| Funded Research | Back to Research |
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Completed Studies |
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Ovulation-inducing factor in alpaca semen Gregg P. Adams, DVM, PhD. Western College of Veterinary Medicine, University of Saskatchewan, CANADA Camelids have been categorized as induced ovulators and present dogma suggests that physical stimulation during copulation is primarily responsible for eliciting ovulation. Recent discoveries, however, challenge this dogma. The project focuses on the isolation and characterization of an ovulation-inducing factor (OIF) present in the seminal plasma of camelids. The factor was initially reported in Bactrian camels, but has not been documented in any other species. Studies were conducted to document the existence of an OIF in the seminal plasma of alpacas and llamas. In Experiment 1, female alpacas were given alpaca seminal plasma or saline intramuscularly or by intrauterine infusion. Only alpacas that were given seminal plasma intramuscularly ovulated (93%). In Experiment 2, ovulation was detected in 90% llamas at a mean of 29 hours after seminal plasma treatment. Plasma progesterone concentrations were maximal 9 days after treatment and back to minimum at 12 days after treatment. In Experiment 3, females were given seminal plasma, GnRH (positive control), or saline (negative control), and ovulation was detected in 100%, 83% and 0% in the respective groups. Blood samples taken every 15 minutes for 8 hours after treatment revealed that seminal plasma caused circulating luteinizing hormone (LH) to become elevated within 1 hour and remain elevated for over 8 hours. Compared to the GnRH group, the corpus luteum (CL; progesterone-producing gland in the ovary necessary for maintenance of pregnancy) grew larger and plasma progesterone concentration was twice as high in the seminal plasma group. Results show, for the first time, that a potent ovulation-inducing factor is present in the semen of alpacas and llamas. Treatment-induced ovulation was associated with a surge in circulating concentrations of LH and enhancement of CL form and function. The existence and nature of this factor has direct implications on fertility, infertility, breeding management, and commercial development of therapeutic drugs for alpacas. The evolutionary conservation of such a factor raises the possibility of its existence in other induced and spontaneously ovulating species; hence, the characterization of OIF in the seminal plasma of alpacas may have much broader implications. Further studies are being conducted to isolate and characterize the chemical in semen of alpacas and to determine if it is present in other species. Publications as a result of Alpaca Research Foundation funding: Adams GP, Ratto MH, Huanca W, Singh J (2005) Ovulation-inducing factor in the seminal plasma of alpacas and llamas. Biology of Reproduction 73:452-457. Ratto MH, Huanca W, Huanca T, Singh J, Adams GP (2004) Ovulation-inducing factor in seminal plasma: species comparison and molecular weight determination. Proceedings of the annual meeting of the Society for the Study of Reproduction, Vancouver, BC August 2004, Abstract 181. Adams GP, Ratto MH, Singh J (2004) Ovulation-inducing factor in the seminal plasma of llamas. International Congress on Animal Reproduction, Porto Seguro, Brazil August 2004, p 217. Ratto MH, Huanca W, Singh J, Adams GP. (2005). Effect of OIF on ovulation rate and luteal development in llamas. 1st Annual Reproductive Science and Medicine Research Symposium. March 3, 2005, p 18. (Best basic science paper, 2nd Place)
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Expression of matrix metalloproteinases in CSF fluid of Alpacas with Meningeal worm: Role in pathophysiology of neurologic deficits. Jeffrey Lakritz, DVM, Ph.D. ,The Ohio State University Paralytic spinal cord/brain meningeal worm infection in South American Camelids remains an important problem in spite of studies evaluating deworming agents and vaccines. Great clinical progress has been achieved in some animals while mortality remains high. This proposal aims to study one aspect of the inflammatory response associated with meningeal worm infections in hopes of identifying new treatment modalities. The proposed work focuses on the host inflammatory response to parasite migration in nervous tissue and associated expression of tissue degrading enzymes (matrix metalloproteinases ) in CNS tissue. Detailed info rmation about key events in the inflammatory response will allow development of new strategies to treat this devastating disease. We will evaluate the spinal fluid from documented meningeal worm cases in comparison to control CSF samples obtained from healthy animals to define the expression and activity of host proteolytic enzymes. We will characterized the CSF expression of host proteins to determine their activity and inhibitor specificity. In vitro studies evaluating protease inhibitors will provide data needed for determination of suitable pharmacologic candidates to treat this disease. |
