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Non-invasive methods for the determination of body and carcass composition in livestock: dual-energy X-ray absorptiometry, computed tomography, magnetic resonance imaging and ultrasound: invited review.

Scholz AM, Bünger L, Kongsro J, Baulain U, Mitchell AD - Animal (2015)

Bottom Line: The techniques rely on specific device-driven signals, which interact with tissues in the body or carcass at the atomic or molecular level, resulting in secondary or attenuated signals detected by the instruments and analyzed quantitatively.CT, MRI and US can provide volume data, whereas only DXA delivers immediate whole-body composition results without (2D) image manipulation.A combination of simple US and more expensive CT, MRI or DXA might be applied for farm animal selection programs in a stepwise approach.

View Article: PubMed Central - PubMed

Affiliation: 1Livestock Center Oberschleißheim,Ludwig-Maximilians-University Munich,Sankt-Hubertusstrasse 12,85764 Oberschleißheim,Germany.

ABSTRACT
The ability to accurately measure body or carcass composition is important for performance testing, grading and finally selection or payment of meat-producing animals. Advances especially in non-invasive techniques are mainly based on the development of electronic and computer-driven methods in order to provide objective phenotypic data. The preference for a specific technique depends on the target animal species or carcass, combined with technical and practical aspects such as accuracy, reliability, cost, portability, speed, ease of use, safety and for in vivo measurements the need for fixation or sedation. The techniques rely on specific device-driven signals, which interact with tissues in the body or carcass at the atomic or molecular level, resulting in secondary or attenuated signals detected by the instruments and analyzed quantitatively. The electromagnetic signal produced by the instrument may originate from mechanical energy such as sound waves (ultrasound - US), 'photon' radiation (X-ray-computed tomography - CT, dual-energy X-ray absorptiometry - DXA) or radio frequency waves (magnetic resonance imaging - MRI). The signals detected by the corresponding instruments are processed to measure, for example, tissue depths, areas, volumes or distributions of fat, muscle (water, protein) and partly bone or bone mineral. Among the above techniques, CT is the most accurate one followed by MRI and DXA, whereas US can be used for all sizes of farm animal species even under field conditions. CT, MRI and US can provide volume data, whereas only DXA delivers immediate whole-body composition results without (2D) image manipulation. A combination of simple US and more expensive CT, MRI or DXA might be applied for farm animal selection programs in a stepwise approach.

No MeSH data available.


Comparison of ‘obese’ and ‘standard’ pigs (using a variable 2.5 to 5 MHz ‘backfat’17-cm transducer).
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fig4: Comparison of ‘obese’ and ‘standard’ pigs (using a variable 2.5 to 5 MHz ‘backfat’17-cm transducer).

Mentions: Two-dimensional US images from so-called B-mode (brightness) devices provide informationabout adipose tissue depots and cross-sectional areas of muscles, whereas A-mode devices(amplitude) can be used for simple distance measurements of fat or muscle (meat) layers.Real-time B-mode information (2D or 3D images) result from rapid electronic switching orphased array transducers (a number of piezoelectric elements) of different shapes (Starcket al., 2001). At present, most of the US devices for performancetesting use (linear) phased array transducers to convert electronic energy tohigh-frequency ultrasonic (mechanical) energy that travels through the animal body inshort pulses. As soon as ultrasonic waves meet at an interface between two tissues thatdiffer in acoustical properties, a part of the (longitudinal) ultrasonic waves arereflected back to the receiver probe (the phased array transducer). Variations in fat,muscle or bone tissue depths or in the distribution of, for example, intermuscular andespecially IMF result in time differences in reflected ultrasonic wave signals affectedadditionally by absorption and refraction (scatter) of the mechanical energy (Starcket al., 2001). These effects combined with variations caused by theexpertise of the testing person, age/weight of the animal and the behavior of the animaltested lead in some cases to a challenging interpretation of the US imaging or scanningresults, as can be seen from Figure 4. They makethe measurement of areas or even volumes (weights) less accurate in comparison with MRI orCT. Depending on the transducer and on the scan settings in terms of frequency, it mightbe the case that the measurement of, for example, the loin eye area becomes almostimpossible and requires a lot of educated ‘anatomical’ guessing in order to providereasonable data (Figure 4). Related to the abovemeasurement site on the (beef) animal, Harangi (2013) stated for Charolais bulls that the relationship between ultrasound rib eyearea (UREA) and ‘planimeter’ carcass rib eye area (CREA) was higher when measured betweenthe 12th and 13th rib instead of between the 11th and12th rib with R2 of 0.91 and 0.84 (CV 2.16% v. 5.3%), respectively. Töröket al. (2009) found slightly modified relationships between UREA andCREA for four different beef breeds (Limousin R2=0.92, Charolais R2=0.64, Angus and Simmental R2=0.55).Figure 4


Non-invasive methods for the determination of body and carcass composition in livestock: dual-energy X-ray absorptiometry, computed tomography, magnetic resonance imaging and ultrasound: invited review.

