Female Alpacas Research Articles

100 Use of Seminal Plasma, Human Chorionic Gonadotropin, and Follicular Ablation on the Interval to Follicular Wave Emergency and Dominant Follicle in Alpacas (Vicugna pacos)

Alpacas, as other camelids, are inducer ovulators and FIO/NGF-β, a protein present in the seminal plasma (SP) is reported as the responsible of the ovulation (Kershaw-Young et al. 2012 Reprod. Fertil. Dev. 24, 1093-1097, 10.1071/RD12039). However, limited and controversial information exists regarding characteristics of follicular wave in alpacas post-induction of ovulation with SP or other stimulus. The experiment was designed to determine the effect of 3 external stimulations on the interval to follicular wave emergence and the interval to dominant follicle. Adult female alpacas between 5 and 6 years old were assigned to 1 of 3 treatments: (1) SP (n = 6): 1 mL of SP IM; (2) hCG (n = 5): 1000 IU of hCG (Pregnyl, Organon-Holland, Amsterdam, the Netherlands), via IM; or (3) follicular ablation (FA, n = 6): animals were induced by ultrasound-guided ablation of the dominant follicle ≥7 mm. Alpacas from treatments 1 and 2 were examined by ultrasonography (Aloka SSD 500, transducer 7.5 MHz; Aloka, Tokyo, Japan) at 1- to 2-h intervals between 22 and 30 h after treatment or until ovulation occurred, whichever occurred first. All animals were evaluated by ultrasonography every day from Day 2 to Day 7 post-treatment and after that on Days 9, 12, and 15 post-treatment. Data from one alpaca (FA group) was excluded because of problems in the timing of ablation. Therefore, the total number of alpaca used was 16 (SP = 6, hCG = 5, and FA = 5). Results of the effect in external stimulation were analysed using ANOVA. In conclusion, interval to the emergence of a new follicular wave on the detection of follicles ≥3 mm and interval to dominant follicle ≥7 mm differed for FA compared with hCG but not compared with SP treatment. Table 1.Follicular wave emergence (mean ± SEM) under 3 external stimulations: seminal plasma (SP), hCG, or follicular ablation (FA)

111 BIOCHEMICAL COMPOSITION OF FOLLICULAR FLUID IN RELATION TO THE STIMULUS TO INDUCE OVULATION IN ALPACAS (VICUGNA PACOS)

Alpacas, like other camelids, are induced ovulators. A study was designed to determine the effect of the ovulation-inducing stimulus on the biochemical composition of follicular fluid. Adult female alpacas (n = 18) were examined daily for 3 days by transrectal ultrasonography using a 5-MHz linear-array transducer (Aloka SSD-500, Tokyo, Japan). When the largest growing ovarian follicle was ≥7 mm, alpacas were given 1.0 mL of seminal plasma intramuscularly (SP, n = 9) or 40 µg of busereline acetate intramuscularly (GnRH, n = 9). A transvaginal transducer with an attached needle guide (Aloka UST-945BP-5) was used for collection of follicular fluid 22 h post-induction. Follicular contents were then centrifuged at 800 × g for 20 min to separate the fluid from the cells. The follicular fluid was collected and stored at –20°C until analysis with a semi-automatic biochemical analyzer (SINOWA, China). The results were glucose 49.17 and 47.95 (mg/dL; P > 0.05), total protein 1.85 and 1.15 (g/dL; P < 0.05), albumin 1.11 and 1.13 (g/dL; P > 0.05), triglycerides 3.94 and 3.16 (mg/dL; P > 0.05), cholesterol 39.01 and 42.5 (mg/dL; P > 0.05), phosphatase 32.68 and 21.36 (IU/L; P < 0.05), alanine aminotransferase 3.66 and 5.07 (IU/L; P > 0.05), and lactate dehydrogenase 42.17 and 27.27 (IU/L; P > 0.05) for SP or GnRH treatments, respectively. Results suggest the need to continue research to explain the effect of possible differences in total protein, cholesterol, and phosphatase on oocyte-expressed genes and follicular development. Research was supported by the project no. 405-PNICP-PIAP-2014-UNMSM.