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Development of microsatellite DNA markers
for gene mapping of alpacas and Llamas
Synteny Mapping of Coding Genes in New World
Camelids
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| Effects of
Insulin on Glucose Clearance and Hydrocortisone-Mediated Hyperglycemia in Alpacas Dr. Christopher Cebra American Journal
of Veterinary Research These researchers were following up on the observation that alpacas and llamas tend to have modest elevations of sugar in their blood. They took 5 female and 5 gelded male alpacas, withheld food for 12 hours and then gave them an injection of a sugar directly into the blood stream. They made two important observations. First, sugar stayed high in the blood of alpacas and llamas for a longer period of time than in other species. Second, alpacas and llamas did not secrete insulin in response to the injection of sugar. Insulin secretion is a normal response to an elevation of blood sugar and if it is lacking it indicates an abnormality in the way sugar is metabolized. The failure of alpacas and llamas to quickly remove sugar from the bloodstream means they can’t use sugar efficiently to fuel various metabolic processes. Even more of a concern, it means that llamas and alpacas may be prone to diabetic like disorders when exposed to an abundance of sugar. Effects of hydrocortisone on substrates of energy metabolism in alpacas.
American Journal of Veterinary Research 63: 1269-1274, 2002
Effects of Exogenous Insulin on Glucose
Tolerance in Alpacas American Journal of Veterinary Research. 62(10):1544-7, 2001 Oct.
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Using objective measurements to identify superior characteristics of U.S. huacaya alpaca and assist in making long-term breeding decisions. Angus McColl, C. J. Lupton, and R. H. Stobart, 1 Yocom-McColl Testing Laboratories, Inc., Denver, Texas A & M University System, San Angelo, and University of Wyoming, Laramie. A study was conducted to establish a comprehensive profile of U.S. huacaya alpaca fiber characteristics that will be useful for educational, promotional, policy, selection, and breeding purposes. Specifically, the ranges, means, and distributions of all important fiber characteristics and body weights of U.S. alpacas were measured and calculated using internationally accepted objective test methods. Animals in specified age ranges and of known sex representing six geographical regions in the U.S. were weighed and sampled in approximate proportion to their population density in the respective regions. Fiber samples were shorn from the mid-side of six hundred and six alpacas representing female, male, and castrated male registered animals in the three age categories: one- and two-year-old and adult, and then sent to the commercial testing laboratory. Each sample was measured for average fiber diameter (and SD and CV), comfort factor, average fiber curvature (and SD and CV), medullation (white and light fawn samples only), lab scoured yield, average staple length (and SD and CV), staple strength, position of break, resistance to compression, color differences (colored samples) and brightness and yellowness (white samples).Summary statistics are presented in Table 1. In addition, data were analyzed (results to be presented in a refereed journal article) in terms of sex, age, region, color, and their interactions. Funding by the Alpaca Research Foundation is gratefully acknowledged. Table 1. Summary data for
properties measured on
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| Determination of a Periparturient
Rise in the Excretion of Giardia Cysts and Nematode Eggs
in South American Camelids Lora R Ballweber, DVM Sheep, llamas, and alpacas share a wide variety of gastrointestinal nematode parasites. In sheep, some adult animals lose immunity to their worms around the time of parturition and during lactation. When this happens, worms they have ingested during grazing can easily mature and lay eggs. These eggs are then passed with the feces of the animal onto pasture. Many worms laying eggs at the same time results in relatively high, persistent fecal worm egg counts and massive pasture contamination. This, in turn, increases the chance of parasite transmission to the lambs. To control this, anthelmintic treatment of the dam is often needed at or near parturition. It has not been clear if this increased fecal worm egg shedding occurs in llamas/alpacas. Therefore, to investigate this, the effect of date of parturition on changes in fecal nematode egg counts was evaluated. No increased shedding of eggs was detected. This indicates that parasite control programs for llamas/alpacas may not need to include anthelmintic treatment at or near parturition in contrast to those programs designed for sheep. |
