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Total body water (TBW) in 17 suckling and six lactating llamas was estimated from isotope dilution at three different post natum and lactation stages using both (18)O and deuterium oxide (D(2)O). In total, 69 TBW measurements were undertaken. While TBW in lactating dams, expressed in kilogram, remained stable during the three measurement periods (91.8 +/- 15.0 kg), the body water fraction (TBW expressed in percent of body mass) increased slightly (P = 0.042) from 62.9% to 65.8%. In contrast, TBW (kilogram) in suckling llamas increased significantly (P < 0.001) with age and decreased slightly when expressed as a percentage of body mass (P = 0.016). Relating TBW to body mass across all animals yielded a highly significant regression equation (TBW in kilogram = 2.633 + 0.623 body mass in kilogram, P < 0.001, n = 69) explaining 99.5% of the variation. The water fraction instead decreased in a curve linear fashion with increasing body mass (TBW in percent of body mass = 88.23 body mass in kilogram(-0.064), P < 0.001, R (2) = 0.460). The present results on TBW can serve as reference values for suckling and lactating llamas, e.g., for the evaluation of fluid losses during disease. Additionally, the established regression equations can be used to predict TBW from body mass, providing that the body masses fall inside the range of masses used to derive the equations.

Nitric oxide (NO) and alpha-melanocyte-stimulating hormone (alpha-MSH) have been correlated with the synthesis of melanin. The NO-dependent signaling of cellular response to activate the hypothalamopituitary proopiomelanocortin system, thereby enhances the hypophysial secretion of alpha-MSH to stimulate alpha-MSH-receptor responsive cells. In this study we investigated whether an NO-induced pathway can enhance the ability of the melanocyte to respond to alpha-MSH on melanogenesis in alpaca skin melanocytes in vitro. It is important for us to know how to enhance the coat color of alpaca. We set up three groups for experiments using the third passage number of alpaca melanocytes: the control cultures were allowed a total of 5 days growth; the UV group cultures like the control group but the melanocytes were then irradiated everyday (once) with 312 mJ/cm(2) of UVB; the UV+L-NAME group is the same as group UV but has the addition of 300 microM L-NAME (every 6h). To determine the inhibited effect of NO produce, NO produces were measured. To determine the effect of the NO to the key protein and gene of alpha-MSH pathway on melanogenesis, the key gene and protein of the alpha-MSH pathway were measured by quantitative real-time PCR and Western immunoblotting. The results provide exciting new evidence that NO can enhance alpha-MSH pathway in alpaca skin melanocytes by elevated MC1R. And we suggest that the NO pathway may more rapidly cause the synthesis of melanin in alpaca skin under UV, which at that time elevates the expression of MC1R and stimulates the keratinocytes to secrete alpha-MSH to enhance the alpha-MSH pathway on melanogenesis. This process will be of considerable interest in future studies., ((c) 2010 Elsevier Inc. All rights reserved.)

Two experiments were conducted to determine the effect of estradiol benzoate (EB) and intravaginal progestagen treatment on ovarian follicular dynamics and superstimulatory response in eCG-treated llamas. The purpose of Experiment 1 was to evaluate the effect of EB and progestagen treatment starting at different phases of dominant follicle (DF1) development on regression pattern and subsequent follicle wave emergence (WE2) in lactating and non-lactating llamas. Early lactating (n=24, 30+/-4 days postpartum) and non-lactating (n=24) females were assigned in equal numbers (n=8) to one of three groups according to the phase of DF1 (growing, static or regressing) determined by ultrasonography from day -3 to day 0. At day 0, llamas received an intravaginal sponge (MPA, 150 mg) and 5mg of MPA (i.m.). Half of the females (n=4) of each group were injected with 2mg (i.m.) of EB and half were not (control group). A 2 x 2 x 3 (lactational status, EB treatment and follicular phases) factorial design was used. Each sponge was removed 8 days later. Ovaries were monitored from day 0 to day 12. Daily blood samples were taken to determine 17beta-estradiol (E(2)) profiles from day 0 to day 8. The DF1 regression pattern was not affected (P>0.05) by the phase of follicle wave at the start of the treatment or any interactions among main effects. Follicle wave emergence in EB-treated llamas was delayed (P<0.05) by 2.3 days compared with non-treated llamas. Following EB treatment, plasma concentrations of E(2) were greater (P<0.05) from day 1 to day 5 in the treated than in non-treated females, but not from day 6 onward (P>0.05). Experiment 2 was designed to evaluate the effect of this treatment on the ovarian superovulatory response and embryo yield following eCG treatment administered on day of follicular wave emergence as determined in the Experiment 1. The same lactating (n=18, 61+/-4 days postpartum) and non-lactating (n=18) llamas at random stages of follicle wave were treated as those in Experiment 1 and received 1200IU of eCG at the time of WE2 (EB-treated=day 6.5 and non-treated=day 4.5). Llamas were mated 5 days after sponge withdrawal. A second mating was allowed 24h later. Embryos were collected between 7 and 8 days after the first mating and blood samples were taken to determine progesterone (P(4)) concentrations. The mean number of follicles on day of mating and the number of CL on day of embryo collection were not affected by lactational status, EB treatment or their interactions (P>0.05). Ovulation rate and mean (+/-SEM) number of recovered embryos for EB treatment group (67.5% and 2.4+/-0.4) were greater (P<0.05) than for no EB treatment (51.1% and 1.1+/-0.4). Plasma P(4) concentrations and number of CL per llama were correlated (r=0.49; P=0.014). In conclusion, progestagen plus EB treatment facilitates the prediction of the emergence of a new follicular wave approximately 6 days after treatment and resulted in a higher ovulation rate and embryo production in ovarian superstimulated llamas regardless of lactational status., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)

Background: Previously, we documented the presence of ovulation-inducing factor (OIF) in the seminal plasma of llamas and alpacas. The purpose of the study was to define the biochemical characteristics of the molecule(s) in seminal plasma responsible for inducing ovulation., Methods: In Experiment 1, llama seminal plasma was centrifuged using filtration devices with nominal molecular mass cut-offs of 30, 10 and 5 kDa. Female llamas (n = 9 per group) were treated i.m. with whole seminal plasma (positive control), phosphate-buffered saline (negative control), or the fraction of seminal plasma equal or higher than 30 kDa, 10 to 30 kDa, 5 to 10 kDa, or < 5 kDa. In Experiment 2, female llamas (n = 7 per group) were given an i.m. dose of seminal plasma treated previously by: 1) enzymatic digestion with proteinase-K, 2) incubation with charcoal-dextran, 3) heating to 65 degrees C, or 4) untreated (control). In Experiment 3, female llamas (n = 10 per group) were given an i.m. dose of pronase-treated or non-treated (control) seminal plasma. In all experiments, llamas were examined by transrectal ultrasonography to detect ovulation and CL formation. Ovulation rate was compared among groups by Fisher's exact test and follicle and CL diameters were compared among groups by analyses of variance or student's t-tests., Results: In Experiment 1, all llamas in the equal or higher than 30 kDa and positive control groups ovulated (9/9 in each), but none ovulated in the other groups (P < 0.001). In Experiment 2, ovulations were detected in all llamas in each treatment group; i.e., respective treatments of seminal plasma failed to inactivate the ovulation-inducing factor. In Experiment 3, ovulations were detected in 0/10 llamas given pronase-treated seminal plasma and in 9/10 controls (P < 0.01)., Conclusions: We conclude that ovulation-inducing factor (OIF) in llama seminal plasma is a protein molecule that is resistant to heat and enzymatic digestion with proteinase K, and has a molecular mass of approximately equal or higher than 30 kDa.