Cross-sectional observational survey of serum biochemistry values in a population of 69 adult female alpacas (Vicugna pacos) in South Australia.

Blood samples were collected from 69 'healthy' female alpacas aged ≥12 months from 11 properties in South Australia. The 10-90 percentile ranges of the 16/19 analytes measured in this sample population were within the published ranges of four healthy alpaca populations from other geographic locations. Marginal exceptions were glutamate dehydrogenase and bicarbonate. Potassium was notably elevated, probably because of haemolysis of some samples. The sample size was insufficient to provide the appropriate statistical power to define diagnostic references ranges according to international standards. The health status of the sample population of alpacas was presumptive based on a physical examination.

Efecto de la suplementación con ensilado ("Festuca dolichophylla, Avena sativa y Vicia sativa") sobre la ganancia de peso y mortalidad en alpacas adultas ("Vicugna pacos")

This study was conducted in order to evaluate the effect of supplementation with silage ( Festuca dolichophylla , Avena sativa and Vicia sativa ) on weight gain and mortality in adult alpacas, during the months of dry season (June to August) in Huancavelica region. 300 female alpacas 3 and 4 years of age (physiological state: pregnant) were used, which were assigned to the following treatments: SP, grazing only PSE15, grazing plus supplementation of 1.5 kg of silage. Alpacas were supplemented once daily. In each alpaca they were recorded live weight at the beginning and end of the experiment. The weight gain was -0.02 y 2.05 kg for SP and PSE15 respectively (p <0.001) treatments. Mortality was 5.3% and 2.7% for SP and PSE15 respectively (p=0.073) treatments. It can be concluded under the conditions of this trial silage supplementation has effect on weight gain and maybe also on mortality in alpacas.

MRI evaluation of spontaneous intervertebral disc degeneration in the alpaca cervical spine.

Animal models have historically provided an appropriate benchmark for understanding human pathology, treatment, and healing, but few animals are known to naturally develop intervertebral disc degeneration. The study of degenerative disc disease and its treatment would greatly benefit from a more comprehensive, and comparable animal model. Alpacas have recently been presented as a potential large animal model of intervertebral disc degeneration due to similarities in spinal posture, disc size, biomechanical flexibility, and natural disc pathology. This research further investigated alpacas by determining the prevalence of intervertebral disc degeneration among an aging alpaca population. Twenty healthy female alpacas comprised two age subgroups (5 young: 2-6 years; and 15 older: 10+ years) and were rated according to the Pfirrmann-grade for degeneration of the cervical intervertebral discs. Incidence rates of degeneration showed strong correlations with age and spinal level: younger alpacas were nearly immune to developing disc degeneration, and in older animals, disc degeneration had an increased incidence rate and severity at lower cervical levels. Advanced disc degeneration was present in at least one of the cervical intervertebral discs of 47% of the older alpacas, and it was most common at the two lowest cervical intervertebral discs. The prevalence of intervertebral disc degeneration encourages further investigation and application of the lower cervical spine of alpacas and similar camelids as a large animal model of intervertebral disc degeneration.

Carcass traits and saleable meat yield of alpacas (Vicugna pacos) in Australia

Carcass traits and saleable meat yield (SMY) of female and castrated male alpacas in Australia at 18, 24 and 36months of age were investigated. Fifty huacaya alpacas, evenly distributed across 14, 20, 32month ages and two genders, were grazed on coastal summer pastures for four months. Dressing percentage and carcass length were collected at slaughter. At 24h post-mortem the carcasses were prepared into four SMY combinations. Thirty six month animals had heavier hot carcass weights (33.7±1kg) and longer carcasses (81.2±0.7cm) as expected. The percentage of total carcass bone (17.5±0.2%), fat trim (1.4±0.1%) and meat trim (7.8±0.4%) was assessed as a proportion of cold carcass weight. The proportion of fat increased and bone decreased with age. Females had more trim than males. SMY decreased in females and increased in males with age across all combinations suggesting that males are preferable for meat production.