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| Molecular
Diagnostics-Mycobacterial
Diseases in Alpacas Dr. Robert Whitlock Alpacas are susceptible to mycobacterial infections causing Johne's disease. Affected alpacas can gradually lose weight despite a good appetite. The affected animal can become so weak it cannot rise. These mycobacterial infections localize in the intestinal tract to reduce nutrient absorption due to a thickened intestinal lining resulting in hypoproteinemia (low blood protein). Many of these mycobacteria are difficult to grow in the laboratory. If they do grow it can take weeks or months to be able to identify them. This research project aims to develop a PCR-DNA based test to detect these types of bacteria in a few days. One of the major obstacles in developing these tests has been the presence of PCR (test) inhibitors in fecal samples that prevent the detection of mycobacteria. Our laboratory has developed a technique to counteract these inhibitors and allows the detection of the mycobacteria present in the fecal sample. At the present time the PCR test is less sensitive than the fecal cultures. By using methods to concentrate the mycobacteria, we are hopeful to have a PCR test that is more sensitive than the most sensitive fecal culture method now available. During the development of this new molecular diagnostic test if veterinarians or alpaca owners suspect Johne's disease, or other mycobacterial diseases in alpacas, they may submit samples to our laboratory for diagnostic testing at substantially reduced cost. These samples will help in the test development. For more information aboutmycobacterial disease or Johne's disease call (610) 444-5800 ext.2321 (Dr. Whitlock's office) or Terry Fyock at (610) 444-5800 ext. 2245 or contact Dr. Robert Whitlock by email at: whitlock@vet.upenn.edu. |
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Assessment of the Effects of Epinephrine and Insulin on Plasma and Serum Biochemical Variables in Llamas and Alpacas. Cebra CK. Tornquist SJ. American Journal of Veterinary Research. 65(12):1692-6, 2004. Abstract 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 males). 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 time points. RESULTS: Administration of epinephrine induced mobilization of glucose, triglycerides, nonesterified fatty acids, and beta-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 of triglycerides. 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.
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Assessment of the Effects of Exogenous Long-acting Insulin on
Glucose Tolerance in Alpacas.
American Journal of Veterinary Research. 65(12):1688-91, 2004. Abstract 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% NaCI) 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 insulin-treated 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.
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Pharmacokinetics After Intravenous, Subcutaneous, and Oral Administration of Enrofloxacin to Alpacas. Gandolf AR. Papich MG. Bringardner AB. Atkinson MW. American Journal of Veterinary Research. 66(5):767-71, 2005. Abstract OBJECTIVE: To determine plasma concentrations of enrofloxacin and the active metabolite ciprofloxacin after p.o, s.c., and i.v. administration of enrofloxacin to alpacas. ANIMALS: 6 adult female alpacas. PROCEDURE: A crossover design was used for administration of 3 single-dose treatments of enrofloxacin to alpacas, which was followed by an observational 14-day multiple-dose regimen. Single-dose treatments consisted of i.v. and s.c. administration of injectable enrofloxacin (5 mg/kg) and p.o administration of enrofloxacin tablets (10 mg/kg) dissolved in grain to form a slurry. Plasma enrofloxacin concentrations were measured by use of high-performance liquid chromatography. The multiple-dose regimen consisted of feeding a mixture of crushed and moistened enrofloxacin tablets mixed with grain. Behavior, appetite, and fecal quality were monitored throughout the 14-day treatment regimen and for 71 additional days following treatment. RESULTS: Mean half-life following i.v., s.c., and p.o. administration was 11.2, 8.7, and 16.1 hours, respectively. For s.c. and p.o administration, mean total systemic availability was 90.18% and 29.31%, respectively; mean maximum plasma concentration was 3.79 and 1.81 microg/mL, respectively; and area under the curve (AUC) was 50.05 and 33.97 (microg x h)/mL, respectively. The s.c. or p.o administration of a single dose of enrofloxacin yielded a ratio for AUC to minimum inhibitory concentration > 100 for many grampositive and gram-negative bacterial pathogens common to camelids. Conclusions and Clinical Relevance-The administration of enrofloxacin (5 mg/kg, s.c., or 10 mg/kg, p.o) may be appropriate for antimicrobial treatment of alpacas.
