[Show abstract][Hide abstract] ABSTRACT: Plasma concentration time curves following intravenous (i.v.) administration of 1.5 mg/kg of ranitidine, 0.2 mg/kg, 0.4 mg/kg and 0.8 mg/kg of omeprazole, respectively, were analysed in six llamas. Plasma profiles after i.v. administration of both drugs showed plasma concentrations declining in a biexponential manner with a rapid distribution phase. Pharmacokinetics parameters after ranitidine administration to six llamas showed a mean elimination half-life of 1.53 +/- 0.26 h. The mean volume of distribution (Vdss) in llamas was 1.77 +/- 0.31 L/kg, and mean body clearance in llamas was 0.778 +/- 0.109 L/kg/h. Ranitidine produced only a small transitory (<1 h) decline in acid production when administered i.v. at a dose of 1.5 mg/kg. Omeprazole showed dose-dependent nonlinear pharmacokinetics. The mean half-life of 0.2 mg/kg i.v. omeprazole was shorter than that of 0.4 and 0.8 mg/kg i.v. omeprazole, i.e. 0.61, 0.72 and 1.07 h, respectively. The area under the curve (AUC) and mean residence time (MRT) increased with increasing dose, while clearance decreased as dose increased. The decline in acid production following 0.2 mg/kg i.v. omeprazole was highly variable and did not produce a clinically useful suppression of third compartment acid production. In contrast, both 0.4 mg/kg and 0.8 mg/kg omeprazole i.v. administration significantly reduced third compartment acid production. The reduction in acid production following 0.8 mg/kg omeprazole was not significantly greater than the reduction observed following 0.4 mg/kg dosage. Misoprostol (10 microg/kg) was administered i.v. in an absolute alcohol solution. Two animals collapsed following drug administration. While the side-effects could have been produced by either misoprostol or the alcohol vehicle, the clinical changes were more consistent with an adverse drug reaction. Unfortunately, the limitation of UV detection did not provide the sensitivity needed to quantify the amount of misoprostol in llama plasma, and the pharmacokinetics could not be evaluated.
Full-text · Article · Feb 2001 · Journal of Veterinary Pharmacology and Therapeutics
[Show abstract][Hide abstract] ABSTRACT: As part of a larger project investigating the development and heritability of choanal atresia glama), it was necessary to develop a protocol for aborting llamas at various stages of gestation. Twenty-seven animals between 4 and 7 mo of gestation were successfully aborted a total of 53 times following two 250 microg intramuscular injections of cloprostenol at 24 h intervals. Abortion was induced once in 10 animals and multiple times (range 2 to 5) in 17 animals. Twenty-four animals (45.2%) aborted 3 d following the first injection, with 20 animals (37.7%) aborting 4 d post prostaglandin administration. Other animals aborted at 2 d (n=6, 11.3%), 5 d (n=2, 3.8%), and 7 d (n=1, 1.9%) following drug administration. Forty-nine (92.5%) of the abortions occurred following a single series of injections, while 4 animals (7.5%) aborted following a second series of injections. No confirmed pregnant animals failed to abort following the second series of cloprostenol injections. Conception rates in animals rebred 2 to 4 wk following an abortion were comparable to those of untreated animals in the research herd. Unlike the severe hypertension and death that has been reported following dinoprost tromethamine administration in the llama, no adverse reactions were observed in this study following cloprostenol administration. The results demonstrate that llamas can be safely and effectively aborted up to 7 mo of gestation (normal full term gestation = 342 +/- 10 days) without adverse effects on subsequent fertility.
[Show abstract][Hide abstract] ABSTRACT: Paratuberculosis has recently become a concern of the South American camelid (SAC) industry, although the disease is currently uncommon in SACs in North America. In particular, an outbreak in Australian alpacas demonstrated that the pathology and epidemiology of paratuberculosis in camelids and ruminants are similar. Clinical presentation can vary considerably, and the issue of age-related susceptibility to Mycobacterium avium paratuberculosis infection in camelids remains unresolved. All SACs with diarrhea and weight loss should be isolated from other SACs to minimize possible transmission. In addition to investigating the more common parasitic and nutritional causes of diarrhea and weight loss, a complete diagnostic workup should include submitting fecal or tissue samples for mycobacterial culture and tissue biopsies for histopathology. Although serology, histopathology, and other techniques may be rapid screening tools that provide a quick presumptive diagnosis, all results should be confirmed by culture. Llamas and alpacas housed with other hoofstock species are apparently at greatest risk for acquiring paratuberculosis.