165 EFFECT OF INJECTION OF SEMINAL PLASMA ON OVULATION RATE, CORPUS LUTEUM DEVELOPMENT, AND SENSITIVITY TO PROSTAGLANDIN IN ALPACAS (VICUGNA PACOS)

The seminal plasma (SP) of camelids contains a protein identified as β Nerve Growth Factor with capacity of induced ovulation and develop a corpus luteum. A study was designed to evaluate the effect of application of SP on the interval of time from injection of stimulus to the ovulation and corpus luteum (CL) size (Experiment 1, n = 24) and on the sensitivity of CL to the injection of prostaglandin (196 µg of tiaprost) (PG) at different periods from ovulation (Experiment 2, n = 86). Exp. 1: Adult female alpacas with presence of a follicle ≥7 mm were assigned to the application of 1 mL of SP via IM (T: n = 12) or application of 50 µg of acetate of busereline IM (T2: n = 12). Exp. 2: Alpacas with presence of a follicle ≥7 mm were induced to ovulation with 50 µg of acetate of busereline or 1 mL IM of SP. Animals were evaluated by ultrasound to confirm the ovulation and were assigned to the following treatment: T1 (n = 8): SP + PG Day 4; T2 (n = 8): buserelin acetate + PG Day 4; T3 (n = 8): SP + PG Day 5; T4 (n = 8): buserelin acetate + PG Day 5; T5 (n = 8): SP + PG Day 6; T6 (n = 8): buserelin acetate + PG Day 6; T7 (n = 8): SP + PG Day 7; T8 (n = 8): buserelin acetate + PG Day 7; T9 (n = 8): SP + PG Day 8; T10 (n = 8): buserelin acetate + PG Day 8 and T11 (n = 6) (Control): Application of 1 mL of saline solution. The animals were evaluated by ultrasound with an Aloka SSD500 (Aloka, Tokyo, Japan) and 7.5-MHz linear transducer each 2 h (Exp. 1) and each 12 h (Exp. 2) after of application of PG. In Exp. 1, the ovulation rate was 95.7% to T1 and T2 and an interval of time between injection of stimulus and ovulation was 27.4 ± 2.5 h and 26.8 ± 1.8 to T1 and T2, respectively. In Exp. 2, luteolysis was 0.0%, 0.0%, 25.0%, 0.0%, 100.0%, 100.0%, 100.0%, 100.0%, 100.0%, 100.0%, and 0.0% for the treatments T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, and T11 respectively. The results suggest that no differences exist between in the ovulation rate and interval to the ovulation between the application of buserelin acetate or SP and that the CL was sensible at Day 5 to the prostaglandin respect SP and with similar response to the sensibility of CL from Day 6 to Day 8.

SEROPREVALENCIA DE ANTICUERPOS ANTI-Toxoplasma gondii EN ALPACAS DE UN CENTRO DE CRIANZA DE CUSCO, PERÚ.

The aim of this study was to determine the seroprevalence of anti-Toxoplasma gondiiantibodies in alpacas of a breeding centre in the province of Canchis, Cusco, Peru, by theindirect inmunofluorescence technique (IFAT) using a cut off of 1:200. A total of318blood samples were collected from female alpacas. The seroprevalence was of 25.8 ± 4.8% (82/318). Out of 82 positive sera, 62.2% showed titres of 1:200. The results confirmthe presence of specific anti-T. gondii antibodies in alpacas in Cusco

Effects of varying doses of β-nerve growth factor on the timing of ovulation, plasma progesterone concentration and corpus luteum size in female alpacas (Vicugna pacos).

