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Ultrasound back fat thickness: Difference between revisions

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Ultrasonic back fat thickness is adjusted to a common age (e.g., 365 days of age) and in multi-breed settings is also adjusted for breed composition.
Ultrasonic back fat thickness is adjusted to a common age (e.g., 365 days of age) and in multi-breed settings is also adjusted for breed composition.


===Contempory Group===
===Contemporary Group===
<!-- Discuss how contemporary groups are formed -->
<!-- Discuss how contemporary groups are formed -->
Animals of the same  sex,  reared  and  managed  together  up  until  the  time  of  scanning  form  a contemporary group.  Scanning  contemporary group  definition  includes  the  following:  herd  code,  weaning  date, weaning  management  group  (pasture,  creep,  non-creep,  etc.), scanning  date,  and  post-weaning  management  group  designation.  For  animals  scanned  at  a  central  test,  the  contemporary  group  definition  for  an  animal should  include its  herd  of  origin  and  other  birth  and  weaning  contemporary  group information.
Animals of the same  sex,  reared  and  managed  together  up  until  the  time  of  scanning  form  a contemporary group.  Scanning  contemporary group  definition  includes  the  following:  herd  code,  weaning  date, weaning  management  group  (pasture,  creep,  non-creep,  etc.), scanning  date,  and  post-weaning  management  group  designation.  For  animals  scanned  at  a  central  test,  the  contemporary  group  definition  for  an  animal should  include its  herd  of  origin  and  other  birth  and  weaning  contemporary  group information.
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     Discuss in what circumstances the trait is an ERT or an indicator trait and how the trait should be used and not used.
     Discuss in what circumstances the trait is an ERT or an indicator trait and how the trait should be used and not used.
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Ultrasound back fat is an indicator trait that is measured on seedstock animals. It is used to help predict the genetic merit of animals for carcass back fat. The majority of beef breed organizations do not publish an ultrasund back fat EPD but rather publish a back fat EPD on a carcass basis that is the product of a multi-trait model including the ultrasound indicator trait.
Ultrasound back fat is an indicator trait that is measured on seedstock animals. It is used to help predict the genetic merit of animals for carcass back fat. The majority of beef breed organizations do not publish an ultrasound back fat EPD but rather publish a back fat EPD on a carcass basis that is the product of a multi-trait model including the ultrasound indicator trait.

Revision as of 22:09, 9 December 2019


Phenotype

The ultrasound rib fat thickness measurement can be made from the same image used to estimate ribeye area. Fat thickness at the 12th-13th rib is measured at a point three fourths of the distance from the medial end of the longissimus dorsi muscle (12-13th rib interface) and perpendicular to the surface of the hanging ribbed carcass. Ultrasound scanning protocol requires the collection of an image made between the 12th-13thribs using a linear-array transducer and standoff guide that conforms to the curvature of the animal’s back

Adjusted Value

Ultrasonic back fat thickness is adjusted to a common age (e.g., 365 days of age) and in multi-breed settings is also adjusted for breed composition.

Contemporary Group

Animals of the same sex, reared and managed together up until the time of scanning form a contemporary group. Scanning contemporary group definition includes the following: herd code, weaning date, weaning management group (pasture, creep, non-creep, etc.), scanning date, and post-weaning management group designation. For animals scanned at a central test, the contemporary group definition for an animal should include its herd of origin and other birth and weaning contemporary group information.

Genetic Evaluation

Given the ultrasound measure of back fat is an indicator of the economically relevant trait of carcass back fat, it is generally included in multi-trait models that include carcass back fat and potentially other carcass fat related traits (e.g., percentage of intramuscular fat, marbling). There are no maternal effects fitted for ultrasound or carcass traits given the maternal influence declines post-weaning.

Usage

Ultrasound back fat is an indicator trait that is measured on seedstock animals. It is used to help predict the genetic merit of animals for carcass back fat. The majority of beef breed organizations do not publish an ultrasound back fat EPD but rather publish a back fat EPD on a carcass basis that is the product of a multi-trait model including the ultrasound indicator trait.