No preview · Article · Sep 1999 · Compendium on Continuing Education for the Practising Veterinarian -North American Edition-
[Show abstract][Hide abstract] ABSTRACT: To identify factors associated with hepatic lipidosis (HL) in llamas and alpacas.
Retrospective case series.
30 llamas and 1 alpaca.
Medical records were searched to identify llamas or alpacas in which a histologic diagnosis of HL was made. Information was retrieved on signalment, history, clinical and laboratory findings, and results of necropsy or examination of biopsy specimens. Data were analyzed using descriptive statistics and chi 2 analyses.
Females were affected more often than males; however, the sex distribution was not different from that of the camelid population in the diagnostic laboratory's database. Fifty-four percent of the females were pregnant, and 46% were lactating. Most affected camelids were 6 to 10 years old. Anorexia and recent weight loss were common (51.6% of camelids). An infective agent was found in only one ilama, and toxins and mineral deficiencies were not identified. The most common abnormalities on serum biochemical analysis were a high concentration of bile acids, high activities of gamma-glutamyltransferase (GGT) and aspartate aminotransferase (AST), and hypoproteinemia. Concentrations of nonesterified fatty acids (NEFA) and beta-hydroxybutyrate (beta-HB) were high in those camelids in which these compounds were assayed. Twenty-nine camelids did not survive.
Sick camelids should be considered at risk for developing HL, especially those with anorexia or the metabolic demands of pregnancy and lactation. Other stresses also appear to contribute. High concentrations of NEFA, beta-HB, and bile acids; high activities of GGT and AST; and hypoproteinemia may indicate that HL has developed.
No preview · Article · Jun 1999 · Journal of the American Veterinary Medical Association
[Show abstract][Hide abstract] ABSTRACT: To establish reference values for blood concentrations of total calcium (Ca), inorganic phosphorus (P), iron (Fe), copper (Cu), zinc (Zn), selenium (Se), and vitamin E (Vit E) in clinically normal llamas.
270 llamas ranging in age from < 1 month to > 15 years and grouped by age, sex, pregnancy status, and stage of gestation. Selected llamas were from 21 farms in Oregon, did not have previous health problems, and met specific health criteria on examination.
Serum and blood samples were obtained and analyzed for concentrations of Ca, P, Fe, Cu, Se, Zn, and Vit E, and total iron binding capacity (TIBC) and percentage of transferrin saturation (% Sat). Mean differences by age, sex, pregnancy status, and stage of gestation, as well as all interactions, were compared to establish reference values.
Mean values and reference ranges for most of the minerals and vitamins were similar to previously reported values. Male versus female differences were not identified for any measurements. Age was a significant variable for Ca, P, Fe, and Se concentrations, as well as Ca-to-P ratio and TIBC. Identified age-based effects were modeled by use of linear regression. Copper and Zn concentrations and % Sat did not differ as a function of age. Serum Vit E concentration was influenced by an age by sex interaction and stage of gestation.
Age was found to be an important variable influencing many blood nutrient concentrations in healthy llamas.
Clinical diagnosis of metabolic disease may be improved with use of age-based reference values, especially for neonates.
