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Objective: To determine pharmacokinetic and pharmacodynamic properties of midazolam after IV and IM administration in alpacas., Animals: 6 healthy alpacas., Procedures: Midazolam (0.5 mg/kg) was administered IV or IM in a randomized crossover design. Twelve hours prior to administration, catheters were placed in 1 (IM trial) or both (IV trial) jugular veins for drug administration and blood sample collection for determination of serum midazolam concentrations. Blood samples were obtained at intervals up to 24 hours after IM and IV administration. Midazolam concentrations were determined by use of tandem liquid chromatography-mass spectrometry., Results: Maximum concentrations after IV administration (median, 1,394 ng/mL [range, 1,150 to 1,503 ng/mL]) and IM administration (411 ng/mL [217 to 675 ng/mL]) were measured at 3 minutes and at 5 to 30 minutes, respectively. Distribution half-life was 18.7 minutes (13 to 47 minutes) after IV administration and 41 minutes (30 to 80 minutes) after IM administration. Elimination half-life was 98 minutes (67 to 373 minutes) and 234 minutes (103 to 320 minutes) after IV and IM administration, respectively. Total clearance after IV administration was 11.3 mL/min/kg (6.7 to 13.9 mL/min/kg), and steady-state volume of distribution was 525 mL/kg (446 to 798 mL/kg). Bioavailability of midazolam after IM administration was 92%. Peak onset of sedation occurred at 0.4 minutes (IV) and 15 minutes (IM). Sedation was significantly greater after IV administration., Conclusions and Clinical Relevance: Midazolam was well absorbed after IM administration, had a short duration of action, and induced moderate levels of sedation in alpacas.

Objective: To characterize serum trace mineral, sex steroid hormone, and vitamin D concentrations and identify factors associated with metacarpophalangeal and metatarsophalangeal hyperextension in llamas and alpacas., Samples: Serum samples from 79 llamas and 15 alpacas and owner survey data for 573 llamas and 399 alpacas., Procedures: Serum samples were stored at -20°C until analysis and were evaluated for trace mineral, vitamin D, estradiol, progesterone, and testosterone concentrations. Information regarding age of onset, number of affected animals in herd, feed and supplements given, type of housing, and management practices was obtained in an owner survey., Results: Higher serum zinc and iron concentrations were associated with metacarpophalangeal and metatarsophalangeal hyperextension in camelids, compared with controls. In summer and fall months, vitamin D concentrations were significantly higher in affected camelids than controls. Overall prevalence was 13.3% in llamas, compared with 0.7% in alpacas. No management factors were found to be predictive of this condition. No other factors examined were associated with metacarpophalangeal and metatarsophalangeal hyperextension., Conclusions and Clinical Relevance: Despite similar supplementation practices and environmental conditions between affected and unaffected animals, an association of high serum zinc, iron, and vitamin D concentrations in affected camelids, compared with controls, may indicate differences of intake or absorption of dietary supplements.

Objective: To measure and compare insulin secretion and sensitivity in healthy alpacas and llamas via glucose clamping techniques., Animals: 8 llamas and 8 alpacas., Procedures: Hyperinsulinemic euglycemic clamping (HEC) and hyperglycemic clamping (HGC) were performed on each camelid in a crossover design with a minimum 48-hour washout period between clamping procedures. The HEC technique was performed to measure insulin sensitivity. Insulin was infused IV at 6 mU/min/kg for 4 hours, and an IV infusion of glucose was adjusted to maintain blood glucose concentration at 150 mg/dL. Concentrations of blood glucose and plasma insulin were determined throughout. The HGC technique was performed to assess insulin secretion in response to exogenous glucose infusion. An IV infusion of glucose was administered to maintain blood glucose concentration at 320 mg/dL for 3 hours, and concentrations of blood glucose and plasma insulin were determined throughout., Results: Alpacas and llamas were not significantly different with respect to whole-body insulin sensitivity during HEC or in pancreatic β-cell response during HGC. Alpacas and llamas had markedly lower insulin sensitivity during HEC and markedly lower pancreatic β-cell response during HGC, in comparison with many other species., Conclusions and Clinical Relevance: New World camelids had lower glucose-induced insulin secretion and marked insulin resistance in comparison with other species. This likely contributes to the disorders of fat and glucose metabolism that are common to camelids.

Objective: To evaluate respiratory mechanical function and bronchoalveolar lavage (BAL) cytologic results in healthy alpacas., Animals: 16 client-owned adult alpacas., Procedures: Measurements of pulmonary function were performed, including functional residual capacity (FRC) via helium dilution, respiratory system resistance via forced oscillatory technique (FOT), and assessment of breathing pattern by use of respiratory inductive plethysmography (RIP) in standing and sternally recumbent alpacas. Bronchoalveolar lavage was performed orotracheally during short-term anesthesia., Results: Mean ± SD measurements of respiratory function were obtained in standing alpacas for FRC (3.19 ± 0.53 L), tidal volume (0.8 ± 0.13 L), and respiratory system resistance at 1 Hz (2.70 ± 0.88 cm H(2)O/L/s), 2 Hz (2.98 ± 0.70 cm H(2)O/L/s), 3 Hz (3.14 ± 0.77 cm H(2)O/L/s), 5 Hz (3.45 ± 0.91 cm H(2)O/L/s), and 7 Hz (3.84 ± 0.93 cm H(2)O/L/s). Mean phase angle, as a measurement of thoracoabdominal asynchrony, was 19.59 ± 10.06°, and mean difference between nasal and plethysmographic flow measurements was 0.18 ± 0.07 L/s. Tidal volume, peak inspiratory flow, and peak expiratory flow were significantly higher in sternally recumbent alpacas than in standing alpacas. Cytologic examination of BAL fluid revealed 58.52 ± 12.36% alveolar macrophages, 30.53 ± 13.78% lymphocytes, 10.95 ± 9.29% neutrophils, 0% mast cells, and several ciliated epithelial cells., Conclusions and Clinical Relevance: Pulmonary function testing was tolerated well in nonsedated untrained alpacas. Bronchoalveolar lavage in alpacas yielded samples with adequate cellularity that had a greater abundance of neutrophils than has been reported in horses.

