Genetics and Genomics Commons^™

Genotype By Environment Interaction And Heteroscedasticity Influence The Expression Of Parasite Resistance In Katahdin Sheep, Brian C. Arisman, Joan M. Burke, James L. M. Morgan, Ronald M. Lewis

Department of Animal Science: Faculty Publications

Increasingly, sheep producers are choosing breeds that express resistance to gastrointestinal parasites due to reduced efficacy of anthelminthic drugs. One such breed is Katahdin. Katahdins are raised in various climates and management systems in the United States, which can be combined into eco-management clusters to describe production environments more holistically. The objectives of this study were to determine if genotype by environment interaction (G × E) and heteroscedasticity existed across these eco-management clusters for traits indicative of parasite resistance. Body weights (BW), FAMACHA scores (FAM), and fecal egg counts (FEC) were collected at around 90 d in 3,527 Katahdin lambs …

Clustering Climate And Management Practices To Define Environmental Challenges Affecting Gastrointestinal Parasitism In Katahdin Sheep, Brian C. Arisman, Joan M. Burke, James L. M. Morgan, Ronald M. Lewis

Department of Animal Science: Faculty Publications

Gastrointestinal nematodes (GIN) negatively affect the performance and well-being of sheep. Due to anthelmintic resistance, GIN are difficult to control leading producers to choose breeds that can exhibit resistance to parasitism. An example is Katahdin sheep. Katahdins are raised in various climates and management systems in the United States. These environmental factors can be combined to form eco-management groupings or clusters. We hypothesized that GIN challenge varies predictably based on the characteristics of these environmental clusters. Forty Katahdin producers from across the United States were surveyed for management information, with body weights (BW), fecal egg counts (FEC), and FAMACHA scores …

Genetic Structure And Admixture In Sheep From Terminal Breeds In The United States, Kimberly M. Davenport, C. Heimke, S. D. Mc Kay, J. W. Thorne, Ronald M. Lewis, Todd Taylor, B. M. Murdoch

Department of Animal Science: Faculty Publications

Selection for performance in diverse production settings has resulted in variation across sheep breeds worldwide. Although sheep are an important species to the United States, the current genetic relationship among many terminal sire breeds is not well characterized. Suffolk, Hampshire, Shropshire and Oxford (terminal) and Rambouillet (dual purpose) sheep (n = 248) sampled from different flocks were genotyped using the Applied Biosystems Axiom Ovine Genotyping Array (50K), and additional Shropshire sheep (n = 26) using the Illumina Ovine SNP50 BeadChip. Relationships were investigated by calculating observed heterozygosity, inbreeding coefficients, eigenvalues, pairwise Wright’s FST estimates and an identity by state matrix. …

Genome-Wide Association Study To Identify Genetic Loci Associated With Gastrointestinal Nematode Resistance In Katahdin Sheep, G. M. Becker, K. M. Davenport, Joan M. Burke, Ronald M. Lewis, J. E. Miller, J. L.M. Morgan, D. R. Notter, B. M. Murdoch

Department of Animal Science: Faculty Publications

Resistance to gastrointestinal nematodes has previously been shown to be a moderately heritable trait in some breeds of sheep, but the mechanisms of resistance are not well understood. Selection for resistance currently relies upon faecal egg counts (FEC), blood packed cell volumes and FAMACHA visual indicator scores of anaemia. Identifying genomic markers associated with disease resistance would potentially improve the selection process and provide a more reliable means of classifying and understanding the biology behind resistant and susceptible sheep. A GWAS was conducted to identify possible genetic loci associated with resistance to Haemonchus contortus in Katahdin sheep. Forty animals were …

Genetic Structure And Admixture In Sheep From Terminal Breeds In The United States, Kimberly M. Davenport, C. Hiemke, Stephanie D. Mc Kay, J. W. Thorne, Ronald M. Lewis, Todd Taylor, B. M. Murdoch