Ovulation in camelids is induced by the seminal plasma protein ovulation-inducing factor (OIF), recently identified as β-nerve growth factor (β-NGF). The present study measured the total protein concentration in alpaca seminal plasma using a bicinchoninic acid (BCA) protein quantification assay and found it to be 22.2±2.0mgmL(-1). To measure the effects of varying doses of β-NGF on the incidence and timing of ovulation, corpus luteum (CL) size and plasma progesterone concentration, 24 female alpacas were synchronised and treated with either: (1) 1mL 0.9% saline (n=5); (2) 4µg buserelin (n=5); (3) 1mg β-NGF protein (n=5); (4) 0.1mg β-NGF (n=5); or (5) 0.01mg β-NGF (n=4). Females were examined by transrectal ultrasonography at 1-2-h intervals between 20 and 45h after treatment or until ovulation occurred, as well as on Day 8 to observe the size of the CL, at which time blood was collected to measure plasma progesterone concentrations. Ovulation was detected in 0/5, 5/5, 5/5, 3/5 and 0/4 female alpacas treated with saline, buserelin, 1, 0.1 and 0.01mg β-NGF, respectively. Mean ovulation interval (P=0.76), CL diameter (P=0.96) and plasma progesterone concentration (P=0.96) did not differ between treatments. Mean ovulation interval overall was 26.2±1.0h. In conclusion, buserelin and 1mg β-NGF are equally effective at inducing ovulation in female alpacas, but at doses ≤0.1mg, β-NGF is not a reliable method for the induction of ovulation.

Computed tomographic characterization of the pulmonary system in clinically normal alpacas

To characterize and quantitatively assess the typical pulmonary anatomy of healthy adult alpacas with multidetector row CT. 10 clinically normal adult female alpacas. CT examination of the thorax was performed before and after IV administration of iodinated contrast medium in sedated alpacas in sternal recumbency. Measurements of the trachea, bronchi and related blood vessels, and selected vertebrae as well as the extent and density of lung parenchyma were performed with a Digital Imaging and Communications in Medicine (DICOM) viewer. Morphometric and quantitative data were summarized. Separation of individual lung lobes could not be identified, except for the accessory lung lobe. In all alpacas, both lungs extended farther caudally at the medial aspect than at the lateral aspect. The right lung extended farther in both cranial and caudal directions than did the left lung. The branching pattern of the bronchial tree varied only slightly among alpacas and consisted of 1 cranial bronchus and 3 caudal bronchi bilaterally, with a right accessory bronchus. Luminal diameters of first-generation bronchi ranged from 3 to 9 mm. Mean ± SD parenchymal lung density was -869 ± 40 Hounsfield units (HU) before contrast injection and -825 ± 51 HU after contrast injection. Mean difference in diameter between bronchi and associated arteries or veins was 0.8 ± 0.9 mm. Knowledge of the typical anatomy of the lungs and bronchial tree in healthy alpacas as determined via CT will aid veterinarians in clinical assessment and bronchoscopic evaluation of alpacas.

EFECTO DE LA COPULACIÓN DURANTE EL CELO POSTOVULATORIO EN LA MORTALIDAD EMBRIONARIA EN ALPACAS

The objetive of this research work was to study the effect of the frequency of copulation during the post-ovulatory estrous on the embryonic mortality in alpacas. Forty four female alpacas were selected having a post-partum sexual rest >20 days and bearing in the ovaries a pre-ovulatory follicle >7 mm of diameter. Animals were mated (time of coitus: >15 minutes) using a male with proven fertility and received 6 �g of busereline i.m. after copula to ensure ovulation. Three experimental groups were then ramdomly organized: the first group (S 1 , n = 14) did not receive additional matings, the second gropup (S 2 , n = 15) received an additional mating on day three post-ovulation, and the third group (S 3 , n = 15) received additional matings on days three and four postovulation. Ovulation was confirmed through ultrasound images by disappearance of the pre-ovulatory follicle 42 hours post-mating and the presence of a corpus luteum on day 5 post-ovulation. In addition, the size of the corpus luteum, morfological changes of the uterine horns and presence of an embryo were recorded on days 13-14 and 19 postmating. These observations were complemented with the observation of sexual receptivity using a male on days 6, 13-14, 19 and 26 post-mating. Ovulation rate was 91%. There was a higher tendency on embryo survival at day 19 post-mating in those alpacas that received an additional mating on days 3 (S 2 = 80%) and 3 and 4 (S 3 = 85%) post-ovulation than in those animals without additional mating (S 1 = 75%). An additional study in four inducedovulated alpacas was done to detect fertilized ova at days 2, 3 and 4 post-ovulation. Recovery of the fertilized ova from oviduct was possible only until day 3 post-ovulation.

