15,869 research outputs found
Jointly selecting for fibre diameter and fleece weight: A market-level assessment of the QPLU$ Merino breeding project
No full textThe QPLU$ Merino breeding project began in the early 1990s. The aim of the project was to demonstrate the efficiency of using a selection index to achieve breeding objectives. A number of selection lines were created from three strains of Merino sheep. During the ten-year course of the project, selection of each line was undertaken using an index based on measurements of fleece weight and fibre diameter. Different emphases were placed on each trait in each selected line. This paper estimates the potential aggregate returns of the project to the Australian sheep and wool industries using an equilibrium displacement model.Australian sheep and wool industries, equilibrium displacement model, cross-commodity relationships, R&D evaluation, Livestock Production/Industries, Research and Development/Tech Change/Emerging Technologies, Research Methods/ Statistical Methods,
Selection for growth, muscling and fatness alters the maternal performance and intermediary metabolism of Merino ewes
No full textThere is growing interest in selectively breeding Merinos with higher growth and muscling and lower fatness. The effects of selection for these traits on ewe intermediary metabolism, body composition, reproduction and milk production and on lamb birthweight, survival and growth were studied in a series of experiments and analyses.
Ewes with higher genetic propensity for early growth had higher mature weight, reproductive rate, lamb birthweight, ewe milk production and lamb growth rate. Ewes with higher growth also had a higher circulating level of growth hormone during lactation.
Ewes with higher genetic propensity for muscling had a higher reproductive rate and produced lambs that were lighter at birth, but this did not result in lower lamb survival. Ewes with higher muscling maintained a higher condition score which may be at least partly attributed to a lower response to adrenaline at the level of the muscle in these higher muscled ewes. Similarly higher muscled ewes had lower growth hormone concentration in lactation which would result in lower mobilisation of tissues. In addition peripheral tissues were less responsive to insulin in high muscled ewes and blood glucose levels were also higher during the non-breeding state in high muscled ewes.
The genetic fatness of ewes was positively associated with lamb birthweight but only when nutrition was restricted suggesting that ewes with a higher genetic propensity for fatness can buffer lamb birthweight under periods of poor nutrition. Ewes with higher genetic fatness had lower circulating growth hormone and a greater response to insulin providing potential mechanisms for the observed higher fatness. Furthermore, response to adrenaline at the level of liver was greater in ewes with higher fatness suggestive of a higher capacity for gluconeogenesis. The combined results of this work suggest that actively selecting Merino ewes to have higher growth, muscling and fatness is likely to have positive reproduction and therefore economic outcomes
Galindo Merino, M. M. y M. C. Méndez (eds.) (2022). La lingüística del amor: de la pasión a la palabra. Pie de página editorial, 322 páginas
No full textBook review: Galindo Merino, M. M. y M. C. Méndez (eds.) (2022). La lingüística del amor: de la pasión a la palabra. Pie de página editorial, 322 páginas.Reseña del libro: Galindo Merino, M. M. y M. C. Méndez (eds.) (2022). La lingüística del amor: de la pasión a la palabra. Pie de página editorial, 322 páginas
Combined genomic evaluation of Australian Merino and Dohne Merino sheep populations
No full textHistorically, the Merino has been the dominant sheep breed in Australia having first been imported to the country over 200 years ago. In addition, starting in the late 1990s, sheep producers began importing Dohne Merino embryos from South Africa to improve on attributes such as reproduction and carcase composition. Since then, this breed has continued to expand in Australia but the number of genotyped and phenotyped purebred individuals remains low, calling into question the feasibility of genomic selection in this breed. The Australian Merino on the other hand has a very large reference population in a separate genomic evaluation. Many studies have shown that combined genomic evaluation of several populations can be advantageous in terms of accuracy when it involves genetically close populations. In particular, combined evaluations can be very advantageous for small breeds that can benefit from the large reference population of another breed. This study was based on 27,632 Australian Merino (M), Dohne Merino (D) and crossbred (C) genotyped individuals and a pedigree of more than 4 million animals and more than 5.2 million phenotypes for two wool traits (fibre diameter and greasy fleece weight) and one weight trait (yearling liveweight). The first objective of this study was to characterize the genomic structure and relationships between these populations. A Principal Component Analysis of the genomic relationship matrix as well as computations of Hudson's fixation index (Fst), that were below 0.08, revealed a low genetic differentiation between M, D and C populations. This suggests that crossbred or combined predictions may be feasible. In the following step of this work, we will investigate the accuracy of genomic evaluation in a Dohne validation population based on purebred D, purebred M, crossbred C or the combination of these three reference populations
An archaeological perspective on the nineteenth century development of land, landscape and sheep farming in the Karoo
