DESPITE current tough seasonal conditions there is considerable value in keeping steers growing during summer and early autumn, according to a feedlot study.
Focusing on lowering methane emissions in beef cattle, it may also lead to more Meat Standards Australia four-star and five-star graded beef.
Funded as a Department of Agriculture, Forestry & Fisheries 'Carbon Farming Futures Action on the Ground project', it looks at the impact of post-weaning growth-rates on greenhouse emissions.
Animals with higher daily weight gains can be turned-off at a younger age, therefore emitting less methane, and are expected to have improved meat quality.
The three-year project which started in June last year, will track 3000 steers through the Wanderribby feedlot at Meningie to processing at Thomas Foods International's Murray Bridge abattoir.
University of Adelaide researcher and project leader Stephen Lee said it was exciting that the results could lead to more steers being turned-off to export weights at a younger age.
He said there was a large variation, with some steers finished at 15 months and others not reaching target weights until two years.
"In this project there are some steers being weaned straight into the feedlot at around 350 kilograms to 400kg and reaching export weights up to nine months earlier than steers in pasture-based finishing systems," he said.
Dr Lee said the project would examine whether it was feasible to take animals into feedlots at lighter weights, and how this affected feedlot performance, meat quality, and methane emissions.
It is estimated that steers with high growth rates of 1.3kg a day from weaning to slaughter would consume less than half of the energy required by a steer in a more conventional pasture-based finishing system growing at an average of 0.5kg/day.
"For an autumn-calving system the critical period is from weaning until the season break the following year," he said.
"A good strategy for producers is to allocate their best feed to growing stock. To ensure efficient conversion of feed to weight gain producers should aim for 0.5kg weight gain across summer."
The feedlot steers would be compared with grass-finishing systems in the South East which sold 300kg-plus carcaseweight steers between 18 and 24 months.
Dr Lee said higher post-weaning growth rates had also been shown to produce higher marble-score carcases.
In addition, steers reached their target weights at a younger age, so had a lower ossification score, pushing them higher on the MSA grading scheme.
*Full report in Stock Journal, April 18 issue, 2013.