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Pharmacokinetics and Bioavailability of
Trimethoprim-sulfamethoxazole in Alpacas
Journal of
Veterinary Pharmacology & Therapeutics. 25(5):321-7, 2002. The pharmacokinetics and bioavailability of trimethoprim-sulfamethoxazole (TMP-SMX) were studied in six healthy male-castrate alpacas (Lama pacos) after intravenous (i.v.) or oral (p.o.) drug administration of 15 mg/kg TMP-SMX using a crossover design with a 2-week washout period. After 90 days one group (n = 3) was given a p.o. dose of 30 mg/kg TMP-SMX and the other group (n = 3) was given a p.o. dose of 60 mg/kg TMP-SMX. After i.v. administration of 15 mg/kg of TMP-SMX the mean initial plasma concentration (C0) was 10.75 +/- 2.12 microg/mL for trimethoprim (TMP) and 158.3 +/- 189.3 microg/mL for sulfamethoxazole (SMX). Elimination half-lives were 0.74 +/- 0.1 h for TMP and 2.2 +/- 0.6 h for SMX. The mean residence times were 1.45 +/- 0.72 h for TMP and 2.8 +/- 0.6 h for SMX. The areas under the respective concentration vs. time curves (AUC) were 2.49 +/- 1.62 microg h/mL for TMP and 124 +/- 60 microg h/mL for SMX. Total clearance (Clt) for TMP was 21.63 +/- 9.85 and 1.90 +/- 0.77 mL/min kg for SMX. The volume of distribution at steady state was 2.32 +/- 1.15 L/kg for TMP and 0.35 +/- 0.09 L/kg for SMX. After intragastric administration of 15, 30 and 60 mg/kg the peak concentration (Cmax) of SMX were 1.9 +/- 0.8, 2.6 +/- 0.4 and 2.8 +/- 0.7 microg/mL, respectively. The AUC was 9.1 +/- 5, 25.9 +/- 3.3 and 39.1 +/- 4.1 microg h/mL, respectively. Based upon these AUC values and correcting for dose, the respective bioavailabilities were 7.7, 10.5 and 7.94%. Trimethoprim was not detected in plasma after intragastric administration. These data demonstrate that therapeutic concentrations of TMP-SMX are not achieved after p.o. administration to alpacas. (MAF study partitially funded by ARF)
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Humoral Response to West Nile Virus Vaccination in Alpacas and
Llamas.
Abstract OBJECTIVE: To determine humoral responses to an equine West Nile virus (WNV) vaccine in healthy alpacas and llamas and compare responses in alpacas and llamas with responses in horses. DESIGN: Clinical trial. ANIMALS: 28 alpacas, 56 llamas, and 16 horses. PROCEDURE: Horses received 2 vaccinations at 4-week intervals, and alpacas and llamas received 3 vaccinations at 3-week intervals. Fifty-five llamas received a fourth vaccination 3 weeks after the third. Blood samples were collected immediately prior to each vaccination, 3 weeks after the last vaccination for alpacas and llamas, and 4 weeks after the last vaccination for horses and tested for virus-neutralizing antibodies. Samples from 29 randomly selected vaccinated llamas were used. RESULTS: None of the animals developed any local or systemic adverse reactions. Four of 28 (14%) alpacas, 4 of 29 (14%) llamas, and 7 of 16 (44%) horses were seropositive 3 (llamas and alpacas) or 4 (horses) weeks after administration of the first vaccination; 27 of 28 (96%) alpacas, 26 of 29 (90%) llamas, and 15 of 16 (94%) horses were seropositive after administration of the second vaccination; and all 28 alpacas and 28 of 29 (97%) llamas were seropositive 3 weeks after administration of the third vaccination. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that vaccination with the equine WNV vaccine is safe in alpacas and llamas. Administration of 3 vaccinations generally resulted in virus-neutralizing antibody titers similar to those observed following 2 vaccinations in horses; however, because it is not known what antibody titer would be protective against clinical WNV disease in alpacas or llamas, we cannot conclude that the vaccine was efficacious.
