The Experts below are selected from a list of 59226 Experts worldwide ranked by ideXlab platform
Cino Pertoldi - One of the best experts on this subject based on the ideXlab platform.
-
population Viability analysis on domestic horse breeds equus caballus
Journal of Animal Science, 2009Co-Authors: Janne Pia Thirstrup, Lars A Bach, Volker Loeschcke, Cino PertoldiAbstract:In this study, we performed a population Viability analysis on 3 domestic horse breeds (Equus caballus) of Danish origin, namely, the Frederiksborg, the Knabstrupper, and the Jutland breeds. Because of their small population sizes, these breeds are considered endangered. The Vortex software simulation package was used for the population Viability analysis. First, we investigated the Future Viability of these breeds based on present demographic and environmental parameters. Second, a sensitivity analysis revealed the most important variables for the Viability of these breeds. Third, we examined management scenarios in which one of the studbooks was closed. According to the Vortex analysis, 2 of the breeds (Knabstrupper and Jutland) will persist for the next 200 yr, whereas the smaller breed (Frederiksborg) could become extinct within 40 yr. The sensitivity analyses indicated that the variables concerning reproduction of the mares had the greatest impact, with the number of mares actively breeding being the most influential on the population forecasts. The results suggest that closing the Knabstrupper studbooks can be done only if increasing the number of mares actively breeding counteracts the loss of genetic variation attributable to such a management strategy. It is recommended, based on these results, that the number of Frederiksborg and Knabstrupper mares actively breeding must be increased to approximately 30% in the 2 breeds that are presently using only 13%, while leaving the third (Frederiksborg) at its present 30% level. Monitoring of the breeds in the Future, however, may be exploited to adjust the breeding strategies. We suggest that the large amount of data required by Vortex makes it very useful for analyzing domestic animals because of the comprehensive data material often available. The results of this analysis accord with other studies on the Prezwalski horse, indicating robustness in the parameter sensitivity for horses. (Less)
-
population Viability analysis on domestic horse breeds equus caballus
Journal of Animal Science, 2009Co-Authors: Janne Pia Thirstrup, Lars A Bach, Volker Loeschcke, Cino PertoldiAbstract:In this study, we performed a population Viability analysis on 3 domestic horse breeds (Equus caballus) of Danish origin, namely, the Frederiksborg, the Knabstrupper, and the Jutland breeds. Because of their small population sizes, these breeds are considered endangered. The Vortex software simulation package was used for the population Viability analysis. First, we investigated the Future Viability of these breeds based on present demographic and environmental parameters. Second, a sensitivity analysis revealed the most important variables for the Viability of these breeds. Third, we examined management scenarios in which one of the studbooks was closed. According to the Vortex analysis, 2 of the breeds (Knabstrupper and Jutland) will persist for the next 200 yr, whereas the smaller breed (Frederiksborg) could become extinct within 40 yr. The sensitivity analyses indicated that the variables concerning reproduction of the mares had the greatest impact, with the number of mares actively breeding being the most influential on the population forecasts. The results suggest that closing the Knabstrupper studbooks can be done only if increasing the number of mares actively breeding counteracts the loss of genetic variation attributable to such a management strategy. It is recommended, based on these results, that the number of Frederiksborg and Knabstrupper mares actively breeding must be increased to approximately 30% in the 2 breeds that are presently using only 13%, while leaving the third (Frederiksborg ) at its present 30% level. Monitoring of the breeds in the Future, however, may be exploited to adjust the breeding strategies. We suggest that the large amount of data required by Vortex makes it very useful for analyzing domestic animals because of the comprehensive data material often available. The results of this analysis accord with other studies on the Prezwalski horse, indicating robustness in the parameter sensitivity for horses.
Charles F Nicholson - One of the best experts on this subject based on the ideXlab platform.
-
smallholder dairying under transactions costs in east africa
World Development, 1997Co-Authors: Steven J Staal, Christopher L Delgado, Charles F NicholsonAbstract:Abstract It is argued that dairying is vital to Future Viability of many small farms in East Africa and that high transactions costs for dairy production and marketing limit participation by asset- and information-poor smallholders. Case studies from Kenya and Ethiopia illustrate the role of dairy cooperatives in reducing transactions costs. Analysis of the determinants of producer prices received by a sample of dairy producers near Addis Ababa suggests that different levels of access to infrastructure, assets, and information explain why they contemporaneously accept widely different producer prices for fluid milk.