No full textIncludes bibliographical references.The nineteenth century was one of considerable change within the Cape Colony. There was the change from Dutch VOC control to a British government early in the nineteenth century which exposed small scale Trekboer sheep farmers of the Karoo to a wider mercantile capitalism, especially with the adoption of Merino sheep for the global export market. This thesis charts the early nineteenth century history of colonial Trekboer society into the Karoo with a specific focus on the region to the north of the Roggeveld Mountains and west of the Nieuweveld Mountains. Of particular importance in this history is the change in land rights whereby title deeds and ownership were introduced by the British early in the nineteenth century. The distribution and chronology of title deeds are explored in this area of the Karoo using GIS to map and determine the chronological spread of deeded farms and possible links with environmental and ecological variability. While some correlations can be made under the assumption that better areas were claimed earlier in the nineteenth century other factors were also important. In particular the spread of Merino sheep, for wool production, from the Eastern Cape accounts for some of the geographic emphasis in title deed chronology, while technological innovations may underpin others. Furthermore, the thesis also examines the relationship between the title deeds and the distribution of corbelled buildings, a unique nineteenth century vernacular architecture associated with the Trekboer farmer
Merino and Merino-derived sheep breeds: a genome-wide intercontinental study
No full textBACKGROUND: Merino and Merino-derived sheep breeds have been widely distributed across the world, both as purebred and admixed populations. They represent an economically and historically important genetic resource which over time has been used as the basis for the development of new breeds. In order to examine the genetic influence of Merino in the context of a global collection of domestic sheep breeds, we analyzed genotype data that were obtained with the OvineSNP50 BeadChip (Illumina) for 671 individuals from 37 populations, including a subset of breeds from the Sheep HapMap dataset. RESULTS: 000359398500001Based on a multi-dimensional scaling analysis, we highlighted four main clusters in this dataset, which corresponded to wild sheep, mouflon, primitive North European breeds and modern sheep (including Merino), respectively. The neighbor-network analysis further differentiated North-European and Mediterranean domestic breeds, with subclusters of Merino and Merino-derived breeds, other Spanish breeds and other Italian breeds. Model-based clustering, migration analysis and haplotype sharing indicated that genetic exchange occurred between archaic populations and also that a more recent Merino-mediated gene flow to several Merino-derived populations around the world took place. The close relationship between Spanish Merino and other Spanish breeds was consistent with an Iberian origin for the Merino breed, with possible earlier contributions from other Mediterranean stocks. The Merino populations from Australia, New Zealand and China were clearly separated from their European ancestors. We observed a genetic substructuring in the Spanish Merino population, which reflects recent herd management practices. CONCLUSIONS: Our data suggest that intensive gene flow, founder effects and geographic isolation are the main factors that determined the genetic makeup of current Merino and Merino-derived breeds. To explain how the current Merino and Merino-derived breeds were obtained, we propose a scenario that includes several consecutive migrations of sheep populations that may serve as working hypotheses for subsequent studies
La transferibilidad de los permisos de maternidad y paternidad en la encrucijada. Entrevista con Patricia Merino
No full textWe present a dialogue held in the fall of 2019 with Patricia Merino, master`s degree in feminist studies from the Complutense University of Madrid, is the author of the essay Maternidad, igualdad y fraternidad: las madres como sujeto político en las sociedades postlaborales and, is the spokeswoman for the Platform of Feminist Mothers for the Expansion of Transferable Permits too. We talked with her about feminism and PETRA's trajectory and its political goals, about the mothers as a political subject as well as of the need for more support for parenting and childhood. We address, especially, the critical stance that PETRA supports against the approval of Royal Decree-Law 6/2019, which extended to 4 months the non-transferable paternity rights in the Spain.Presentamos un diálogo realizado en el otoño de 2019 con Patricia Merino, Máster en Estudios Feministas por la Universidad Complutense de Madrid, autora del ensayo Maternidad, igualdad y fraternidad: las madres como sujeto político en las sociedades postlaborales y portavoz de la Plataforma de Madres Feministas por la Ampliación de los Permisos Transferibles. Hablamos de feminismo, de la trayectoria de la PETRA y sus objetivos políticos, de las madres como sujeto político, así como de la necesidad de más ayudas a la crianza y a la infancia. Abordamos, especialmente, la postura crítica que sostiene la plataforma PETRA frente a la aprobación del Real Decreto-ley 6/2019, que ampliará progresivamente hasta los 4 meses los derechos de paternidad intransferibles en España
Galindo Merino, M. M. y M. C. Méndez (eds.) (2022). La lingüística del amor: de la pasión a la palabra. Pie de página editorial, 322 páginas
No full textReseña del libro: Galindo Merino, M. M. y M. C. Méndez (eds.) (2022). La lingüística del amor: de la pasión a la palabra. Pie de página editorial, 322 páginas.</jats:p
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