The objective of the present study was to describe ovarian activity in 11 adult non-mated guanacos, evaluated every second day for 40 days by transrectal ultrasonography and by plasma estradiol-17beta and progesterone concentrations. An inverse relationship (r = -0.29, P < 0.001) was observed between the diameter of the largest ovarian follicle and the total number of follicles indicating that follicular growth in guanacos occurs in waves. The mean duration of follicular wave was 15.1 +/- 4.2 days with a range from 9 to 26. The follicular growth phase was 7.0 +/- 2.4 days, the static phase 3.0 +/- 1.2 days, the regression phase 5.2 +/- 2.1 days and the inter-wave interval was 12.6 +/- 5.6 days. The maximum follicular diameter in each follicular wave was 10.2 +/- 2.1 mm with a range from 7.2 to 16.1 mm. Inter-wave intervals of longer duration were associated with a larger maximum follicle diameter (P < 0.001). Follicular activity alternated between ovaries in 93% of the waves with 48% of dominant follicles occurring in the left and 52% in the right ovary without differences (P > 0.05). Plasma estradiol-17beta concentrations showed a wave-like pattern, varying from 20.0 to 92.1 pmol/L. Plasma progesterone concentrations remained below 1 nmol/L without any ultrasonic evidence of ovulation during the study. These results in guanacos suggest a follicular wave pattern more similar to the llama (Lama glama) than previously described in other South American and Old World camelid species., (Copyright 2009. Published by Elsevier B.V.)

Sperm binding to oviductal epithelium would be involved in sperm reservoir formation in the utero tubal junction (UTJ). Although in other mammals sperm-oviduct interaction has been proved to be mediated by carbohydrate-recognition mechanisms, the factors implicated in the sperm adhesion to oviductal epithelium of llama are still unknown. In order to assess the role of carbohydrates present in the mucosa surface, we examined the distribution of glycoconjugates in the llama oviduct by confocal lectin-histochemistry. Mannosyl, glucosyl, N-acetylglucosaminyl, galactosyl, N-acetylgalactosaminyl and sialic acid residues were detected in the oviductal mucose glycocalyx. By incubation of UTJ oviductal explants with LCA, DBA, UEA-1 or PNA lectin previous to co-culture with sperm, we observed a significant decrease in sperm binding only with LCA lectin. In the mucosa surface there were numerous d-glucosyl and D-manosyl residues, which were spotted by this lectin. Probably, this fact promotes the whole covering of the oviduct luminal surface by the sugar-lectin complex, preventing sperm access and adhesion of further residues. However, sperm incubation with mannose or glucose does not significantly prevent binding, which means that glucose and mannose would not be involved in a specific sperm-oviduct interaction. On the other hand, we observed a high reduction in sperm binding to UTJ explants with N-acetylgalactosamine and galactose (p<0.001). Coincidentally, binding sites for N-acetylgalactosamine-PAA-FITC conjugate were observed on the whole surface of the sperm, supporting the concept that llama sperm have lectin-like molecules in their surface, as is the case in other mammals. Probably, these lectin-like molecules, by means of N-acetylgalactosamine and galactose recognition, could link the sperm to the oviductal mucosa with the purpose of forming storing sites in the UTJ. Our results support the idea that more than one carbohydrate could participate in sperm reservoir formation in the llama UTJ oviductal segment., (Copyright 2009 Elsevier B.V. All rights reserved.)

Llama semen is characterized by great structural viscosity and minimal sperm progressive motility. These characteristics, inherent to South American Camelid ejaculates, have slowed down the development of assisted reproductive techniques in these species. The aim of the present research was to evaluate the effect of different combinations of dilutions and incubation time with H-TALP-BSA medium, with and without adding 0.1% collagenase, on the qualitative and quantitative semen characteristics, for its use in assisted fertility techniques. Ejaculates (n=8; r=3) were obtained using electroejaculation. Each ejaculate was evaluated and then split into four aliquots. Two of these were diluted 4:1 and 8:1 in 0.1% collagenase in H-TALP-BSA (treatments 1 and 3) and the other two 4:1 and 8:1 in H-TALP-BSA without collagenase (treatments 2 and 4). Treatments 1 and 2 were incubated 4 min at 37 degrees C while treatments 3 and 4 were incubated 8 min. All aliquots were centrifuged at 800 x g for 4 min immediately after incubation. Supernatants were pipetted to observe thread formation and pellets were re-diluted in H-TALP-BSA. Supernatants from samples treated with collagenase did not form a thread when pipetted, while the ones from samples that were not treated with the enzyme did. Only semen samples treated with collagenase showed progressive sperm motility, with averages over 40%. There were no significant differences (P>0.05) for the percentage of live spermatozoa and for the percentage of detached heads between raw and treated semen samples. Percentages of spermatozoa with functional membranes were significantly higher (P< or =0.05) in samples treated with collagenase than in raw semen and in samples incubated without collagenase. These results show that treating semen with 0.1% collagenase in H-TALP-BSA improves semen rheological properties while facilitates the separation of spermatozoa from seminal plasma in llama; it also promotes sperm progressive motility, while maintaining sperm membrane functionality and integrity. Consequently, this protocol could be used for in vitro llama embryo production with ejaculated spermatozoa.

Background: Llamas (Lama glama) are induced ovulators and the process of ovulation depends on dominant follicular size. In addition, a close relationship between behavioural estrus and ovulation is not registered in llamas. Therefore, the exogenous control of follicular development with hormones aims to predict the optimal time to mate. Oestradiol-17beta (E2) and its esters are currently used in domestic species, including camelids, in synchronization treatments. But, in llamas, there is no reports regarding the appropriate dosages to be used and most protocols have been designed by extrapolation from those recommended for other ruminants. The aim of the present study was to characterize plasma E2 concentrations in intact female llamas following a single intramuscular (i.m.) injection of two oestradiol esters: oestradiol benzoate (EB) and oestradiol cypionate (ECP)., Methods: Twelve non pregnant and non lactating sexually mature llamas were i.m. injected on day 0 with 2.5 mg of EB (EB group, n = 6) or ECP (ECP group, n = 6). Blood samples were collected immediately before injection, at 1, 6, 12, 24 h after treatment and then daily until day 14 post injection. Changes in hormone concentrations with time were analyzed in each group by analysis of variance (ANOVA) using a repeated measures (within-SS) design. Plasma E2 concentrations and area under the concentration-time curve (AUC) values were compared between groups by ANOVA. In all cases a Least-Significant Difference test (LSD) was used to determine differences between means. Hormonal and AUC data are expressed as mean +/- S.E.M., Results: Peak plasma E2 concentrations were achieved earlier and were higher in EB group than in ECP group. Thereafter, E2 returned to physiological concentrations earlier in EB group (day 5) than in ECP group (day 9). Although plasma E2 profiles differed over time among groups there were no differences between them on AUC values., Conclusions: The i.m. injection of a single dose of both oestradiol esters resulted in plasma E2 concentrations exceeding physiological values for a variable period. Moreover, the plasma E2 profiles observed depended on the derivative of oestradiol administered. This basic information becomes relevant at defining treatment protocols including oestrogens in llamas.