Full-text · Article · Aug 1998 · American Journal of Veterinary Research
[Show abstract][Hide abstract] ABSTRACT: Fifty clinically healthy llamas, 0.5-13 years of age (22 intact males, 10 neutered males, 18 females), with no biochemical evidence of liver disease or hematologic abnormalities, were selected to establish serum bile acid reference intervals. Serum samples submitted to the clinical pathology laboratory were analyzed using a colorimetric enzymatic assay to establish bile acid reference intervals. A nonparametric distribution of llama bile acid concentrations was 1-23 micromol/liter for llamas >1 year of age and 10-44 micromol/liter for llamas < or = 1 year of age. A significant difference was found between these 2 age groups. No correlation was detected between gender and bile acid concentrations. The reference intervals were 1.1-22.9 micromol/liter for llamas >1 year of age and 1.8-49.8 micromol/liter for llamas < or = 1 year of age. Additionally, a separate group of 10 healthy adult llamas (5 males, 5 females, 5-11 years of age) without biochemical or hematologic abnormalities was selected to assess the effects of feeding and time intervals on serum bile acid concentrations. These 10 llamas were provided fresh water and hay ad libitum, and serum samples were obtained via an indwelling jugular catheter hourly for 11 hours. Llamas were then kept from food overnight (12 hours), and subsequent samples were taken prior to feeding (fasting baseline time, 23 hours after trial initiation) and postprandially at 0.5, 1, 2, 4, and 8 hours. In feeding trials, there was no consistent interaction between bile acid concentrations and time, feeding, or 12-hour fasting. Prior feeding or time of day did not result in serum bile acid concentrations outside the reference interval, but concentrations from individual llamas varied within this interval over time.
Preview · Article · Apr 1998 · Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc
[Show abstract][Hide abstract] ABSTRACT: The disposition of five therapeutic antimicrobial agents was studied in llamas (Lama glama) following intravenous bolus administration. Six llamas were each given ampicillin, tobramycin, trimethoprim, sulfamethoxazole, enrofloxacin and ceftiofur at a dose of 12 mg/kg, 1 mg/kg, 3 mg/kg, 15 mg/kg, 5 mg/kg, and 2.2 mg/kg of body weight, respectively, with a wash out period of at least 3 days between treatments. Plasma concentrations of these antimicrobial agents over 12 h following i.v. bolus dosing were determined by reverse phase HPLC. Disposition of the five antimicrobial agents was described by a two compartment open model with elimination from the central compartment, and also by non-compartmental methods. From compartmental analysis, the elimination rate constant, half-life, and apparent volume of distribution in the central compartment were determined. Statistical moment theory was used to determine noncompartmental pharmacokinetic parameters of mean residence time, clearance, and volume of distribution at steady state. Based on the disposition parameters determined, and stated assumptions of likely effective minimum inhibitory concentrations (MIC) a dose and dosing interval for each of five antimicrobial agents were suggested as 6 mg/kg every 12 h for ampicillin; 4 mg/kg once a day or 0.75 mg/kg every 8 h for tobramycin; 3.0 mg/kg/15 mg/kg every 12 h for trimethoprim/sulfamethoxazole; 5 mg/kg every 12 h for enrofloxacin; and 2.2 mg/kg every 12 h for ceftiofur sodium for llamas. Steady-state peak and trough plasma concentrations were also predicted for the drugs in this study for llamas.
Full-text · Article · Jan 1997 · Journal of Veterinary Pharmacology and Therapeutics
[Show abstract][Hide abstract] ABSTRACT: To evaluate vitamin D concentrations in juvenile llamas and alpacas with hypophosphatemic rickets.
Prospective cohort study.
21 llamas (14 with rickets, 7 clinically normal) and 9 alpacas (6 with rickets, 3 clinically normal).
Blood samples were collected at the time of diagnosis and prior to the initiation of treatment. Serum concentrations of calcium, inorganic phosphorus, and 25-hydroxycholecalciferol (vitamin D3) were determined on all samples. Comparisons were completed for disease status, age, sex, species, month of birth, and all interactions.
Serum concentrations of phosphorus and vitamin D were lower in affected llamas and alpacas than in clinically normal llamas and alpacas, even when mean concentrations were adjusted for age differences. Species (llama or alpaca), sex, and age did not affect any of the metabolite concentrations within this study population. Month of birth influenced vitamin D concentrations and number of affected llamas and alpacas per month. The greatest number of affected llamas and alpacas was identified between January through March, suggesting a seasonal pattern to this syndrome. Treatment of affected llamas and alpacas with vitamin D resulted in increased concentrations of phosphorus and vitamin D. Serum phosphorus concentration was best predicted by 2 independent variables (serum vitamin D concentration and month of birth).
