Selection for improved carcass composition in Suffolk Sheep : Interim Results

It is likely that returns from lamb production in future will depend, much more than at present, on producing leaner carcasses. There are several short-term changes in management which could produce leaner carcasses. However, In the longer term genetic Improvement, particularly by within-breed selection In terminal sire breeds, is likely to provide permanent, cumulative and cost-effective benefits In carcass composition. In the early 1980s a research project was started at the Edinburgh School of Agriculture, using Suffolk sheep, to examine the genetic potential for Improving carcass composition In terminal sires. The work commenced with an evaluation of techniques for in vivo measurement of carcass composition (Simm, 1987) and derivation of selection indices to incorporate In vivo measurements (Simm and Dingwall, 1989). Since 1985 In vivo measurement and Index selection have been practised In the experimental flock, which now numbers about 220 ewes. This paper reports the interim results of selection.

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Genetic variation and relationship of ultrasonic measures and carcass composition in Suffolk cross lambs

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200593089 ◽

1996 ◽

Vol 1996 ◽

pp. 111-111

Author(s):

V.C. Flamarique ◽

R.M. Lewis ◽

G. Simm

Keyword(s):

Genetic Variation ◽

Selection Criteria ◽

Live Weight ◽

Ultrasonic Measurement ◽

Carcass Composition ◽

Selection Indices ◽

Terminal Sire ◽

Relationship Of ◽

The Relationship

Excess fat in lamb is regarded as an important reason for less lamb meat being purchased by consumers. This has encouraged the development and use (particularly in Terminal Sire breeds) of selection indices that can identify animals that will sire leaner progeny. These indices usually include live weight and in vivo predictors of body composition, such as an ultrasonic measurement of muscle and fat depth, as selection criteria (Simm and Dingwall, 1989). But the usefulness of such in vivo measurements as predictors of carcass composition depends on the correlation between, and the variation in, live and carcass measures. The objectives of this study were to determine the strength of the relationship between ultrasound and dissection measures of carcass composition, and the degree of genetic variation in these measures, in crossbred progeny of Suffolk rams.

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215 Selection response for meat quality and carcass composition in commercial pigs using crossbred and purebred traits as predictors

Journal of Animal Science ◽

10.1093/jas/skz258.089 ◽

2019 ◽

Vol 97 (Supplement_3) ◽

pp. 45-45

Author(s):

Emmanuel A Lozada-Soto ◽

Justin Fix ◽

Clint Schwab ◽

Francesco Tiezzi

Keyword(s):

Meat Quality ◽

Lower Cost ◽

Economic Value ◽

Cost Effective ◽

Selection Response ◽

Carcass Composition ◽

Direct Selection ◽

Selection Indices ◽

Breeding Objectives ◽

Selection For

Abstract Meat quality (MQ) and carcass composition (CC) are traits with high economic value, but their phenotyping costs makes direct selection for these traits economically unsustainable. Evaluation of traits with lower cost of collection in crossbred (CB) and purebred (PB) animals for use in selection for MQ and CC remains limited. The aim of this study was to measure the response to selection of economically important MQ and CC traits using different selection indices built on cost-effective correlated traits. Phenotypic and genomic information (using 60K SNP chips) was collected for three-way CB (n = 1227 to 5117 phenotyped, n = 1252 genotyped) and PB (n = 3,251 phenotyped, n = 1035 genotyped) Duroc animals belonging to 28 paternal half-sib families. The three breeding objectives (for which response was estimated) were intramuscular fat (IMF), slice shear force (SSF), and loin weight (LW). In total 7 different selection indices (A-G) were used to estimate the selection response for each breeding objective (Table 1). Heritability and genetic correlation parameters for all traits were estimated using GIBBS1F90. Selection response was obtained as expected response per generation weighed by the accuracy of breeding values estimated from a 4-fold cross validation, where animals were grouped based on sire relatedness. For all three breeding objectives, the index which provided best selection response was A (direct selection), with values of 0.35%, -0.72 kg, and 0.85 kg for IMF, SSF, and LW respectively. The index which provided the second-best selection response was B (color and pH traits) for all three breeding objectives, with values of 0.15%, -0.26kg, and 0.30kg for IMF, SSF, and LW respectively. Results for selection response using indices C-G can be found in Table 1. In the absence of direct selection due to high costs of phenotyping, respectable selection response can be achieved by indirect selection using traits with lower cost of collection.

