A selection index for lean meat production in sheep

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).

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

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.

Selection indices for terminal sire beef breeds

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.

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

1987 ◽  
Vol 45 (1) ◽  
pp. 87-96 ◽  
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.

An economic selection index for lean meat production in New Zealand sheep

1987 ◽  
Vol 45 (3) ◽  
pp. 465-475 ◽  
Author(s):  
G. Simm ◽  
M. J. Young ◽  
P. R. Beatson
Keyword(s):  
New Zealand ◽  
Selection Index ◽  
Live Weight ◽  
Breeding Value ◽  
Index Selection ◽  
Meat Production ◽  
Total Fat ◽  
Terminal Sire ◽  
Economic Selection ◽  
Lean Weight

ABSTRACTAn economic selection index was derived for terminal sire sheep breeds or strains, using physical and financial results from New Zealand export lamb-producing flocks. The aggregate breeding value of the index comprised carcass lean weight and carcass total fat weight. Index measurements were live weight, ultrasonic fat depth and ultrasonic muscle depth. Economic values used for lean and fat weights (NZ$5·65 and NZ$–1·2 per kg, respectively) were the change in profit per kg increase in lean or fat weight from that in the average carcass of lambs slaughtered in 1984/85. The s.d. of the aggregate breeding value was NZS3·20, and the correlation between the full index and the aggregate breeding value was 0·23. This correlation fell to 0·18, 0·15 and 0·07, respectively, when muscle depth or fat depth or muscle and fat depths were omitted from the index. Selection on the full index, or on the index omitting muscle depth was expected to lead to an increase in carcass lean weight and a slight decrease in carcass fat weight. Selection on the index omitting fat depth, or selection on live weight alone, was expected to lead to an increase in both fat and lean weights.

The consequences of index selection on carcass composition in Suffolk sheep

1999 ◽  
Vol 1999 ◽  
pp. 46-46 ◽  
Author(s):  
R. M. Lewis ◽  
G. C. Emmans ◽  
G. Simm ◽  
W. S. Dingwall ◽  
J. FitzSimons ◽  
...  
Keyword(s):  
Performance Test ◽  
Selection Index ◽  
Live Weight ◽  
Growth Index ◽  
Carcass Composition ◽  
Control Line ◽  
Lean Growth ◽  
Selection Decisions ◽  
Terminal Sire ◽  
And Control

Early in the 1980s a selection index was designed at SAC to improve the rate of lean growth in terminal sire sheep which combined ultrasound measurements of fat and muscle depth, and live weight at 150 days of age (Simm and Dingwall, 1989). Beginning in 1985, this index was applied in the SAC Suffolk flock in a performance test. In 1994, rams from a line selected on this index weighed on average 12% more (8 kg) and had 12% lower fat depth (– 0.9 mm) and 10% higher muscle depth (2.9 mm) than rams from an unselected Control line. Comparison of Selection and Control line animals has thus far been based on live predictors of carcass composition at weights substantially heavier than typical market lamb weights. The aims of this study were to test whether selection decisions based on the lean growth index produced an improvement in actual carcass composition in purebred terminal sire sheep and whether these changes persisted at live weights different from those under which selection was carried out.

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

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.

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

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.

scholarly journals 194 Carcass and Meat Quality of Pasture-raised Lamb and Goat

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 67-67
Author(s):  
Jung Lee
Keyword(s):  
Meat Quality ◽  
Energy Levels ◽  
Small Ruminants ◽  
Live Weight ◽  
High Energy ◽  
Carcass Composition ◽  
Meat Production ◽  
Sheep And Goats ◽  
Feeding Systems

Abstract Various trials have been proceeded to develop forage feeding systems that meet nutritional requirements for meat producing sheep and goats under the SCC-81 project: Sustainable Small Ruminant Production in the Southeastern United States. Small ruminants are fed most of their required nutrients from forages to increase the profit to the livestock producers. However, pasture-based production systems have a limitation because of seasonal variation of nutrient contents in pastures. This often means pasture alone does not always provide adequate nutrition for fast growing animals. Furthermore, different forms and energy levels of diets influence carcass composition and meat properties in food animals. Meat animal carcasses vary in composition through genetic, nutritional, and environmental factors. In general, dressing percentages of sheep and goats ranged from around 40% to 60%, and their shoulder and leg cuts represent more than half of their entire carcass weight. Pasture-based systems of meat production have sustained low live weight gains relative to those achieved with intensive grain-based systems. Subsequently, sheep and goats finished at pasture have produced lighter carcasses with a low fat content, which is rich in beneficial fatty acids such as alpha-linolenic and conjugated linoleic acids. Meat-producing sheep and goats with high-energy intake generally increased the juiciness, tenderness, and texture of their meat, but the consumer acceptability was lower because of higher content of fat in their meat than those from sheep and goats finished on forage diets. A brief overview of the recent works in the SCC-81 project will be presented in order to illustrate the impacts of newly developed forage feeding systems on carcass characteristics and meat quality of sheep and goats.

scholarly journals Straw or hay as environmental improvement and its effect on behaviour and production traits of fattening pigs

2008 ◽  
Vol 51 (6) ◽  
pp. 549-559 ◽  
Author(s):  
D. Jordan ◽  
S. Žgur ◽  
G. Gorjanc ◽  
I. Štuhec
Keyword(s):  
Growth Rate ◽  
Environmental Enrichment ◽  
Production Systems ◽  
Live Weight ◽  
Total Activity ◽  
Carcass Composition ◽  
Production Traits ◽  
Lean Meat ◽  
Housing Systems ◽  
Fattening Pigs

Abstract. Fattening pigs are commonly kept in intensive housing systems with slatted floor which represent a very barren environment, causing poor animal welfare. To improve such conditions a small amount of straw or hay (100 g per animal per day laid daily in a rack) was used in our study as an environmental enrichment (EE). Two replications, each including 96 fattening pigs of both sexes (3 pens of 16 females and 3 pens of 16 male castrates) from 60 kg to slaughter at average 96 kg live weight, were used to test the effect of EE and sex on behaviour, growth rate, and carcass composition. EE significantly increased the proportion of total activity during the illumination period (between 6 a. m. and 2 p. m.) on account of increased occupation with substrate (P<0.01). EE also significantly reduced time spent biting pen bars and frequency of aggressive encounters (P<0.01). The EE increased total activity in female animals during the observation period, but not in male castrates. None of the EE significantly influenced pigs‘ growth rate and lean meat percentage; however females in enriched environment grew slower and had greater lean meat percentage than the castrated males. Provision of a small amount of straw or hay to pigs in intensive housing systems can enrich barren environment in inexpensive and efficient way. Therefore such enrichment can be widely used also in large commercial pig production systems.

Selection for improved carcass composition in Suffolk Sheep : Interim Results

1990 ◽  
Vol 1990 ◽  
pp. 9-9
Author(s):  
G Simm ◽  
W S Dingwall ◽  
S V Murphy ◽  
J FitzSimons ◽  
W R Brown
Keyword(s):  
Cost Effective ◽  
Carcass Composition ◽  
Short Term ◽  
Genetic Potential ◽  
Selection Indices ◽  
Selection For ◽  
Breed Selection ◽  
Terminal Sire ◽  
Suffolk Sheep

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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