Luis Raggi - Academia.edu (original) (raw)

Papers by Luis Raggi

Research paper thumbnail of Ram semen deterioration by short-term exposure to high altitude is prevented by improvement of antioxidant status

Animal, 2018

Ovine reproduction efficiency in herds at high altitude (ha) is lower than that at low altitude (... more Ovine reproduction efficiency in herds at high altitude (ha) is lower than that at low altitude (la). In ewes, ha effects are due to hypoxia and oxidative stress. Our aim was to establish the effect of antioxidant vitamin supplementation on semen traits and antioxidant status of rams exposed to short or long time ha. A total of 32 rams native to la (~500 m) were used, 16 were kept at la and the other 16 were brought to ha (~3600 m), where they were placed in the same flock as the ha native rams (n = 16). Half of the animals in each group were supplemented daily with vitamins C 600 mg and E 450 IU per os, during the entire experimental period, starting the 4th day after animal's arrival at ha (day 0). At days 0, 30 and 60 of treatment, blood and semen samples were collected for evaluation of antioxidant status and semen standard characteristics. Data were compared within each experimental time by analysis of variance using a general linear model. Elevated concentrations of oxidative stress biomarkers were present in blood from animals maintained at ha. Ejaculates from ha exposed rams showed decreased sperm concentration, progressive motility and viability, in addition to decreased antioxidant status in seminal fluid. A total of 30 days of oral supplementation with vitamins C and E prevented some ha negative effects on semen characteristics, mainly in recently ha exposed rams. It is concluded that exposure of rams to ha negatively affects semen quality, where oxidative stress plays a predominant role. These effects are mainly prevented by oral supplementation of vitamins C and E, which constitutes a simple and cheap alternative to improve semen quality of rams when they are moved to ha.

Research paper thumbnail of Intoxicación por palqui (Cestrum Parqui L'herit) en camélidos domésticos mantenidos en el secano de la Zona Central de Chile

Avances en Ciencias Veterinarias, 2010

Research paper thumbnail of One current viral threat to wildlife or in captivity

Open Access Research Journal of Biology and Pharmacy, 2022

In general, it is assumed that there are many differences between human beings and other animal s... more In general, it is assumed that there are many differences between human beings and other animal species. That may be true, but in terms of diseases caused by viruses and microorganisms that difference is much narrower. As André Lwoff, Nobel Prize winner in 1965, said, “viruses are viruses” and therefore the fact that they affect animal species makes no difference. Over the centuries, the human species has been threatened by various bacterial and viral pathogens. In this respect, animal species are not immune. Currently, a ribovirus (SARS-CoV-2) affects the human species presenting several variants, the last known being omicron. Likewise, in animals and initially in dogs, the Canine Vistemper virus was described, of which several genotypes are also known that make any vaccination plan tremble, including other families besides the Canidae. Due to the above, it is not unreasonable to propose CDV as a latent threat in animal species, wild or in captivity. A dizzying read…!!

Research paper thumbnail of Esophageal fistulation in the alpaca

Research paper thumbnail of Exportaciones de camélidos sadamericanos domésticos; crónica de un error que pudo ser evitado

Research paper thumbnail of Regulación del consumo voluntario de alimentos en rumiantes

Monografias De Medicina Veterinaria, 1988

Research paper thumbnail of Desarrollo de un sistema de registro automático del tiempo de pastoreo en rumiantes

Monografias De Medicina Veterinaria, 1990

Research paper thumbnail of Expression of vascular endothelial growth factor and endothelial nitric oxide synthase is increased in the placenta of sheep at high altitude in the Andes

Canadian journal of veterinary research = Revue canadienne de recherche veterinaire, 2010

Fetal weight and the placenta of sheep at high altitude (HA) are affected by hypoxia. Placental c... more Fetal weight and the placenta of sheep at high altitude (HA) are affected by hypoxia. Placental changes (an increase in placental size and vascularization) are greater in ewes from populations that have lived for several generations at HA than in those exposed during just 1 gestation. This study investigated placental expression of vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS), 2 molecules involved in placental angiogenesis that could be upregulated by hypoxia. Two groups of ewes were maintained at HA (3589 m) during pregnancy: HA-native ewes (group HH) and ewes native to lowlands but moved to HA immediately after the diagnosis of pregnancy (group LH). A control group (LL) was kept at sea level. Near term, placentomes were removed, weighed, and processed for immunohistochemical detection of VEGF and eNOS, as well as for vascular area measurement. Placental weight was significantly higher in the HH group than in the LH and LL groups; between t...

