Murray Rogerson



Inflation is somewhat like Bacon’s description of hope, it provides a mighty breakfast but leaves you pretty hungry by supper. Many stud breeders pursue the art of index inflation by crossing different strains of blue ink, morally questionable but not illegal whilst many others have crossed the legal barrier with good inflationary results.

In my experience there is no doubt that heterosis gains between breeds can at times stretch to 15% to 20% but also depending on the traits, breeds and strains may be as little as 1%. Before the composite movement since 1990 8% between Merino strains in Australia and 15% between breeds in England were recorded for bodyweight.

At the 1999 Dohne start date the AA index cut-off was 105 whilst the A standard of excellence cut-off was 100 and the top value approached 120. 20 years later by 2019 it had reached 204, almost doubling or 4% compound inflation.

Suspecting that adult weight was a driver of index, I had 1500 adult weights inserted into my Sheep genetics databank in February 2019. The below Table is the results.

The weights represent 270 Stirling ewes in a breed databank of 17500.
6 traits AWT, YWT, YEMD, YFAT, YFD & YCVFD declined by an average of 41% or back to 1999 levels.
No traits have yet fully recovered after 18 months.
Like paper money actuals do inflate and deflate with seasonal change but drought of this magnitude is hard to imagine.