Tooth eruption and the development of occlusion are significant ontogenetic changes in the masticatory apparatus of mammals. Here, we test the hypothesis that changes in masseter activity are correlated with increased occlusal contacts at major stages of dental development in the alpaca, Lama pacos. We compare electromyographic data from the superficial and deep masseter in infant and juvenile alpacas prior to and following m1 occlusion and from adults with full permanent dentitions. The pre-m1 and post-m1 occlusion groups exhibit similar masseter activity durations, chewing cycle durations, and with the exception of the balancing-side deep masseter, similar timing differences between the jaw muscles. On average, the balancing-side deep masseter fires significantly later in the post-m1 occlusion group. The m2-m3 group exhibits significantly longer chewing cycle length and an even later firing balancing-side deep masseter. Increased occlusion is also associated with an increase in the relative amount of working-side superficial and deep masseter muscle activity when compared with the balancing side muscles. Although the development of occlusal relations in infant and juvenile alpacas are associated with minor changes in masseter activation patterns, additional molar occlusal contacts increase chewing cycle duration resulting in concomitant changes in masseter recruitment patterns. Currently, we cannot rule out that musculoskeletal development influences masseter activity as demonstrated in other mammals. However, the data presented here indicate that alpacas have a relatively delayed onset of the adult motor pattern that may be correlated with changes in occlusal relations due to tooth eruption., ((c) 2009 Wiley-Liss, Inc.)

Genus-specific reproductive processes and strategies displayed by equids, camelids and elephantids are compared and contrasted to illustrate the amazing diversity of reproductive physiology between genera and the equally surprising conservation of reproductive processes across a genus in the face of other dramatic phenotypic modifications and adaptation to prosper in the prevailing environment. From intrauterine conceptus mobility and chorionic gonadotrophic secretion by specialised invasive trophoblast cells in equids, through induced ovulation, an asymmetrical uterus and an almost absurdly short dioestrous interval in camelids, to intrabdominal testes, the testosterone-driven expression of musth and a very tenuous intrauterine attachment of the placenta in elephantids, reproductive physiology remains a discipline of great fascination and academic merit with much yet to be discovered and understood across the whole mammalian kingdom., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Sperm reservoirs in South American Camelids would be crucial for successful fertilization. Since ovulation occurs approximately 36 h after mating, the maintenance of the sperm viability in the oviduct waiting for the ovum is a critical reproductive event. Our study aimed at determining whether the isthmus or the utero tubal junction (UTJ) could function as a sperm reservoir in llama by means of in vivo and in vitro experiments. For the in vivo experiments, the oviducts of adult females with a dominant follicle bigger than 7 mm were examined for the presence of sperm at 6, 18, 24, 28 and 35 h after mating. The results using scanning and transmission electron microscopy showed ultrastructural differences between isthmus and UTJ with respect to (1) predominance of secretory cells in the UTJ and ciliated cells in the isthmus epithelium and (2) cytoplasmic bulbous projection of the secretory cells in the UTJ. Sperm adhered by a mucus-like substance were seen only in the UTJ at 6, 18, 24 and 28 h postmating. Lack of sperm adhered to oviductal mucosa was observed around ovulation (35 h). In vitro experiments demonstrated higher ability of UTJ epithelial cell explants with respect to isthmus explants to bind sperm in a co-cultured system. The anatomical features and the presence of a sperm bonding agent in the UTJ together with the in vitro differential binding of sperm to UTJ explants strongly suggest that both may be feasible mechanisms that facilitate sperm storage in this oviductal region in llama.

Plasma concentrations of progesterone (P4), estradiol-17beta (E2), estrone (E1) and estrone sulfate (E1S) were measured during gestation in eight guanacos kept in captivity. Gestational length was 346.1+/-9.8 days. P4 plasma concentrations increased after ovulation and remained elevated until parturition. However, during the last 4 weeks of gestation, a gradual decrease from 4.17x1.17(+/-1)nmol/L to 2.02x1.95(+/-1)nmol/L on day 5 before parturition was observed, followed by a more abrupt final decline to baseline concentrations which were reached on the day after parturition. Mean E2 plasma concentrations started to increase during the eighth month of gestation, and were significantly elevated up to maximum concentrations of 484.7x1.21(+/-1)pmol/L during the last 2 months of pregnancy. Concentrations returned to baseline during the last 2 days of gestation. An increase of E1S concentrations (p<0.01) was observed in the eleventh month of gestation. Mean E1S concentrations remained rather constant during the last 3 weeks of gestation between 4 to 8nmol/L until parturition, when a steep precipitous decline was observed. E1 concentrations were slightly elevated during the last 4 weeks of gestation, however, maximum concentrations did not exceed 1.5nmol/L. The results show distinct species specific features of gestational steroid hormone profiles in the guanaco in comparison to domestic South American camelids, such as a more pronounced gradual prepartal decrease of P4 concentrations prior to the final decline to baseline, and clearly lesser E1S concentrations during the last 4 weeks of gestation, which lack a continuous prepartal increase.

Limited published reports of nutritional diseases affecting llamas and alpacas were found in a detailed review of relevant literature sources. Anecdotal clinical experiences and nutritional diseases that have been reported range from those diagnosed in common with other species to diseases having a presentation unique to camelids. Vitamin D-associated rickets and greater susceptibility to hepatic lipidosis and zinc deficiency are distinctive nutritional problems for llamas and alpacas. This article will review commonly encountered nutritional diseases, based on literature reports and clinical experience, in llamas and alpacas.

The objective of the study was to compare the ovulatory response and embryo production in llamas (Lama glama) treated with a single dose of equine chorionic gonadotropin (eCG) alone or combined with intravaginal medroxyprogesterone acetate (MPA) at the time of follicular wave emergence. Llamas with a growing follicle >or=7 mm in diameter were assigned to one of the following groups: (1) Control (n=28): Nonstimulated llamas were mated and embryos were collected 7 d after mating. (2) eCG (n=32): Llamas were given 5mg luteinizing hormone (LH) (Day 0) to induce ovulation, 1000 IU eCG on Day 2, a luteolytic dose of prostaglandin F(2alpha) on Day 6, mating on Day 7, and embryo collection on Day 14. (3) eCG+MPA (n=34): Llamas were treated as those in the eCG group, but a sponge containing 60 mg MPA was placed intravaginally from Days 2 to 6. Llamas that did not respond to synchronization or superstimulation were excluded, leaving data from n=26, 26, and 27 in the control, eCG, and eCG+MPA groups, respectively, for statistical analysis. The mean (+/-SD) number of follicles>7 mm at the time of mating was greatest in the eCG group, intermediate in the eCG+MPA group, and lowest in the control group (16.6+/-5.3, 12.9+/-3.7, and 1.0+/-0.0, respectively, P<0.001). The number of corpora lutea was similar between eCG and eCG+MPA groups (10.1+/-2.9 and 8.6+/-3.7, respectively); both were higher (P<0.001) than in controls (0.9+/-0.3). The number of embryos did not differ significantly between the eCG and eCG+MPA groups (4.8+/-2.8 and 3.5+/-3.0, respectively), but both were higher (P<0.001) than in the controls (0.7+/-0.4). In conclusion, eCG, with or without MPA effectively induced a superovulatory response and multiple embryo production in llamas.

