Page 12 - Woodbank Matariki 2021 Catalogue ebook

Angus Pure 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.

Checking individual EBVs relevant to your herd is advised.

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.

Checking individual bull EBVs to make sure the index and the EBVs match your expectations are
advised. Using the flow chart may help you with your decisions.

10 Woodbank Angus & Matariki Herefords Bull Sale 2021