Page 11 - Woodbank-Matariki ebook
P. 11

AngusPure Index (API)

           New Zealand Angus AngusPure Index - Predicted Response
 INDEX DESCRIPTIONS
 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   Expected Change in Individual Traits
 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.
          CEd  CEm  GL  BW  200W  400W  600W  MCW  Milk  SS  DC  Cwt  EMA  Rib  Rump  RBY  IMF
 Self Replacing Index (SRI)  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),
 New Zealand Angus Self-Replacing Index - Predicted Response  a negative response is desirable.
      Genetic Selection of bulls using only the API tool will on
 Expected Change in Individual Traits  •  Improved weaning rate through increased fertility
      average over time develop a cow herd with the following:

       and easier calving
      •  A slowly increasing cow weight/size, and milk production
      •  Progeny will be prime at heavy carcase weights where the
       improved marbling and subsequent eating quality traits
       can be expressed.
      These characteristics are ideal for an environment where
 CEd  CEm  GL  BW  200W  400W  600W  MCW  Milk  SS  DC  Cwt  EMA  Rib  Rump  RBY  IMF  the cow herd can be managed with extra feed if seasonal feed
      deficits occur.
 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),   Comparison of SRI and API
 a positive response is desirable and for others (e.g. days to calving),
 a negative response is desirable.  SRI is a maternal trait emphasised index. API is also a maternal
      driven index with added carcase trait emphasis.
 Genetic Selection of bulls using only the SRI tool will on
 average over time develop a cow herd with the following:  API selected animals can produce more net profit per animal
      through extra performance when feed is abundant.
 •  Improved weaning rate through increased fertility   Finished progeny can be taken to heavier weights with increased
 and easier calving  likelihood of achieving marbling premiums.
 •  A slowly decreasing cow size, milk and slowly increasing
 body condition  SRI selected animals can produce more net profit per animal
      through extra performance in environments where
 •  Progeny will be prime at a younger age for slaughter
      the cow herd is likely to be challenged by regular seasonal feed
 These characteristics are ideal for an environment where the herd   deficits, maintaining body condition is critical
 is exposed to prolonged seasonal feed deficits and feeding   to longevity and feeding out is not a viable option.
 supplement is unlikely.




      Woodbank Angus & Matariki Herefords Bull Sale 2021   9
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