Research paper thumbnail of Effect of hypobaric hypoxia on lamb intrauterine growth: comparison between high- and low-altitude native ewes

Reproduction, Fertility and Development, 2005

The present studies assessed the effect of hypobaric hypoxia on fetal lamb growth in high-altitud... more The present studies assessed the effect of hypobaric hypoxia on fetal lamb growth in high-altitude (HA) and low-altitude (LA) native ewes. Growth patterns of fetal biparietal diameter (BPD), abdominal diameter (AD) and thorax height (TH) were described by consecutive ultrasound measurements throughout the entire pregnancy. Three groups of animals were used: (1) pregnant LA ewes kept at LA (control; ‘LL’ group); (2) pregnant LA ewes moved to HA immediately after confirmation of pregnancy (‘LH’ group); and (3) pregnant HA ewes kept at HA throughout the entire pregnancy (‘HH’ group). The slope of the BPD curve was higher in LL fetuses followed by that in LH fetuses. During the last month of pregnancy, TH was higher in LH and HH fetuses, whereas AD was higher in LL than in LH fetuses. The length of gestation was longer in HH ewes (153.2 ± 4.3 days) than in LH and LL ewes (146.0 ± 5.5 and 145.0 ± 3.0 days, respectively). Bodyweight at birth was higher for LL newborns (4.2 ± 0.3 kg) than ...

Research paper thumbnail of Estudio comparativo de la conducta de pastoreo invernal de alpacas mantenidas en el altiplano y en la zona central de Chile

Monografias De Medicina Veterinaria, 1992

Con el objetivo de estudiar la conducta de pastoreo invernal de la alpaca en distintos ecosistema... more Con el objetivo de estudiar la conducta de pastoreo invernal de la alpaca en distintos ecosistemas y bajo diferentes condiciones de manejo, se realizaron experiencias en el altiplano y en el secano precordillerano de la zona central de Chile. Se utilizaron 25 alpacas adultas manejadas en forma extensiva y en estabulacion, las variables medidas fueron: peso de los animales, distancia recorrida durante el periodo de pastoreo, tiempo dedicado al consumo de alimentos, movimientos mandibulares y selectividad. En los animales estabulados se midio el consumo de alimento y agua. Los resultados muestran que las alpacas mantenidas en su ambiente natural deben realizar un mayor esfuerzo en la obtencion de sus recursos nutricionales, sin lograr alcanzar los pesos de los animales mantenidos en la zona central del pais.

Research paper thumbnail of Efectos de la secretina y colecistoquinina-pancreozimina exógenas sobre la secreción pancreática exocrina en el pollo

Avances en Ciencias Veterinarias, 2010

Research paper thumbnail of Use of fetal biometry to determine fetal age in late pregnancy in llamas

Animal Reproduction Science, 2002

Sixty-three pregnant llamas of known breeding date were used in this study. Forty-six of them wer... more Sixty-three pregnant llamas of known breeding date were used in this study. Forty-six of them were submitted to surgery between 186 and 320 days of gestation (52-91% of average gestation period, respectively). Under general anesthesia their fetuses were exteriorized and fetal weight (W), biparietal diameter (BPD) and femoral (F), tarsus-hoof (T-H), tibial (T)) and fronto-occipital (F-O) length were determined. Additionally, the same variables were determined on 16 newborn llamas. The weight was measured in kg and the length in cm. All the collected data was entered into a spreadsheet and different regression analyses as a function of gestational age (GA) were assessed. The best fit equations and their correlation for linear regression were the following: GA=169.448+16.66(*)W, r=0.99; GA=-51.713+44.77(*)BPD, r=0.88; GA=-72.139+39.48(*)F-O, r=0.71; GA=39.304+8.35(*)T-H, r=0.97; GA=91.276+8.23(*)T, r=0.86; GA=102.029+9.94(*)F, r=0.91. For multiple regression, the dependent variable GA can be predicted by the following equation: GA=67.462+11.163(*)W+20.297(*)BPD. Results of the present study indicated measured variables to be highly correlated with GA. This could be useful on daily basis in clinical examination of the neonates, in assessment of fetal growth and well being with cesarean sections, in the determination of GA in late gestation abortions, and in perinatal and reproductive research in the llama.

