When selecting rams for a commercial enterprise the first step is to set your breeding objective. Spend a few minutes to write down precisely what you are aiming for, including the levels of performance and by when you want to achieve it. Find more information on setting a breeding objective.
Because the most effective way to select for a trait or characteristic is to directly measure or assess that characteristic, you should buy rams from a stud that objectively measures or collects scores (using a standardized system) for the traits you wish to improve.
For instance, staple strength can be selected with much higher accuracy if the stud directly measures staple strength on its rams, rather than just having the ASBV calculated from related measurements such as fibre diameter coefficient of variation.
However, the ram’s own performance is only part of the picture. What you see in the ram isn’t necessarily what you will get in the progeny because much of the ram’s performance is a result of the ‘environment’.
Nutritional differences between animals are a key environmental element and not only come from what they eat, but whether they were born or reared as a twin or their mother was a maiden ewe—giving them less nutrition during pregnancy and lactation than for a single lamb and/or from a mature ewe.
Also, climate, disease and management differences will affect how they perform.
If you know these environmental factors for each individual, and if you have been able to inspect all of the animal’s relatives and see their performance data, you’d be able to predict very accurately, how the progeny will look and perform.
However, this is not practical for you to do, so studs that provide you with Australian Sheep Breeding Values (ASBVs) already have this information taken into account. Pedigree information, management groups, data from relatives and relationships to rams used in the stud and elsewhere are all accounted for and very important when calculating Australian Sheep Breeding Values.
Importantly, you can accurately compare rams from different studs (whether at opposite sides of the country or having had quite different management) if they both provide ASBVs for the same trait.
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