Objective: To evaluate molecular and histologic characteristics of the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), and suspensory ligament (SL) and assess trace-mineral concentrations in serum, liver, and hair of juvenile llamas with metacarpophalangeal and metatarsophalangeal joint hyperextension., Animals: 12 juvenile llamas (6 with bilateral hyperextension of metacarpophalangeal joints, metatarsophalangeal joints, or both and 6 clinically normal control llamas)., Procedures: Radiography and ultrasonography of metacarpophalangeal and metatarsophalangeal regions were performed. Llamas were euthanized, and SDFT, DDFT, and SL samples were collected for histologic evaluation of collagen and elastin content and orientation, proteoglycan content, and collagen type III immunohistochemistry. Total RNA was isolated from SL tissue, and gene expression of collagen types I and III, lysyl oxidase, and matrix metalloproteinase-13 was evaluated via real-time quantitative reverse transcriptase PCR assay. Liver, serum, and hair samples were evaluated for trace mineral content., Results: Collagen type III gene expression and proteoglycan content were significantly increased in SL samples of affected juvenile llamas, compared with those of control llamas. No difference was detected in collagen and elastin content and orientation or in gene expression of collagen type I, lysyl oxidase, or matrix metalloproteinase-13 between groups. Affected llamas had significantly increased serum molybdenum and decreased liver cobalt concentrations, compared with values for control llamas., Conclusions and Clinical Relevance: Increased collagen type III gene expression and proteoglycan content in SL samples of affected juvenile llamas provided evidence of ongoing SL matrix repair. Trace mineral differences may have been attributable to dietary imbalances in affected llamas.

Objective: To compare the effects of hetastarch and lactated Ringer's solution (LRS) on plasma colloid osmotic pressure (pCOP) and other hematologic variables in healthy llamas., Design: Prospective crossover study., Animals: 6 healthy female llamas. Procedures-Llamas were administered LRS (45 mL/kg [20.5 mL/lb]) and, after a 3-day washout period, hetastarch (15 mL/kg [6.8 mL/lb]) during 60-minute IV infusions. Serum total protein, serum albumin, and hemoglobin concentrations and Hct were measured before each infusion (baseline), immediately after each infusion was completed (0 hours), and at 2, 4, 8, and 12 hours. The pCOP was measured at baseline and at 0, 2, 4, 8, 12, 24, 36, and 48 hours after each infusion was completed; additional measurements of pCOP were obtained 72 and 96 hours after hetastarch infusion., Results: Hetastarch administration significantly increased mean ± SEM pCOP from 23.5 ± 0.3 mm Hg (baseline) to a peak of 28.4 ± 0.6 mm Hg (12 hours); significant increases in pCOP persisted at 96 hours after hetastarch administration. Administration of LRS significantly decreased albumin and total protein concentrations; in addition, mean ± SEM pCOP decreased from 24.1 ± 0.4 mm Hg (baseline) to 18.0 ± 0.3 mm Hg (0 hours). Hetastarch administration caused more pronounced decreases in Hct (0 hours) and concentrations of hemoglobin (0 hours), albumin (all time points), and total protein (all time points) than did LRS administration., Conclusions and Clinical Relevance: Hetastarch administration increased pCOP in healthy llamas for 96 hours with no clinically important complications.

Objective: To study the effect of the reproductive state of female alpacas (ie, maiden [never bred before], barren [bred but failed to conceive or maintain pregnancy in previous breeding season], or gave birth and currently lactating) on embryonic mortality rate., Animals: 167 female alpacas (54 lactating, 44 barren, and 69 maiden) that ovulated following a single breeding., Procedures: During the first 45 days following breeding, female alpacas underwent periodic transrectal ultrasonography to determine the presence or absence of an embryonic vesicle. Serum progesterone concentrations were determined during the same period. Embryonic survival rate was analyzed for each group of females (lactating, barren, and maiden)., Results: The presence of an embryonic vesicle or embryo was positively associated with high serum progesterone concentrations (>2 ng/mL). The embryonic mortality rate in barren females (21/44 [47.7%]) was significantly higher than in maiden (20/69 [29.0%]) and lactating (16/54 [29.6%]) females. In females that underwent embryonic loss (n=57), 3 patterns of events in terms of serum progesterone concentrations were identified: concomitant decrease of serum progesterone concentration and embryonic loss (24/57 [42.1%]), decrease in serum progesterone concentration before embryonic loss (12/57 [21.1%]), and persistent serum progesterone concentrations beyond embryonic loss (21/57 [36.8%]). Patterns of serum progesterone concentration and embryonic loss did not differ significantly among lactating, barren, and maiden female alpacas., Conclusions and Clinical Relevance: Embryonic loss in alpacas occurred without any discernible pattern in serum progesterone concentrations. Barren female alpacas had the highest embryonic mortality rate.

