Page 11 - Ariki ebook
P. 11

AngusPure Index (API)

          New Zealand Angus AngusPure 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 API tool will on
     average over time develop a cow herd with the following:
     •  Improved weaning rate through increased fertility
       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
     the cow herd can be managed with extra feed if seasonal feed
     deficits occur.
     Comparison of SRI and API
     SRI is a maternal trait emphasised index. API is also a maternal
     driven index with added carcase trait emphasis.
     API selected animals can produce more net profit per animal
     through extra performance when feed is abundant.
     Finished progeny can be taken to heavier weights with increased
     likelihood of achieving marbling premiums.
     SRI selected animals can produce more net profit per animal
     through extra performance in environments where
     the cow herd is likely to be challenged by regular seasonal feed
     deficits, maintaining body condition is critical
     to longevity and feeding out is not a viable option.

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