Clinical laboratory data including hematology, hemostasis, biochemical, and cytologic findings contribute to diagnosis and monitoring of numerous conditions in camelids. Establishment of reference intervals and descriptions of normal components of fluids in these species have improved our ability to interpret test results.

The clinical signs associated with acute abdominal pain in South American camelids tend to be subtle and less frequent (similar to ruminants) as compared with that of horses. Abdominocentesis and transabdominal ultrasound are useful tools in determining the necessity of an exploratory laparotomy. Preoperative anticipation of the lesion location helps determine the surgical approach to the abdomen. Perioperative management is vital to improve chances for survival. Timely surgical intervention for correctable gastrointestinal lesions is expected to minimize postoperative complications and improve outcomes.

The area of herd health is particularly important when considering camelid operations because of the high frequency of travel for exhibition, breeding, and boarding. This article outlines the considerations for routine husbandry, facility and animal maintenance, and infectious disease control in the form of biosecurity, vaccination, and health testing that should be included in any farm's herd-health plan. Veterinary input into the design of programs for biosecurity and infectious disease prevention is critical and requires an active veterinary client-patient relationship with identification of the goals of the operation. Risk assessments should be made based on farm activities and should be the foundation for herd-health program design.

It has been nearly 30 years since the first imported llamas and alpacas have been commercially raised in the United States. Nutritional requirements for these animals have not been well understood and most feeding practices were based on extrapolated and experiential information. Only recently has a National Research Council committee reviewed the available published information relative to nutrient requirements of llamas and alpacas. This article summarizes current nutrient requirement recommendations and provides some practical feeding recommendations and methods to assess nutritional status.

The aim of the present study was two-fold. Experiment I: evaluate the effect of buserelin on llama's oocyte maturation after exogenous follicular activity suppression, followed by ovarian superstimulation with different doses of equine chorionic gonadotropin (eCG). Experiment II: compare the number of follicles aspirated and the number of cumulus-oocyte complexes (COCs) recovered according to different doses of eCG followed by buserelin. Experiment I consisted in a control group (without buserelin) and a treatment group (with buserelin), both subdivided according to eCG dose administered: A: 500 IU; B: 1000 IU; C: 1500 IU. The treatment group received a single i.v. dose of 8 microg of buserelin when two or more dominant follicles were found at ultrasound evaluation and 20 h later were subjected to surgery. In group A, 83% of the llamas did not respond to superstimulation. In groups B and C differences were observed between the control and the treatment groups for the degree of COCs maturation (p < 0.05). In experiment II animals were divided into two groups according to the eCG dose administered: 1000 and 1500 IU. Twenty hours before surgery females received a single i.v. dose of 8 microg of buserelin. Average number of follicles aspirated and COCs recovered was higher (p < 0.05) with the administration of 1500 IU of eCG. A larger number of expanded COCs were obtained from follicles > or =7 mm in diameter. We conclude that buserelin aids the recovery of a larger number of expanded COCs. Administration of 1500 IU of eCG produces a higher number of follicles for aspiration and number of COCs recovered.

The present study with alpacas determined effect of dam's age on body weight and survival of cria during the first week of life. Pregnant dams (n=424) and their crias were used in the study. Cria body weight (kg) was determined at time of placenta expulsion. Placenta weight and larger width were measured immediately after expulsion. Crias were monitored for the first week and a necropsy was performed if death occurred. Data were analyzed using analysis of variance. The body weight of crias at birth, the weight, and the largest width of placenta increased with age of the dam (P<0.05), reaching a peak at 9 years and then declined progressively. Placental efficiency also increased with the dam's age, and showed a bimodal shape, peaking at 6- and 11-year-old dams (P<0.05). Altogether, 398 crias survived and 26 died; of those 6 died of starvation, 5 of hypothermia, 4 were stillborn and the rest from other miscellaneous causes. More crias died from 2-year-old dams than from dams of any other age (P<0.05). In addition, dead crias had lesser body weights (6.4kg) than those of crias that survived (7.8kg, P<0.05). The weight and width of the placenta was similar for live and dead crias.

Background: Limited information exists regarding hemostasis in camelids despite the importance of platelet function testing in the accurate identification of platelet disorders. As further importation of llamas to North America is restricted, variability in breeding stock will continue to decrease, potentially leading to an increase in heritable bleeding disorders., Objective: The objective of this study was to measure platelet aggregation responses in clinically healthy llamas and provide baseline data to which abnormal platelet function may be compared in the future., Methods: Blood samples were collected from 39 healthy adult llamas, citrated, and centrifuged to produce platelet-rich plasma (PRP). Within 4 hours of the blood draw, 20 microL of each agonist reagent were added to 180 microL of PRP. Final concentrations of agonists were 2 x 10(-5) M ADP, 0.19 mg collagen/mL PRP, 1 x 10(-4) M epinephrine, and 500 microg arachidonic acid/mL PRP., Results: Llama platelets were most responsive to ADP and collagen, with a maximum percent aggregation (mean+/-SD) of 71.3+/-18.6% and 55.8+/-19% and aggregation rates of 9.5+/-3.9 and 6.7+/-3.7 cm/min, respectively. Llama platelet aggregation in response to epinephrine and arachidonic acid was minimal to absent., Conclusions: This study is the first of its kind to establish baseline values for platelet aggregation in healthy adult llamas.

The interest for South American camelids has increased in the last years. The aim of the present research was to compare the in vitro production of Lama glama embryos using two techniques: in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). For IVF technique, we compared the effect of adding or not, heparin, penicillamine and hypotaurine as sperm capacitating agents. In the oocyte group subjected to ICSI, activation with or without, ionomycin and 6-dimethylaminopurine (6-DMAP) was assessed. Semen samples were obtained by electroejaculation and incubated at 38 degrees C in a 25% (v/v) collagenase solution. The cleavage and embryo development rates were compared between the different experimental groups. Only the number of cleaved oocytes was less when ICSI with no activation was used (p<0.05).

The role of nutrition, especially the role of energy and protein status, on reproductive performance of production animals has been well documented. Comparatively, there is a true paucity of literature regarding nutritional mediation of reproductive performance in llamas and alpacas. Following seasonal patterns of feed availability in South America, adverse effects of nutritional deprivation on reproductive performance are well recognized, suggesting similar nutrition-reproduction interrelationships. Camelids, with their unique metabolism, may have some peculiar interrelationships between reproduction and protein and phosphorus nutrition. This presentation will review basic issues of energy and protein nutrition relative to reproductive performance in llamas and alpacas, based primarily on hypotheses and extrapolation from other species. Opportunities for research on this topic will be discussed, including preliminary data from current research.

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.