Department of Animal Science: Faculty Publications

Selection for performance in diverse production settings has resulted in variation across sheep breeds worldwide. Although sheep are an important species to the United States, the current genetic relationship among many terminal sire breeds is not well characterized. Suffolk, Hampshire, Shropshire and Oxford (terminal) and Rambouillet (dual purpose) sheep (n = 248) sampled from different flocks were genotyped using the Applied Biosystems Axiom Ovine Genotyping Array (50K), and additional Shropshire sheep (n = 26) using the Illumina Ovine SNP50 BeadChip. Relationships were investigated by calculating observed heterozygosity, inbreeding coefficients, eigenvalues, pairwise Wright’s FST estimates and an identity by state matrix. …

Sheep Updates 2016, Mick Keogh, David Cornish, Michael Chilvers, Gerry Hinkley, Danielle England, Rosemary Bartle, Brad Wooldridge, Norm Santich, John Young, Ashley Herbert, Jamie Heinrich, Graeme Howie, Bruce Mullan

Sheep Updates

This session covers eleven papers from different authors:

1. Forward, Dr Bruce Mullan, Director Sheep Industry Development, Department of Agriculture and Food Western Australia

2. The Australian sheep industry in 2025, Mick Keogh, Australian Farm Institute

3. Decision making in a risky environment, David Cornish, Cornish Consulting

4. Business Transitioning, Michael Chilvers, Nile Tasmania

5. Advisory Boards in WA Agriculture - making life 'easier' for everyone, Gerry Hinkley, Producer, Tincurrin and Danielle England, Aginnovate

6. Principles of Successful Family Business Succession Strategies, Rosemary Bartle, Succession Planning Facilitator, Rabobank

7. Diversifying the Feedbase...is the …

Sheep Updates 2015 - Merredin, Bruce Mullan, Kate Pritchett, Kimbal Curtis, Chris Wilcox, Lynne Bradshaw, Geoff Lindon, Katherine Davies, Joe Young, Stephen Lee, Dawson Bradford, Khama Kelman, Lucy Anderton, Jaq Pearson, Jackie Jarvis, Ben Patrick

Sheep Updates

This session covers fourteen papers from different authors:

1. The Sheep Industry Business Innovation project, Bruce Mullan, Sheep Industry Development Director, Department of Agriculture and Food, Western Australia

2. Western Australian sheep stocktake, Kate Pritchett and Kimbal Curtis, Research Officers, Department of Agriculture and Food, Western Australia

3. Wool demand and supply - short term volatility, long term opportunities, Chris Wilcox, Principal of Poimena Analysis

4. Myths, Facts and the role of animal welfare in farming, Lynne Bradshaw, president, RSPCA WA

5. Latest research and development on breech strike prevention, Geoff Lindon, Manager Productivity and Animal Welfare, AWI

6. …

Sheep Updates 2015 - Katanning, Bruce Mullan, Kate Pritchett, Kimbal Curtis, Chris Wilcox, Mike Hyder, Leigh Sonnerman, Lynne Bradshaw, Geoff Lindon, Katherine Davies, Joe Young, Stephen Lee, Ian Robertson, Lucy Anderton, Hayley Norman, Ed Barrett-Lennard, Jackie Jarvis, Ben Patrick

Sheep Updates

This session covers fourteen papers from different authors:

1. The Sheep Industry Business Innovation project, Bruce Mullan, Sheep Industry Development Director, Department of Agriculture and Food, Western Australia

2. Western Australian sheep stocktake, Kate Pritchett and Kimbal Curtis, Research Officers, Department of Agriculture and Food, Western Australia

3. Wool demand and supply - short term volatility, long term opportunities, Chris Wilcox, Principal of Poimena Analysis

4. Lifetime management for maternal ewes, Mike Hyder, Research Officer, Department of Agriculture and Food, Western Australia

5. National Livestock Identification System (NLIS) for sheep and goats - what is the NLIS database? Leigh Sonnermann, …

Sheep Updates 2015 - Moora, Bruce Mullen, Kate Pritchett, Kimbal Curtis, Daniel Real, Jaq Pearson, Lynne Bradshaw, Geoff Lindon, Katherine Davies, Kevin Hepworth, Stephen Lee, Dawson Bradford, Lucy Anderton, Jackie Jarvis, Ben Patrick

Sheep Updates

This session covers thirteen papers from different authors:

1. The Sheep Industry Business Innovation project, Bruce Mullan, Sheep Industry Development Director, Department of Agriculture and Food, Western Australia

