SPRY BRED STEER WINS
Are our mature cow weights becoming too big?
Understanding ‘frame creep’
Given the influence of sires used within herds extends over three generations, it’s likely that mature cow size in many herds may continue to increase. I’ve seen this increase described as ‘frame creep’ where mature cow size gradually over generations as a result of past genetic decisions, and the tendency at selection to choose larger females as replacements.
Having observed the gradual increase mature cow size in northern NSW for the past two decades, I
am fairly sure the increasing trend is a result of ‘frame creep’, rather than a specific approach by
However, the flow on impact has implications that industry is now grappling with, as focus is bought
on both cow maintenance needs in drought and carcase weight for processors.
It is also important to highlight the economic impact ‘frame creep’ has over time within a herd. As
highlighted earlier, the cost to maintain an Angus female has increased over the past 30 years by
Other examples highlight that increasing mature cow size fails to increase returns per hectare.
Some interesting More Beef from Pastures work by Dr John Webb-Ware demonstrated that at low
stocking rates, larger cows can be reasonably profitable, but once average or higher stocking rates
are achieved, there is no real economic advantage to cows exceeding a 550kg mature weight.
The inclusion of Mature Cow Weights within the EBVs for most breeds offers an opportunity for
producers to consider and select for mature weights most appropriate for their country and carrying
A key feature of BreedObject Verion 6 is the creation of Indexes which include consideration of
maintenance requirements for cows, and this will offer producers increased opportunity to select
more appropriately suited genetics.
While there may be a natural inclination to attempt to select larger animals for replacements, it is
important to consider how much more feed larger animals demand and the impacts this has in
nutritionally challenging times, as well as on the efficiency of the breeding herd in general.