Research paper thumbnail of Plasma progesterone in alpaca (Lama pacos) during pregnancy, parturition and early postpartum

Animal Reproduction Science, 1999

Plasma progesterone concentration during pregnancy and the early postpartum period was Ž. measure... more Plasma progesterone concentration during pregnancy and the early postpartum period was Ž. measured by radioimmunoassay in five alpacas Lama pacos , of the Huacaya breed, whose pregnancy length had a mean of 344.8 " 4.4 days. Concentration of progesterone increased Ž. Ž. P-0.001 from low premating values 0.11 " 0.06 nmolrl to greater values at 30 days of Ž. pregnancy 8.05 " 1.13 nmolrl and remained high up to 2 months of pregnancy. A slight transitory decline was observed between 3 to 7 months. Concentration of plasma progesterone dropped markedly during the 72 h before parturition especially, at the day of parturition.

Research paper thumbnail of Prediction of gestational age by ultrasonic fetometry in llamas (Lama glama) and alpacas (Lama pacos)

Animal Reproduction Science, 2001

Fetal biparietal diameter (BPD) and thorax height (TH) were measured by ultrasound during intraut... more Fetal biparietal diameter (BPD) and thorax height (TH) were measured by ultrasound during intrauterine growth in pregnant llamas (Lama glama) and alpacas (Lama pacos). The goal was to establish representative curves that allows estimation of gestational age (GA) from real-time ultrasonic measurements of these fetal structures at any stage of gestation. Llamas and alpacas were mated under controlled conditions. Ultrasound exams were conducted to determine pregnancy status 1 month later. Measurements of fetal BPD and TH were conducted from the second month of pregnancy until term. Observation and assessment of fetal TH was difficult during the last 3 months of pregnancy, specially in llamas. Regression curves were calculated from the data as a function of GA, with the best fit represented by the following equations: llama GA =

Research paper thumbnail of Ovine placenta at high altitudes: Comparison of animals with different times of adaptation to hypoxic environment

Animal Reproduction Science, 2006

Fetal growth and newborn weight from ovine gestations at high altitudes (HA) are greater in ewes ... more Fetal growth and newborn weight from ovine gestations at high altitudes (HA) are greater in ewes that live at HA for several generations than in those native to low altitudes (LA) exposed to HA only during pregnancy. Because the placenta is a key regulator of fetal growth, the present study compared placental characteristics in term pregnancies among ewes native to HA and LA. Conception occurred at HA and ewes continued to reside at HA throughout pregnancy or conception occurred at LA and ewes were transported to HA or remained at LA (controls). Ewes native to LA were moved to HA shortly after mating (group LH) and joined with pregnant ewes native to HA (group HH). After parturition, placental cotyledons were counted and measured for total area and histological estimation of surface occupied by vasculature. The total surface of the cotyledons and surface occupied by vasculature were greater at HA, whereas the number of cotyledons was smaller at HA. These changes were more pronounced in ewes of the HH compared with the LH group. The present study showed that exposure to HA induces, in pregnant ewes, placental morphological changes that may improve maternal-fetal exchange. Moreover, because of accentuation of placental changes in ewes with long-term residence at HA, this appears to be an efficient mechanism of adaptation to hypobaric hypoxia.