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Abstract A male alpaca acutely developed signs of anorexia and fever. Within 2 days, neurologic signs (head tremors and asymmetric ataxia) developed. West Nile virus (WNV) infection was considered a primary differential diagnosis on the basis of 6 previous cases on nearby alpaca farms on which animals had similar clinical signs. Four days after the male alpaca became ill, a female alpaca from the same farm developed similar neurologic signs. In addition to anti-inflammatory and supportive treatments, both alpacas received a transfusion of llama plasma with antibodies against WNV Seven days after the onset of clinical signs, the female alpaca had made a full recovery; however, the more severely affected male died. West Nile virus infection was confirmed post mortem by use of reverse transcriptase-polymerase chain reaction assay and immunohistochemical staining.
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| The Contribution of Llama IGG
Subclasses to Immunity
Kenneth H. Roux In addition to the conventional forms of antibodies which are found in all species, llamas possess an unusual form of antibody in their bloodstream that is difficult to detect. The role of these unusual antibodies in protecting llamas against infection is currently unknown. These investigators developed better methods of detecting these antibodies and measuring their levels in blood. This methodology will be used to determine whether these unusual antibodies are important in the response of llamas to vaccines and in the defense against infections. The methodology will also be used to determine how well these antibodies are passed on to newborn crias in the colostrum. Current tests only determine the level of conventional antibodies, or IgG in the cria’s blood. This is definitely a work in progress. Initial funding led to the development of the methodology. But additional studies will have to be conducted before it is known whether these unusual antibodies have an important pathophysiological role in protecting llamas against infection. |
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Mycobacterium
Paratuberculosis (Johne’s Disease) in the Llama Bradford B. Smith Johne’s disease is a serious intestinal disease in the llama and alpaca caused by the bacteria, mycobacterium paratuberculosis and characterized by ill health, chronic weight loss and severe diarrhea. The goals of this study were to establish a) the temporal relationship between infection and shedding of the bacteria in feces (indicator of infectivity), b) the time of onset of clinical symptoms after infection, and c) the development of antibodies to the infection (critical in identification of infected but non-shedding animals).
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Bioavailability and Pharmacokinetics of Oral Omeprazole in Llamas |
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Bioavailability and Pharmacokinetics of Phenylbutazone and Flunixin Meglumine in Llamas Jeffery Musser This was a pharmacokinetic study of two anti-inflammatory agents called phenylbutazone and flunixin meglumine. Anti-inflammatory agents are prescribed for muscle and joint inflammation and pain management. |
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Abstract This study determined the disposition of sulfadimethoxine in six, healthy, adult, gelded male llamas (Llama glama) by using a nonrandomized crossover design with i.v. dosing (58.8 +/- 3.0 mg/kg based on metabolic scaling) followed by oral dosing (59.3 mg/kg +/- 8.3). Blood samples were collected intermittently for a 72-hr period, and serum sulfadimethoxine concentrations were quantified using high-performance liquid chromatography. Serum sulfadimethoxine concentrations across time were subjected to standard pharmacokinetic analysis based on linear regression. Mean maximum serum concentration after oral dosing was 23.6 +/- 14.9 microg/ml, and extrapolated peak concentration after i.v. administration was 246.6 +/- 15.8 microg/ml. Total clearance of sulfadimethoxine was 45.4 +/- 13.9 L/kg. Half-lives after i.v. and oral administration were 541 +/- 111 min and 642.4 +/- 204.8 min, respectively. Oral bioavailability was 52.6 +/- 15%. These data suggest that the oral dose administered to llamas in this study, based on metabolic scaling from cattle, may be inadequate when compared with the reported minimum inhibitory concentration (512 microg/ml) breakpoint for sulfadimethoxine. (MAF study partially funded by ARF).
