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.

Selection indices to improve the efficiency of lean meat production in cattle

1986 ◽  
Vol 42 (2) ◽  
pp. 183-193 ◽  
Author(s):  
G. Simm ◽  
C. Smith ◽  
J. H. D. Prescott
Keyword(s):  
Growth Rate ◽  
Birth Weight ◽  
Conversion Efficiency ◽  
Breeding Value ◽  
Meat Production ◽  
Food Conversion ◽  
Lean Meat ◽  
Selection Indices ◽  
Efficiency Of Selection ◽  
Food Conversion Efficiency

ABSTRACTSelection indices to improve the efficiency of lean meat production in cattle were derived with an aggregate breeding value which comprised growth rate, food conversion efficiency, killing-out proportion and carcass lean proportion. Index measurements were growth rate, food conversion efficiency and ultrasonic fat area. Relative economic values of traits in the aggregate breeding value were calculated for an 18/20-month beef system, assuming a fixed national output of lean meat. Literature estimates of phenotypic and genetic parameters were used. Two indices were derived, one with a complete restriction on genetic changes in birth weight, and the other without restriction. Correlations between the index and the aggregate breeding value were 0·53 for the restricted index, and 0·57 for the unrestricted index. The maximum proportional reduction in expected economic response, due to complete restriction of birth weight was about 0·08. Selection on either index would actually lead to a slight decrease in carcass lean proportion, but this was less than the decrease expected from selection solely on growth rate. Correlations between the indices and the aggregate breeding value (measuring the accuracy of selection) fell by only about 0·01 when ultrasonic measurements were omitted from the index, but fell by about 0·09 when food conversion efficiency was omitted. Sensitivity of the indices to changes in parameters was also examined. With proportional changes of ±0·5 in individual economic weights, or absolute changes of ±0·2 in genetic correlations or −0·2 in heritabilities, the efficiency of selection ranged from 0·93 to 1·00.

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.

Genetic parameters of lamb carcase composition at three endpoints; age, weight and fat cover.

1993 ◽  
Vol 1993 ◽  
pp. 104-104
Author(s):  
G.E. Pollott ◽  
D.R. Guy ◽  
D. Croston
Keyword(s):  
Genetic Parameters ◽  
Common Point ◽  
Breeding Value ◽  
Meat Production ◽  
Lean Meat ◽  
Fixed Weight ◽  
Breeding Programmes ◽  
The Common ◽  
Terminal Sire ◽  
The Relationship

The common point at which lambs are compared is an important aspect of selection programmes for lamb carcase composition. Terminal sire flocks in the Meat and Livestock Commission's (MLC) Sheepbreeder scheme have an estimated breeding value for lean meat production calculated on their lambs at a fixed age, 20 or 21 weeks depending on the breed. However, lambs sold for slaughter from commercial flocks are killed at a commercially acceptable fat cover. In addition, many of the estimates of genetic parameters used to estimate breeding values for carcase characteristics have been calculated at a fixed weight. Little information is available on the relationship between genetic parameters calculated at these three endpoints or the effect of selecting lambs at one endpoint in breeding programmes and using a second endpoint for the slaughter generation. These issues are investigated in this paper.

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.

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.

Understanding the impact of sire lean meat yield breeding value on carcass composition, meat quality, nutrient and mineral content of Australian lamb

Meat Science ◽  
2020 ◽  
Vol 170 ◽  
pp. 108236
Author(s):  
Matthew I. Knight ◽  
Kym L. Butler ◽  
Nick P. Linden ◽  
Viv F. Burnett ◽  
Alex J. Ball ◽  
...  
Keyword(s):  
Meat Quality ◽  
Mineral Content ◽  
Carcass Composition ◽  
Breeding Value ◽  
Meat Yield ◽  
Lean Meat ◽  
The Impact

Evaluation of specific populations of commercial pigs produced in Québec for feed performance, carcass yield and lean meat colour

1995 ◽  
Vol 75 (4) ◽  
pp. 517-524 ◽  
Author(s):  
K. L. Hammell ◽  
J. P. Laforest ◽  
J. J. Dufour
Keyword(s):  
Growth Rate ◽  
Body Composition ◽  
Carcass Composition ◽  
The Body ◽  
Feed Consumption ◽  
Feed Conversion ◽  
Carcass Yield ◽  
Lean Meat ◽  
Key Words Pig ◽  
Meat Colour

Data from approximately 850 commercial pigs tested in 12 trials, from 1987 to 1990 at the Beaumont test station in Québec were used to determine the effect of growth rate and body composition on growth performance, carcass yield and lean meat colour. Pigs were housed four to a pen and were fed commercial diets. Feed intake and growth rate were measured during the test, and carcass measurements were taken at slaughter and at 24 or 72 h following slaughter. The different groups of pigs were defined according to a 2 × 2 factorial, with one factor being the growth rate [fast growth (FG) or slow growth (SG)] and the second factor being the body composition of the carcass [fat (F) or lean (L)]. The FG commercial pigs reach market weight at a younger age with lower overall feed consumption and generally a better feed conversion than SG pigs. Furthermore, FG pigs have more backfat, longer carcasses and a slightly darker meat. The L commercial pigs had similar growth performances with a better lean meat yield than the F commercial pigs. Growth variables and composition of the carcass had little effect on the meat characteristics measured. The proportion of barrows compared to gilts was higher in the FG and F groups than in the SG and L groups, which could account for some of the differences observed between groups. However, the rate of growth and the type of body composition affected the growth and feed consumption performances as well as the carcass yield in a similar way for both sexes. Overall, less than 3% and less than 2% of the pigs produced meat with a colour standard of 1 (extremely pale) or 5 (extremely dark), respectively. The SG-L group had a slightly higher proportion of pigs with a pale meat colour compared to the other groups. Key words: Pig, backfat, growth rate, carcass composition, meat colour

The growth and development of nine European sheep breeds. 1. British breeds: Scottish Blackface, Welsh Mountain and Shetland

1997 ◽  
Vol 65 (3) ◽  
pp. 409-426 ◽  
Author(s):  
N. C. Friggens ◽  
M. Shanks ◽  
I. Kyriazakis ◽  
J. D. Oldham ◽  
T. H. McClelland
Keyword(s):  
Growth Rate ◽  
Growth And Development ◽  
Live Weight ◽  
Growth Function ◽  
Carcass Composition ◽  
Full Description ◽  
Meat Production ◽  
Mature Weight ◽  
Pelleted Diet ◽  
Entire Male

AbstractThe objective of this study was to assess the growth and development of carcass composition of entire male and female lambs of three British hill breeds (Scottish Blackface, Welsh Mountain, and Shetland), from weaning to approaching maturity, when kept under conditions designed to be nutritionally non-limiting. Lambs were weaned at 8 weeks of age and given a high-quality pelleted diet ad libitum until slaughter at one offive different degrees of maturity. The Gompertz growth function was used to characterize, for each genotype, the growth curve and to provide estimates of mature weight. As expected, there were significant effects of breed and sex on both food intake and growth rate. Growth rate was depressed, relative to the Gompertz fit, during the months of October to January, and intake was similarly depressed. The estimates of mature weight for the females of each breed were: Scottish Blackface, 69; Welsh Mountain, 61; Shetland, 46 kg. The mature weights of the males were found to be not significantly different from 1-3 times the mature weight offemales. Relationships between carcass composition and live weight were derived by allometric regression. This study provides the first full description of the growth and meat production potential of the three breeds.

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