Research paper thumbnail of Early pregnancy diagnosis in alpaca (Lama pacos) and llama (Lama glama) by ultrasound

Animal Reproduction Science, 1997

Research paper thumbnail of Productividad de un rebaño de camélidos sudamericanos domésticos en un sector de la provincia de Parinacota, Chile I.Variación estacional de la composición botánica, disponibilidad de materia seca, valor pastoral y

Research paper thumbnail of Milk composition in alpaca (lama pacos): comparativestudy in two regions of Chile

El objetivo de este estudio fue determinar la influencia de diferentes condiciones medioambiental... more El objetivo de este estudio fue determinar la influencia de diferentes condiciones medioambientales (calidad de los pastos y altura) sobre la composicion del calostro y la leche de alpacas,durante los primeros cinco meses de lactacion.Los principales componentes de la leche fueron determinados y comparados entre alpacas en lactacion mantenidas en dos diferentes regiones de Chile. Las muestras de leche fueron tomadas a partir de las 48 horas posparto (calostro) y subsecuentemente cada 30 dias hasta los 5 meses de lactacion, en dos grupos de alpacas. Un grupo fue mantenido en el altiplano Andino (4400 metros sobre el nivel del mar; n=24) y el otro en la Patagonia (12 metros sobre el nivel del mar; n=18). Ambos grupos se alimentaron ad libitum sobre praderas naturales. Se midio el porcentaje de materia seca, proteina, grasa, lactosa y ceniza. Los valores obtenidos para cada componente de la leche se compararon entre grupos y entre meses de lactacion. La composicion del calostro fue sim...

Research paper thumbnail of Botanical Composition and Diet Quality of the Vicuñas (Vicugna vicugna Mol.) in Highland Range of Parinacota, Chile

Animals

Understanding the botanical composition of herbivores’ diets and their nutritional quality is an ... more Understanding the botanical composition of herbivores’ diets and their nutritional quality is an important question in the development of sustainable strategies for the management of natural resources. In Chilean highland vicuña-grazed grasslands, there is little information in this regard and, therefore, this study aimed to determine the year-round profile of the diet’s botanical composition and quality. In highland grasslands, on an area of 21.9 ha, continuously grazed for 3.06 VU/ha/year (18°03′ S, 69°13′ W; 4425 m.o.s.l), twelve feces piles were sampled monthly and were analyzed through microhistology, and the nitrogen concentration [NF, OM basis] was determined. The botanical composition, diversity (J) and selectivity index (Ei) of the main species were estimated. Diets were composed of dry–grassland grasses (37.7%), wet–grassland grasses (36.6%), graminoids (14.3%) and forbs (10.2%). The diet diversity ranged from 0.79 (dry–winter) to 0.87 (wet–summer). The main dominant grass...

Research paper thumbnail of Lanametric Determination of the Alpaca Fiber (Vicugna Pacos) in Tucayta, Province of Cañar

Journal of Veterinary Science & Medicine

Alpaca fiber (Vicugna pacos) is classified as one of the finest animal fibers in the world, after... more Alpaca fiber (Vicugna pacos) is classified as one of the finest animal fibers in the world, after the vicuña (Vicugna vicugna). Therefore, they are highly valued fibers by the textile industry. Its valuation is determined, among other variables, by fineness, which indicates its quality. To analyze some of the textile characteristics of these fibers, Optical-based Fibre Diameter Analyser 2000; (OFDA) equipment was used, in which it was possible to determine the average fiber diameter, length, and comfort factor. These characteristics were analyzed based on the variables of sex, age, color of the fleece, and body region. For this study, a multifactorial ANOVA was applied under a completely randomized design, and the R Project software was used. For separation of means, the Bonferroni test was used (P<0.05). The correlations between parameters were evaluated by the Pearson correlation coefficient. Results were: mean fiber diameter 22.6 μm ± 5.2; mean fiber length 60.8 mm, and mean comfort factor 86.8 %. In this way, the fibers analyzed are within the Baby alpaca category, cataloged fibers of better quality, with a high percentage of comfort factors. Additionally, it was observed that age, the body region and the fleece color directly influence the textile characteristics such as diameter, length and comfort factor; parameters that are very significant in the valuation of fiber for commercial purposes. In addition, the measurements could be used to compare with alpaca fiber used by native peoples in order to know the variations in these parameters over the centuries and to establish possible mechanisms to determine the origin of the fiber used in the ancient textiles.

