Page 7 - Ranui Angus Sale Catalogue eBook
P. 7

Eye Muscle Area EBV (sq cm) is calculated from measurements from
      live animal ultrasound scans and from abattoir carcase data, adjusted
      to a standard 400 kg carcase.  This EBV estimates genetic differences
      in eye muscle area at the 12/13th rib site of a 400 kg dressed carcase.
      More positive EBVs indicate better muscling on animals.  Sires with
      relatively higher EMA EBVs are expected to produce better-muscled
      and higher percentage yielding progeny at the same carcase weight
      than will sires with lower EMA EBVs.
      Rib Fat and Rump Fat EBVs (mm) are calculated from measurements
      of subcutaneous fat depth at the 12/13-rib site and the P8 rump site
      (from live animal ultrasound scans and from abattoir carcases) and
      are adjusted to a standard 400 kg carcase.  These EBVs are indicators
      of the genetic differences in fat distribution on a standard 400 kg
      carcase.  Sires with low, or negative, fat EBVs are expected to produce
      leaner progeny at any particular carcase weight than will sires with
      higher EBVs.
      Retail Beef Yield EBV  (%)  indicates  genetic  differences  between
      animals for retail yield percentage in a standard 400 kg carcase.
      Sires with larger EBVs are expected to produce progeny with higher
      yielding carcases.
      Intramuscular Fat EBV (%) is an estimate of the genetic difference in
      the percentage of intramuscular fat at the 12/13th rib site in a 400 kg
      carcase.  Depending on market targets, larger more positive values
      are generally more favourable.
      Docility EBV (%) is an estimate of the genetic differences between
      animals in temperament.  Docility EBVs are expressed as differences
      in the percentage of progeny that will be scored with acceptable
      temperament (ie. either “docile” or “restless”).
      Selection Indexes

      There  are  currently  two  different  selection  indexes  calculated
      for New Zealand  Angus animals.  These are Self-Replacing and
      AngusPure.  Each selection index describes a different production/
      market scenario and relates to a typical commercial herd in New
      Zealand that is targeting the following specifications.
      Index values are reported as EBVs, in units of relative earning
      capacity ($’s) for a given market.  They reflect both the short-term
      profit generated by a sire through the sale of his progeny, and the
      longer-term  profit  generated  by  his  daughters  in  a  self-replacing
      cow herd.  More information is available on selecting animals using
      a selection index.
      The Index values are derived using BreedObject technology.  More
      information is available from the BreedObject web site.
      Self-Replacing Index  ($)  -  Estimates  genetic  differences  between
      animals  in  net  profitability  per  cow  joined  for  a  self-replacing
      commercial herd, targeting the production of grass finished steers.
      Steers are assumed marketed at 525 kg live weight (280 kg carcase
      weight and 10 mm fat depth) at 16 months of age.


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