EFECTO DE LA GnRH EN EL PROCESO DEL RECONOCIMIENTO MATERNAL DE LA PREÑEZ SOBRE LA SUPERVIVENCIA EMBRIONARIA EN ALPACAS

The effect of GnRH administered around the time of maternal recognition of prenancy on the embryonic survival rate was studied. It was used 67 adult female alpacas sexually receptive to the male, and bearing a preovulatory follicle ≥7mm, detected by rectal ultrasonography. Animals were distributed in three groups: G0 (n=23) as control; G1 (n=22) received 6 µg GnRH on day 4 after ovulation; and G2 (n=22) received 4 µg GnRH on days 8 and 9 after ovulation. The ocurrence of ovulation was confirmed through the detection of a corpus luteum (CL) on day 5 after ovulation. Fertilization and gestation viab-ility were monitored by CL development, structural changes of the uterine horns and presence of the embryonic vesicle on days 12, 18, 25 and 30 after ovulation, using rectal ultrasonography. The female sexual receptivity to the male was simultaneously evaluated. The number of females that ovulate was 20, 22 and 21 in G0, G1, and G2 respectively, and was presumed that conception has occurred. However, on day 12, the embryo survival rate was 90.5% in G1, 75.0% in G0, and 76.2% in G2. These values were statistically different (p<0.05) on day 25 and 30 between G1 (76.2%) and G2 (42.9%). The follicle diameter in G2 showed a continuos decrease from day 0 to day 5 and 12 after ovulation (7.4, 7.3 and 6.3 mm, respectively). The CL size of females that maintained pregnancy showed an increase from day 5 to day 12 and 18 after ovulation, while those of females that had embryonic mortality showed a significant (p<0.01) decrease since day 12 onwards. There was an inverse relationship between the diameter of CL and follicle size with embryonic mortality. It is concluded that GnRH decreased the size of the dominant follicle and embryo survival rate when applied around the time of maternal recognition of pregnancy.

ESTIMULACIÓN ELÉCTRICA DE CANALES DE ALPACAS PARA MEJORAR SU CALIDAD ORGANOLÉPTICA

Electrical stimulation is a technique that may reduce the lenght of maturity, rigor mortis and acidity of meat, as well as improving sensory characteristics. The objetive of the study was to show that the electrical stimulation has a significant effect on the quality of alpaca meat such as tenderness, juiceness, flavor, odor and sanitary condition. Twelve female alpacas from 4 to 5 year old and 50-60 kg of body weight were used. They were slaughtered and electrically stimulated 60 minutes later using electrodes on muscular tissue. All half carcasses were stimulated with 500 v per 60 s (T1), 500 v per 30 s (T2), 600 v per 60 s (T3), and 600 v per 30 s (T4). All other half carcasses were kept without electrically stimulation. The results indicated that the electrical stimulation had a significant effect (p=0.00) on the pH alpaca meat reducing microbial growth 24 h after stimulation (p=0.004), where treatment T2 (500 v/60s) showed the best effect. The evaluation of sensory characteristics showed a significant effect for odor on treatment T1 (p=0.009), flavor on treatment T4 (p=0.002), tenderness on treatments T2 (p=0.023) and T3 (p=0.004), and juiceness on treatment T4 (p=0.005).

