Objective—To determine the insulin response curve
during IV glucose tolerance testing of mature Holstein
Animals—8 Holstein bulls between 5 and 8 years old
and weighing between 911.5 and 1035.5 kg.
Procedure—A 50% glucose solution was rapidly
administered IV so that each bull received a mean
dose of 258 mg of glucose/kg of body weight. Serum
glucose and insulin concentrations were determined
before and 30, 60, 120, and 240 minutes after glucose
Results—Serum glucose concentrations 30 and 60
minutes after infusion were significantly greater than
baseline concentration. Concentrations returned to
baseline values 120 minutes after infusion. Serum
insulin concentration was significantly greater 30 minutes
after glucose administration, compared with
baseline and 240-minute concentrations.
Conclusions and Clinical Relevance—Intravenous
glucose tolerance testing of mature Holstein bulls
resulted in a characteristic insulin response curve.
Baseline and peak insulin concentrations were higher
in these bulls, compared with values reported for
mature Norwegian Red cows. (Am J Vet Res 2000;
Objective—To estimate intraocular pressure (IOP) in
eyes of healthy camelids, using applanation tonometry.
Animals—The eyes of 34 camelids (16 llamas [Lama
glama] and 18 alpacas [L pacos]) that did not have
major abnormalities of the ocular surface or intraocular
Procedure—Tonometry measurements were
obtained from each eye 3 times during a 24-hour period.
Each measurement was the mean of several
corneal applanations obtained by use of an applanation
tonometer. Data were analyzed, using an ANOVA
for a repeated-measures design.
Results—Mean (± SEM) IOP of llamas and alpacas
was 13.10 ± 0.35 and 14.85 ± 0.45 mm Hg, respectively.
Range of IOP was 7 to 18 mm Hg for llamas
and 11 to 21 mm Hg for alpacas. Mean IOP of llamas
was significantly less than the mean IOP of alpacas.
Significant differences in IOP were not detected
between the right and left eye of animals. Significant
differences in IOP were not attributed to sex, age, or
time of measurement within llamas or alpacas.
Conclusions and Clinical Relevance—Establishing
the mean and range of IOP of clinically normal llamas
and alpacas provides a frame of reference that is
important for use in a complete ophthalmic examination
of camelids, which can assist clinicians in the
diagnosis of glaucoma and uveitis. Reasons for the
difference in mean IOP between llamas and alpacas
are unknown. Although the difference may be unimportant
clinically, this finding reiterates the fact that
caution must be used when extrapolating IOP among
species. (Am J Vet Res 2000;61:1542–1544)