Objective: To describe a technique for abdominocentesis in camelids and report peritoneal fluid biochemical and cytologic findings from healthy llamas and alpacas., Design: Prospective study. 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/microL, with < 2,000 neutrophils/microL and < 1,040 large mononuclear cells/microL. All but 1 had peritoneal fluid protein concentrations of > or = 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 validate the use of noninvasive pulmonary function testing in sedated and nonsedated llamas and establish reference range parameters of respiratory mechanical function., Animals: 10 healthy adult llamas., Procedures: Pulmonary function testing in llamas included the following: measurement of functional residual capacity (FRC) via helium dilution, respiratory inductance plethysmography (RIP) to assess breathing pattern and flow limitations, esophageal-balloon pneumotachography, and a monofrequency forced oscillatory technique (FOT; 1 to 7 Hz) before and after IM administration of xylazine (0.2 mg/kg)., Results: The following mean +/- SD measurements of respiratory function were obtained in nonsedated llamas: FRC (5.60 +/- 1.24 L), tidal volume (1.03 +/- 0.3 L), dynamic compliance (0.83 +/- 0.4 L/cm H(2)O), pulmonary resistance (R(L); 1.42 +/- 0.54 cm H(2)O/L/s), and respiratory system resistance (2.4 +/- 0.9, 2.3 +/- 0.7, 2.2 +/- 0.6, 2.7 +/- 0.7, and 2.5 +/- 0.5 cm H(2)O/L/s at 1, 2, 3, 5, and 7 Hz, respectively) by use of FOT. Measurements of flow limitations via RIP were comparable to other species. Sedation with xylazine induced significant increases in R(L) and maximum change in transpulmonary pressure. Following sedation, a mean 127% increase in R(L) and mean 116% increase in respiratory system resistance were observed across 1 to 7 Hz. The magnitude of change in respiratory system resistance increased with decreasing impulse frequency, suggesting bronchoconstriction., Conclusions and Clinical Relevance: Noninvasive pulmonary function testing is well tolerated in untrained unsedated llamas. These techniques have clinical applications in the diagnosis and treatment of respiratory tract disease, although testing should not be performed after sedation with xylazine.

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 i.v. 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 i.v. 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 microU/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.

Objective: To determine electrocardiographic parameters in healthy llamas and alpacas., Animals: 23 llamas and 12 alpacas., Procedure: Electrocardiography was performed in nonsedated standing llamas and alpacas by use of multiple simultaneous lead recording (bipolar limb, unipolar augmented limb, and unipolar precordial leads)., Results: Common features of ECGs of llamas and alpacas included low voltage of QRS complexes, variable morphology of QRS complexes among camelids, and mean depolarization vectors (mean electrical axes) that were directed dorsocranially and to the right. Durations of the QT interval and ST segment were negatively correlated with heart rate., Conclusions and Clinical Relevance: ECGs of acceptable quality can be consistently recorded in nonsedated standing llamas and alpacas. Features of ECGs in llamas and alpacas are similar to those of other ruminants. Changes in the morphology of the QRS complexes and mean electrical axis are unlikely to be sensitive indicators of ventricular enlargement in llamas and alpacas.

Objective: To assess the effects of prolonged feed deprivation on glucose tolerance, insulin secretion, and lipid homeostasis in llamas., Animals: 9 adult female llamas., Procedure: On each of 2 consecutive days, food was withheld from the llamas for 8 hours. Blood samples were collected before and 5, 15, 30, 45, 60, 120, and 240 minutes after IV injection of dextrose (0.5 g/kg) for determination of plasma insulin and serum glucose, triglyceride, and nonesterified fatty acid concentrations. Between experimental periods, the llamas received supplemental amino acids IV (185 mg/kg in solution). The llamas were then fed a limited diet (grass hay, 0.25% of body weight daily) for 23 days, after which the experimental procedures were repeated., Results: Feed restriction decreased glucose tolerance and had slight effects on insulin secretion in llamas. Basal lipid fractions were higher after feed restriction, but dextrose administration resulted in similar reductions in serum lipid concentrations with and without feed restriction. Insulin secretion was decreased on the second day of each study period, which lessened reduction of serum lipid concentrations but did not affect glucose tolerance., Conclusions and Clinical Relevance: Despite having a comparatively competent pancreatic response, feed-restricted llamas assimilated dextrose via an IV bolus more slowly than did llamas on full rations. However, repeated administration of dextrose reduced insulin secretion and could promote hyperglycemia and fat mobilization. These findings suggested that veterinarians should use alternative methods of supplying energy to camelids with long-term reduced feed intake or consider administering agents to improve the assimilation of glucose.

Objective: To evaluate the effects of administration of hydrocortisone on plasma concentration of insulin and serum concentrations of glucose, triglyceride, and nonesterified fatty acids (NEFAs) in llamas before and after feed restriction., Animals: 9 adult female llamas., Procedure: Feed was withheld from llamas for 8 hours. Blood samples were collected before (0 minutes) and 120, 180, 240, and 300 minutes after IV injection of hydrocortisone sodium succinate (1 mg/kg) for determination of plasma insulin concentration and serum concentrations of glucose, triglyceride, and NEFAs. The llamas were then fed a limited diet (grass hay, 0.25% of body weight daily) for 21 days, after which the experimental procedures were repeated., Results: Compared with llamas that were not feed-restricted, llamas after feed restriction had significantly higher plasma insulin concentration and serum concentrations of triglycerides and NEFAs. Feed-restricted llamas after hydrocortisone injection had a significantly smaller increase in serum glucose concentration, a decrease (rather than an increase) in serum concentration of NEFAs, and no change in blood concentrations of insulin or triglycerides., Conclusions and Clinical Relevance: Short-acting glucocorticoid hormones did not appear to increase blood lipid concentrations in healthy llamas, regardless of ongoing fat mobilization. Thus, these hormones appear unlikely to be major direct contributors to diseases such as hepatic lipidosis or hyperlipemia. Although administration of hydrocortisone reduced serum concentration of fatty acids in feed-restricted llamas, its use has not been evaluated in sick camelids and cannot be considered therapeutically useful.

