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Byaduk, Australia

Lambe N.R.,Roslin Institute | Wall E.,Roslin Institute | Ludemann C.I.,AbacusBio Pty Ltd. | Bunger L.,Roslin Institute | Conington J.,Roslin Institute
Small Ruminant Research | Year: 2014

Scottish Blackface hill sheep from two research flocks, based in environments of differing climatic severity, were selected for 8 years based on a selection index incorporating ewe and lamb traits, designed to improve flock sustainability and profitability. Compared to a control line of sheep kept at average performance, after 8 years of selection, sheep selected on this index have shown increased overall profitability, largely due to an increase in the weight of lambs at weaning (2-2.5. kg, depending on farm). A model was used to estimate greenhouse gas (GHG) emission changes in hill sheep systems when performance traits were altered, to investigate the potential to use genetic selection as a tool to reduce GHG. Results from this model suggested that the actual genetic changes observed in the hill flocks are likely to have increased GHG emissions, both at the level of the breeding ewe and per kg of lamb produced, mainly as a result of an increase in ewe mature size (2.8-3. kg difference vs. the control line after 8 years of selection). Any future selection index designed to minimise GHG emissions, would need to incur heavier penalties for increasing ewe mature weight, compared to the current economic index, which would be likely to reduce selection response in lamb growth. These changes are only likely to occur if payment or subsidy systems were to change in a way that would reward producers for reducing GHG emissions. © 2014 Elsevier B.V. Source

Smith K.F.,Australian Department of Primary Industries and Fisheries | Smith K.F.,AbacusBio Pty Ltd. | Fennessy P.F.,AbacusBio Ltd
Crop and Pasture Science | Year: 2011

Despite the large number of active programs breeding improved forage plants, relatively little is known about the weightings that breeders consciously or subconsciously give to specific traits when selecting individual plants or that agronomists and producers use when assessing the relative merits of contrasting cultivars. This is in contrast to most modern animal breeding programs where the relative merits of novel genetics may be assessed against an index-based breeding objective. These technologies have not been widely used in crop or forage plant breeding but their use in forest tree breeding is relatively common. We have assessed the usefulness of discrete choice experiment techniques in the development of weightings for specific traits in forage plant improvement based on the views of an expert panel (plant breeders and non-breeders agronomists, nutritionists, senior managers in breeding companies and consultants) asked to consider the requirements in four species (white clover, lucerne, perennial ryegrass and tall fescue). The results indicate that criteria related to abiotic stress tolerance, adaptation or the costs of pasture (root growth, drought tolerance, persistence, resistance to invertebrate pests, tolerance of hostile soil conditions) were deemed to be particularly important for white clover, while the highest-rated criteria for lucerne were not dissimilar, being tolerance of hostile soil conditions, persistence and tolerance of transient water-logging. For perennial ryegrass, three of the five highest-weighted criteria (drought tolerance, root growth, rate of recovery of pasture after water) are related to yield in environments where too much or too little water is a problem, highlighting the importance that the experts placed on the ability of the plant to withstand this important abiotic stress. For tall fescue, the highest-rated criteria were seedling vigour, drought tolerance, and persistence. Overall the preference weightings tended to reflect the perceived limitations of the various species, such as the priority of seedling vigour in tall fescue. This focus on the importance of abiotic stress is especially interesting as previous attempts to identify priorities have focused on the forage quality traits rather than analysing their importance relative to traits related to herbage yield or stress tolerance. This study highlights the importance of further work to help determine the focus of breeding objectives and selection criteria for different pasture species across production systems. © 2011 CSIRO. Source

Amer P.R.,AbacusBio Ltd | Ludemann C.I.,AbacusBio Pty Ltd. | Hermesch S.,University of New England of Australia
Journal of Animal Science | Year: 2014

The objective of this study was to develop a transparent, comprehensive, and flexible model for each trait for the formulation of breeding objectives for sow traits in swine breeding programs. Economic values were derived from submodels considering a typical Australian pig production system. Differences in timing and expressions of traits were accounted for to derive economic weights that were compared on the basis of their relative size after multiplication by their corresponding genetic standard deviation to account for differences in scale and genetic variability present for each trait. The number of piglets born alive had the greatest contribution (27.1%) to a subindex containing only maternal traits, followed by daily gain (maternal; 22.0%) and sow mature weight (15.0%). Other traits considered in the maternal breeding objective were preweaning survival (11.8%), sow longevity (12.5%), gilt age at puberty (8.7%), and piglet survival at birth (3.1%). The economic weights for number of piglets born alive and preweaning piglet survival were found to be highly dependent on the definition of scale of enterprise, with each economic value increasing by approximately 100% when it was assumed that the value of extra output per sow could be captured, rather than assuming a consequent reduction in the number of sows to maintain a constant level of output from a farm enterprise. In the context of a full maternal line index that must account also for the expression of direct genetic traits by the growing piglet progeny of sows, the maternal traits contributed approximately half of the variation in the overall breeding objective. Deployment of more comprehensive maternal line indexes incorporating the new maternal traits described would lead to more balanced selection outcomes and improved survival of pigs. Future work could facilitate evaluation of the economic impacts of desired-gains indexes, which could further improve animal welfare through improved sow and piglet survival. The results justify further development of selection criteria and breeding value prediction systems for a wider range of maternal traits relevant to pig production systems. © 2014 American Society of Animal Science. All rights reserved. Source

Hermesch S.,University of New England of Australia | Ludemann C.I.,AbacusBio Pty Ltd. | Amer P.R.,AbacusBio Ltd
Journal of Animal Science | Year: 2014

The objective of this paper was to derive economic weights for performance and survival traits of growing pigs including feed conversion ratio (FCR), daily feed intake (DFI), ADG, postweaning survival of the growing pig (SG), and carcass fat depth at the P2 site (CFD). An independent model was developed for each trait to derive economic values directly based on a typical Australian production system. This flexible approach may be used to customize economic values for different production systems and alternative trait combinations in breeding objectives. Discounted genetic expressions were used as a means of taking into account differences in frequency and timing of expression of traits to obtain economic weights. Economic values for SG were derived based on a costsaving and a lost-revenue approach. The correct formulation of the economic value of ADG depends on how feed cost is included in the breeding objective. If FCR is defined as a breeding objective trait, then savings in feed costs through earlier slaughter should not be counted in the economic value of ADG. In contrast, if DFI is included in the breeding objective instead of FCR, then feed-cost savings through earlier slaughter need to be attributed to the economic value for ADG, as a benefit from faster ADG. The paper also demonstrates that economic weightings in indexes for FCR can potentially be overestimated by 70% when it is assumed that DFI or FCR records taken from a limited duration test period reflect the corresponding trait over the full lifetime of the growing pig destined for slaughter. Postweaning survival of the growing pig was the most important breeding objective trait of growing pigs. The relative importance of each breeding objective trait in a sire-line index based on the genetic SD of each trait was 44.5, 27.0, 17.4, and 11.1% for SG, FCR, ADG, and CFD, respectively. Further studies to better clarify the extent of genetic variation that exists in SG under nucleus-farm and commercial-farm conditions are warranted, given the high economic importance of this survival trait of growing pigs. © 2014 American Society of Animal Science. All rights reserved. Source

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