2. Western Australian sheep stocktake, Kate Pritchett and Kimbal Curtis, Research Officers, Department of Agriculture and Food, Western Australia

3. Tedera - a perenial forage legume to reduce your supplementary feeding in summer and autumn, Dr. Daniel Real, Senior Plant Breeder, Department of Agriculture and Food, Western Australia

4. National Livestock Identification System (NLIS) for sheep and goats - what is the NLIS database? Jac Pearson, Biosecurity Officer, Department of Agriculture and …

Sheep Updates 2015 - Ravensthorpe, Bruce Mullan, Kate Pritchett, Kimbal Curtis, Chris Wilcox, Mike Hyder, Leigh Sonnerman, Lynne Bradshaw, Geoff Lindon, Katherine Davies, Joe Young, Stephen Lee, Ian Robertson, Lucy Anderton, Hayley Norman, Ed Barrett-Lenard, Jackie Jarvis, Ben Patrick

Sheep Updates

This session covers fourteen papers from different authors:

1. The Sheep Industry Business Innovation project, Bruce Mullan, Sheep Industry Development Director, Department of Agriculture and Food, Western Australia

2. Western Australian sheep stocktake, Kate Pritchett and Kimbal Curtis, Research Officers, Department of Agriculture and Food, Western Australia

3. Wool demand and supply - short term volatility, long term opportunities, Chris Wilcox, Principal of Poimena Analysis

4. Lifetime management for maternal ewes, Mike Hyder, Research Officer, Department of Agriculture and Food, Western Australia

5. National Livestock Identification System (NLIS) for sheep and goats - what is the NLIS database? Leigh Sonnermann, …

Comparative Digestibility By Cattle Versus Sheep: Effect Of Forage Quality, S. A. Soto-Navarro, R. Lancaster, C. Sankey, B. M. Capitan, B. P. Holland, L. A. Balstad, C. R. Krehbiel

Department of Animal Science: Faculty Publications

The objective was to determine the effect of forage quality on apparent total tract digestibility and ruminal fermentation in cattle versus sheep. Five yearling English crossbred (Hereford × Angus) steers (440.4 ± 35.6 kg of initial BW) and 5 yearling whiteface (Rambouillet × Columbia × Debouillet) wethers (44.4 ± 4.6 kg of initial BW), each fitted with a ruminal cannula, were randomly assigned to 1 of 3 forage sources within ruminant specie, and the study was conducted over 3 periods. For forage source, both animal and period served as the blocking factor with all forage sources represented once within each …

Index Selection In Terminal Sires Improves Early Lamb Growth, G. C. Márquez, W. Haresign, M. H. Davies, G. C. Emmans, Rainer Roehe, L Bünger, G. Simm, Ronald M. Lewis

Department of Animal Science: Faculty Publications

The use of terminal sires (TS) for crossbreeding is integral to the UK sheep industry where approximately 71% of market lambs are sired by TS rams. Early growth of these crossbred lambs affects profitability. The objectives of this study were i) to evaluate the effectiveness of index selection among TS on BW and ADG of their crossbred offspring; and ii) to compare the efficacy of that selection within TS breeds. The most widely used TS breeds in the United Kingdom are Charollais, Suffolk, and Texel. These participated in sire referencing schemes in which they were evaluated on a lean growth …

Feed Intake Of Sheep As Affected By Body Weight, Breed, Sex, And Feed Composition, R. M. Lewis, G. C. Emmans

Department of Animal Science: Faculty Publications

The hypotheses tested were that genetic size-scaling for mature BW (A, kg) would reduce variation in intake between kinds of sheep and that quadratic polynomials on u = BW/A with zero intercept would provide good descriptions of the relationship between scaled intake (SI, g/A0.73 d) and degree of maturity in BW (u) across feeds of differing quality. Both sexes of Suffolk sheep from 2 experimental lines (n = 225) and from 3 breed types (Suffolk, Scottish Blackface, and their cross; n = 149) were recorded weekly for ad libitum feed intake and BW; recording of intake was from weaning through, …