Research paper thumbnail of Ram semen deterioration by short-term exposure to high altitude is prevented by improvement of antioxidant status

Animal, 2018

Ovine reproduction efficiency in herds at high altitude (ha) is lower than that at low altitude (... more Ovine reproduction efficiency in herds at high altitude (ha) is lower than that at low altitude (la). In ewes, ha effects are due to hypoxia and oxidative stress. Our aim was to establish the effect of antioxidant vitamin supplementation on semen traits and antioxidant status of rams exposed to short or long time ha. A total of 32 rams native to la (~500 m) were used, 16 were kept at la and the other 16 were brought to ha (~3600 m), where they were placed in the same flock as the ha native rams (n = 16). Half of the animals in each group were supplemented daily with vitamins C 600 mg and E 450 IU per os, during the entire experimental period, starting the 4th day after animal's arrival at ha (day 0). At days 0, 30 and 60 of treatment, blood and semen samples were collected for evaluation of antioxidant status and semen standard characteristics. Data were compared within each experimental time by analysis of variance using a general linear model. Elevated concentrations of oxidative stress biomarkers were present in blood from animals maintained at ha. Ejaculates from ha exposed rams showed decreased sperm concentration, progressive motility and viability, in addition to decreased antioxidant status in seminal fluid. A total of 30 days of oral supplementation with vitamins C and E prevented some ha negative effects on semen characteristics, mainly in recently ha exposed rams. It is concluded that exposure of rams to ha negatively affects semen quality, where oxidative stress plays a predominant role. These effects are mainly prevented by oral supplementation of vitamins C and E, which constitutes a simple and cheap alternative to improve semen quality of rams when they are moved to ha.

Research paper thumbnail of Intoxicación por palqui (Cestrum Parqui L'herit) en camélidos domésticos mantenidos en el secano de la Zona Central de Chile

Avances en Ciencias Veterinarias, 2010

Research paper thumbnail of One current viral threat to wildlife or in captivity

Open Access Research Journal of Biology and Pharmacy, 2022

In general, it is assumed that there are many differences between human beings and other animal s... more In general, it is assumed that there are many differences between human beings and other animal species. That may be true, but in terms of diseases caused by viruses and microorganisms that difference is much narrower. As André Lwoff, Nobel Prize winner in 1965, said, “viruses are viruses” and therefore the fact that they affect animal species makes no difference. Over the centuries, the human species has been threatened by various bacterial and viral pathogens. In this respect, animal species are not immune. Currently, a ribovirus (SARS-CoV-2) affects the human species presenting several variants, the last known being omicron. Likewise, in animals and initially in dogs, the Canine Vistemper virus was described, of which several genotypes are also known that make any vaccination plan tremble, including other families besides the Canidae. Due to the above, it is not unreasonable to propose CDV as a latent threat in animal species, wild or in captivity. A dizzying read…!!

Research paper thumbnail of Esophageal fistulation in the alpaca

Research paper thumbnail of Exportaciones de camélidos sadamericanos domésticos; crónica de un error que pudo ser evitado

Research paper thumbnail of Regulación del consumo voluntario de alimentos en rumiantes

Monografias De Medicina Veterinaria, 1988

Research paper thumbnail of Desarrollo de un sistema de registro automático del tiempo de pastoreo en rumiantes

Monografias De Medicina Veterinaria, 1990

Research paper thumbnail of Expression of vascular endothelial growth factor and endothelial nitric oxide synthase is increased in the placenta of sheep at high altitude in the Andes

Canadian journal of veterinary research = Revue canadienne de recherche veterinaire, 2010

Fetal weight and the placenta of sheep at high altitude (HA) are affected by hypoxia. Placental c... more Fetal weight and the placenta of sheep at high altitude (HA) are affected by hypoxia. Placental changes (an increase in placental size and vascularization) are greater in ewes from populations that have lived for several generations at HA than in those exposed during just 1 gestation. This study investigated placental expression of vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS), 2 molecules involved in placental angiogenesis that could be upregulated by hypoxia. Two groups of ewes were maintained at HA (3589 m) during pregnancy: HA-native ewes (group HH) and ewes native to lowlands but moved to HA immediately after the diagnosis of pregnancy (group LH). A control group (LL) was kept at sea level. Near term, placentomes were removed, weighed, and processed for immunohistochemical detection of VEGF and eNOS, as well as for vascular area measurement. Placental weight was significantly higher in the HH group than in the LH and LL groups; between t...

