Feed and Nutrition Herd Management

Feeding for Cost Effective Compliance

AUSTRALIA -Researchers are investigating the best ways to supplement cattle in northern Australia to boost growth rates and produce younger, heavier stock for turnoff into higher value markets.

21 September 2012

3 minute read

Oceania

Reducing the age of bullocks for slaughter by 12 months, to about 30 months of age, has been shown to substantially lift MSA compliance rates.

This lessens the chances of cattle exceeding four teeth (although dentition is not an MSA grade input), lowers ossification scores and increases the likelihood of stock achieving MSA premium boning groups of 10 or less.

These boning groups have been out of reach for many northern cattle because of a combination of tropical breed content and slow annual growth rate issues.

Queensland Alliance for Agriculture and Food Innovation (QAAFI) principal research fellow, Dr Stuart McLennan, heads a team of scientists investigating how to costeffectively lift whole-of-life growth rates in cattle grazing tropical pastures. He said increasing growth rates and reducing time to turnoff invariably involved improved nutrition at some stage of the animal’s life.

A four-year grazing trial, co-funded by MLA and the Department of Agriculture, Fisheries and Forestry, has been set up at Swans Lagoon Research Station, near Ayr, to track lifetime steer growth paths against the timing of additional dietary treatments – in the form of supplements or improved pasture.

Supporting pen trials at Brian Pastures Research Station, near Gayndah, are also analysing delivery options and cattle responses to protein meal, grain and molasses-based feed supplements.

Stuart said results from the grazing trial showed a high-input post-weaning supplement – such as a mix of molasses, urea and protein meal – or use of leucaena pasture could boost cattle growth rates and finish cattle 12 months earlier for premium markets.

He said using high input supplements only in the second dry season reduced costs by about $60/head without sacrificing animal performance, compared to feeding in both the first and second dry seasons.

“It was also found that reducing the age of finishing from three-and-a-half to two-and-a-half years old by supplementation reduced overall pasture intake by more than 50 per cent,” he said.

“This would provide options to carry more stock or reduce grazing pressure.”

HGP challenges

Stuart said cattle finished at 30 months without the use of HGPs generally graded MSA and thus received the applicable price premium.

But he said MSA compliance was difficult to achieve when HGPs were used continuously from weaning to slaughter. This was because of the automatic penalty imposed in the MSA system and associated higher ossification that affected the MSA score.

“Still, the HGP implanted steers in the trials returned an average $50/head more than those not implanted because of higher carcase weight,” he said.

“The challenge will be to devise implant strategies that have a lesser impact on MSA grades, without jeopardising the growth responses to the HGP.”

The right mix Pen trials have shown up to 40% higher cattle growth responses to a barley/urea mix than to the molasses/urea/copra meal mix used in the grazing study.

“Researchers are now looking at ways to increase the growth response to the molasses mix – which is the preferred option for safe feeding in northern regions.”

Pen trials also found older cattle of about 30 months had similar growth responses to young cattle of about 10 months. This means for every kilogram of supplement fed, growth responses would be the same for the two age groups.