Page 10 - Ranui Angus 2021 ebook
P. 10


       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.

                        Checking individual EBV’s relevant to your herd is advised.

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