Objective: To determine the in vitro effect of prostaglandin (PG) E2, PGF2alpha, and the nonsteroidal anti-inflammatory drugs (NSAIDs) indomethacin, ketoprofen, and nabumetone on the contractile strength of the circular smooth muscle layer of the third compartment of the stomach of llamas., Sample Population: Specimens of the third compartment obtained from 5 healthy adult llamas., Procedure: Full-thickness tissue samples were collected from the third compartment immediately after euthanasia. Specimens were cut into strips oriented along the circular muscle layer and mounted in a tissue bath system. Incremental amounts of ketoprofen, nabumetone, indomethacin, PGE2, and PGF2alpha were added, and contractile strength (amplitude of contractions) was recorded., Results: Generally, PGE2 reduced contractile strength of the circular smooth layer of the third compartment, whereas PGF2alpha, increased the strength of contractions. The activity of the NSAIDs was generally excitatory in a concentration-dependent manner, although significant changes were induced only by administration of indomethacin., Conclusions and Clinical Relevance: On isolated smooth muscle strips of the third compartment of llamas, exogenous PGE2 and PGF2alpha had a variable effect on contractile strength. Administration of the NSAIDs did not inhibit contractility and would not be likely to induce stasis of the third compartment in the absence of an underlying disease process.

Objective: To establish reference range values for synovial fluid from clinically normal New World camelids., Animals: 15 llamas and 15 alpacas., Procedure: Llamas and alpacas were anesthetized with an IM injection of a xylazine hydrochloride, butorphanol tartrate, and ketamine hydrochloride combination. Synovial fluid (1 to 2 ml) was obtained by aseptic arthrocentesis from the radiocarpal and tarsocrural joints. Synovial fluid evaluation included determination of total nucleated cell count (NCC), absolute number and percentage of polymorphonuclear (PMN) and mononuclear leukocytes, total protein, and specific gravity., Results: Synovial fluid evaluation revealed a total NCC of 100 to 1,400 cells/microl (mean +/- SD, 394.8+/-356.2 cells/microl; 95% confidence interval [CI], 295.2 to 494.6 cells/microl). Mononuclear leukocytes were the predominant cell type with lymphocytes, composing 50 to 90% (mean, 75.6+/-172%; 95% CI, 70.8 to 80.4%) of the mononuclear leukocytes. Approximately 0 to 12% (mean, 1.3+/-2.9%; 95% CI, 0.49 to 2.11%) of the cells were PMN leukocytes. Total protein concentrations ranged from 2.0 to 3.8 g/dl (mean, 2.54+/-0.29 g/dl; 95% CI, 2.46 to 2.62 g/dl); the specific gravity ranged between 1.010 and 1.026 (mean, 1.017+/-0.003; 95% CI, 1.016 to 1.018)., Conclusion and Clinical Relevance: In llamas and alpacas, significant differences do not exist between species or between limbs (left vs right) or joints (radiocarpal vs tarsocrural) for synovial fluid values. Total NCC and absolute number and percentage of PMN and mononuclear leukocyte are similar to those of other ruminants and horses. However, synovial fluid total protein concentrations in New World camelids are high, compared with other domestic species.

Objective: To determine density of corneal endothelial cells, corneal thickness, and corneal diameters in normal eyes of llamas and alpacas., Animals: 36 llamas and 20 alpacas., Procedure: Both eyes were examined in each camelid. Noncontact specular microscopy was used to determine density of corneal endothelial cells. Corneal thickness was measured, using ultrasonographic pachymetry. Vertical and horizontal corneal diameters were measured, using Jameson calipers., Results: Values did not differ significantly between the right and left eyes from the same camelid. There was no significant effect of sex on density of corneal endothelial cells or corneal thickness in either species. Mean density of endothelial cells was 2,669 cells/mm2 in llamas and 2,275 cells/mm2 in alpacas. Density of endothelial cells decreased with age in llamas. Polymegathism was observed frequently in both species. Mean corneal thickness was 608 microm for llamas and 595 microm for alpacas. Corneal thickness and density of endothelial cells were negatively correlated in llamas. Older (> 36 months old) llamas had significantly larger horizontal and vertical corneal diameters than younger llamas, and older alpacas had a significantly larger vertical corneal diameter than younger alpacas., Conclusions and Clinical Relevance: Density of corneal endothelial cells is only slightly lower in camelids than other domestic species. Density of endothelial cells decreases with age in llamas. Age or sex does not significantly affect corneal thickness in normal eyes of llamas and alpacas. Specular microscopy is useful for determining density of corneal endothelial cells in normal eyes of camelids.

Objective: To evaluate disposition of butorphanol after i.v. and i.m. administration, effects on physiologic variables, and analgesic efficacy after i.m. administration in llamas., Design: Nonrandomized crossover study., Animals: 6 healthy adult male llamas., Procedure: Butorphanol (0.1 mg/kg [0.045 mg/lb] of body weight) was administered i.m. first and i.v. 1 month later. Blood samples were collected intermittently for 24 hours after administration. Plasma butorphanol versus time curves were subjected to pharmacokinetic analysis. Two months later, butorphanol (0.1 mg/kg) was administered i.m., and physiologic variables and analgesia were assessed., Results: Extrapolated peak plasma concentrations after i.v. and i.m. administration were 94.8 +/- 53.1 and 34.3 +/- 11.6 ng/ml, respectively. Volume of distribution at steady state after i.v. administration was 0.822 +/- 0.329 L/kg per minute and systemic clearance was 0.050 +/- 0.014 L/kg per minute. Slope of the elimination phase was significantly different, and elimination half-life was significantly shorter after i.v. (15.9 +/- 9.1 minutes) versus i.m. (66.8 +/- 13.5 minutes) administration. Bioavailability was 110 +/- 49% after i.m. administration. Heart rate decreased and rectal temperature increased. Somatic analgesia was increased for various periods. Two llamas became transiently sedated, and 2 became transiently excited after butorphanol administration., Conclusions and Clinical Relevance: Although i.v. administration of butorphanol results in a short half-life that may limit its analgesic usefulness, the elimination half-life of butorphanol administered i.m. is likely to be clinically useful. The relationship among plasma butorphanol concentration, time, and analgesia differed with the somatic analgesia model; clinically useful analgesia may occur at lower plasma concentrations than those reported here.