Research paper thumbnail of Effect of hypobaric hypoxia on lamb intrauterine growth: comparison between high- and low-altitude native ewes

Reproduction, Fertility and Development, 2005

The present studies assessed the effect of hypobaric hypoxia on fetal lamb growth in high-altitud... more The present studies assessed the effect of hypobaric hypoxia on fetal lamb growth in high-altitude (HA) and low-altitude (LA) native ewes. Growth patterns of fetal biparietal diameter (BPD), abdominal diameter (AD) and thorax height (TH) were described by consecutive ultrasound measurements throughout the entire pregnancy. Three groups of animals were used: (1) pregnant LA ewes kept at LA (control; ‘LL’ group); (2) pregnant LA ewes moved to HA immediately after confirmation of pregnancy (‘LH’ group); and (3) pregnant HA ewes kept at HA throughout the entire pregnancy (‘HH’ group). The slope of the BPD curve was higher in LL fetuses followed by that in LH fetuses. During the last month of pregnancy, TH was higher in LH and HH fetuses, whereas AD was higher in LL than in LH fetuses. The length of gestation was longer in HH ewes (153.2 ± 4.3 days) than in LH and LL ewes (146.0 ± 5.5 and 145.0 ± 3.0 days, respectively). Bodyweight at birth was higher for LL newborns (4.2 ± 0.3 kg) than ...

Research paper thumbnail of Estudio comparativo de la conducta de pastoreo invernal de alpacas mantenidas en el altiplano y en la zona central de Chile

Monografias De Medicina Veterinaria, 1992

Con el objetivo de estudiar la conducta de pastoreo invernal de la alpaca en distintos ecosistema... more Con el objetivo de estudiar la conducta de pastoreo invernal de la alpaca en distintos ecosistemas y bajo diferentes condiciones de manejo, se realizaron experiencias en el altiplano y en el secano precordillerano de la zona central de Chile. Se utilizaron 25 alpacas adultas manejadas en forma extensiva y en estabulacion, las variables medidas fueron: peso de los animales, distancia recorrida durante el periodo de pastoreo, tiempo dedicado al consumo de alimentos, movimientos mandibulares y selectividad. En los animales estabulados se midio el consumo de alimento y agua. Los resultados muestran que las alpacas mantenidas en su ambiente natural deben realizar un mayor esfuerzo en la obtencion de sus recursos nutricionales, sin lograr alcanzar los pesos de los animales mantenidos en la zona central del pais.

Research paper thumbnail of Efectos de la secretina y colecistoquinina-pancreozimina exógenas sobre la secreción pancreática exocrina en el pollo

Avances en Ciencias Veterinarias, 2010

Research paper thumbnail of Use of fetal biometry to determine fetal age in late pregnancy in llamas

Animal Reproduction Science, 2002

Sixty-three pregnant llamas of known breeding date were used in this study. Forty-six of them wer... more Sixty-three pregnant llamas of known breeding date were used in this study. Forty-six of them were submitted to surgery between 186 and 320 days of gestation (52-91% of average gestation period, respectively). Under general anesthesia their fetuses were exteriorized and fetal weight (W), biparietal diameter (BPD) and femoral (F), tarsus-hoof (T-H), tibial (T)) and fronto-occipital (F-O) length were determined. Additionally, the same variables were determined on 16 newborn llamas. The weight was measured in kg and the length in cm. All the collected data was entered into a spreadsheet and different regression analyses as a function of gestational age (GA) were assessed. The best fit equations and their correlation for linear regression were the following: GA=169.448+16.66(*)W, r=0.99; GA=-51.713+44.77(*)BPD, r=0.88; GA=-72.139+39.48(*)F-O, r=0.71; GA=39.304+8.35(*)T-H, r=0.97; GA=91.276+8.23(*)T, r=0.86; GA=102.029+9.94(*)F, r=0.91. For multiple regression, the dependent variable GA can be predicted by the following equation: GA=67.462+11.163(*)W+20.297(*)BPD. Results of the present study indicated measured variables to be highly correlated with GA. This could be useful on daily basis in clinical examination of the neonates, in assessment of fetal growth and well being with cesarean sections, in the determination of GA in late gestation abortions, and in perinatal and reproductive research in the llama.

