Meat Science 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 …

Effects Of Increasing Dietary Zinc Sulfate Fed To Gestating Ewes: Ii. Milk Somatic Cell Count, Microbial Populations, And Fatty Acid Composition, C. M. Page, R. M. Knuth, T. W. Murphy, D. C. Rule, B. Bisha, J. B. Taylor, W. C. Stewart

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Objective: The objective of the research was to evaluate the effects of increasing dietary Zn sulfate concentration for primiparous gestating ewes on subsequent milk SCC, intramammary microbial identifications, and fatty acid composition.

Materials and Methods: Commercial white-face (WF; n = 27) and black-face (BF; n = 24) ewes (age ≈18 mo; BW = 87.48 ± 8.37 kg) were sorted into breed-type groups and within groups ranked by BW, and then, they were randomly divided into 3 dietary supplement treatment groups: CON (n = 13; 40 mg/kg Zn; ≈1 × NASEM recommendations), Zn500 (n = 21; 500 mg/kg Zn; …

Invited Review: Mineral Nutrition Considerations For Extensive Sheep Production Systems, W. C. Stewart, J. D. Scasta, J. B. Taylor, T. W. Murphy, A. A.M. Julian

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Purpose: Our purpose is to discuss contemporary and pertinent considerations related to mineral-supplementation strategies for sheep grazing marginal rangelands in extensively managed production systems. Sources: Grey literature, peer-reviewed literature, and data (published and unpublished) from co-authors were used. Synthesis: Precision trace-mineral nutrition of sheep that are grazing extensive production systems requires a comprehensive understanding of the sheep and the grazing environment. Generally, extensive sheep production systems are found in remote geographical regions composed of marginal rangelands not suitable for cultivated crop farming or improved forages. Sheep production is subject to the accessibility and availability of grazable forage, which may vary …

Relationships Among Intramammary Health, Udder And Teat Characteristics, And Productivity Of Extensively Managed Ewes, Ryan M. Knuth, Whitney C. Stewart, Joshua B. Taylor, Bledar Bisha, Carl J. Yeoman, Megan L. Van Emon, Thomas W. Murphy

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Mastitis is an economically important disease and its subclinical state is difficult to diagnose, which makes mitigation more challenging. The objectives of this study were to screen clinically healthy ewes in order to 1) identify cultivable microbial species in milk, 2) evaluate somatic cell count (SCC) thresholds associated with intramammary infection, and 3) estimate relationships between udder and teat morphometric traits, SCC, and ewe productivity. Milk was collected from two flocks in early (<5 >d) and peak (30 to 45 d) lactation to quantify SCC (n = 530) and numerate cultivable microbial species by culture-based isolation followed by matrix-assisted laser …

Comparison Of Performance Of F1 Romanov Crossbred Ewes With Wool And Hair Breeds During Spring Lambing Under Intensive And Extensive Production Systems, Brad A. Freking, Thomas W. Murphy

Roman L. Hruska U.S. Meat Animal Research Center: Reports

The objective was to evaluate wool (Dorset and Rambouillet) and hair (Dorper, Katahdin, and White Dorper) breeds for their ability to complement Romanov germplasm in two distinct production systems by estimating direct sire and grandsire effects on lamb growth, survival, and ewe productivity traits. Rams of the five breeds (n = 75) were mated to Romanov ewes (n = 459) over a 3-yr period to produce five types of crossbred lambs (n = 2,739). Sire breed (P > 0.06) did not impact body weight or survival traits of the first-generation crossbred (F1) lambs. The productivity of retained crossbred ewes (n = …

Small Farm Husbandry: Cow, Sheep And Goat For Meat Production, Nicole Burton

Sustainability Education Resources

This course provides students with a farmer’s perspective on the sustainable management of cows, sheep and goats on a small farm. The course provides students with a clear understanding of how to think through the planning and management of cows, sheep and goats for meat production. All aspects from purchasing and nutrition to marketing and finances will be addressed. This course also brings awareness to the U.S. meat industry and supports students in becoming educated consumers and producers. Students will walk away with a rudimentary plan on how to incorporate ruminants into their small farm plan.

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. …

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 …

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, …

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. …

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 …

Controlling Sheep Meat Disorders, Michael Paton Dr

Bulletins 4000 -

No abstract provided.

Investigating Teeth Eruption And Eating Quality, Sarah Weisse, Rob Davidson, Brian Mcintyre, David Pethick, John Thompson

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

In Australia, a sheep ceases to be a lamb as soon as the eruption of its first permanent incisor teeth is evident. As part of a wider program to investigate a number of aspects of sheep meat eating quality, a project was undertaken to determine whether lamb eating quality would be compromised if sheep with partially erupted teeth continued to be classified as lamb.

Overall, the results indicated that meat from young sheep with partially erupted teeth was unlikely to be inferior in eating quality than the meat currently classified as lamb.

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 …

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 …

Control Of Cheesy Gland In Sheep, Michael Paton

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

Cheesy gland is a widespread problem in Western Australian sheep flocks. Less than 1 per cent of flocks are free of this disease, and all sheep in one line of 550 cull ewes slaughtered at Katanning Abattoir were infected.

A study of what affects new cheesy gland . infection found that shower dipping and keeping sheep under cover after shearing increased new infections. Farmers who shower dip sheep should consider vaccinating them against cheesy gland. Sheep should be let out into the open as soon as possible after shearing.

The total cost of the disease in Australia is about $30 …

Rejections Of Sheep And Lamb Carcasses Are Costly, R H. Wroth, R. J. Suiter

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

A 1976 survey of more than 48 000 sheep and 25 000 lambs slaughtered at two of Western Australia's export abattoirs has indicated a high rejection rate for W.A. carcasses. Rejections may be for disfiguring, blemishes requiring trimming or for diseases which can lead to condemnation.

Savings that producers can make by simple management changes, could thus save the industry $3.12 million a year. Reduction in other causes of rejection or further reduction in some of those mentioned id feasible but requires more research and may be more difficult to achieve.

Sheep Meat Production Trial, Department Of Agriculture, Western Australia

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

Better understanding of Middle- East, European and Asian market requirements for Australian sheep has influenced the design of a large meat production trial at Avondale Research Station.

The trial will supply basic information on sheep meat production and involves examples of breed types available in Western Australia and capable of supplying young, lean animals all the year round.