The objective of the present study was to evaluate the effect of semen collection method (electroejaculation "EE" as compared with the artificial vagina "AV"), the season (summer versus winter) and the male used on macroscopic and microscopic characteristics of ejaculates in llamas. A total of 110 ejaculates were collected from six males and 92 of them were analyzed. Ejaculate volume, concentration, total sperm and the following sperm characteristics were studied: motility, membrane function (HOS test), membrane integrity (CFDA/PI fluorochromes) and morphology. A mixed linear model, that considered season and collection method as the fixed variables and the male as the random variable, was used for the statistical analysis. Variability was found between males (p

Aims: To study the nitric oxide (NO) and carbon monoxide roles in the regulation of the pulmonary circulation in lowland and highland newborn sheep and llamas., Methods and Results: We used neonatal sheep (Ovis aries) and llamas (Lama glama) whose gestation and delivery took place at low (580 m) or high (3600 m) altitude. In vivo, we measured the cardiopulmonary function basally and with a NO synthase (NOS) blockade and calculated the production of carbon monoxide by the lung. In vitro, we determined NOS and soluble guanylate cyclase (sGC) expression, NOS activity, and haemoxygenase (HO) expression in the lung. Pulmonary arterial pressure was elevated at high altitude in sheep but not in llamas. Sheep at high altitude relative to sea level had significantly greater total lung NOS activity and eNOS protein, but reduced sGC and HO expression and carbon monoxide production. In contrast, llamas showed no difference in NO function between altitudes, but a pronounced increase in pulmonary carbon monoxide production and HO expression at high altitude., Conclusions: In the llama, enhanced pulmonary carbon monoxide, rather than NO, protects against pulmonary hypertension in the newborn period at high altitude. This shift in pulmonary dilator strategy from NO to carbon monoxide has not been previously described, and it may give insight into new treatments for excessive pulmonary vasoconstriction.

Energy expenditure and water flux were measured in free-ranging alpacas Lama pacos, a South American camelid, on natural pastures of the Peruvian Andes (altitude: 4,400 m above sea level). Water influx rate (WIR) was estimated in 16 males (age 2 years, weight 48.5+/-8.6 kg) labelled with 2H. In addition, the field metabolic rate (FMR) was measured in four of these animals labelled with both an oxygen (18O) and a hydrogen (2H) isotope. The WIR averaged 3.62 L H2O/day and the mean total body water 33.1 kg, equal to 68.2% of body weight (BW). The FMR of the four doubly labelled animals was 14.05 MJ/day. New allometric equations were calculated describing the relationships between WIR or FMR and BW, respectively, including published data on ruminants and the present alpaca results. The regression equation indicates that daily WIR scales to a similar metabolic size (kilograms of BW(0.94)) in alpacas than in wild or domesticated ruminants and camelids originating from arid and semiarid habitats. The resulting regression equation for FMR explained over 99% of the variation and corresponded to the function FMR (kilojoules per day)=1079 (kilograms of BW0.668) (n=5, r2=0.995, P<0.001). The FMR measured in this study, the first reported for a South American camelid species, suggests that free-ranging alpacas have similar energy expenditures on a metabolic weight basis as other wild ruminants living under harsh climatic conditions.

Estradiol is a potential candidate for the blastocyst signal responsible for maternal recognition of pregnancy in the llama (Lama glama). Two experiments were conducted to determine if the llama blastocyst produces estradiol during the presumed period of maternal recognition of pregnancy and if exogenous estradiol can extend the luteal phase. In Experiment 1, llamas were superovulated with eCG and mated 7 days later (Day 0=day of mating). Blastocysts were collected nonsurgically on Days 7, 9, or 11 or at necropsy on Days 13 and 15 post-mating and cultured for 48h. Conditioned medium was recovered, replaced with fresh medium at 24-h intervals, and assayed for estradiol-17beta. Estradiol production (pg/blastocyst) over the 48-h culture increased (P<0.05) by day of gestation where more estradiol (P<0.05) was produced by Day 11 compared to Day 7 blastocysts, Day 13 compared to Days 7-11 blastocysts, and Day 15 compared to Days 7-13 blastocysts. A dramatic increase was observed between Days 11 and 13 when estradiol production by Day 13 blastocysts increased (P<0.05) more than 50-fold. In Experiment 2, 30 females were induced to ovulate with hCG (Day 0=day of hCG injection). Starting on Day 7 and continuing through Day 15, animals received daily injections i.m. of 0 (n=11), 5 (n=7), or 10mg (n=12) estradiol benzoate (EB) dissolved in isopropylmyristate. Sera were collected immediately prior to each injection and on Days 16, 17, 18, 20, and 22 and analyzed for progesterone. Progesterone concentrations were greater (P<0.05) on Days 14, 15, 16, and 17 in llamas treated with 10mg EB compared to llamas treated with 0mg EB. These results demonstrate that llama blastocysts produce estradiol and exogenous estradiol can enhance and transiently extend luteal progesterone production. Estradiol produced by the preimplantation llama blastocyst may play a role in maternal recognition of pregnancy and early luteal support.

Compared with lowland species, fetal life for mammalian species whose mothers live in high altitude is demanding. For instance, fetal llamas have to cope with the low fetal arterial PO2 of all species, but also the likely superimposition of hypoxia as a result of the decreased oxygen environment in which the mother lives in the Andean altiplano. When subjected to acute hypoxia the llama fetus responds with an intense peripheral vasoconstriction mediated by alpha-adrenergic mechanisms plus high plasma concentrations of catecholamines and neuropeptide Y (NPY). Endothelial factors such as NO and endothelin-1 also play a role in the regulation of local blood flows. Unlike fetuses of lowland species such as the sheep, the llama fetus shows a profound cerebral hypometabolic response to hypoxia, decreasing cerebral oxygen consumption, Na-K-ATPase activity and temperature, and resulting in an absence of seizures and apoptosis in neural cells. These strategies may have evolved to prevent hypoxic injury to the brain or other organs in the face of the persistent hypobaric hypoxia of life in the Andean altiplano.

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.

Estrogen receptor-alpha (ERalpha) and progesterone receptor (PR) were characterized in different endometrial cell types as luminal and glandular epithelium and stroma during the follicular (FP) and the luteal phase (LP) in llamas. Animals were examined daily by transrectal ultrasonography for the determination of the presence of an ovulatory follicle and ovulation was immediately induced by a GnRH injection (Day 0). Endometrial samples were obtained by transcervical biopsies from the left uterine horn on Day 0 (FP) and 9 days after the GnRH injection (Day 9, LP). Blood samples were collected on these days for estradiol 17beta and progesterone determination by RIA. An immunohistochemical technique was used to visualize ERalpha and PR immunostaining which was then analyzed by two independent observers. Total positive area and average staining for ERalpha were affected by the phase of the ovarian activity: in the three cell types there was more positive area and intense staining during the FP than during the LP. Similar findings were observed for PR, more positive stained areas were found during the FP than during the LP in the epithelia. In addition, the three cell types had more intense staining during the FP than during the LP. An effect of the cell type for ERalpha and PR was observed; epithelia (luminal and glandular) had more positive stained areas and greater intensity than stromal cells. In conclusion, the results of the present study suggest that in llamas, like in other ruminants, estradiol has a stimulatory effect while progesterone downregulates the ERalpha and PR and that the receptor is cell type specific., ((c)2006 Elsevier B.V. All rights reserved.)

We investigated patterns of jaw-muscle coordination during rhythmic mastication in three species of ungulates displaying the marked transverse jaw movements typical of many large mammalian herbivores. In order to quantify consistent motor patterns during chewing, electromyograms were recorded from the superficial masseter, deep masseter, posterior temporalis and medial pterygoid muscles of goats, alpacas and horses. Timing differences between muscle pairs were evaluated in the context of an evolutionary model of jaw-muscle function. In this model, the closing and food reduction phases of mastication are primarily controlled by two distinct muscle groups, triplet I (balancing-side superficial masseter and medial pterygoid and working-side posterior temporalis) and triplet II (working-side superficial masseter and medial pterygoid and balancing-side posterior temporalis), and the asynchronous activity of the working- and balancing-side deep masseters. The three species differ in the extent to which the jaw muscles are coordinated as triplet I and triplet II. Alpacas, and to a lesser extent, goats, exhibit the triplet pattern whereas horses do not. In contrast, all three species show marked asynchrony of the working-side and balancing-side deep masseters, with jaw closing initiated by the working-side muscle and the balancing-side muscle firing much later during closing. However, goats differ from alpacas and horses in the timing of the balancing-side deep masseter relative to the triplet II muscles. This study highlights interspecific differences in the coordination of jaw muscles to influence transverse jaw movements and the production of bite force in herbivorous ungulates.

