New Zealand Journal of Agricultural Research abstracts

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Some effects of diet on beef meat and fat attributes

C. C. DALY*
O. A. YOUNG
A. E. GRAAFHUIS
S. M. MOORHEAD

MIRINZ Food Technology and Research
P.O. Box 617
Hamilton, New Zealand

H. S. EASTON

AgResearch Grasslands
Private Bag 11008
Palmerston North, New Zealand

*Present address: Agresearch, Ruakura Research Centre, P.O. Box 3123, Hamilton New Zealand.

Abstract  Steers were fed for nine weeks on either ryegrass/clover pasture or maize (six animals per group), to evaluate the effects of diet on attributes of meat and fat. Feed intake was restricted in the grain-fed group with the intention of producing equivalent growth rates in the two treatment groups, but this resulted in significantly slower weight gain, reduced carcass weight, and reduced subcutaneous and intramuscular fat. Nevertheless, the glycolytic potential (an estimate of pre-slaughter glycogen) in the M. longissimus dorsi lumborum was approximately 20% higher (P < 0.05) in the grain-fed cattle, while the ultimate pH of the meat was equivalent for both groups. The results suggest that grain-based diets can increase muscle glycogen concentrations independent of the higher calorific intake normally associated with grain diets, probably in response to changes in rumen fatty acid production. Compared with grain diet, pasture diet resulted in significantly higher (P < 0.01) muscle tocopherol content, but did not influence meat colour. The dietary treatments influenced fat colour, but both carotene content and energy intake may be responsible for this effect. The microbiological profile of meat during chilled storage was not affected by diet.

Keywords  beef; pasture; maize; meat colour; fat colour; pH; tocopherol; glycogen; stress; creatine kinase; lactate dehydrogenase; microbiology

New Zealand Journal of Agricultural Research, 1999, Vol. 42: 279-287

0028-8233/99/4203-0279 $7.00/0 (c) The Royal Society of New Zealand 1999

PDF file of entire paper: medium quality (785K); (scanned from paper original: notes about this process)

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