Research paper thumbnail of Plasma progesterone in alpaca (Lama pacos) during pregnancy, parturition and early postpartum

Animal Reproduction Science, 1999

Plasma progesterone concentration during pregnancy and the early postpartum period was Ž. measure... more Plasma progesterone concentration during pregnancy and the early postpartum period was Ž. measured by radioimmunoassay in five alpacas Lama pacos , of the Huacaya breed, whose pregnancy length had a mean of 344.8 " 4.4 days. Concentration of progesterone increased Ž. Ž. P-0.001 from low premating values 0.11 " 0.06 nmolrl to greater values at 30 days of Ž. pregnancy 8.05 " 1.13 nmolrl and remained high up to 2 months of pregnancy. A slight transitory decline was observed between 3 to 7 months. Concentration of plasma progesterone dropped markedly during the 72 h before parturition especially, at the day of parturition.

Research paper thumbnail of Prediction of gestational age by ultrasonic fetometry in llamas (Lama glama) and alpacas (Lama pacos)

Animal Reproduction Science, 2001

Fetal biparietal diameter (BPD) and thorax height (TH) were measured by ultrasound during intraut... more Fetal biparietal diameter (BPD) and thorax height (TH) were measured by ultrasound during intrauterine growth in pregnant llamas (Lama glama) and alpacas (Lama pacos). The goal was to establish representative curves that allows estimation of gestational age (GA) from real-time ultrasonic measurements of these fetal structures at any stage of gestation. Llamas and alpacas were mated under controlled conditions. Ultrasound exams were conducted to determine pregnancy status 1 month later. Measurements of fetal BPD and TH were conducted from the second month of pregnancy until term. Observation and assessment of fetal TH was difficult during the last 3 months of pregnancy, specially in llamas. Regression curves were calculated from the data as a function of GA, with the best fit represented by the following equations: llama GA =

Research paper thumbnail of Ovine placenta at high altitudes: Comparison of animals with different times of adaptation to hypoxic environment

Animal Reproduction Science, 2006

Fetal growth and newborn weight from ovine gestations at high altitudes (HA) are greater in ewes ... more Fetal growth and newborn weight from ovine gestations at high altitudes (HA) are greater in ewes that live at HA for several generations than in those native to low altitudes (LA) exposed to HA only during pregnancy. Because the placenta is a key regulator of fetal growth, the present study compared placental characteristics in term pregnancies among ewes native to HA and LA. Conception occurred at HA and ewes continued to reside at HA throughout pregnancy or conception occurred at LA and ewes were transported to HA or remained at LA (controls). Ewes native to LA were moved to HA shortly after mating (group LH) and joined with pregnant ewes native to HA (group HH). After parturition, placental cotyledons were counted and measured for total area and histological estimation of surface occupied by vasculature. The total surface of the cotyledons and surface occupied by vasculature were greater at HA, whereas the number of cotyledons was smaller at HA. These changes were more pronounced in ewes of the HH compared with the LH group. The present study showed that exposure to HA induces, in pregnant ewes, placental morphological changes that may improve maternal-fetal exchange. Moreover, because of accentuation of placental changes in ewes with long-term residence at HA, this appears to be an efficient mechanism of adaptation to hypobaric hypoxia.