Objective: To evaluate composition of aqueous humor obtained from normal eyes of llamas (Lama glama) and alpacas (Lama pacos)., Sample Population: Aqueous humor obtained from 10 male llamas and 10 male alpacas., Procedure: All animals had normal eyes, as determined by ocular examination. Aqueous humor samples were obtained via paracentesis of the anterior chamber of animals that were heavily sedated. Chemical analysis included measurement of concentrations of sodium, potassium, magnesium, chloride, bicarbonate, phosphorus, and glucose as well as osmolality and pH., Results: With the exception of potassium concentrations, values for aqueous humor composition did not differ significantly between llamas and alpacas. Mean +/- SD values for llamas and alpacas, respectively, were: sodium, 154.7 +/- 2.1 and 152.7 +/- 2.1 mEq/L; potassium, 5.3 +/- 0.4 and 4.6 +/- 0.4 mEq/L; magnesium, 1.8 +/- 0.1 and 1.7 +/- 0.1 mg/dl; chloride, 130.0 +/- 1.6 and 127.0 +/- 3.3 mEq/L; bicarbonate, 19.2 +/- 1.5 and 20.2 +/- 2.3 mEq/L; phosphorous, 2.7 +/- 0.3 and 2.5 +/- 0.4 mg/dl; glucose, 80.3 +/- 3.9 and 80.8 +/- 7.3 mg/dl; total protein, 29.0 +/- 8.6 and 31.5 +/- 10.1 mg/dl; and osmolality, 305.8 +/- 11.8 and 306.2 +/- 4.9 mOsm. The pH ranged from 7.5 to 8.0 for both species. Potassium concentrations were significantly higher in llamas than alpacas., Conclusions and Clinical Relevance: Except for potassium, composition of aqueous humor did not differ significantly between llamas and alpacas. Aqueous humor composition of llamas and alpacas is similar to that of other species that have been examined.

Objectives: To determine whether feed restriction induces hepatic lipidosis (HL) in llamas and to evaluate the metabolic changes that develop during feed restriction., Animals: 8 healthy adult female llamas., Procedure: Llamas were fed grass hay at a rate of 0.25% of their body weight per day for 13 to 28 days. Llamas were monitored by use of clinical observation, serum biochemical analyses, and ultrasound-guided liver biopsies., Results: All 8 llamas lost weight and mobilized fat. Five llamas developed HL, including 4 that were nursing crias. During the period of feed restriction, mean serum concentration of bile acids and activities of aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH), and gamma-glutamyl transferase (GGT) were significantly higher in llamas that developed HL, compared with llamas that did not. Mean insulin-to-cortisol concentration ratios were lower in llamas with HL before and up to 7 days of feed restriction, compared with those that did not develop HL., Conclusions and Clinical Relevance: HL in llamas may be induced by severe feed restriction, particularly in the face of increased energy demand. Llamas with weight loss attributable to inadequate dietary intake may develop biochemical evidence of hepatopathy and HL. Increases in serum concentration of bile acids and activities of GGT, AST, and SDH may indicate the development of HL in llamas and identify affected animals for aggressive therapeutic intervention.

Objective: To estimate intraocular pressure (IOP) in eyes of healthy camelids, using applanation tonometry., Animals: The eyes of 34 camelids (16 llamas [Lama glamal and 18 alpacas [L. pacos]) that did not have major abnormalities of the ocular surface or intraocular abnormalities., 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.

A 3-year-old female llama that was 3 months into her first lactation and 10 weeks pregnant was evaluated for anorexia of 24 hours' duration. On physical examination, the llama was in lateral recumbency, bradycardic, tachypneic, and hyperthermic. Palpation per rectum confirmed the presence of a possible dry fecal mass in the spiral colon. A tissue biopsy specimen of the liver was obtained, and histologic examination revealed moderate diffuse lipid accumulation within the hepatocytes. Lactated Ringer's solution was administered for rehydration, and partial parenteral nutrition was then initiated. Hepatic lipidosis is a disease characterized by abnormal accumulation of lipid in the liver and is associated with high mortality in camelids. Anorexia associated with hepatic lipidosis promotes further lipid mobilization and fatty infiltration of the liver. Partial parenteral nutrition with enteral supplementation may be used to maintain adequate energy intake and minimize further lipid mobilization. The distinctive metabolism of camelids may require higher amino acid supplementation relative to nonprotein calories in parenteral solutions than those traditionally provided to other species. Treatment with insulin may be effective

Clinical signs of tolazoline toxicosis developed in a 4-year-old llama that received 2 doses of tolazoline hydrochloride to reverse xylazine-induced sedation. The full first dose (4.3 mg/kg [2.0 mg/lb] of body weight) was erroneously injected i.v., and the second dose was administered half i.v., half i.m. 45 minutes later, because the llama became weak and recumbent. Signs of anxiety, hyperesthesia, profuse salivation, and tachypnea were the first detectable clinical signs of tolazoline toxicosis. Convulsions, hypotension, gastrointestinal tract hypermotility, and diarrhea also developed. The llama was treated successfully with i.v. administration of diazepam, phenylephrine, and lactated Ringer's solution supplemented with potassium chloride and oxygen administered via nasal insufflation. We suggest that the maximum dose of tolazoline administered at any one time to llamas not exceed 2 mg/kg (0.91 mg/lb). Furthermore, tolazoline should be administered slowly i.v. or i.m. to reduce the risk of adverse reactions.