The objective of the study was to estimate daily milk intake in llama crias and relate nutrient intakes at peak lactation to growth data. Milk intake in 11 suckling llamas was estimated from water kinetics using deuterium oxide (D2O) at d 17, 66, and 128 postpartum. Daily milk intakes averaged 2.6, 2.3, and 2.0 kg at 17, 66, and 128 d postpartum, respectively. Milk intake decreased with age when expressed as daily amount, percentage of body weight (BW), or per kilogram of metabolic size, but the influence of age was eliminated when expressed per gram of daily gain. Because llamas only have one young per parturition, milk intake was equivalent to the daily milk output of the dam, which ranged from 27.6 to 96.9 g/kg of maternal BW(0.75). Compared with different ruminant species, milk production in llamas appears to lie between wild and domestic ruminants used for meat production. Nutrients (dry matter, fat, protein, and lactose) and energy intakes from the milk calculated by combining milk intake and milk composition data decreased with age when expressed as daily amount or per 100 g of BW, but when expressed per gram of daily gain, no clear trend was observed. Maintenance requirement for suckling llamas at peak lactation (17 d postpartum) was 312 kJ of ME/kg of BW(0.83). Combined with milk composition data, the present milk intake estimations at different stages of the lactation can be used to establish recommendations for nutrient and energy requirements of suckling llamas.

The objective of the present study was to compare the ovarian follicular response, cumulus-oocyte complex (COC) collection rate, and maturational status of COC collected from alpacas subsequent to treatment with two different superstimulatory protocols. Alpacas (n=7 per group) were treated with: (1) 200mg of FSH im divided bid for 3d, plus a single i.v. dose of 1000IU hCG 24h after the last FSH treatment, or (2) 1200IU of eCG as a single i.m. dose, plus a single i.v. dose of 1000IU of hCG on day 3 after eCG treatment (day 0=start of superstimulatory treatment). At 20-24h post-hCG treatment, the ovaries were surgically exposed and COC were collected by needle aspiration of all follicles > or =6mm. The FSH and eCG treatment groups did not differ with respect to the number of follicles > or =6mm at the time of COC collection (20.0+/-7.5 versus 27.0+/-3.3; P=0.5), the number of COC collected (26.2+/-8.4 versus 23.3+/-3.7; P=0.7), or the collection rate per follicle aspirated (89% versus 87%; P=0.7). No differences were detected between FSH- and eCG-treated alpacas in the number of expanded COC collected per alpaca (11.5+/-2.9 versus 8.8+/-2.8; P=0.54), the number of expanded COC in metaphase II (8.5+/-1.9 versus 6.0+/-2.1; P=0.1), or the number of compact COC with > or =3 layers of cumulus cells (12.5+/-4.3 versus 14.3+/-2.6; P=0.72). A greater proportion (P<0.05) of compact COC collected after FSH treatment matured in vitro to the metaphase II stage than after eCG treatment. Eight expanded alpaca COC were fertilized in vitro with llama sperm, three of which were fixed and stained 18h after exposure to sperm and five were cultured in vitro. Two of the three stained oocytes were in the pronuclear stage, and all five of the cultured oocytes developed to the two-cell and morula stages at 2 and 7 days, respectively, after in vitro fertilization. In summary, FSH and eCG treatments were equally effective for ovarian superstimulation and oocyte collection. Cumulus-oocyte complexes were collected from more than 80% of follicles aspirated during laparotomy. Nearly one third of the COC collected after superstimulation were in metaphase II, and more than 70% of the remaining COC progressed to metaphase II after in vitro maturation for 26h, bringing the mean number of oocytes available for in vitro fertilization to 16 per alpaca. Preliminary results support the hypothesis that alpaca oocytes obtained after superstimulation in the absence of progesterone are developmentally competent since morulae developed from all five COC fertilized and cultured in vitro.

Objective: To determine the minimum alveolar concentration (MAC) of desflurane in llamas and alpacas., Design: Prospective study. Animals Six healthy adult llamas and six healthy adult alpacas., Procedure: Anesthesia was induced with desflurane delivered with oxygen through a mask. An endotracheal tube was inserted, and a port for continuous measurement of end-tidal and inspired desflurane concentrations was placed between the endotracheal tube and the breathing circuit. After equilibration at an end-tidal-to-inspired desflurane concentration ratio >0.90 for 15 minutes, a 50-Hz, 80-mA electrical stimulus was applied to the antebrachium until a response was obtained (i.e. gross purposeful movement) or for up to 1 minute. The vaporizer setting was increased or decreased to effect a 10-20% change in end-tidal desflurane concentration, and equilibration and stimulus were repeated. The MAC was defined as the average of the lowest end-tidal desflurane concentration that prevented a positive response and the highest concentration that allowed a positive response., Results: Mean +/- SD MAC of desflurane was 7.99 +/- 0.58% in llamas and 7.83 +/- 0.51% in alpacas., Conclusions and Clinical Relevance: The MAC of desflurane in llamas and alpacas was in the range of that reported for other species.

Streptococcus mutans is the main cause of dental caries. We evaluated the therapeutic effect of variable regions of a llama heavy chain antibody fragments directed against S. mutans named S36-VHH (S for Streptococcus) alone or fused with glucose oxidase (GOx) from Aspergillus niger. Western blot analysis and ELISA revealed binding of the S36-VHH to the streptococcal antigen I/II adhesin molecule of S. mutans serotype C. In a rat-desalivated caries model, daily administration of S36-VHH significantly reduced the development of smooth surface caries. No additional therapeutic effect of GOx was observed. Our results suggest that llama VHH antibodies may be a potential benefit as prophylaxis against dental caries.

We have recently reported the presence of an ovulation-inducing factor (OIF) in the seminal plasma of llamas and alpacas-species characterized as induced ovulators. The study was designed to test the hypothesis that the seminal plasma of bulls will induce ovulation in llamas, and to compare the ovulation-inducing effect of seminal plasma of conspecific versus hetero-specific males. The seminal plasma of alpacas, a closely related induced ovulator (Lama pacos), and cattle, a distantly related ruminant species (Bos taurus) considered to be spontaneous ovulators, were compared with that of the llama (Lama glama). Ovulation and maximum corpus luteum diameter were compared by ultrasonography among female llamas (n=19 per group) treated intramuscularly with 2 mL of phosphate buffered saline (PBS, negative control) and those treated with 2 mL of seminal plasma of bulls, alpacas, or llamas (conspecific control). The diameter of the preovulatory follicle did not differ among groups at the time of treatment. Bull seminal plasma induced ovulations in 26% (5/19) of llamas compared to 0% (0/19) in PBS group (P<0.001). The proportion of females that ovulated was lower (P<0.01) in bull seminal plasma group compared to the groups treated with alpaca or llama seminal plasma (100%). A corpus luteum was detected on Day 8 (Day 0=treatment) in all llamas in which ovulation was detected earlier (Day 2) by ultrasonography. The diameter of the CL did not differ among groups. Results document the presence of an ovulation-inducing factor in the seminal plasma of B. taurus. The interspecies effects of seminal plasma on ovulation and luteal development provide rationale for the hypothesis that OIF is conserved among both spontaneous and induced ovulating species.