-
smallholder dairying under transactions costs in east africa
Research Papers in Economics, 1996Co-Authors: Steven J Staal, Christopher L Delgado, Charles F NicholsonAbstract:It is argued that dairying is vital to Future Viability of many small farms in East Africa and that high transactions costs for dairy production and marketing limit participation by asset- and information-poor smallholders. Case studies from Kenya and Ethiopia illustrate the role of dairy cooperatives in reducing transactions costs. Analysis of the determinants of producer prices received by a sample of dairy producers near Addis Ababa suggests that different levels of access to infrastructure, assets, and information explain why different households contemporaneously accept widely different producer prices for fluid milk.
Janne Pia Thirstrup - One of the best experts on this subject based on the ideXlab platform.
-
population Viability analysis on domestic horse breeds equus caballus
Journal of Animal Science, 2009Co-Authors: Janne Pia Thirstrup, Lars A Bach, Volker Loeschcke, Cino PertoldiAbstract:In this study, we performed a population Viability analysis on 3 domestic horse breeds (Equus caballus) of Danish origin, namely, the Frederiksborg, the Knabstrupper, and the Jutland breeds. Because of their small population sizes, these breeds are considered endangered. The Vortex software simulation package was used for the population Viability analysis. First, we investigated the Future Viability of these breeds based on present demographic and environmental parameters. Second, a sensitivity analysis revealed the most important variables for the Viability of these breeds. Third, we examined management scenarios in which one of the studbooks was closed. According to the Vortex analysis, 2 of the breeds (Knabstrupper and Jutland) will persist for the next 200 yr, whereas the smaller breed (Frederiksborg) could become extinct within 40 yr. The sensitivity analyses indicated that the variables concerning reproduction of the mares had the greatest impact, with the number of mares actively breeding being the most influential on the population forecasts. The results suggest that closing the Knabstrupper studbooks can be done only if increasing the number of mares actively breeding counteracts the loss of genetic variation attributable to such a management strategy. It is recommended, based on these results, that the number of Frederiksborg and Knabstrupper mares actively breeding must be increased to approximately 30% in the 2 breeds that are presently using only 13%, while leaving the third (Frederiksborg) at its present 30% level. Monitoring of the breeds in the Future, however, may be exploited to adjust the breeding strategies. We suggest that the large amount of data required by Vortex makes it very useful for analyzing domestic animals because of the comprehensive data material often available. The results of this analysis accord with other studies on the Prezwalski horse, indicating robustness in the parameter sensitivity for horses. (Less)
-
population Viability analysis on domestic horse breeds equus caballus
Journal of Animal Science, 2009Co-Authors: Janne Pia Thirstrup, Lars A Bach, Volker Loeschcke, Cino PertoldiAbstract:In this study, we performed a population Viability analysis on 3 domestic horse breeds (Equus caballus) of Danish origin, namely, the Frederiksborg, the Knabstrupper, and the Jutland breeds. Because of their small population sizes, these breeds are considered endangered. The Vortex software simulation package was used for the population Viability analysis. First, we investigated the Future Viability of these breeds based on present demographic and environmental parameters. Second, a sensitivity analysis revealed the most important variables for the Viability of these breeds. Third, we examined management scenarios in which one of the studbooks was closed. According to the Vortex analysis, 2 of the breeds (Knabstrupper and Jutland) will persist for the next 200 yr, whereas the smaller breed (Frederiksborg) could become extinct within 40 yr. The sensitivity analyses indicated that the variables concerning reproduction of the mares had the greatest impact, with the number of mares actively breeding being the most influential on the population forecasts. The results suggest that closing the Knabstrupper studbooks can be done only if increasing the number of mares actively breeding counteracts the loss of genetic variation attributable to such a management strategy. It is recommended, based on these results, that the number of Frederiksborg and Knabstrupper mares actively breeding must be increased to approximately 30% in the 2 breeds that are presently using only 13%, while leaving the third (Frederiksborg ) at its present 30% level. Monitoring of the breeds in the Future, however, may be exploited to adjust the breeding strategies. We suggest that the large amount of data required by Vortex makes it very useful for analyzing domestic animals because of the comprehensive data material often available. The results of this analysis accord with other studies on the Prezwalski horse, indicating robustness in the parameter sensitivity for horses.
Teresa Tarifa - One of the best experts on this subject based on the ideXlab platform.