We believe vitamin D deficiency is the primary cause of hypophosphatemic-rickets of growing camelids, and the observed hypophosphatemia is secondary to a primary deficiency of vitamin D. Appropriate treatment with vitamin D supplements can correct hypophosphatemia and vitamin D deficiency in camelids.
No preview · Article · Oct 1996 · Journal of the American Veterinary Medical Association
[Show abstract][Hide abstract] ABSTRACT: The diagnosis of third compartment ulcers in the llama and alpaca is largely one of exclusion. Clinical signs may include mild to severe colic, inappetence, decreased fecal output, bruxism, and depression. Abdominocentesis results are usually unremarkable if C3 perforation has not occurred but reflective of a generalized peritonitis if full thickness ulceration has occurred. The H-2 receptor antagonists cimetidine and ranitidine do not suppress C3 acid production for a significant period of time and are of questionable efficacy in the management of C3 ulcers.
No preview · Article · Aug 1994 · Veterinary Clinics of North America Food Animal Practice
[Show abstract][Hide abstract] ABSTRACT: To provide long-term gastric fistulas for collection of third-compartment gastric contents, Janeway mucosal tube gastrostomy was performed, using a gastrointestinal stapling instrument, in 6 castrated adult male llamas. Mean operative time (+/- SEM) was 65 +/- 4.16 minutes. All llamas survived the 6-week study period. Of the 6 llamas, 5 did not have signs of abdominal pain and returned to preoperative food consumption amounts within 36 hours. One llama had mild intermittent signs of abdominal pain daily for 7 days before returning to preoperative amount of food consumption. All gastrostomies leaked small amounts of gastric contents around indwelling 6- to 8-mm cannulas at the skin surface. Gastric contents did not leak when cannulas were dislodged from gastrostomy stomas. Replacement of cannulas was rapid and easy. Gravity-flow sample collection was best accomplished through 8-mm cannulas. Mean (+/- SEM) weight loss was detected in all llamas (15 +/- 3 kg) and was associated with frequent nonfeeding and stress of sample collection. Gross necropsy findings were unremarkable in 5 of 6 llamas. All mucosal tube gastrostomies were patent, and there was no evidence of peritonitis. One llama had a single fibrous adhesion connecting the operative site with the ascending colon. Histologically, small (2.5- to 15-mm diameter) partial-thickness mucosal erosions identified at the tube gastrostomy-gastric wall junctions may have been associated with indwelling gastric cannulas. The Janeway gastrostomy was generally well tolerated in the llamas and should be considered as a useful long-term fistulation technique.
No preview · Article · Mar 1994 · American Journal of Veterinary Research
[Show abstract][Hide abstract] ABSTRACT: Normal growth characteristics of llamas (Lama glama) were evaluated from conception until 1 week after parturition in pregnant females (study 1) and from 1 month after birth to maturity (study 2). In study 1, pregnant multiparous llamas (n = 10) were measured at monthly intervals from conception until 1 week after parturition; in study 2, llamas (n = 270) were measured once. Body weight of pregnant llamas (study 1) did not increase significantly until after the eighth month of pregnancy. Llamas of study 2 reached mature height, length, thoracic circumference, and weight at 18, 24, 36, and 36 months of age, respectively. From 1 month of age to maturity, the growth characteristics of males, nonpregnant females, and females during the first 8 months of pregnancy did not differ. Correlations (r2) between height, length, and thoracic circumference related to body weight for all but the pregnant llamas during the last 3 months of pregnancy were 0.822, 0.834, and 0.948, respectively. The equation describing thoracic circumference as a predictor of body weight was: Weight (kg) = (1.005 x 10(-3)) x circumference (cm)2.424.