Objective: To determine changes in results of selected serum biochemical tests after a single percutaneous liver biopsy and changes in results of hematologic and selected serum biochemical tests after multiple percutaneous liver biopsies in alpacas and llamas., Animals: 5 llamas and 10 alpacas., Procedure: A single percutaneous liver biopsy was performed in 5 llamas and 6 alpacas. Blood samples were collected before and 1, 2, and 3 days after liver biopsy, and submitted for serum biochemical analysis. In the other 4 alpacas, liver biopsy was performed on day 0 and then weekly for 4 weeks. Blood samples were collected at the time of each biopsy, and CBC and serum biochemical analyses were performed. Attitude and appetite of all animals were evaluated daily., Results: None of the animals developed clinically apparent adverse effects. A mild decrease in sorbitol dehydrogenase activity was detected in animals that underwent a single liver biopsy, and mild decreases in plasma protein and albumin concentrations were detected in animals that underwent multiple biopsies. Other significant changes were not detected., Conclusions: Results of this study suggest that liver biopsy is safe in healthy llamas and alpacas and that, if necessary, multiple weekly liver biopsies can be performed safely in healthy alpacas.

Objective: To evaluate the safety and efficacy of percutaneous paracentesis for fluid collection from the first gastric compartment of healthy llamas and to describe characteristics of that fluid., Design: Prospective study., Animals: 10 healthy adult llamas., Procedure: Physical examinations were performed prior to sample collection and for 14 days afterwards. A CBC was performed prior to sample collection and 5 days later. A 16-gauge, 7.5-cm stainless steel needle, positioned approximately 20 cm caudal to the costochondral junction of the last rib, was pointed in a dorsocraniomedial direction and pushed through the abdominal wall into the lumen of the first gastric compartment. Fluid was aspirated and analyzed immediately for color, odor, consistency, pH, methylene blue reduction (MBR) time, protozoa, and bacteria., Results: Fluid samples were obtained from 9 of 10 llamas. Mean volume was 4.1 ml, mean pH was 6.67, and mean MBR time was 173 seconds. Odor was slightly acidic, color was light brown-green to light yellow-green, and consistency was moderate. Small protozoa with variable iodine staining and gram-negative bacteria were commonly detected. With few exceptions, results of physical examinations and CBC remained within reference ranges., Clinical Implications: Fluid samples from the first gastric compartment can be successfully obtained by percutaneous paracentesis. Fluid characteristics were similar to those of fluid collected via orogastric tube in llamas and cattle.

Objective: To determine the role of nitric oxide and an apamin-sensitive nonadrenergic-noncholinergic inhibitory transmitter in in vitro contractile activity of the third compartment in llamas., Sample Population: Isolated strips of third compartment of the stomach from 5 llamas., Procedure: Strips were mounted in tissue baths containing oxygenated Kreb's buffer solution and connected to a polygraph chart recorder to measure contractile activity. Atropine, guanethidine, and indomethacin were added to tissue baths to inhibit muscarinic receptors, adrenoreceptors, and prostaglandin synthesis. Responses to electrical field stimulation following addition of the nitric oxide antagonist Nwo-nitro-L-arginine methyl ester (L-NAME) and apamin were evaluated., Results: Electrical field stimulation (EFS) resulted in a reduction in the amplitude and frequency of contractile activity, followed by rebound contraction when EFS was stopped. Addition of L-NAME resulted in a significant reduction in inhibition of contractile activity. Addition of apamin also resulted in a significant reduction in inhibitory contractile activity at most stimulation frequencies. The combination of L-NAME and apamin resulted in a significant reduction in inhibition at all frequencies., Conclusion: Nitric oxide and a transmitter acting via an apamin-sensitive mechanism appear to be involved in inhibition of contractile activity of the third compartment in llamas., Clinical Relevance: Results suggest that nitric oxide plays an important role in mediating contractile activity of the third compartment in llamas. Use of nitric oxide synthase inhibitors may have a role in the therapeutic management of llamas with lesions of the third compartment.

Objective: To determine a dose of medetomidine that will induce sedation in llamas, to assess effects of medetomidine sedation on arterial blood gas variables, and to determine efficacy of atipamezole in reversing medetomidine-induced sedation., Design: Prospective, randomized clinical trial., Animals: 15 clinically normal adult llamas., Procedure: 9 llamas received various doses of medetomidine (0.01, 0.02, or 0.03 mg/kg [0.005, 0.009, or 0.014 mg/lb] of body weight, i.m.). Heart and respiratory rates and sedative effects were recorded. Using the lowest dose that induced deep sedation, 6 different llamas were used to assess effects of medetomidine on arterial blood gas variables. These same 6 llamas were later given atipamezole (0.125 mg/kg [0.057 mg/lb], i.v.) 30 minutes after medetomidine injection. Heart and respiratory rates, sedative effects, and time from atipamezole injection to standing were recorded., Results: Sedation began 6.67 +/- 1.15 minutes (mean +/- SD) after medetomidine administration (0.03 mg/kg, i.m.). Arterial blood gas variables measured 30 and 60 minutes after injection were not different from baseline. Llamas that did not receive atipamezole remained recumbent for 91.50 +/- 24.68 minutes. After atipamezole administration, llamas were able to stand in 5.80 +/- 3.27 minutes., Clinical Implications: Medetomidine induced light to deep sedation in a dose-dependent manner in clinically normal llamas. A dose of 0.03 mg/kg induced deep sedation with a short period of analgesia. Atipamezole rapidly reversed effects of medetomidine, and llamas recovered quickly and were soon able to stand.

Objective: To evaluate selected cardiopulmonary responses to propofol 2 infusion rates in nonpretreated llamas breathing room air., Animals: 5 adult llamas (3 males, 2 females) with mean +/- SD body weight of 135 +/- 17.7 kg., Procedure: After anesthesia induction with propofol (2 mg/kg of body weight, IV), llamas received either propofol infusion 0.2 mg/kg/min (group 1) or 0.4 mg/kg/min (group 2) for 60 minutes. Measurements, taken before anesthesia induction and at regular intervals during infusion were: direct blood pressures, heart and respiratory rates, cardiac output, and arterial blood gas tensions. Systemic and pulmonary vascular resistance, cardiac and stroke indices, and plasma bicarbonate and base excess concentrations were calculated., Results: At 3 to 60 minutes after either dosage of propofol, PaCO2 and heart rate increased in all llamas; at the same time, PaO2 and arterial pH decreased. Mean pulmonary artery and central venous pressures, and stroke index decreased at 3 to 60 minutes after either dosage of propofol. Mean arterial pressure decreased at 30 to 60 minutes after infusion of 0.4 mg of propofol/kg/min; pulmonary arterial wedge pressure decreased at 20 to 40 minutes and 3 to 60 minutes after infusion of 0.2 and 0.4 mg of propofol/kg/min, respectively. Mean time from termination of infusion to sternal recumbency was 7 (group 1) and 13 (group 2) minutes. Standing was achieved in a mean 11 (group 1) and 22 (group 2) minutes., Conclusion: Propofol infusion rate of 0.2 mg/kg/min was considered too low to maintain a suitable depth of anesthesia, but 0.4 mg/kg/min was considered sufficient for noninvasive procedures with minimal cardiopulmonary depression.