Genetic Relationship Between Longevity And Objectively Or Subjectively Assessed Performance Traits In Sheep Using Linear Censored Models, W. Mekkaway, Rainer Roehe, Ronald M. Lewis, M. H. Davies, L. Bünger, G. Simm, W. Haresign

Department of Animal Science: Faculty Publications

Genetic parameters of longevity in crossbred mule ewes, and genetic relationships among longevity, growth, body composition, and subjectively assessed traits on mule lambs and ewes have been estimated using Bayesian linear censored models. Additionally, the genetic associations between longevity and culling reasons were examined. Data comprised 1,797 observations of mule ewes for longevity, culling reasons, growth, body composition, mouth scores, and type traits. Longevity was defined as the time (in years) from 2 yr of age (the age at first lambing of most ewes) to culling or death. Censored data (i.e., observations for which only the lower bound of the …

Sheep Updates 2007 - Part 2, Ian Mcfarland, Catherine Stockman, Anne Barnes, David Pethick, Jenny Davis, Brett Thompson, Ron Leng, Sally Pieruzzini, Elizabeth Jackson, Mohammed Quaddus, Nazrul Islam, John Stanton, Melanie Dowling

Sheep Updates

This session covers six papers from different authors:

CONCURRENT SESSIONS

FINISHING LAMB AND BEEF

1. Precision Feedlot Lamb, Ian McFarland, Department of Agriculture and Food, Western Australia

2. Feeding sheep under high heat load did not decrease intake of feedlot rations, Catherine Stockman, Department of Agriculture and Food, Western Australia & Murdoch University, Anne Barnes, Murdoch University David Pethick, Murdoch University

3. Taking the stress out of fifishing lambs and cattle - EasyFeed solutions, Jenny Davis, Brett Thomson, Milne AgriGroup, Welshpool WA, Ron Leng, Emeritus Professor, University of New England, Armidale, NSW

WOOL

4. DAFWA …

Sheep Updates 2005 - Part 7, S. M. Liu, A. C. Schlink, J. R. Williams, M. E. Dowling, J. C. Greeff, Roy Butler, Keith Croker, L. G. Butler, Rob Davidson, Ken Hart, Doug Harrington, Mario D'Antuono, Julian Gardner, Geoff Duddy, R. G. Woodgate, A. Le Feuvre, A Bailey, R. B. Besier, N. Campbell, I. Carmichael, S. Love, Richard Stovold

Sheep Updates

This session covers eight papers from different authors:

POSTERS

1. Sulpher in wool and its implications for fleece weight and sheep health, SM Liu, AC Schlink, JR Williams, CSIRO Livestock Industries Wembley WA, ME Dowling,JCGreef, Department of Agriculture Western Australia.

2. Stubbles for sheep: a reality check, Roy Butler, Keith Croker, Department of Agriculture Western Australia.

3. Genetic benchmarking using artificial insemination, LC Butler, JC Greeff, Department of Agriculture Western Australia.

4. The potential lambing performances of ewes in mixed age flocks, Kieth Croker, Department of Agriculture Western Australia, Rob Davidson, WAMMCO International, formally University of Western Australia, Ken Hart, …

Effects Of Food Quality On Growth And Carcass Composition In Lambs Of Two Breeds And Their Cross, R. M. Lewis, J. M. Macfarlane, G. Simm, G. C. Emmans

Department of Animal Science: Faculty Publications

The effects offood quality, breed type and sex (ram and ewe) on Iamb growth and carcass composition, and their changes throughout growth, were measured. The three breed typeswereScottish Blackface (B; no. = 24), Suffolk (S; no. = 28) and their reciprocal crosses (X; no. 33). The lambs had free access to a nutritionally non-limiting food, H, or a bulky food, L. Each lamb was scanned using X-ray computed tomography to measure the weights offat, lean and bone in the carcass at three degrees of maturity (0·30, 0·45 and 0·65) in live weight. Live weight and food intake data were recorded …

Effects Of Index Selection On The Performance And Carcass Composition Of Sheep Given Foods Of Different Protein Concentrations Ad Libitum., R. M. Lewis, G. C. Emmans, G. Simm

