Genetic analyses of novel traits derived from CT scanning for implementation in terminal sire sheep breeding programmes

2021 ◽  
pp. 104555
Author(s):  
A. McLaren ◽  
K. Kaseja ◽  
K.A. McLean ◽  
S. Boon ◽  
N.R. Lambe
Keyword(s):  
Ct Scanning ◽  
Genetic Analyses ◽  
Sheep Breeding ◽  
Novel Traits ◽  
Breeding Programmes ◽  
Terminal Sire

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

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.

Genetic parameters for live weight, ultrasonic measurements and conformation in Bluefaced Leicester sheep

1999 ◽  
Vol 1999 ◽  
pp. 122-122 ◽  
Author(s):  
A.M. van Heelsum ◽  
R.M. Lewis ◽  
D.W. Jones ◽  
W. Haresign ◽  
M.H. Davies
Keyword(s):  
Selection Index ◽  
Live Weight ◽  
Carcass Quality ◽  
Export Markets ◽  
Acceptable Quality ◽  
Breeding Programmes ◽  
The Uk ◽  
Terminal Sire ◽  
Sire Breed

Currently fewer than 50% of UK lambs produce carcasses of acceptable quality for the domestic and export markets, which compromises the competitiveness of sheep farming. Carcass quality can be changed by selection, and this is now being taken advantage of in terminal sire breeds and, to a lesser extent, in hill breeds. However, little attention has yet been focused on the crossing breeds, which have relatively poor carcass quality, in spite of the large impact such breeds have on the slaughter generation. Recently, a long-term project began to develop breeding programmes relevant to crossing sire (‘longwool’) breeds. Its objective is to produce a selection index to improve carcass quality without compromising the reproductive performance or maternal ability of these breeds. The Bluefaced Leicester is the most prevalent crossing sire breed with its crossbred (‘Mule’) daughters out of draft hill ewes accounting for 89% of crossbred (longwool x hill) ewes in the UK (Pollot, 1998).

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.

Computerised tomography for carcass analysis

2001 ◽  
Vol 2001 ◽  
pp. 250-254 ◽  
Author(s):  
M. J. Young ◽  
G. Simm ◽  
C.A. Glasbey
Keyword(s):  
Ct Scanning ◽  
Human Medicine ◽  
Accurate Assessment ◽  
Living Animal ◽  
Computerised Tomography ◽  
Cross Sectional ◽  
Non Invasive ◽  
Novel Traits ◽  
Wide Range ◽  
Mathematical Algorithms

Computer tomography (CT) scanning is a method for non-invasive imaging of subjects developed for use in human medicine. It allows cross-sectional images, containing a wealth of information, to be obtained for a living animal (Davies et al., 1987). These can be used to provide very accurate assessment of body composition in live animals in a welfare-friendly manner. Not only is accuracy improved but also a wide range of novel traits lend themselves to assessment and objective measurements can be collected rapidly, using mathematical algorithms for image analysis (Glasbey & Robinson, 1999; Glasbey et al., 1999).

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