No preview · Article · May 1992 · Journal of the American Veterinary Medical Association
[Show abstract][Hide abstract] ABSTRACT: A syndrome characterized by anemia, erythrocyte dyscrasia, low body weight, and hypothyroidism was observed in 8 llamas (Lama glama). At initial examination (1 to 23 months of age; median, 7.5 months), llamas (3 males, 5 females) were markedly underweight (29 to 55 kg; median, 36 kg) and anemic (PCV, 12.9 to 25.5% [median, 19%]). Five of the llamas became progressively more anemic over time; in 2 of them, PCV decreased to less than 10%. Erythrocyte changes included severe poikilocytosis, anisocytosis, asymmetric distribution of hemoglobin within the cytoplasm, and cytoplasmic extensions from one or both poles. Six llamas had moderate to severe valgus deformities of the carpus. All llamas had low baseline serum thyroxine concentration and diminished response to thyrotropin administration. Baseline and post-thyrotropin triiodothyronine concentrations did not have consistent patterns. Five llamas were hypophosphatemic and 7 had low serum iron concentration (iron concentration was not determined in 1 llama). Orally administered iron supplementation did not induce clinical improvement. Because 3 of the affected llamas were full sisters, a genetic basis for the problem has to be considered. It was not possible to evaluate the familial relationship of the other 5 affected llamas. Although the underlying cause of the problem was not established, the prognosis for affected llamas is guarded to poor.
No preview · Article · Feb 1991 · Journal of the American Veterinary Medical Association
[Show abstract][Hide abstract] ABSTRACT: Previous studies have shown that the generation of cytotoxic T lymphocytes (CTL) following allogeneic tumor challenge is suppressed in Ah-responsive C57Bl/6 mice treated with a single oral dose of the toxic, Ah receptor-binding 3,4,5,3',4',5'-hexachlorobiphenyl (HxCB). The present studies have examined the specific role of the Ah receptor in this immunotoxic response by utilizing HxCB isomers of known, varied affinity for the Ah receptor as well as by comparing effects of high-affinity Ah receptor ligands (3,4,5,3',4',5'-HxCB and 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD]) on the CTL response of mice that differ only at the Ah locus, that is, Ah-responsive (Ahbb) and Ah-nonresponsive (Ahdd) congenic C57Bl/6 mice. Correlative changes in thymic weight, serum corticosterone (CS) levels, and spleen cellularity were also measured. The potency of HxCB congeners (3,4,5,3',4',5'-; 2,3,4,5,3',4'-; 2,4,5,2',4',5'-) and 2,3,7,8-TCDD to suppress the CTL response, to reduce spleen cellularity, to cause thymic atrophy, and to elevate serum CS levels was directly correlated with the binding affinity of the congener for the Ah receptor. Furthermore, these parameters of immunotoxicity in Ahdd C57Bl/6 mice were significantly more resistant to alterations induced by either 3,4,5,3',4',5'-HxCB or 2,3,7,8-TCDD as compared to Ahbb C57Bl/6 mice. These results strongly support an Ah receptor-dependent immunotoxic mechanism in suppression of the CTL response following acute exposure to halogenated aromatic hydrocarbons.
