DON'T mix cattle within two weeks of slaughter - that's the message from a recent study by the Beef Co-operative Research Centre.
The study, which looked at the physiological responses of cattle when their social groups change, showed that regrouping cattle up to two weeks before slaughter may reduce meat quality.
While most producers run cattle in their contemporary groups, feedlots often draft cattle for slaughter, retaining those cattle which don't meet the required guidelines.
But Dr Ian Colditz, CSIRO Livestock Industries, said within two weeks of slaughter cattle enter a period when any stress may compromise meat quality.
"Cattle are very social animals. Separating them or mixing them with unfamiliar animals can evoke a stress response," Dr Colditz said.
"Their immunity decreases and they are more susceptible to disease. The glycogen they produce breaks down quickly when cattle are stressed. This can affect post-mortem muscle pH levels and meat quality."
The experiment, designed to keep the cattle as two separate groups and at four, two or one weeks before slaughter, mix or regroup the steers, showed the biggest effect in the steers regrouped one week before feedlot exit.
"This group had significantly higher meat compression values than the control steers," Dr Colditz said.
Increased compression and shear force are measures of meat toughness and are usually associated with consumer perceptions of tougher meat.
Minimising the exposure of cattle to stressors during this period seems appropriate if you want to maximise beef quality, he said.