Objective: To evaluate use of fluprostenol, dexamethasone, and oxytocin for induction of parturition in alpacas, and to determine viability of the newborn crias., Design: Prospective, randomized, controlled trial., Animals: 36 pregnant alpacas within 10 days of parturition., Procedure: Animals were randomly assigned to treatment groups. Plasma progesterone and plasma and urine estrone sulfate concentrations were measured for 5 days after treatment. Clinical signs of the neonates were determined., Results: Time between treatment and parturition was significantly shorter for animals that received fluprostenol than for animals in any other group. The highest dose of dexamethasone (0.5 mg) caused fetal death. None of the other treatments induced early parturition. Time between birth and first suckling, body weight, rectal temperature, pulse rate, and respiratory rate at birth and serum IgG concentration 24 hours after birth were not different between crias born after fluprostenol treatment and crias born to control alpacas., Clinical Implications: Fluprostenol was effective at inducing parturition in these alpacas, but dexamethasone and oxytocin were not. Crias born after fluprostenol treatment were similar to crias born to control alpacas.

Objective: To determine concentrations of estrone sulfate in serum, estrone sulfate in urine, relaxin in serum, and progesterone in serum in pregnant llamas and alpacas and to assess the potential of these hormones as pregnancy indicators., Design: Prospective study., Animals: 19 parous pregnant camelids (8 llamas and 11 alpacas)., Procedure: Estrone sulfate concentrations (in serum and in urine) and progesterone concentrations (in serum) were determined by enzyme immunoassay. Relaxin concentrations (in serum) were measured by radioimmunoassay. Serum and urine samples were collected daily for the first 30 days after breeding and, thereafter, once weekly until parturition., Results: Estrone sulfate concentrations (in serum and in urine) peaked twice during pregnancy. The first took place 21 days after breeding and the second during the last month of pregnancy. Relaxin concentrations increased at 3 months of gestation to > 20 ng/mL, decreased at 5 months to 5 ng/mL, then increased from 8 months of pregnancy until parturition. Progesterone concentrations were detectable 4 days after breeding and were maintained > 2 ng/mL throughout pregnancy., Clinical Implications: The first increase in estrone sulfate concentration over basal values may indicate early interaction between mother and embryo, whereas the second increase may reflect fetal viability. Use of estrone sulfate concentration to diagnose pregnancy in llamas and alpacas is highly dependent on time of sampling. Relaxin concentration in serum is a superior indicator of pregnancy after the second month in the Ilama and alpaca because its existence is suggestive of interaction between mother and fetus, and concentrations are greater than basal values for a long period of pregnancy. Progesterone is not a direct product of the embryo or fetus and only indirectly confirms a diagnosis of pregnancy.

Objective: To compare the strength of the sutured linea alba, in vitro, using 2 suture patterns., Animals: 12 clinically normal llamas., Procedure: 2 incisions in the linea alba of 12 llamas were closed with a simple continuous or inverted cruciate pattern, and tissue was harvested after 10 days. In 6 llamas the simple continuous line was intact; the inverted cruciate specimens contained 6 sutures. In 6 llamas, 1 knot was excised in the simple continuous pattern to simulate a failed line; the cruciate pattern contained 5 knots. Tissue sections were taken from cranial, between, and caudal to the linea alba incisions to compare fascial thickness. The sutured specimens were mounted in a mechanical testing system and tested to failure. A mixed-model ANOVA was used to evaluate the effects of suture pattern and incisional position on mechanical properties., Results: Significant differences were not found between suture patterns or between location for yield force, failure force, or yield strain, whereas failure strain was lower for the intact simple continuous pattern than the inverted cruciate pattern (P = 0.003). From histomorphometric analysis, the caudal tissue specimens were significantly thinner than the middle tissue specimen cranial to the umbilicus (P = 0.006)., Conclusion: There was no significant difference in monotonic breaking strength of the linea alba sutured with the simple continuous or inverted cruciate pattern., Clinical Relevance: These results justify the use of the simple continuous pattern over the cruciate pattern for ventral midline closure in llamas because of the ease of placement and speed.

Adult male guanacos were immobilized by use of tiletamine/zolazepam. The effective dosage (mean +/- SD) was 5.0 +/- 1.1 mg/kg of body weight. Mean time from injection to immobilization was 7.3 minutes. Usually, immobilization was of sufficient duration (mean, 61 minutes) to allow guanacos to be weighed, measured, and to have ear tags inserted and blood samples collected. Adverse effects included twitching and rigidity of muscles, salivation, chewing movements, retching, vocalization, and stumbling during the recovery phase. All guanacos recovered without apparent complications.

Blood samples were obtained from each of 30 llamas: 22 females that had been exposed to a male and were assumed to be pregnant (gestational stage, 2 to 244 days), 1 female that had not been exposed to a male, 3 sexually intact males, 1 castrated male, and 3 females with congenital reproductive anomalies. Serum was tested for the presence of pregnancy-specific protein B, using a radioimmunoassay that accurately detected pregnancy in cattle, sheep, and other ruminants. Pregnancy-specific protein B was not detected in the serum of the 30 llamas. On the basis of our results, the radioimmunoassay for pregnancy-specific protein B cannot be used in llamas for detection of pregnancy.

