Dohne sire evaluation focus

"Sire evaluation has been going since 1989 and is the world's longest running genetic program," Mr Swain said.

"We have been continuously joining Merino rams around Australia for over thirty years and it is all about progeny testing - it is not about the rams."

Mr Swain emphasised the evaluation is not a ram show but about the productive performance of the progeny of those rams when run under the same conditions and from a common dam base.

"We assess the genetic merit of the rams through testing their progeny," he said.

"It is very independent and it is very robust, so everything we do is independent - independent sheep classers, independent fleece testers, carcase scanners - and we currently operate over nine different sites."

Mr Swain said a wide range of visual traits are assessed and many more than the measured traits.

"A lot of people think sire evaluation is just about the number, but it is as much about the classing than it is the numbers," he said.

About 150 rams are measured across Australia each year and which cost is borne by the ram's breeder, with the current entry fee into sire evaluation averaging about $4000.

"We use link sires between all the sites which allows us to compare the data and the results from this site to any other," Mr Swain said.

"We measure everything, if you can think of something in a wool growing animal that should be measured we will measure it."

When it comes to understanding the results, Mr Swain pointed out there are three types to be considered and that breeders should be aware off.

"We use raw data which is exactly the data we have measured here on the progeny from the carcase scanning and on the fleece," he said.

"You won't see a lot of raw data reported in the sire evaluation results because they can be a little misleading in terms of being a true representation of the sire."

To make those allowances, Mr Swain explained the use of Adjusted Sire Means where the average performance of all the progeny of a sire are adjusted for an individual's birth type, rear type, age of dam and management group.

The adjustments improve the accuracy of the result and the size of the adjustment is based on the actual influence of these factors on the drop.

"They take the raw data and adjust it for all the non-genetic affects which influence the sheep's production," he said.

"A good example is whether it has been born as a single or twin and in an AI program, that is a non-genetic affect, it was born a single or a twin because of the artificial influence of the AI program."

Mr Swain said there were a lot more twins born in some sires groups in the Dohne sire evaluation than other sire groups, and if those sire groups were assessed using the raw data they would be at a disadvantage.

"We know the twins are going to be smaller at weaning and they will cut less wool, there's lots of thing we know about twins that occur because they are a twin, not because of their genetic makeup," he said.

"So we adjust the raw data to even the playing field - so if a ram has lots of twins he will actually be boosted for a whole range of traits.

The next stage is when the Flock Breeding Values (FBVs) are analysed, which have been calculated from data recorded within-site and within-group and express the expected genetic performance of a sire relative to another sire in the evaluation when mated to a common ewe base.

FBVs improve the sire results because they account for the association between traits, the heritability of the trait and non-genetic affects such as birth and rear type, sex, and the number of progeny a sire has in the analysis.

"They are an estimate of how that sire is going to pass on his genetics to future generations," Mr Swain said.

"We have the raw data, we have the Adjusted Sire Means and we have the FBV's and as we go through each of those steps, our selection accuracy increases - the data gets better and it allows us to select rams with more accuracy, with more confidence they are going to breed what we expect.

"We have more confidence in the data we are using is actually what we are going to see when the lambs are born."