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Genetic variation and relationship of ultrasonic measures and carcass composition in Suffolk cross lambs

Proceedings of the British Society of Animal Science ◽

10.1017/s0308229600030798 ◽

1996 ◽

Vol 1996 ◽

pp. 111-111

Author(s):

V.C. Flamarique ◽

R.M. Lewis ◽

G. Simm

Keyword(s):

Genetic Variation ◽

Selection Criteria ◽

Live Weight ◽

Ultrasonic Measurement ◽

Carcass Composition ◽

Selection Indices ◽

Terminal Sire ◽

Relationship Of ◽

The Relationship

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Genetic improvement of meat production in sheep and cattle -current industry schemes and future possibilities

BSAP Occasional Publication ◽

10.1017/s0263967x00003372 ◽

1988 ◽

Vol 12 ◽

pp. 202-220

Author(s):

G Simm ◽

D E Steane

Keyword(s):

Genetic Improvement ◽

Cost Effective ◽

Carcass Composition ◽

Meat Production ◽

The Past ◽

Structural Problems ◽

Early Results ◽

Beef Carcasses ◽

Terminal Sire

ABSTRACTOverfatness of lamb and beef carcasses is a problem in many countries. Genetic improvement of carcass composition, particularly in specialised terminal sire (meat) breeds, should lead to permanent, cumulative, and cost-effective improvements. In the past, selection in these breeds has been mainly on liveweight. However, the use of in vivo estimates of carcass composition is expected to lead to higher rates of progress. In ruminants index selection is likely to be most useful, and early results from selection experiments are encouraging. Although schemes for recording performance and estimating breeding values are in operation in many countries, structural problems such as small herd or flock sizes, and lack of comparisons between herds or flocks impede progress. To some extent, these problems could be overcome by cooperation amongst breeders and wider use of new statistical techniques. Genetic improvement of meat production could be further enhanced by improved techniques for in vivo estimation of carcass composition, and by use of embryo transfer to increase “annual selection intensity” of females.

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Physiological responses to selection for carcass lean content in a terminal sire breed of sheep

Proceedings of the British Society of Animal Production (1972) ◽

10.1017/s0308229600019772 ◽

1991 ◽

Vol 1991 ◽

pp. 25-25

Author(s):

N.D. Cameron

Keyword(s):

Lipid Metabolism ◽

Genetic Improvement ◽

Selection Index ◽

Carcass Composition ◽

Physiological Traits ◽

Esterified Fatty Acids ◽

Breeding Programmes ◽

Selection For ◽

Terminal Sire ◽

Sire Breed

Sheep breeding programmes for genetic improvement in carcass composition of terminal sires measure livewelght and ultrasonic backfat and muscle depths for inclusion in a selection index to predict genetic merit. Physiological traits which were genetically correlated with carcass traits could be incorporated into the selection index to increase the accuracy of selection and the rate of genetic improvement.This study examined differences in physiological traits between lines selected for high or low carcass lean content. The measured physiological traits were chosen according to their role in protein and lipid metabolism : b-hydroxybutyrate (BHB) and glucose (GLUC) : indicators of energy balance; triglyceride (TRIG) and non-esterified fatty acids (NEFA) : intermediaries of lipid metabolism; UREA and creatinine (CREA) : indicators of nitrogen / amino acid metabolism and insulin-like growth factor-1 (IGF-1): an Indicator of growth hormone status.

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Selection indices for terminal sire beef breeds

Proceedings of the British Society of Animal Production (1972) ◽

10.1017/s0308229600014045 ◽

1984 ◽

Vol 1984 ◽

pp. 44-44

Author(s):

G. Simm ◽

C. Smith ◽

J.H.D. Prescott

Keyword(s):

Growth Rate ◽

Meat Production ◽

Food Conversion ◽

Animal Products ◽

Lean Meat ◽

Biological Indices ◽

Animal Fats ◽

Selection Indices ◽

Terminal Sire

Rising living standards and an increasing awareness of the health risks of a diet high in saturated fats have led to strong consumer discrimination against animal fats. Additionally the surplusses of animal products in Europe suggest that more attention should be paid to the inputs in animal production, rather than solely increasing output. Improving the efficiency of lean meat production is therefore an important consideration in all meat animal systems. In 1976 Fowler, Bichard and Pease proposed the ‘biological indices’ lean growth rate and lean food conversion as selection criteria in pigs. These traits may be estimated as the product of growth rate (GR) or food conversion efficiency (FCE), and in vivo estimates of killing out and carcass lean proportions. However, in cattle and sheep the relatively low coefficient of variation of estimated killing out and of lean proportions, means that the biological indices are frequently dominated by GR and FCE. In such cases there may be little difference in response from selection solely on GR and FCE (Simm, 1983). The objective of the present study was to derive economic selection indices for terminal sire beef breeds, which might give appropriate economic weighting to the components of efficient lean meat production.