Milk samples were collected weekly from 10 llamas during the first 27 wk after parturition under controlled stable conditions. Mean values for the concentrations of the major milk components across the lactation period were 4.70% fat, 4.23% protein, 5.93% lactose, 15.61% dry matter, and 22.62 mg/dL of milk urea N. All constituents were affected by the stage of lactation. There was an increase in fat to protein ratio as protein concentration declined and fat concentration increased. Fat, protein, and lactose concentrations changed during the transition from colostrum to milk. In the first month postpartum, fat concentration remained constant, protein decreased, and lactose increased. Starting with wk 5 postpartum, fat and protein increased and lactose decreased until the end of lactation. Among the major constituents fat had the highest variation. The mean gross energy concentration of milk was 3.88 kJ/g and showed a similar course as protein. Fat contributed 48.0%, protein 26.3%, and lactose 25.7% to the gross energy in the milk. Milk urea N values were higher than those found in ruminants and increased with stage of lactation, whereas the pH decreased. The analyzed milk components were not affected by the lactation number of the animal, except milk urea N. Somatic cell counts indicated the absence of mastitis and revealed that the average somatic cell count of uninfected llamas is lower than in animals usually used for milk production. The 2 algebraic models fitted by a nonlinear regression procedure to the data resulted in suitable prediction curves for the constituents (R2 = 0.76 to 0.94). The courses of major milk constituents in llamas during lactation are similar to those in domesticated ruminants, although different in their values. The established curves facilitate the composition of milk replacers at different stages of lactation for nursing llamas whose dams died or are agalactic.

Reproductive losses in camelids are due to infertility, pregnancy loss, udder diseases and neonatal mortality caused by a variety of infectious diseases. Uterine infection and abortion represent the major complaint in camelid veterinary practice. The major infectious organisms in endometritis and metritis are E. coli and Streptococcus equi subspecies zooepidemicus. Abortion rates due to infectious diseases vary from 10% to more than 70% in some areas. Leptospirosis, toxoplasmosis and chlamydiosis have been diagnosed as the major causes of abortion in llamas and alpacas. In camels, brucellosis and trypanosomiasis represent the major causes of infectious abortion in the Middle East and Africa. Mastitis is rare in South American camelids. The prevalence of subclinical udder infection in camels can reach very high proportions in dairy camels. Udder infections are primarily due to Streptococcus agalactiae and Staphylococcus aureus. Neonatal mortality is primarily due to diarrhea following failure of passive transfer and exposure to E. coli, rotavirus, coronavirus, Coccidia and Salmonella. This paper reviews the etio-pathogenesis of these causes of reproductive losses, as well as the major risk factors and strategies to prevent their occurrence.

Gonadotropins and GnRH have been used to electively induce ovulation in llamas and alpacas, but critical evaluation of the natural interval to ovulation after mating has not been performed nor has a direct comparison of the effects of natural mating versus hormone treatments on this interval and subsequent luteal development. The objectives of this study were to compare the effects of hormonal treatments and natural mating on ovulation induction, interval to ovulation, and luteal development in llamas. The ovaries of llamas were examined by transrectal ultrasonography once daily. Llamas with a large follicle were assigned randomly to be: (1) mated with an intact male (mated; n=10); (2) given 5 mg of LH im (LH; n=11); or (3) 50 microg of GnRH im (GnRH; n=10). Ultrasound examinations were performed every 4h from treatment (day 0) to ovulation and thereafter once daily for 15 consecutive days to monitor CL growth and regression (n=5 per group). Plasma progesterone concentrations were measured at days 0, 3, 6, 9, and 12 after treatment to evaluate CL function. The size of the largest preovulatory follicle at the time of treatment did not differ among groups (11+/-0.6, 10.5+/-0.8, 11.8+/-0.9 mm, for mated, LH, and GnRH groups, respectively; P=0.6). No differences were detected among groups (mated, LH, and GnRH) in ovulation rate (80%, 91%, 80%, respectively; P=0.6), or interval from treatment to ovulation (30.0+/-0.5, 29.3+/-0.6, 29.3+/-0.7h, respectively; P=0.9). Similarly, no differences were detected among groups (mated, LH, and GnRH) in maximum CL diameter (14.2+/-0.3, 13.2+/-0.5, and 13.0+/-0.7 mm, respectively; P=0.5), the day of maximum CL diameter (7.6+/-0.2, 7.6+/-0.2, and 7.4+/-0.4 mm, respectively; P=0.6), or the day on which the CL began to regress (12.3+/-0.3 [non-pregnant, n=3], 11.8+/-0.6, 12.2+/-0.4, respectively; P=0.4). The diameter of the CL and plasma progesterone concentrations changed over days (P<0.0001) but the profiles did not differ among groups. In summary, ovulation rate, interval to ovulation, and luteal development were similar among llamas that were mated naturally or treated with LH or GnRH. We conclude that both hormonal preparations are equally reliable for inducing ovulation and suitable for synchronization for artificial insemination or embryo transfer program.

Seventeen llamas and 23 alpacas of various coat and iris colors were evaluated for: (1) deafness by using brainstem auditory evoked response testing; and (2) for ocular abnormalities via complete ophthalmic examination. No animals were deaf. The most common ocular abnormalities noted were iris-to-iris persistent pupillary membranes and incipient cataracts.

Most studies in alpaca reproductive biology have been focused on female physiology. Only recent research is being conducted in order to increase the knowledge on males. Semen characteristics during breeding periods will contribute to understanding the poor fertility rates in alpaca. Ten adult male alpacas were distributed randomly into two groups and submitted alternatively to two regimens of semen collection of 12 days duration (day 1, initial day of semen collection). Semen samples were collected using an artificial vagina and a receptive, non-pregnant female. With regimen 1, males were maintained with females except for the days of sexual rest (6 and 7). Semen was collected on days 1, 5, 8 and 12. With regimen 2, males were exposed to females for daily semen collection only, before and after sexual rest. Mating duration, color and volume of ejaculates, spermatozoa concentration and morphology were evaluated. No statistical differences for the variables were found between regimens that were used for semen collection. With respect to influence of day, however, the total numbers of spermatozoa ejaculated on days 1 and 5 of semen collection were statistically different (p<0.05). Azoospermic samples increased on days 5 and 12 of semen collection. Partial recovery in spermatozoa concentration and number of spermatozoa ejaculated were observed after sexual rest. Although normal spermatozoa percentage was less on day 1 (p<0.05) as compared with values found in the following ejaculates (days 5 and 12), the total number of normal spermatozoa was greater. These results support the conclusion that when male alpaca have a daily ejaculation during five consecutive days, they might copulate without having enough spermatozoa for fertilization towards the end of the mating period.

