Examinando por Autor "Cordero, Aida"

Mostrando 1 - 4 de 4

Biotecnologías reproductivas en camélidos sudamericanos domésticos: avances y perspectivas
(Asociación Latinoamericana de Producción Animal, 2007-10-31) Huanca, Wilfredo; Cordero, Aida; Huanca Mamani, Teodosio; Adams, Gregg P.
La crianza de camélidos domésticos, alpacas y llamas, es una de las actividades de mayor importancia e impacto en el desarrollo socioeconómico de la población altoandina del Perú, debido a su capacidad de adaptación a condiciones ambientales difíciles, por encima de los 4,000 msnm, y a su utilización como fuente de proteína de origen animal y de transporte y en el caso de la alpaca, para la producción de fibra de buena calidad. El Perú cuenta con más de 3 millones de alpacas (87% de la población mundial) y la segunda población mundial de llamas (+1 millón); sin embargo, las deficiencias en los esquemas tradicionales de crianza, como la crianza conjunta de alpacas y llamas, con los consecuentes cruces no programados, han contribuido a reducir la calidad genética de los animales, ocasionando una pérdida en la cantidad y calidad de fibra, reportándose que el 45% de la producción de fibra tiene una finura de 26.0 micras y el 46% una de 33.0 micras y sólo el 8% tiene una fibra de 22.0 micras. La aplicación de biotecnologías reproductivas como la Inseminación Artificial (IA) ha contribuido al progreso genético obtenido en especies domésticas como el ganado lechero. En camélidos, la posibilidad de mejora genética de los rebaños productores mediante pruebas de progenie, con la formación de núcleos reproductores, requiere años de trabajo y está limitada, entre otros factores, por el largo intervalo generacional y la capacidad fisiológica de una hembra que sólo puede tener hasta 4 crías, a lo largo de su vida reproductiva. El objetivo de este trabajo es mostrar el estado actual del conocimiento, especialmente en Inseminación Artificial, Transferencia Embrionaria y Fertilización In Vitro; con el propósito de contar con alternativas tecnológicas que puedan servir como herramientas para el mejoramiento genético de camélidos domésticos, alpacas y llamas; así como la posibilidad de su uso potencial en camélidos no domésticos.
Detection of specific antibodies to Neospora caninum and Toxoplasma gondii in naturally infected alpacas (Lama pacos), llamas (Lama glama) and vicuñas (Lama vicugna) from Peru and Germany
(Elsevier B.V., 2005-04-29) Wolf, Dennis; Schares, Gereon; Cárdenas Minaya, Oscar Efraín; Huanca López, Wilfredo; Cordero, Aida; Bärwald, Andrea; Conraths, Franz; Gauly, Matthias; Zahner, Horst; Bauer, Christian
Sera of an experimentally Neospora caninum infected llama and a non-infected control llama were used to establish an immunoblot, an ELISA and an IFAT to detect antibodies against N. caninum tachyzoites. Subsequently, serum samples collected from a total of 871 South American Camelids (SAC: Lama glama, Lama pacos, Lama vicugna) of two farms in Peru and from 32 SAC of a farm in central Germany were examined for antibodies against N. caninum and Toxoplasma gondii. Based on the recognition of specific bands in the immunoblot, sera of SAC from Peru were differentiated into N. caninum-positive (n = 18) and T. gondii-positive (n = 30) samples and into samples negative or inconclusive for both parasites. Using the immunoblot results as the reference, a modified version of the p38-ELISA and the IFAT were evaluated for detecting N. caninum antibodies in SAC sera. Applying a cut-off as determined by two graph-receiver operating characteristic analysis both, the ELISA and the IFAT, exhibited a sensitivity and specificity of about 95% in the SAC sera from Peru. Serological testing confirmed that SAC may become infected with N. caninum under field conditions in Peru. In addition to alpacas and llamas also 114 wild living vicuñas had been examined for antibodies against N. caninum. However, only the alpacas and llamas but no vicuñas were found N. caninum-positive. In contrast, T. gondii-seropositive animals were detected in all three SAC species. The lack of N. caninum-seropositive vicuñas indicates that in the study area in Peru wild canids might not serve as definitive hosts of N. caninum while for T. gondii a life cycle including wild felids is likely. On the German farm no N. caninum- but only T. gondii-seropositive SAC (n = 14) were detected. The seroprevalence of T. gondii infection was significantly higher in adult SAC (alpacas in Peru, llamas in Germany) than in crias (i.e. <12 months old foals) indicating that the predominant route of infection is post natal. Since the present study was restricted to a few farms, the seroprevalences determined are not representative. However, our results confirm natural infections with N. caninum and T. gondii in SAC. Whether these infections are linked to any disease, e.g. reproductive losses, has to be clarified in further studies.
Embryo transfer in camelids: Study of a reliable superovulatory treatment in llamas
(Wageningen Academic Publishers, 2006-12-01) Huanca López, Wilfredo; Ratto, Marcelo; Santiani Acosta, Alexei Vicent; Cordero, Aida; Huanca Mamani, Teodosio
Ovarian response and embryo production in llamas treated with equine chorionic gonadotropin alone or with a progestin-releasing vaginal sponge at the time of follicular wave emergence
(Elsevier Inc., 2009-07-18) Huanca López, Wilfredo; Cordero, Aida; Huanca Mamani, Teodosio; Cárdenas Minaya, Oscar Efraín; Adams, Gregg P.; Ratto, Marcelo
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 ≥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 5 mg luteinizing hormone (LH) (Day 0) to induce ovulation, 1000 IU eCG on Day 2, a luteolytic dose of prostaglandin F2α 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.