Page 75 - Hereford Magazine 2021

Explanation of the revised

NZ Herefords selection indexes

Words: Adapted by NZH breed manager Posy Moody. Original supplied by Breedplan technical consultant Dr Boyd Gudex.

or buyers of registered Herefords, selection indexes
can be a great tool, offering a quick glimpse at
overall ratings that best fit your farming practice.
Selection indexes have been developed to assist
Fbeef producers to make ‘balanced’ selection decisions,
taking into account the relevant growth, carcass, fertility, and
efficiency attributes of each animal, to identify the animal that is Figure 1: Selection index rankings can by obtained by accessing
most profitable for their particular commercial enterprise. internet solutions via the NZ Herefords website drop-down online
This article explains what indexes are, why and how they search menu.
are updated, and describes the three new indexes that
have been selected. While working on the new indexes, the clicking on the index name to sort the animals or catalogue
varying markets for bulls were given much consideration. you have selected. (See Fig 1, above).
The NZ Herefords technical committee finally identified three
markets they believe best meet the requirements. While they iii. Consider the individual EBVs of importance. Selection
acknowledge there may be other markets, it’s believed that indexes could be viewed as an initial drafting gate but
the majority of bulls would be able to fit in one of the three it is important to look closer. Two bulls could have a
selection indexes. similar dollar index value but quite different EBVs. For
Selection indexes were not designed to be a tool for stud example, one could have more growth and another bull
breeders to be basing their selection on, because they will be might have more marbling. Which traits are important
referring to individual EBVs as opposed to indexes, however it to your breeding objectives? If you know the EBVs of
is a viable tool for commercial breeders. previous bulls you have bought you can use this to help
your decision making. If there is a particular part of your
What are selection indexes? system that is letting you down, then you need to focus
on the EBVs affecting it directly. For example, if you are
Like breeding values (EBVs), selection index technology is a disappointed with pregnancy scanning, keep a close eye
well-established, science-based methodology that is used in on the days to calving and scrotal EBVs. If you are happy
many livestock species around the world. Selection indexes with your growth rates but you are missing out on quality
provide an overall score of an animal’s genetic value for profit premiums, then look at the IMF EBV.
for a specific production system and are calculated based
on weightings placed on individual traits that are deemed to iv. Consider other traits of importance that aren’t included
be important for that production system. As such, selection in the genetic evaluation. Structure, bull fertility,
indexes account for both sides of the profit equation (costs bull docility, genetic conditions, and pedigree are all
as well as income), and also reflect both the short-term profit important considerations in this step.
generated by a bull through the sale of his progeny, and the
longer-term profit generated by his daughters if they are The BreedObject system
retained in the herd.
The selection indexes calculated by Breedplan are generated
Best practice guide to using selection indexes using a software package called BreedObject. The Animal
Genetics and Breeding Unit (AGBU) developed the
Incorporating selection index information into selection BreedObject technology, and the development process
decisions takes all the hard work out of trying to decide how involves four major steps. These steps are:
much emphasis you need to put on individual EBVs when
determining which animals you want to retain in your herd or 1. A detailed description of the input costs (e.g. feed) and
purchase. The recommended strategy for selecting animals is value generation (e.g. sale animals) of the commercial herd
to complete the following steps: and target market system. For NZ Herefords, some of these
values were sourced from:
i. Identify the selection index of most relevance to your or a. A meeting with a group of New Zealand producers in
your clients’ breeding objectives. This decision should 2019.
be aided by the index descriptions available in the help b. Past research including Beef + Lamb New Zealand
centre section on the Breedplan website. progeny tests.
c. Lincoln University Financial Budget Manual.
ii. Rank animals on the selection index. This can be done
easily from the NZ Herefords website by accessing internet 2. Once the target production systems have been described,
solutions on the red drop-down ‘online search’ menu and the BreedObject software then evaluates how each

Year 2021 HEREFORD MAGAZINE 73