Department of Animal Science: Faculty Publications

Sheep of a line selected on an index to increase carcass lean content at 150 days of age (selected (S); no. = 90), and an unselected control line (control (C); no. = 90), were given ad libitum foods of three different protein concentrations (192, 141 and 120 g/kg dry matter). Growth was measured from about 21 to 114 kg live weight. The carcasses of each line were analysed for lean, fat and bone at three widely varying weights in both males and females. Level of protein did not affect the extent to tohidi S was superior to C in the …

Effects Of Two Dried Forages, And A Choice Between Them, On Intake, Growth And Carcass Composition In Lambs Of Two Breeds And Their Cross, R. M. Lewis, J. M. Macfarlane, G. C. Emmans

Department of Animal Science: Faculty Publications

The effects of for age type, breed type and sex on lamb growth and carcass composition, and their changes throughout growth, were measured. The three breed types were Scottish Blackface (no. =31), Suffolk (no. =28) and their reciprocal cross (no. =30). The lambs were given ad libitum a pelleted rye grass alone, pelleted lucerne alone or a choice of both. Each lamb was scanned using X-ray computed tomography to measure the weights of fat, lean and bone in the carcass at three proportions of mature body weight (0-30, 0·45 and 0·65). Live weights and food intake data were recorded weekly. …

Sheep Updates 2003 - Wool, Richard Coole, Stephen Gherardi, Chris Oldham, K. Curtis, J. Stanton, Johan Greeff, Chris Oldham, Mike Hyder, Beth Pagamoni, Andrew Thompson, Tom Plaisted, Kazue Tanaka, Mike Ferguson, Darren Gordon, Andrew Peterson, Peter Sommerville

Sheep Updates

This session covers six papers from different authors:1.‘Pastures from space’ - an opportunity to increase the profitability of sheep production Richard Coole Farmer Kojonup W.A. Stephen Gherardi Chris Oldham Department of Agriculture Western Australia 2. K. Curtis Department of Agriculture WA J. Stanton Department of Agriculture WA and Curtin University 3. Is selection of ewe hogget replacement on measurement profitable? Johan Greeff Department of Agriculture of Western Australia 4. Optimising the nutrition/grazing management of ewe flocks Chris Oldham Mike Hyder Beth Paganoni Department of Agriculture of Western Australia Andrew Thompson Department of Primary Industries, Hamilton, Victoria Tom Plaisted Kazue Tanaka …

Sheep Updates 2003 - Husbandry, Paul Barrett, Kevin Bell, J Greeff, L. Butler, S. Brown, K. Hart, A. Gray, John Karlsson, Paula Coombe, Ron Mctarrart, David Scobie, Sandy White

Sheep Updates

This session covers seven papers from different authors:1. Setting up a successful, low input feedlot Paul Barrett, ‘Bimberdong’ Jerramungup 2. Effective mineral supplementation of sheep Kevin Bell, Sheep Management and Production Consultants, Kojonup, WA 3. Genetic benchmarking for WA sheep producers J. Greeff, L. Butler, S. Brown, K. Hart and A. Gray Department of Agriculture Western Australia 4. Does selecting sheep for low WEC reduce scouring? John Karlsson, Johan Greeff and Paula Coombe, Department of Agriculture Western Australia 5. Summer quarters for sheep - stubbles Ron McTaggart, Department of Agriculture Western Australia, Albany 6. Thinking about breeding Easy Care Sheep? …

The Ability Of The N-Alkane Technique To Estimate Intake And Diet Choice Of Sheep, R. M. Lewis, A. M. Magadlela, N. S. Jessop, G. C. Emmans

Department of Animal Science: Faculty Publications

This study assessed the efficacy of the n-alkane technique to estimate intake and diet composition in animals given single foods or a choice of two. In thefirst experiment intakes of pelleted ryegrassand lucerne, given eitheralone or as a choice, were measured in lambshoused indoors in individual pens. Each of the three feeding treatments was given to 12 lambs at two degrees of maturity (0.30 and 0·45 of estimated mature sizes). The 12 lambs were constituted as three replicates of the two sexes of each of two breeds. The measured intakes werecompared with those estimated using the n-alkanes C31 andC33, found …

Genetic Relationships Between Visual And Objective Measures Of Carcass Composition In Crossbred Lambs, H. E. Jones, G. Simm, W. S. Dingwall, R. M. Lewis