-
can a habitat specialist survive urbanization the case of the viscacha lagidium viscacia chinchillidae
Urban Ecosystems, 2014Co-Authors: Francisco E Fonturbel, Teresa TarifaAbstract:Urban growth is a strong driver of habitat degradation and loss. In spite of that, a surprising diversity of native species may survive in urban areas. In the La Paz, Bolivia metropolitan area and surroundings, local populations of “viscachas” (Lagidium viscacia) currently survive in small, isolated habitat patches. We assessed 13 study sites in 1999, 2003, and 2007 to document the effects of urban growth on L. viscacia habitats. Degree of disturbance at the study sites increased more between 1999 and 2003 than it did between 2003 and 2007 due to patterns of urban expansion. Using satellite imagery we determined that the urban area increased 566 ha (from 1987 to 2001) mostly due to southward urban area expansion down the valley where the best viscacha habitats were located. Occupied patch area decreased 74 % between 1999 and 2007, accompanied by significant increases in patch edge-to-area ratios. Currently L. viscacia populations in La Paz are experiencing a habitat attrition process. If a current urban expansion plan for La Paz is approved, about 75 % of the remaining habitat may be lost to urban development in a short time, compromising the Future Viability of this species in the metropolitan area and surroundings. Environmental regulations to control urban growth of the La Paz metropolitan area are urgently required and constitute the only hope for the survival of L. viscacia in the city.
Lars A Bach - One of the best experts on this subject based on the ideXlab platform.
-
population Viability analysis on domestic horse breeds equus caballus
Journal of Animal Science, 2009Co-Authors: Janne Pia Thirstrup, Lars A Bach, Volker Loeschcke, Cino PertoldiAbstract:In this study, we performed a population Viability analysis on 3 domestic horse breeds (Equus caballus) of Danish origin, namely, the Frederiksborg, the Knabstrupper, and the Jutland breeds. Because of their small population sizes, these breeds are considered endangered. The Vortex software simulation package was used for the population Viability analysis. First, we investigated the Future Viability of these breeds based on present demographic and environmental parameters. Second, a sensitivity analysis revealed the most important variables for the Viability of these breeds. Third, we examined management scenarios in which one of the studbooks was closed. According to the Vortex analysis, 2 of the breeds (Knabstrupper and Jutland) will persist for the next 200 yr, whereas the smaller breed (Frederiksborg) could become extinct within 40 yr. The sensitivity analyses indicated that the variables concerning reproduction of the mares had the greatest impact, with the number of mares actively breeding being the most influential on the population forecasts. The results suggest that closing the Knabstrupper studbooks can be done only if increasing the number of mares actively breeding counteracts the loss of genetic variation attributable to such a management strategy. It is recommended, based on these results, that the number of Frederiksborg and Knabstrupper mares actively breeding must be increased to approximately 30% in the 2 breeds that are presently using only 13%, while leaving the third (Frederiksborg) at its present 30% level. Monitoring of the breeds in the Future, however, may be exploited to adjust the breeding strategies. We suggest that the large amount of data required by Vortex makes it very useful for analyzing domestic animals because of the comprehensive data material often available. The results of this analysis accord with other studies on the Prezwalski horse, indicating robustness in the parameter sensitivity for horses. (Less)
-
population Viability analysis on domestic horse breeds equus caballus
Journal of Animal Science, 2009Co-Authors: Janne Pia Thirstrup, Lars A Bach, Volker Loeschcke, Cino PertoldiAbstract:In this study, we performed a population Viability analysis on 3 domestic horse breeds (Equus caballus) of Danish origin, namely, the Frederiksborg, the Knabstrupper, and the Jutland breeds. Because of their small population sizes, these breeds are considered endangered. The Vortex software simulation package was used for the population Viability analysis. First, we investigated the Future Viability of these breeds based on present demographic and environmental parameters. Second, a sensitivity analysis revealed the most important variables for the Viability of these breeds. Third, we examined management scenarios in which one of the studbooks was closed. According to the Vortex analysis, 2 of the breeds (Knabstrupper and Jutland) will persist for the next 200 yr, whereas the smaller breed (Frederiksborg) could become extinct within 40 yr. The sensitivity analyses indicated that the variables concerning reproduction of the mares had the greatest impact, with the number of mares actively breeding being the most influential on the population forecasts. The results suggest that closing the Knabstrupper studbooks can be done only if increasing the number of mares actively breeding counteracts the loss of genetic variation attributable to such a management strategy. It is recommended, based on these results, that the number of Frederiksborg and Knabstrupper mares actively breeding must be increased to approximately 30% in the 2 breeds that are presently using only 13%, while leaving the third (Frederiksborg ) at its present 30% level. Monitoring of the breeds in the Future, however, may be exploited to adjust the breeding strategies. We suggest that the large amount of data required by Vortex makes it very useful for analyzing domestic animals because of the comprehensive data material often available. The results of this analysis accord with other studies on the Prezwalski horse, indicating robustness in the parameter sensitivity for horses.