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Summary of Humoral Response to EEE Vaccination in Healthy Alpacas The EEE vaccine trial ended as planned in mid March, 2006 with final results from the lab received in June. A manuscript describing the detailed findings is in preparation. Dr. Bedenice has agreed that this summary should be provided now, for breeders and their veterinarians to consider. One firm finding was that the vaccine appeared to be safe in the adult males tested, with no adverse reactions reported in any of the subject animals. Just over three quarters of the trial animals developed titers after the three shot series, with the highest number of seropositive animals, and highest mean titers, observed 2 weeks after the third shot. Younger (less than 4 years old) animals in the trial tended to respond “better” than older animals, but the sample size was limited, especially for the older groups. Drs. Bedenice and Bright recommended that farms in high risk areas strongly consider vaccinating in 2006, and several in NH took this advice (including the two farms with all of the animals that developed titers in Fall 2005 from natural exposure). Several hundreds of additional serum samples were privately analyzed for EEE antibodies at NVSL through the summer and fall of 2006. They may be of interest because, unlike the trial, they included pregnant females and neonates. The number of animals was small, and the timing of sample collection could not ensure that additional natural exposure to EEE had not caused antibody responses, so the findings are unlikely to pass peer review. However, I offer them to the community. We resampled the naturally exposed animals several times through late 2005 and up to June of 2006. In all cases where the alpacas had developed titers higher than 1:100 when first sampled in October, 2005 they maintained titers at this level or higher through June, 2006. (Most were then vaccinated to boost their immunity prior to peak mosquito season.) One of the naturally exposed females delivered a healthy cria in late May, the cria had a positive titer (1:100) at 9 days of age (we presume the antibodies came from mom, since it was very early in the year for this animal to have been exposed to the live virus). A total of 29 breeding females and their 2006 cria were vaccinated on the 2 NH farms that owned all of the animals with natural antibodies to EEE in 2005 (these farms were clearly at “high risk”). Ten of the females were relatively advanced in their pregnancies, but none reacted adversely to the 3 shot series. Nine of them delivered healthy full term cria during the summer and fall (the tenth lost a breech delivery at term). Results of PRNT on serum samples collected 3.5 to 4.5 months after the first shot (for animals that were negative in fall 2005) were broadly similar to the formal trial. Overall, 65% of the vaccinated animals developed titers and maintained them at least until they were sampled about 2 months after final booster. Like the males in the trial, measurable responses (titers) were less common, and lower when found at all, in the oldest girls. Neonates (first shot given 3-5 weeks post partum) as a group also responded poorly, compared both to the young boys in the trial and the younger breeding girls in their herds. The cria that had the presumed natural titer, transferred from mom, at 9 days of age tested negative at 6 months of age, despite receiving a 4-shot vaccination series. Pat Long, DVM and ARF treasurer, speculates that the maternal antibodies may be antagonistic to the vaccine, and recommends waiting till 3 months of age before vaccinating crias, especially if mom is known to be seropositive.