Research paper thumbnail of Early pregnancy diagnosis in alpaca (Lama pacos) and llama (Lama glama) by ultrasound

Animal Reproduction Science, 1997

Research paper thumbnail of Productividad de un rebaño de camélidos sudamericanos domésticos en un sector de la provincia de Parinacota, Chile I.Variación estacional de la composición botánica, disponibilidad de materia seca, valor pastoral y

Research paper thumbnail of Milk composition in alpaca (lama pacos): comparativestudy in two regions of Chile

El objetivo de este estudio fue determinar la influencia de diferentes condiciones medioambiental... more El objetivo de este estudio fue determinar la influencia de diferentes condiciones medioambientales (calidad de los pastos y altura) sobre la composicion del calostro y la leche de alpacas,durante los primeros cinco meses de lactacion.Los principales componentes de la leche fueron determinados y comparados entre alpacas en lactacion mantenidas en dos diferentes regiones de Chile. Las muestras de leche fueron tomadas a partir de las 48 horas posparto (calostro) y subsecuentemente cada 30 dias hasta los 5 meses de lactacion, en dos grupos de alpacas. Un grupo fue mantenido en el altiplano Andino (4400 metros sobre el nivel del mar; n=24) y el otro en la Patagonia (12 metros sobre el nivel del mar; n=18). Ambos grupos se alimentaron ad libitum sobre praderas naturales. Se midio el porcentaje de materia seca, proteina, grasa, lactosa y ceniza. Los valores obtenidos para cada componente de la leche se compararon entre grupos y entre meses de lactacion. La composicion del calostro fue sim...

Research paper thumbnail of Botanical Composition and Diet Quality of the Vicuñas (Vicugna vicugna Mol.) in Highland Range of Parinacota, Chile

Animals

Understanding the botanical composition of herbivores’ diets and their nutritional quality is an ... more Understanding the botanical composition of herbivores’ diets and their nutritional quality is an important question in the development of sustainable strategies for the management of natural resources. In Chilean highland vicuña-grazed grasslands, there is little information in this regard and, therefore, this study aimed to determine the year-round profile of the diet’s botanical composition and quality. In highland grasslands, on an area of 21.9 ha, continuously grazed for 3.06 VU/ha/year (18°03′ S, 69°13′ W; 4425 m.o.s.l), twelve feces piles were sampled monthly and were analyzed through microhistology, and the nitrogen concentration [NF, OM basis] was determined. The botanical composition, diversity (J) and selectivity index (Ei) of the main species were estimated. Diets were composed of dry–grassland grasses (37.7%), wet–grassland grasses (36.6%), graminoids (14.3%) and forbs (10.2%). The diet diversity ranged from 0.79 (dry–winter) to 0.87 (wet–summer). The main dominant grass...

Research paper thumbnail of Lanametric Determination of the Alpaca Fiber (Vicugna Pacos) in Tucayta, Province of Cañar

Journal of Veterinary Science & Medicine

Alpaca fiber (Vicugna pacos) is classified as one of the finest animal fibers in the world, after... more Alpaca fiber (Vicugna pacos) is classified as one of the finest animal fibers in the world, after the vicuña (Vicugna vicugna). Therefore, they are highly valued fibers by the textile industry. Its valuation is determined, among other variables, by fineness, which indicates its quality. To analyze some of the textile characteristics of these fibers, Optical-based Fibre Diameter Analyser 2000; (OFDA) equipment was used, in which it was possible to determine the average fiber diameter, length, and comfort factor. These characteristics were analyzed based on the variables of sex, age, color of the fleece, and body region. For this study, a multifactorial ANOVA was applied under a completely randomized design, and the R Project software was used. For separation of means, the Bonferroni test was used (P<0.05). The correlations between parameters were evaluated by the Pearson correlation coefficient. Results were: mean fiber diameter 22.6 μm ± 5.2; mean fiber length 60.8 mm, and mean comfort factor 86.8 %. In this way, the fibers analyzed are within the Baby alpaca category, cataloged fibers of better quality, with a high percentage of comfort factors. Additionally, it was observed that age, the body region and the fleece color directly influence the textile characteristics such as diameter, length and comfort factor; parameters that are very significant in the valuation of fiber for commercial purposes. In addition, the measurements could be used to compare with alpaca fiber used by native peoples in order to know the variations in these parameters over the centuries and to establish possible mechanisms to determine the origin of the fiber used in the ancient textiles.