18 April 2011

2 minute read

Finishing beef cattle on legume/cereal wholecrop silage had no effect on muscle fatty acid composition or instrumental meat quality relative to grass silage based diets.

“But we did see an increased level of concentrate supplementation decreased C18:3n-3 proportion and increased redness and yellowness of the meat,” Northern Ireland’s Agri-Food and Biosciences Institute’s Peter Kennedy told delegates at the 2010 British Society of Animal Science’s annual conference, held at Queen’s University, Belfast.

With increasing consumer awareness of meat quality and the relationship between dietary fat and the incidence of cardiovascular related disease, research has been undertaken to manipulate fatty acid (FA) profiles in beef.

Previous research has already found that legume based diets resulted in higher polyunsaturated fatty acid (PUFA) levels in intramuscular fat in beef steers than those offered grass silage. “So the aim of our experiment was to assess the effect of offering lupins/triticale, lupins/wheat, peas/oat wholecrop silage and grass silage to continental beef cattle on instrumental meat quality and FA composition,” said Mr Kennedy.

His team took 90 continental cross steers and allocated them to one of 10 dietary treatments in a five forage and two concentrate level experiment. The five forage diets offered were: perennial ryegrass based grass silage (PGS); fescue/perennial ryegrass based grass silage (FGS); lupins/triticale based silage combined with PGS 50:50 on a dry matter (DM) basis; lupins/wheat based silage combined with PGS 50:50 on a DM basis; and peas/oat wholecrop silage combined with PGS 50:50 on a DM basis.

Each forage diet was offered ad lib and supplemented with either 4kg or 7kg of concentrates/head/day. A representation of steers from each forage and concentrate treatment were slaughtered over each of the four dates, ranging from 109 to 137 days on trial. And instrumental meat quality assessments (cooking loss, Warner Braztler shear force, meat colour) were carried out seven days post mortem. FA analyses carried out on the longissimus dorsi obtained from the fore-rib joint.

“The type of forage offered to continental finishing steers had no effect on FA composition of muscle, but increasing concentrate level significantly decreased concentration of α-linolenic acid but had no effect on total n-3 PUFA, n-6 PUFA, PUFA:SFA ratio and conjugated linoleic acid (CLA) level in muscle,” added Mr Kennedy.