Grain-fed cattle linked to tougher beef

Grain-fed cattle linked to tougher beef
Animals fed on grain for 300 days took two hours longer to reach their minimum temperatures, potentially affecting meat quality.Image: David Oliver

Finishing beef cattle on grain leads to higher body temperatures before and after slaughter, which can diminish meat quality, research says.

According to Meat Standards Australia (MSA) guidelines for optimal eating, the temperature of slaughtered beef should be between 15°C and 35°C when it reaches pH 6.0.

However, if the carcass's temperature is higher than 35°C when its pH falls below 6.0, it can lead to 'high rigor temperature', a condition associated with reduced tenderisation, pale colour, premature browning and reduced water-holding capacity.

Dr Robin Jacob from the Department of Agriculture and Food says with 400 meals derived from each animal, science plays a vital role in helping industry hit the pH window.

"MSA ratings are becoming increasingly important for domestic distributors and consumers, and so Meat and Livestock Australia have been keen to help producers meet the MSA eating quality model," Dr Jacob says.

"We came aboard as part of a wider initiative, and in this instance, found that feedlot-treated cattle had consistently higher , on average 0.3-0.4° higher.

"This led to a reduced rate of cooling post-slaughter, which affects enzyme activity and ultimately the proteins that influence meat quality."

The study compared the and post-slaughter loin temperatures of steers fed on grass pasture for 300 days versus those on short-feedlot (150 days grass, 150 days grain) and long-feedlot (300 days grain).

Previously, higher temperatures for grain-finished steers had been attributed to their greater weight reducing their surface area for cooling, but researchers say the high energy content of a grain-based ration led to greater metabolic load.

This was evidenced by long-feedlot animals taking two hours longer to reach their minimum temperatures overnight, doing so at 8am as compared to 6am for the others.

Heat pipes for cooling

Dr Jacob says the meat industry is continually looking to reduce occurrences of high rigor temperature, so these findings are important in that they expand the knowledge base for future research.

In this spirit, Dr Jacob has also been conducting some 'out of the box' experiments on reducing carcass temperatures, such as assessing the potential of 'heat pipes'.

Used commercially for prepared foods, heat piping involves inserting hollow metal cylinders containing the cooling agent methanol into meat.

"Heat pipes showed some improvement in the rate of loss in the leg, but not the loin. Whether they would be practical for industry, I'm not sure. But we were the first to test the concept," Dr Jacob says.

Provided by Science Network WA

Citation: Grain-fed cattle linked to tougher beef (2014, November 10) retrieved 26 September 2023 from
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