Page 13 - Waigroup Pinebank Pinehill Angus 2021 Catalogue ebook
P. 13

      The following three graphs reflects the relative change if the
      New Zealand Angus Published Sires (at the Mid-August 2020
      TransTasman Angus Cattle Evaluation) were ranked on this
      selection index and the top 10% were used within a breeding
      program. Given that the Published Sires are the sires of the next
      generation(s) of New Zealand Angus cattle and have more highly
      accurate EBVs (due to having progeny) than the average animal
      in the database, these graphs represent the approximate
      selection response one would expect to see in the breed from
      using this index.

      Self Replacing Index (SRI)

          New Zealand Angus Self-Replacing Index - Predicted Response

        Expected Change in Individual Traits

           CEd  CEm  GL  BW  200W  400W  600W  MCW  Milk  SS  DC  Cwt  EMA  Rib  Rump  RBY  IMF
      Above the 0 line (X axis) selects for more positive numbers and below
      the line selects for more negative numbers. For some traits (e.g. growth),
      a positive response is desirable and for others (e.g. days to calving),
      a negative response is desirable.
      Genetic Selection of bulls using only the SRI tool will on
      average over time develop a cow herd with the following:
      •  Improved weaning rate through increased fertility
         and easier calving
      •  A slowly decreasing cow size, milk and slowly increasing
         body condition
      •  Progeny will be prime at a younger age for slaughter
      These characteristics are ideal for an environment where the herd
      is exposed to prolonged seasonal feed deficits and feeding
      supplement is unlikely.

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