Department of Animal Science: Faculty Publications

The aim of this study was to estimate genetic and phenotypic (coroariances between objective measures and carcass visual scores, as a test of the potential value afvisual scores in selection programmes to improve carcass composition in crossbred lambs. In each of 1986, 1987 and 1988, 22 Suffolk rams were chosen with either high or low scores on an index designed to increase lean growth rate. These rams were joined with 18 to20 crossbred ewes each and theirlambs were grov.J11 on grass to one of three target live weights (35·5, 41·5 and 47·0 kg) for slaughter. The carcasses of 1881 lambs …

Identification Of A Genetic Marker For Litter Size In Sheep, Olivia Price

Undergraduate Honors Capstone Projects

The purpose of this experiment was to determine if the estrogen receptor gene (ESR) could be used as a genetic marker for litter size in sheep. The estrogen receptor gene was chosen because it has been successfully used as a genetic marker for litter size in swine. In this study, DNA dilutions from two experimental flocks, totaling approximately 200 animals, were used. Amplification of exon 1/intron 1 of the ESR gene was performed using PCR. Initial results indicated a polymorphism in the gene when cut with the restriction enzyme Ava ll. It appeared that the gene contained a deletion with …

Clones Help Develop Ewe Feeding Strategy, Myra Yelland, Rob Kelly, John Davies, Johan Greeff

Journal of the Department of Agriculture, Western Australia, Series 4

Cloned sheep are not a new animal to the researchers of Agriculture WA, but the method that produced Dolly is.

Cloned sheep have been produced at the great Southern Research Institute as early as the mid 1980s. Myra Yelland, Rob Kelly, John Davies and Johan Greef outline how clones are used in experimental studies on wool production

Better Flock Benchmarking From Wether Trials, David Windsor, Bronwyn Clarke

Journal of the Department of Agriculture, Western Australia, Series 4

Genetic links between wether trials put in place by Agriculture Western Australia's Wool Program are helping farmers benchmark the productivity of their flocks on a statewide basis. David Windsor and Bronwyn Cklarke report on the progress to date.

Ewe Fertility In The Star Accelerated Lambing System, R. M. Lewis, D. R. Notter, D. E. Hogue, B. H. Magee

Department of Animal Science: Faculty Publications

Effects of environmental factors such as ewe age, season of exposure, and time from lambing to exposure on fertility were evaluated using records on 1,084 Dorset ewes in the STAR accelerated lambing system. The STAR program consisted of five 30-d concurrent breeding and lambing periods per year beginning on January 1, March 15, May 27, August 8, and October 20. Fertility in the flock changed in a cyclic and predictable fashion during the year. Changes in prolificacy were less consistent but also tended to show cyclic variation. Matings that occurred within the typical breeding season (August, October, and January) were …

Sheep And Wool Industries Need To Improve Their Performance, Rob Kelly, Tim Marshall

Journal of the Department of Agriculture, Western Australia, Series 4

Today in Western Australia, sheep are run at slightly higher stocking rates, are achieving greater lambing percentages (up JO per cent) and higher wool cuts per animal ( up 0. 6 kg greasy) than in the 1960s. When all components of production are considered, the productivity of sheep fanns has increased by 2. 7 per cent per year over the past 35 years.

The challenge of the next decade is to achieve substantially greater rates of improvement than for past years if the sheep and wool industries are to maintain their significant place in Western Australian agriculture.

Artificial Insemination Of Ewes With Frozen Semen, David Windsor

Journal of the Department of Agriculture, Western Australia, Series 4

The judicious use of artificial insemination (Al) of ewes with frozen semen by ram breeders offers substantial gains for wool producers, but it promises even greater benefits if it can be used more widely within commercial breeding flocks.

In the Western Australian dairy industry, for example, genetic gains between 1971 and /986 are estimated to have been three times as great in herds bred by Al as in herds that were mated naturally.

Embryo Transfer In Sheep, Andras Szell

Journal of the Department of Agriculture, Western Australia, Series 4

The application of artificial breeding in the sheep industry has increased substantially over the past decade.

This article outlines the potential uses and benefits of embry transfer in sheep and describes the procedures involved.