No preview · Article · May 1990 · Fundamental and Applied Toxicology
[Show abstract][Hide abstract] ABSTRACT: Mean (+/- s.d.) pregnancy length for the 14 llamas in this study was 350 +/- 4.5 days. Plasma progesterone concentrations increased by 5 days after mating and remained elevated (greater than 2.0 ng/ml) throughout most of pregnancy. At about 2 weeks before parturition, plasma progesterone concentrations began to decline, dropped markedly during the final 24 h before parturition, and returned to basal concentrations (less than 0.5 ng/ml) by the day of parturition. The combined oestrone + oestradiol-17 beta and oestradiol-17 beta concentrations varied between 6 and 274 pg/ml and 4 and 114 pg/ml, respectively, during the first 9 months of pregnancy. Concentrations increased between 9 months after mating and the end of pregnancy with peak mean concentrations of 827 +/- 58 (s.e.m.) pg oestrone + oestradiol-17 beta/ml (range: 64-1658) and 196 +/- 10 pg oestradiol-17 beta/ml (31-294) during the last week of pregnancy. Concentrations then declined to 87 +/- 14 pg oestrone + oestradiol-17 beta/ml (7-488) and 25 +/- 5 pg oestradiol-17 beta/ml (2.5-142) during the first week post partum. Plasma cortisol concentrations varied between 2.6 and 51.9 ng/ml (14.0 +/- 0.5) from mating until 2 weeks before parturition when the concentrations began to decline. Only a slight increase in plasma cortisol concentrations was observed in association with parturition. Plasma triiodothyronine concentrations varied between 0.5 and 4.5 ng/ml (1.9 +/- 0.1) throughout pregnancy and the periparturient period.(ABSTRACT TRUNCATED AT 250 WORDS)
[Show abstract][Hide abstract] ABSTRACT: This study has characterised the growth patterns of the llama (Lama glama) from birth to 12 months old. Bodyweight growth was described as a function of age. As a means of predicting bodyweight, equations were developed which correlated bodyweight with specific body measurements. Regression analysis revealed a strong positive correlation of logtransformed measurements of thoracic circumference and height with bodyweight. Thoracic circumference (measured in cm) was a good predictor of bodyweight from the equation: bodyweight (kg) = (8.7 x 10(-4)) x circumference2.46 (r2 = 0.91).
No preview · Article · Dec 1989 · The Veterinary record
[Show abstract][Hide abstract] ABSTRACT: Basal serum triiodothyronine (T3) and tetraiodothyronine (T4) concentrations have not been established for the llama (Lama glama). In addition, changes in T3 and T4 concentrations in response to thyroid-stimulating hormone (TSH) administration have not been determined, making clinical evaluation of problems referable to thyroid dysfunction difficult. In study 1, basal T3 and T4 concentrations were determined in serum samples collected from 132 clinically healthy llamas. The llamas were allotted to 3 groups: mature intact or neutered males (group I, n = 25), nonpregnant sexually mature females (group II, n = 21), and pregnant females (group III, n = 86). A mean concentration and a 95% confidence interval were computed for each group. An analysis of variance (ANOVA) indicated that a single confidence interval range (0.45 to 4.18, mean = 1.37 ng T3/ml) adequately defined the normal T3 concentrations for all groups. An ANOVA indicated that the T4 concentrations for the female populations (groups II and III) could be combined with a normal confidence interval range of 39 to 204 ng/ml (mean = 88 ng/ml), whereas a separate range (70 to 220 ng/ml, mean = 124 ng/ml) was determined for the male population. An ANOVA indicated that a single confidence interval range (0.0066 to 0.0321, mean = 0.0146) adequately defined the normal T3/T4 ratio for all groups. In study 2, T3 and T4 concentrations were evaluated in 10 healthy llamas immediately preceding and at 2, 4, 6, 8, and 24 hours after the IV administration of 3 IU of TSH/44 kg of body weight. The T3 and T4 concentrations were significantly higher by 2 hours after TSH administration in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
No preview · Article · Sep 1989 · American Journal of Veterinary Research
[Show abstract][Hide abstract] ABSTRACT: Campylobacter jejuni was inoculated intravenously into pregnant ewes on gestation days 114 and 123 to reproduce ovine abortion. All ewes aborted 7-12 days post-inoculation. High numbers of C. jejuni were isolated from ewe tissues (caruncle, bile, cecal feces), fetal tissues, and placenta. C. jejuni colonies were identified in caruncles and placenta by light microscopy and immunoperoxidase techniques. Histologically, inoculated ewes had a severe purulent endometritis with vasculitis. Placentas from inoculated ewes and field cases showed necrosis and purulent inflammation; however, placentas from inoculated ewes had large numbers of bacterial colonies compared to few bacteria found in field cases. Histologically, only one fetus from the inoculated ewes showed lesions (purulent bronchopneumonia), whereas all fetuses from field cases had a distinct bronchopneumonia, and one fetus showed multifocal hepatic necrosis. These results suggest that C. jejuni (serotypes Penner 1 and Lior 2) is an important abortifacient organism for sheep.
Preview · Article · Oct 1987 · Veterinary Pathology