When buying bulls, first ensure that they are sound and fertile, with an acceptable temperament. BREEDPLAN figures can then assist you to check that their genetics will suit your cows, the type of country, and the market.
Areas in which BREEDPLAN can assist include growth rate, milk, fertility, calving ease, carcase predictions and, in some cases, feed efficiency and docility. Other attributes such as structure, eye pigment etc. still need to be assessed by eye.
The basic descriptive units of BREEDPLAN are estimated breeding values (EBVs). These are calculated from:
Therefore, EBVs are a much better predictor of the performance of a bull’s progeny than single measurements on the bull near sale time (e.g. weight, scrotal size, raw scan measurements).
EBVs are expressed in everyday units, for example:
The values can be positive (+) or negative (–), depending on whether the value for an animal is under or over the ‘base’, which is constant and set at zero. The current breed average is often a more important benchmark than the base (see Using the catalogue).
The EBVs given in a catalogue may be either the EBVs within that herd, or the EBVs across the whole breed as in GROUP BREEDPLAN. Most Australian bull breeders are now using GROUP BREEDPLAN. The major breeds now regularly produce sire and dam summaries with GROUP BREEDPLAN EBVs. These are published in booklets and on society websites. For links to participating breeds, see http://breedplan.une.edu.au.
All GROUP BREEDPLAN catalogues should display the appropriate logo, for example:
Catalogues vary, but most entries should look something like this:
* Accuracy figures (expressed as a percentage) are an indication of how much information has been provided, and hence the ‘reliability’ of each EBV. EBVs of lower accuracy are more likely to change as more information is collected. There is an equal chance of this change being up or down.
The given EBVs are set against a zero base that is held constant. For many breeds the base was set in the 1970s. It is therefore more important to compare EBVs with the breed averages for the year of birth. In this case, 2-year-old bulls for sale in 2003 were born in 2001. In the above example, bull A is above average for all the weights, and average for milk and scrotal size, compared with calves of this breed born in 2001.
We can now examine in more detail how the progeny of the two bulls A and B (in the above catalogue example) would compare.
See other Agnotes in this series for further information on BREEDPLAN and EBVs.
Brian Sundstrom is Cattle Breeding Coordinator with NSW Agriculture. Part of this role involves technical specialist and advisory work with BREEDPLAN from an office at the Agricultural Business Research Institute (ABRI) at Armidale. His other role is with the Beef CRC group.