The electrocardiographic parameters of 40 healthy alpacas (Lama pacos) were recorded with a base-apex lead system to establish the normal resting electrocardiographic parameters in this species. The following parameters were measured: heart rate and rhythm, QRS and T morphology, ST segment position, P amplitude and duration, QRS duration and PQ and QT intervals. The heart rate varied between 50 and 110 bpm, with a mean (sd) of 80 (17.8) bpm, and no significant differences were observed between males and females or between alpacas of different ages. Sinus arrhythmia was observed in 35 of the animals, and a regular sinus rhythm was recorded in the other five. The QRS morphology was variable, with an 'rS' pattern observed in 29 animals, 'RS' in six, 'Rs' in three and 'QS' in the other two. A variable morphology was also observed for the T wave, which was positive in 27 animals, negative in seven and biphasic in the other six. All the electrocardiographic parameters were normally distributed and no significant differences were observed between the sexes, except that the amplitude of the P wave was higher in males. The PQ interval was significantly shorter in animals less than six months old.

In this study we looked for additional evidence to support the hypothesis that fetal llama reacts to hypoxaemia with adaptive brain hypometabolism. We determined fetal llama brain temperature, Na(+) and K(+) channel density and Na(+)-K(+)-ATPase activity. Additionally, we looked to see whether there were signs of cell death in the brain cortex of llama fetuses submitted to prolonged hypoxaemia. Ten fetal llamas were instrumented under general anaesthesia to measure pH, arterial blood gases, mean arterial pressure, heart rate, and brain and core temperatures. Measurements were made 1 h before and every hour during 24 h of hypoxaemia (n = 5), which was imposed by reducing maternal inspired oxygen fraction to reach a fetal arterial partial pressure of oxygen (P(a,O(2))) of about 12 mmHg. A normoxaemic group was the control (n = 5). After 24 h of hypoxaemia, we determined brain cortex Na(+)-K(+)-ATPase activity, ouabain binding, and the expression of NaV1.1, NaV1.2, NaV1.3, NaV1.6, TREK1, TRAAK and K(ATP) channels. The lack of brain cortex damage was assessed as poly ADP-ribose polymerase (PARP) proteolysis. We found a mean decrease of 0.56 degrees C in brain cortex temperature during prolonged hypoxaemia, which was accompanied by a 51% decrease in brain cortex Na(+)-K(+)-ATPase activity, and by a 44% decrease in protein content of NaV1.1, a voltage-gated Na(+) channel. These changes occurred in absence of changes in PARP protein degradation, suggesting that the cell death of the brain was not enhanced in the fetal llama during hypoxaemia. Taken together, these results provide further evidence to support the hypothesis that the fetal llama responds to prolonged hypoxaemia with adaptive brain hypometabolism, partly mediated by decreases in Na(+)-K(+)-ATPase activity and expression of NaV channels.

Studies were conducted to document the existence of an ovulation-inducing factor in the seminal plasma of alpacas (experiment 1) and llamas (experiment 2) and to determine if the effect is mediated via the pituitary (experiment 3). In experiment 1, female alpacas (n = 14 per group) were given alpaca seminal plasma or saline intramuscularly or by intrauterine infusion. Only alpacas that were given seminal plasma i.m. ovulated (13/ 14, 93%; P < 0.01). In experiment 2, ovulation was detected in 9/10 (90%) llamas at a mean of 29.3 +/- 0.7 h after seminal plasma treatment. Plasma progesterone concentrations were maximal by Day 9 and were at nadir by Day 12 posttreatment. In experiment 3, female llamas were given llama seminal plasma, GnRH, or saline i.m., and ovulation was detected in 6/6, 5/ 6, and 0/6 llamas, respectively (P < 0.001). Treatment was followed by a surge (P < 0.01) in plasma LH concentration beginning 15 min and 75 min after treatment with GnRH and seminal plasma, respectively. Plasma LH remained elevated longer in the seminal plasma group (P < 0.05) and had not yet declined to pretreatment levels after 8 h. Compared with the GnRH group, corpus luteum tended to grow longer and to a greater diameter (P = 0.1) and plasma progesterone concentration was twice as high in the seminal plasma group (P < 0.01). Results document the existence of a potent factor in the seminal plasma of alpacas and llamas that elicited a surge in circulating concentrations of LH and induced an ovulatory and luteotropic response.

Auditory function of llamas and alpacas was assessed objectively by means of brainstem auditory-evoked response audiometry (BAER) to establish the normal hearing range and to test the hypothesis of a correlation between blue eyes, white coat, and deafness. Sixty-three camelids were available for the study. Thirteen animals had blue irides; 1 animal had 1 blue and 1 pigmented iris. Wave latencies, amplitudes, and interpeak latencies were measured under general anesthetic. Click stimuli (dB [HL]) were delivered by an insert earphone. Four to five positive peaks could be detected; waves I, II, and V were reproducible; wave II appeared infrequently; and wave IV generally merged with wave V to form a complex. Peak latencies decreased and peak amplitudes increased as stimulus intensity increased. A hearing threshold level of 10-20 dB (HL) was proposed as the normal range in llamas and alpacas. None of the animals with pigmentation of coat and iris showed any degree of hearing impairment. Seven of the 10 blue-eyed, pure-white animals were bilaterally deaf and one of them was unilaterally deaf. However, 2 blue-eyed, white animals exhibited normal hearing ability. Three blue-eyed animals with pigmented coat did not show any hearing impairment. All white animals with normal iris pigmentation had normal auditory function; so did the 1 animal with 1 normal and 1 blue iris. The high frequency (78%) of bilaterally deaf animals with pure white coat and blue iris pigmentation supports the hypothesis of a correlation between pigmentation anomalies and congenital deafness in llamas and alpacas.

Background: Camelids are induced (reflex) ovulators. We have recently documented the presence of an ovulation-inducing factor (OIF) in the seminal plasma of alpacas and llamas. The objective was to test the hypothesis that OIF exerts its effect via a systemic rather than a local route and that endometrial curettage will enhance the ovulatory response to intrauterine deposition of seminal plasma in alpacas., Methods: Female alpacas were assigned randomly to 6 groups (n = 15 to 17 per group) in a 2 x 3 factorial design to test the effect of seminal plasma versus phosphate-buffered saline (PBS) given by intramuscular injection, by intrauterine infusion, or by intrauterine infusion after endometrial curettage. Specifically, alpacas in the respective groups were given 1) 2 ml of alpaca seminal plasma intramuscularly, 2) 2 ml of PBS intramuscularly (negative control group), 3) 2 ml of alpaca seminal plasma by intrauterine infusion, 4) 2 ml of PBS by intrauterine infusion (negative control group), 5) 2 ml of alpaca seminal plasma by intrauterine infusion after endometrial curettage, or 6) 2 ml of PBS by intrauterine infusion after endometrial curettage (negative control group). The alpacas were examined by transrectal ultrasonography to detect ovulation and measure follicular and luteal diameters., Results: Intramuscular administration of seminal plasma resulted in a higher ovulation rate than intrauterine administration of seminal plasma (93% versus 41%; P < 0.01), while intrauterine seminal plasma after endometrial curettage was intermediate (67%). None of the saline-treated controls ovulated. The diameter of the CL after treatment-induced ovulation was not affected by the route of administration of seminal plasma., Conclusion: We conclude that 1) OIF in seminal plasma effects ovulation via a systemic rather than a local route, 2) disruption of the endometrial mucosa by curettage facilitated the absorption of OIF and increased the ovulatory effect of seminal plasma, and 3) ovulation in alpacas is not associated with a physical stimulation of the genital tract, and 4) the alpaca represents an excellent biological model to evaluate the bioactivity of OIF.

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.