Page 12 - Capethorne Riverland Grassmere ebook

AngusPure Index (API) HDT Index (heifer/dairy terminal)

New Zealand Angus AngusPure Index - Predicted Response New Zealand Angus Heifer/Dairy Terminal Index - Predicted Response

Expected Change in Individual Traits 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
CEd CEm GL BW 200W 400W 600W MCW Milk SS DC Cwt EMA Rib Rump RBY IMF negative response is desirable.
Above the 0 line (X axis) selects for more positive numbers and below This index is primarily driven by getting live calves on the ground,
the line selects for more negative numbers. For some traits (e.g. growth), and producing an early maturing prime animal with added
a positive response is desirable and for others (e.g. days to calving),
a negative response is desirable. carcase traits for improved carcase yield and marbling with no
direct selection for maternal traits.
Genetic Selection of bulls using only the API tool will on
average over time develop a cow herd with the following: NB. It is important point to be aware that while no emphasis
has been placed on some traits, for example maternal traits
• Improved weaning rate through increased fertility
and easier calving in the HDT, they still may be selected for indirectly through
positive or negative correlations with other traits, as is the
• A slowly increasing cow weight/size, and milk production case with Days to Calving in the HDT.
• 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.

10 Riverlands, Capethorne, Grassmere Combined Bull Sale 2021