Steers from a Beef Co-operative Research Centre growth experiment, ready for slaughter at 30 months. The pair in the centre experienced severe growth restriction before birth and from birth to weaning. They were then all grown out and finished together.

Severe growth restriction in very young cattle has little effect on tenderness or marbling of finished beef, even though it reduces their potential to grow later during backgrounding and finishing.

While small changes in marbling or increased tenderness do not generally affect return to producers at present, new carcase assessment technology is likely to value them more highly in future.

These findings are among the latest from the Beef Co-operative Research Centre (Beef CRC), which has been refining its recommendations to the industry.

This follows a workshop with extension staff where the latest research on growth was tabled.

For most producers, liveweight gain is one of the main drivers of profit, so there are good reasons to be wary of stunted calves.

They will take longer to finish and may become too old for the market (too many permanent teeth or ossification score too high) before reaching the target weight.

On the positive side, cattle suffering even quite severe early growth restriction can recover and as long as they are well-finished, they will still fit the mainstream market specifications.

The beef quality will generally be acceptable to consumers.

But producers should not ignore the small drop in meat quality because market expectations for quality are rising and so is the ability of processors to measure and pay accordingly.

In Beef CRC trials, VIAscan technology (for estimating carcase yield) is being coupled with Meat Standards Australia grading (for estimating the eating quality of individual cuts) to value individual carcases accurately.

Some niche markets are already paying producers on actual yield and quality.

In these markets, producers can be rewarded for the meat quality improvement that comes with faster growth because younger carcases with better eating quality are graded into a higher MSA boning group.

The processor can then market the key primal cuts at a higher price.

This work has been a focus of the Beef CRC which was initially established in 1993 to support the development of Australia’s ability to produce beef with better eating quality and/or marbling.

A team of beef advisers from NSW Department of Primary Industries is preparing an information package covering the genetic and nutritional effects on growth, carcase yield and meat quality.

It will be released following an industry workshop in 2008.

Loss of compensatory gain

The limit on the ability of cattle to grow is greatest if the restriction is severe and occurs in the early months of life, between birth and weaning but it can occur even earlier.

If cows are restricted severely enough during mid to late pregnancy, the birth weight of the calves can be reduced and this affects their capacity to grow throughout their later life.

Drought-affected calves are likely to be less profitable for backgrounders and feedlots because they will take longer to grow out and finish.

They will have lost the capacity for significant compensatory gain.

Compensatory gain is a period of fast, efficient growth, usually very profitable for backgrounders and feedlots.

It occurs when cattle are recovering on good feed, after a period of slower growth as yearlings.

For maximum compensatory gain however, the cattle must have had a good start in life before their period of slower growth.

Scientists believe cattle should grow from birth to at least 250 kilograms liveweight without meeting a severe growth restriction.