prognosis or the development of thrombophlebitis was more likely for horses with an SAA concentration > 5 μg/mL (OR, 7.6; 95% confidence interval, 1.1 to 52.4). A weak positive correlation (r = 0.30) was observed between cost of treatment and SAA concentration.
CONCLUSIONS AND CLINICAL RELEVANCE Horses with colic that had an abnormally increased SAA concentration were more likely to require surgical intervention, develop thrombophlebitis, or be euthanized because of a poor prognosis despite treatment.
Objective—To determine whether ϵ-aminocaproic
acid (EACA) administered IV affects hemostasis and
fibrinolysis in clinically normal horses and ponies.
Animals—20 clinically normal adult horses and
Procedures—Blood samples were collected 24 hours
before (baseline) and 1 and 5 hours after IV administration
of a low dose (30 mg/kg) or high dose (100
mg/kg) of EACA. Platelet count, fibrinogen concentration,
prothrombin time, partial thromboplastin time
(PTT), D-dimer concentration, α2-antiplasmin activity,
and thrombin-antithrombin complex concentration
were measured. Values at 1 and 5 hours were compared
with baseline values.
Results—1 hour after administration of a low dose of
EACA, mean fibrinogen concentration was significantly
lower than baseline concentration. Mean PTT
was significantly shorter than the baseline value 5
hours after administration of a low dose of EACA.
One hour after administration of 100 mg of EACA/kg,
mean α2-antiplasmin activity was significantly higher
than baseline activity. Mean fibrinogen concentration
was significantly lower than baseline concentration 1
and 5 hours after administration of a high dose of
EACA. Mean PTT was significantly shorter than the
baseline value 5 hours after administration of a high
dose of EACA.
Conclusions and Clinical Relevance—IV administration
of 30 and 100mg of EACA/kg to clinically normal
horses significantly modified some laboratory measures
of hemostasis, consistent with its known
antifibrinolytic effects. Although enhanced clot maintenance
and diminished bleeding were not directly
assessed, the clinical use of EACA may benefit some
patients. ( Am J Vet Res 2005;66:313–318)