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Selection indices for terminal sires to improve lean meat production from sheep in the United Kingdom

Animal Science ◽

10.1017/s0003356100036667 ◽

1987 ◽

Vol 45 (1) ◽

pp. 87-96 ◽

Cited By ~ 4

Author(s):

A. C. Parratt ◽

G. Simm

Keyword(s):

Growth Rate ◽

Carcass Composition ◽

Breeding Value ◽

Meat Production ◽

Lean Meat ◽

The United Kingdom ◽

Ct Measurements ◽

Selection Indices ◽

Efficiency Of Selection ◽

Terminal Sire

AbstractSelection indices to improve lean meat production of terminal sire breeds of sheep were derived. An aggregate breeding value which comprised growth rate, killing-out proportion and carcass lean proportion was examined. Selection criteria included growth rate and ultrasonic or X-ray computer tomography (CT) estimates of carcass composition. Correlations betwen the index and the aggregate breeding value were about 0·38 for indices using ultrasonic fat measurements, and about 0·40 for those using CT measurements. Dropping ultrasonic or CT measurements from the indices reduced the correlations with the aggregate breeding value by only about 0·01 and 002 respectively, indicating that selection on growth rate alone under current economic conditions was highly efficient. Changes in economic weights, and genetic parameters had little effect on the efficiency of selection. The total national discounted value of returns from a single round of selection on the indices was expected to be between £6 and £30·5 million, depending on penetration rates of improved stock, the breeding scheme used, and with a time horizon of 20 years.

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Comparison of Seven Ultrasonic Techniques for In Vivo Estimation of Pig Carcass Composition

Proceedings of the British Society of Animal Production (1972) ◽

10.1017/s0308229600024600 ◽

1993 ◽

Vol 1993 ◽

pp. 135-135

Author(s):

C M Yates ◽

M G Owen

Keyword(s):

Carcass Composition ◽

Muscle Area ◽

Ultrasonic Techniques ◽

Selection For

There are now many ultrasonic techniques, some capable of measuring fat depth, muscle depth and muscle area, which could be used to improve selection for breeding. An evaluation of seven techniques was conducted by the Meat and Livestock Commission to enable users to select the most appropriate technique based on accuracy, practicality and cost.

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Selection for improved carcass composition in terminal sire sheep breeds

BSAP Occasional Publication ◽

10.1017/s0263967x00002251 ◽

1990 ◽

Vol 14 ◽

pp. 166-168

Author(s):

G. Simm ◽

W. S. Dingwall ◽

S. V. Murphy ◽

W. R. Brown

Keyword(s):

Carcass Composition ◽

Sheep Breeds ◽

Selection For ◽

Terminal Sire

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A selection index for lean meat production in sheep

Proceedings of the British Society of Animal Production (1972) ◽

10.1017/s0308229600034954 ◽

1993 ◽

Vol 1987 ◽

pp. 59-59

Author(s):

G. Simm ◽

W.S. Dingwall

Keyword(s):

Selection Index ◽

Live Weight ◽

High Energy ◽

Carcass Composition ◽

Meat Production ◽

Lean Meat ◽

In Vivo Measurements ◽

Terminal Sire ◽

Protein Feed

It is generally accepted that leanness of terminal sire sheep breeds should be increased. However, it is very difficult to define formally a selection goal for these breeds. Put loosely, at a given age, we probably require terminal sires with as much extra lean meat as possible, whilst minimising any increase in fat weight. In the past, selection has been mainly on weight for age, but this may actually increase fatness at the age of selection.Intuitively we expect some in vivo measurements of carcass composition to help in achieving the selection goal. In practice, in vivo measurements of carcass composition in sheep are often imprecise, though the treatment of the animals can affect the relative precision. Ad libitum feeding on a high energy, high protein feed appears to increase the variation in carcass composition of ram lambs compared to those on a lower plane of nutrition (Simm et al, 1985 compared to Cuthbertson et al, 1983). Under these conditions we were able to predict carcass composition reasonably precisely from live weight and ultrasonic measurements (means and original and residual s.d.s for carcass lean weight: 18.30, 1.60 and l.00 kg and for fat weight 13.74, 2.70 and 0.96 kg).

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