Prediction of alpaca fibre quality by near-infrared reflectance spectroscopy

Rapid and efficient methods to evaluate variables associated with fibre quality are essential in animal breeding programs and fibre trade. Near-infrared reflectance spectroscopy (NIRS) combined with multivariate analysis was evaluated to predict textile quality attributes of alpaca fibre. Raw samples of fibres taken from male and female Huacaya alpacas (n = 291) of different ages and colours were scanned and their visible–near-infrared (NIR; 400 to 2500 nm) reflectance spectra were collected and analysed. Reference analysis of the samples included mean fibre diameter (MFD), standard deviation of fibre diameter (SDFD), coefficient of variation of fibre diameter (CVFD), mean fibre curvature (MFC), standard deviation of fibre curvature (SDFC), comfort factor (CF), spinning fineness (SF) and staple length (SL). Patterns of spectral variation (loadings) were explored by principal component analysis (PCA), where the first four PC's explained 99.97% and the first PC alone 95.58% of spectral variability. Calibration models were developed by modified partial least squares regression, testing different mathematical treatments (derivative order, subtraction gap, smoothing segment) of the spectra, with or without applying spectral correction algorithms (standard normal variate and detrend). Equations were selected through one-out cross-validation according to the proportion of explained variance (R2CV), root mean square error in cross-validation (RMSECV) and the residual predictive deviation (RPD), which relates the standard deviation of the reference data to RMSECV. The best calibration models were accomplished when using the NIR region (1100 to 2500 nm) for the prediction of MFD and SF, with R2CV = 0.90 and 0.87; RMSECV = 1.01 and 1.08 μm and RPD = 3.13 and 2.73, respectively. Models for SDFD, CVFD, MFC, SDFC, CF and SL had lower predictive quality with R2CV < 0.65 and RPD < 1.5. External validation performed for MFD and SF on 91 samples was slightly poorer than cross-validation, with R2 of 0.86 and 0.82, and standard error of prediction of 1.21 and 1.33 μm, for MFD and SF, respectively. It is concluded that NIRS can be used as an effective technique to select alpacas according to some important textile quality traits such as MFD and SF.

INSEMINACIÓN ARTIFICIAL DE ALPACAS CON SEMEN COLECTADO POR ASPIRACIÓN VAGINAL Y VAGINA ARTIFICIAL.

Semen from alpacas was collected by two methods: by aspiration from the female’s vagina following mating and with an artificial vagina. Semen was collected, evaluated and extended with Tris buffer, and then used in artificial insemination. Altogether 160 female alpacas with proven reproductive history and five males were used. Semen was collected by vaginal aspiration from 10 females using five males as semen donors; likewise, semen from the same males was collected with an artificial vagina twice a week 50 times. Volume, motility, spermatic concentration, live spermatozoa, viscosity and color was evaluated. Seminal characteristics of semen collected by aspiration and with an artificial vagina were: volume (3.6 and 1.5 mL), motility (73.4 and 69.0%), sperm concentration (75.2 and 80.3 million/mL), live spermatozoa (75.3 and 70.8%) respectively, with statistical difference between methods (p&lt;0.05). Semen was mainly light red (80%) and showed a semi viscous consistency (90%) in semen collected by aspiration, and milky white (60%) and viscous (90%) from artificial vagina. Pregnancy diagnosis by ultrasonography 30 days after insemination was 55% (55/100) when using semen by aspiration and 48% (24/ 50) when using semen from artificial vagina (p&lt;0.01). Semen collection from the vagina following mating yielded greater volume, better quality, and semi viscous consistency, and the percentage of pregnancy was higher than semen from artificial vagina.

Development and Application of Camelid Molecular Cytogenetic Tools

Cytogenetic chromosome maps offer molecular tools for genome analysis and clinical cytogenetics and are of particular importance for species with difficult karyotypes, such as camelids (2n = 74). Building on the available human-camel zoo-fluorescence in situ hybridization (FISH) data, we developed the first cytogenetic map for the alpaca (Lama pacos, LPA) genome by isolating and identifying 151 alpaca bacterial artificial chromosome (BAC) clones corresponding to 44 specific genes. The genes were mapped by FISH to 31 alpaca autosomes and the sex chromosomes; 11 chromosomes had 2 markers, which were ordered by dual-color FISH. The STS gene mapped to Xpter/Ypter, demarcating the pseudoautosomal region, whereas no markers were assigned to chromosomes 14, 21, 22, 28, and 36. The chromosome-specific markers were applied in clinical cytogenetics to identify LPA20, the major histocompatibility complex (MHC)-carrying chromosome, as a part of an autosomal translocation in a sterile male llama (Lama glama, LGL; 2n = 73,XY). FISH with LPAX BACs and LPA36 paints, as well as comparative genomic hybridization, were also used to investigate the origin of the minute chromosome, an abnormally small LPA36 in infertile female alpacas. This collection of cytogenetically mapped markers represents a new tool for camelid clinical cytogenetics and has applications for the improvement of the alpaca genome map and sequence assembly.