Scholz AM, Bünger L, Kongsro J, Baulain U, Mitchell AD - Animal (2015)

Comparison of ‘obese’ and ‘standard’ pigs (using a variable 2.5 to 5 MHz ‘backfat’17-cm transducer).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492221&req=5

fig4: Comparison of ‘obese’ and ‘standard’ pigs (using a variable 2.5 to 5 MHz ‘backfat’17-cm transducer).
Mentions: Two-dimensional US images from so-called B-mode (brightness) devices provide informationabout adipose tissue depots and cross-sectional areas of muscles, whereas A-mode devices(amplitude) can be used for simple distance measurements of fat or muscle (meat) layers.Real-time B-mode information (2D or 3D images) result from rapid electronic switching orphased array transducers (a number of piezoelectric elements) of different shapes (Starcket al., 2001). At present, most of the US devices for performancetesting use (linear) phased array transducers to convert electronic energy tohigh-frequency ultrasonic (mechanical) energy that travels through the animal body inshort pulses. As soon as ultrasonic waves meet at an interface between two tissues thatdiffer in acoustical properties, a part of the (longitudinal) ultrasonic waves arereflected back to the receiver probe (the phased array transducer). Variations in fat,muscle or bone tissue depths or in the distribution of, for example, intermuscular andespecially IMF result in time differences in reflected ultrasonic wave signals affectedadditionally by absorption and refraction (scatter) of the mechanical energy (Starcket al., 2001). These effects combined with variations caused by theexpertise of the testing person, age/weight of the animal and the behavior of the animaltested lead in some cases to a challenging interpretation of the US imaging or scanningresults, as can be seen from Figure 4. They makethe measurement of areas or even volumes (weights) less accurate in comparison with MRI orCT. Depending on the transducer and on the scan settings in terms of frequency, it mightbe the case that the measurement of, for example, the loin eye area becomes almostimpossible and requires a lot of educated ‘anatomical’ guessing in order to providereasonable data (Figure 4). Related to the abovemeasurement site on the (beef) animal, Harangi (2013) stated for Charolais bulls that the relationship between ultrasound rib eyearea (UREA) and ‘planimeter’ carcass rib eye area (CREA) was higher when measured betweenthe 12th and 13th rib instead of between the 11th and12th rib with R2 of 0.91 and 0.84 (CV 2.16% v. 5.3%), respectively. Töröket al. (2009) found slightly modified relationships between UREA andCREA for four different beef breeds (Limousin R2=0.92, Charolais R2=0.64, Angus and Simmental R2=0.55).Figure 4

Bottom Line: The techniques rely on specific device-driven signals, which interact with tissues in the body or carcass at the atomic or molecular level, resulting in secondary or attenuated signals detected by the instruments and analyzed quantitatively.CT, MRI and US can provide volume data, whereas only DXA delivers immediate whole-body composition results without (2D) image manipulation.A combination of simple US and more expensive CT, MRI or DXA might be applied for farm animal selection programs in a stepwise approach.

View Article: PubMed Central - PubMed

Affiliation: 1Livestock Center Oberschleißheim,Ludwig-Maximilians-University Munich,Sankt-Hubertusstrasse 12,85764 Oberschleißheim,Germany.

ABSTRACT
The ability to accurately measure body or carcass composition is important for performance testing, grading and finally selection or payment of meat-producing animals. Advances especially in non-invasive techniques are mainly based on the development of electronic and computer-driven methods in order to provide objective phenotypic data. The preference for a specific technique depends on the target animal species or carcass, combined with technical and practical aspects such as accuracy, reliability, cost, portability, speed, ease of use, safety and for in vivo measurements the need for fixation or sedation. The techniques rely on specific device-driven signals, which interact with tissues in the body or carcass at the atomic or molecular level, resulting in secondary or attenuated signals detected by the instruments and analyzed quantitatively. The electromagnetic signal produced by the instrument may originate from mechanical energy such as sound waves (ultrasound - US), 'photon' radiation (X-ray-computed tomography - CT, dual-energy X-ray absorptiometry - DXA) or radio frequency waves (magnetic resonance imaging - MRI). The signals detected by the corresponding instruments are processed to measure, for example, tissue depths, areas, volumes or distributions of fat, muscle (water, protein) and partly bone or bone mineral. Among the above techniques, CT is the most accurate one followed by MRI and DXA, whereas US can be used for all sizes of farm animal species even under field conditions. CT, MRI and US can provide volume data, whereas only DXA delivers immediate whole-body composition results without (2D) image manipulation. A combination of simple US and more expensive CT, MRI or DXA might be applied for farm animal selection programs in a stepwise approach.

No MeSH data available.