Indices of renal function and damage were measured in 12 healthy male adult llamas fed a diet of mixed alfalfa/grass hay (mixed hay) and water ad libitum. Using a collection bag fitted over the preputial area, urine samples were collected at 6, 12, and 24 hours. Serum samples were obtained concurrently to determine endogenous creatinine clearance (CL), total (TE) and fractional excretion (FE) of electrolytes (Na, K, Cl, P), electrolyte CL, urine and serum osmolality, urine enzyme activities (gamma-glutamyltransferase and N-acetyl-beta-D-glucosaminidase), and urine protein concentration. Urine production was quantified. Three months later, 10 of the 12 llamas were fed a grass hay diet and water ad libitum. Similar samples were obtained, and similar measurements were made. Urine production was higher when the llamas were fed the mixed hay diet. Total urine volume for llamas fed mixed hay ranged from 628 to 1,760 ml/24 h, with a median of 1,307.5 ml/24h, compared with a range of 620 to 1,380 ml/24 h and a median of 927.50 ml/24h for llamas fed grass hay. Median urine osmolality was higher in llamas fed mixed hay (1,906 mOsm/kg of body weight, with a range of 1,237 to 2,529 mOsm/kg), compared with llamas fed grass hay (1,666 mOsm/kg with a range of 1,163 to 2,044 mOsm/kg). Creatinine CL did not vary significantly over time for either diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidural analgesia was achieved at weekly intervals in 6 adults llamas by injection of 2% lidocaine, 10% xylazine, and a combination of 2% lidocaine/10% xylazine at the sacrococcygeal junction. Analgesia was determined by lack of response to pin prick or hemostat pressure in the perineal area. Ataxia could not be accurately evaluated because of the llamas' tendency to assume sternal recumbency when restrained. Time to onset of analgesia was not different between lidocaine (3.16 +/- 0.31 minutes) and lidocaine/xylazine (3.50 +/- 0.56 minutes), but results for both groups were different than those for xylazine (20.67 +/- 3.37 minutes). Duration of analgesia was different among all groups (lidocaine, 71.0 +/- 6.15 minutes; xylazine, 186.83 +/- 14.86 minutes; lidocaine/xylazine, 325.83 +/- 29.39 minutes). Mild sedation developed in 4 llamas given xylazine alone. Lidocaine/xylazine caused mild sedation in 2 llamas and moderate sedation in 1 llama. Significant changes in pulse or respiratory rates were not observed among drugs, but changes were observed over time with all drugs. As has been reported in other species, lidocaine/xylazine provided rapid onset and prolonged duration of analgesia.

Five castrated male llamas (mean body weight, 94 kg) were studied in an energy balance trial to determine maintenance energy requirement of llamas. Llamas were fed a 50% oat hay-50% pelleted concentrate diet (2.43 Mcal of metabolizable energy/kg of diet dry matter) at approximately 1.6% of body weight (BW). An 8-day total collection digestion trial was used to determine fecal and urine energy losses. Heat production and methane emissions were determined via indirect respiration calorimetry measurements on each llama fed at the same level of intake as during the digestion trial and subsequently on days 3 and 4 of a period of nonfeeding. Fecal, urine, and methane energy losses of the llamas fed near-maintenance intake were 32.5, 3.5, and 7.1% of gross energy intake, respectively. The postabsorptive metabolic rate, commonly called nonfed (fasting) heat production, was 59.3 kcal/BW0.75. Using a linear relation between postabsorptive and maintenance energy requirement and efficiency of energy use below maintenance of 0.702, metabolizable energy requirement at maintenance was determined to be 84.5 kcal/BW0.75.

A method of intra-abdominal vasectomy (deferentectomy), using a laparoscopic technique in llamas and alpacas, was evaluated. Food was withheld from 14 animals for 24 hours before sedation and laparoscopy. The ductus deferens was located close to the bladder, and a 2- to 3-cm section of ductus deferens was resected with the aid of a pair of hook scissors. The procedure was completed in 5 to 8 minutes, and animals did not have any adverse effects. Forty-five days after vasectomy, animals were used for detecting sexually receptive females or inducing ovulation during reproductive physiologic studies. The procedure did not impair libido and had no effect on male sexual behavior for many years. The technique is simpler, safer, and faster than the traditional external approach.

A laparoscopic technique was used to observe in situ the ovaries of llamas and alpacas. Use of this technique results in minimal surgical stress and allows repetitive observation of various reproductive stages in the same animal. Ovarian follicular activity before and after breeding, time of ovulation, corpus luteum formation and regression, early embryo death, failure of ovulation, and the early events of pregnancy can be assessed quickly and safely. For 1,291 laparoscopies performed, postsurgical disturbance was not observed, and animals were released from the clinic 1 hour after laparoscopy.

For each of 3 separate evaluations, 6 fasted llamas (Lama glama) were sedated with xylazine (1.1 mg/kg of body weight, IV) and then 15 minutes later were given normal saline solution (5.0 ml, IV; control values), doxapram (2.2 mg/kg, IV), or 4-amino-pyridine (0.3 mg/kg, IV) and yohimbine (0.125 mg/kg, IV). After administration of 4-aminopyridine and yohimbine, the llamas stood in a mean of 11 minutes and resumed eating in a mean of 34 minutes; both means were significantly less (P less than 0.05) than control values (46 minutes and 67 minutes, respectively). Doxapram induced muscle fasciculations, and (compared with control values) did not significantly decrease the time to standing (41 minutes) or the time until the animals resumed eating (68 minutes). Yohimbine and 4-aminopyridine in combination rapidly antagonized xylazine-induced sedation in llamas, whereas doxapram was ineffective as an antagonist of xylazine-induced sedation.