Progesterone, pregnanediol-3-glucuronide, relaxin and oestrone sulphate concentrations in saliva, milk and urine of female alpacas (Vicugna pacos) and their application in pregnancy diagnosis

The pregnancy-associated hormones, progesterone (P4), pregnanediol-3-glucuronide (PdG), relaxin (RLN) and oestrone sulphate (E1S) in plasma, saliva, milk and urine of alpacas were measured in order to assess their potential use...

NIVEL SÉRICO DE ESTRADIOL A LA MONTA Y SU EFECTO SOBRE LA TASA DE CONCEPCIÓN EN ALPACAS

The aim of the study was to determine the serum oestradiol level in adult alpacas during the first post-partum mating and its effect on conception rate. It was selected 85 non-lactating female adult alpacas without calf at foot. Sexual receptive females were mated with a male of proven fertility. Blood samples were collected at mating and the level of oestradiol in serum was determined by radioimmunoassay. Conception was determined by ultrasound at 25-27 days of mating. Oestradiol values were distributed in two groups: A (&lt;0.5 pg/mL) and B (&gt;0.5 pg/mL), where the mean was 0.78 ± 0.39 pg/mL. Conception rate in alpacas with low oestradiol level at time of mating was 52.5% and in alpacas with high level was 66.7% without significant difference. Results indicate the lack of influence of oestradiol levels on conception rate.

β-Nerve growth factor is a major component of alpaca seminal plasma and induces ovulation in female alpacas

Ovulation in camelids is induced by an unidentified protein in the seminal plasma of the male termed 'ovulation-inducing factor'. This protein has been reported to be a 14-kDa protein under reducing conditions, which, when purified from seminal plasma, induces ovulation in llamas. The identification of this protein and investigation of its potential to induce ovulation in camelids may aid the development of protocols for the induction of ovulation. In the present study, alpaca seminal plasma proteins were separated using one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the most abundant protein of 14 kDa was identified as β-nerve growth factor (β-NGF) by liquid chromatography mass spectrometry. Female alpacas (n = 5 per group) were given intramuscular injections of: (1) 1 mL of 0.9% saline; (2) 4 µg buserelin, a gonadotrophin-releasing hormone agonist; (3) 2 mL alpaca seminal plasma; or (4) 1mg human β-NGF. Ovulation was detected by transrectal ultrasonography 8 days after treatment and confirmed by plasma progesterone concentrations. Ovulation occurred in 0%, 80%, 80% and 80% of animals treated with saline, buserelin, seminal plasma and β-NGF, respectively. Treatment type did not affect the diameter of the corpus luteum, but plasma progesterone concentrations were lower in saline-treated animals than in the other treatment groups owing to the lack of a corpus luteum. The present study is the first to identify the ovulation-inducing factor protein in alpacas. β-NGF successfully induces ovulation in alpacas and this finding may lead to new methods for the induction of ovulation in camelids.

SEROPREVALENCIA DE Toxoplasma gondii EN ALPACAS HEMBRAS DE LA SAIS PACHACÚTEC, SIERRA CENTRAL DEL PERÚ.

The objective of this study was to determine the seroprevalence of antibodies against Toxoplasma gondii in alpacas at the production unit of Cuyo, part of SAIS Pachacutec in the Central Sierra of Peru. Blood samples were collected in 258 female alpacas in January 2003. Sera were tested against T. gondii antibodies by the Indirect Immunoflorescence test (IFI). The results showed that 8.5 ± 3.4% (22/258) of animals had antibodies against the parasite. This frequency is lower than in other alpaca breeding regions of the country.