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Hematology of Camelids INTRODUCTION In the last 20 years there have been a few reviews of camelid clinical pathology (Veterinary Clinics of North America: Food Animal Practice, 1989, 1994) outlining the ways in which they are similar to other mammals as well as some unique features of these animals. We continue to learn more about camelid hematology in general as well as some ways in which alpacas and llamas differ. Erythrocytes In addition to the elliptical shape of camelid erythrocytes, other morphologic differences are seen in normal animals. In many camelids, a small to moderate number of hemoglobin crystals are present. These darkly eosinophilic, rhomboid-shaped structures are easily identifiable and appear to have no clinical significance. Occasional camelid erythrocytes have one or more elongated, pointed extensions of their cytoplasm which extend from one or both ends (often called dacryocytes, referring to a tear-drop shape). These are rare in normal camelids, but may occur in high numbers in camelids with severe anemia of a variety of etiologies. Because of the small size and unique shape of camelid erythrocytes, laboratories may have to adapt their techniques when counting them. Manual methods (eg, Unopettes and hemacytometers) are accurate, but if automated instruments are used, threshold settings on these instruments must be adjusted for llama erythrocytes. Single-channel electronic counters with threshold set at 5-8 fl appear to be the most appropriate instruments for counting llama erythrocytes. This low threshold setting allows detection of microcytic erythrocyte populations while excluding most platelets from being counted as erythrocytes. Indices derived from multichannel analyzers may be inaccurate if calibration adjustments are not made. In general, hematocrit and hemoglobin methods which are valid in other species work well with llama blood. Anemia
Moderate to
severe anemia is a relatively
common problem in alpacas presented to referral institutions and in
those seen in private practices. The anemia is, at times, unexplained,
and can be very debilitating. As with other species, it’s important to
try to classify an anemia in order to determine the underlying cause and
possible treatment. Classification of anemia as regenerative or
non-regenerative is particularly helpful in looking to the bone marrow
(if non-regenerative) or elsewhere (if regenerative) as the cause of
anemia. This is made more difficult in camelids, by the fact that they
appear to have more unpredictable regenerative responses to anemia than
some other species. Oxyglobin study With funding from the Alpaca Research
Foundation, we performed a small clinical trial to determine any
possible adverse effects of polymerized ultrapurified bovine hemoglobin
(PUBH) blood substitute in alpacas. Our overall hypothesis was:
Administration of PUBH to anemic,
normovolemic alpacas will result in improved clinical and hemodynamic
parameters without adverse effects on hemostatic, renal, or liver
parameters. The questions we
hoped to answer with this study were:
1) whether adverse effects are seen with administration of PUBH to
anemic alpacas, 2) whether there is an improvement in clinical and
laboratory parameters in these alpacas and 3) whether PUBH works
significantly better than hetastarch, a colloid plasma expander, in
normalizing these parameters. Mycoplasma haemolamae
An effective antibiotic
treatment that consistently clears M. haemolamae infection
(including the carrier state) has not been proven. Injectable and oral
enrofloxacin and injectable florfenicol did not show any efficacy in
controlled studies. Injectable oxytetracycline given subQ every 3rd
day for 5 treatments shows the most efficacy in clearing detectable
organism, but does not usually totally clear the carrier stage. There is
no scientific evidence to show that feeding tetracycline-treated feed or
pellets would be equally or more effective in clearing infection. REFERENCESGarry F, Weiser MG, Belknap E. Clinical Pathology of Llamas in Vet Clin N America: Food Animal, 1994. Garry F. Clinical Pathology of Llamas in Vet Clin N America: Food Animal, 1989. Morin DE, Garry FB Weiser MG. Hematologic responses in llamas with experimentally induced iron deficiency anemia. Vet Clin Pathol. 22:3, 81-86, 1993. Morin DE, Garry FB, Weiser MG, et al: Hematologic features of iron deficiency anemia in llamas. Vet Pathol 29: 29: 400-404,1992. Tornquist SJ, et al Vet Path 2002. 39: 616. |
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Development of a Teaching Model for Venipuncture
and A model was developed for teaching atraumatic venipuncture and
intravenous catheter placement to veterinary students, technicians and
practitioners. A prototype was demonstrated at the 2007 AOBA conference
in Louisville, Kentucky and many alpaca breeders had an opportunity to
use the model to practice venipuncture. The final model design has two
components, a rigid procedural one and a visual reference one. The
reference component shows the topographical anatomy of the head and neck
as well as the anatomy of soft tissues beneath the skin of the ventral
neck and osteology of one side of the skull. The two part model is
available for purchase. |
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Pilot Study: Application of Bovine Genomic Tools to Genome Mapping
in Llama/Alpaca Researchers used two genetic tools to identify similarities between
the llama and alpaca genomes and the bovine genome. They learned that
the genomes have many features in common, making the bovine whole genome
sequence a valuable research tool in studying genetic issues of llamas
and alpacas. That said, genome-specific resources are still needed for
both the llama and alpaca. |