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Thirty-six steers were randomly assigned to one of three dietary treatments fed ad libitum grass silage and concentrate supplements containing either barley/soybean meal (CON), 80% DM corn (CDGS)- or 80% DM wheat (WDGS)-dried distillers' grains with solubles for 124 days pre-slaughter. Chemical and fatty acid composition, shelf-life, and eating quality of longissimus thoracis muscle were determined. Dietary CDGS and WDGS increased the proportion of conjugated linoleic acids (P < 0.05) and tended to increase C18:3n-3 (P = 0.075) and total polyunsaturated fatty acids (P = 0.060) relative to the CON. Feeding diets containing distillers' grains reduced the lipid and colour stability of fresh beef patties stored in modified atmosphere packs (MAP), with CDGS exhibiting an intermediate effect between CON and WDGS. Diet did not negatively influence the texture profile parameters and eating quality attributes of beef stored in MAP. The inclusion of CDGS or WDGS in supplementary concentrates may improve the fatty acid profile but decreased the shelf-life of beef.

The effect of feed restriction (99 days) followed by compensatory growth during a 200 day re-alimentation period on the colour and sensory characteristics of meat from Aberdeen Angus × Holstein-Friesian (AN) and Belgian Blue × Holstein-Friesian (BB) steers was examined. Compensatory growth had no effect on muscle pH and temperature decline, chemical composition, drip loss, fat colour, or juiciness, but increased (P = 0.009) Warner-Bratzler shear force and decreased tenderness (P = 0.08) and overall liking (P = 0.09). Compared to meat from BB steers, meat from AN steers had a higher intramuscular fat concentration and was rated similarly for tenderness, but higher for many of the flavour characteristics examined. While adjustment for intramuscular fat concentration removed some of these differences, genotype-specific flavour differences remained. It is concluded that genotype had greater effects on meat quality than the compensatory growth feeding regime imposed in this study.

International audience; Eating quality of the same meat samples from different animal types cooked at two end-point cooking temperatures (55 degrees C and 74 degrees C) was evaluated by trained panels in France and the United Kingdom. Tenderness and juiciness scores were greater at 55 degrees C than at 74 degrees C, irrespective of the animal type and location of the panel. The UK panel, independently of animal type, gave greater scores for beef flavour (+7 to +24%, P < 0.001) but lower scores for abnormal flavour (-10 to -17%, P < 0.001) at 74 degrees C. Abnormal flavour score by the French panel was higher at 74 degrees C than at 55 C (+26%, P < 0.001). Irrespective of the data set, tenderness was correlated with juiciness and beef flavour. Overall, this study found that cooking beef at a lower temperature increased tenderness and juiciness, irrespective of the location of the panel. In contrast, cooking beef at higher temperatures increased beef flavour and decreased abnormal flavour for the UK panelists but increased abnormal flavour for the French panel.

This study investigated the quality composition, oxidative stability and sensory attributes of beef (longissimus thoracis, LT) from steers offered grass silage and a concentrate supplement in which barley was replaced by 40% and 80% (as-fed basis) of dried citrus pulp (DCP). Dietary treatment did not influence the antioxidant status (α-tocopherol and total phenolic contents) and activities of LT (radical scavenging activity, ferric reducing antioxidant power and iron chelating activity). Feeding DCP significantly increased the proportion of conjugated linoleic acids and polyunsaturated fatty acids in beef. Lipid and colour stability of fresh beef patties stored in modified atmosphere packs (MAP) were unaffected by dietary treatment but feeding 40% DCP reduced (P .05) lipid oxidation in aerobically-stored cooked beef patties. Beef patties stored in MAP for up to 7 days were assessed by sensory panellists to be juicier for those fed 40% DCP compared to 0% and 80% DCP. Results indicated that substitution of barley with DCP improved the fatty acid profiles of beef without negatively influencing the eating quality of beef.

Colour and lipid stability of M. longissimus dorsi (LD) from sheep fed diets containing different lipid sources (Megalac (MG), camelina oil (CO), linseed oil (LO), NaOH-treated camelina seed (CS), NaOH-treated linseed (LS) or CO treated with ethanolamine (CA)) were examined. After 100 days on-feed, samples of LD were collected, fatty acid profile determined and colour and lipid oxidation (2-thiobarbituric acid reactive substances; TBARS) measured during retail display in high oxygen packaging. The LS ration was most effective in increasing the 18:3n-3 and conjugated linoleic acid (CLA) concentration in muscle. Within camelina, CA resulted in the highest 18:3n-3 and lowest CLA concentration in muscle. There was no difference in colour stability. Oil (seed) supplementation increased TBARS compared to MG in the early part of display while linseed-based rations tended to cause higher TBARS than camelina-based rations. Higher muscle 18:3n-3 concentration was associated with higher oxidation during early retail display but this was not reflected in a loss of colour stability.

The objective of this experiment was to determine the contribution of some biochemical processes of postmortem muscle to the variation in tenderness of beef from Belgian Blue bull cross Holstein–Friesian steers (n = 10). These animals were managed optimally from conception to consumption with the aim of reducing tenderness variation. The M. longissimus dorsi (LD) from the left hand side (LHS) and the right hand side (RHS) were analysed for variation in tenderness using Bartletts test. The quality measurements included pH, temperature, Warner Bratzler shear force, sensory tenderness, chemical composition and sarcomere length. Biochemical measurements included myofibrilar proteolysis, glycolytic potential, adenine/inosine ratio and collagen content. No difference for variances or means were observed between LHS and RHS for chemical, quality or biochemical attributes. Biochemical variation was greater than the variation observed in most of the quality attributes measured. Proteolysis was the main biochemical contributor to the variation in shear force tenderness after 2 and 7 as postmortem, but not sensory tenderness. Glycolysis levels and adenine/inosine ratio explained much of the variation in sensory tenderness, but not WBSF. Collagen content in the LD muscles did not explain variation in shear force or sensory tenderness. This would suggest biochemical variation is one of the main contributors to variation in tenderness of beef managed optimally pre- and post-slaughter.

The objective of this experiment was to determine the effectiveness of current “best-practise” management of steers pre- and post-slaughter in reducing variation in the eating quality of beef. Steers sired by one Belgian Blue bull from Holstein–Friesian cows were managed optimally from birth to slaughter. Animals were slaughtered at target body weights and subcutaneous fat scores of 620 kg and 4L (LH) ( n =23) or 720 kg and 4H (HH) ( n =24). On each slaughter occasion, commercial steers with similar carcass weights and classification scores to the homogenous steers were selected from the factory lairage; n =19 for light commercial steers (LC) and n =20 for heavy commercial steers (HC). Carcasses were hung by the pubic bone at 10 °C for 10 h and 2 °C until 24 h postmortem, when M. longissimus dorsi and M. semimembranosus muscles were excised. Following ageing for 2, 7 and/or 14 days postmortem, eating quality was assessed. Muscle from HH steers was more variable in terms of tenderness, protein, moisture and water-holding capacity compared to muscle from LH steers within LD muscle. Muscle from HC steers was more variable in terms of tenderness, redness colour, protein and intramuscular fat compared to muscle from LC steers within LD muscle. Applying best practice management to the homogenous and commercial steers in the present experiment reduced variances in Warner Bratzler shear force (25.69 and 23.9, respectively) compared to variance (154.9) of previous research carried out by the present authors.

The aim of this study was to determine the effect of different diets on beef meat volatile organic compounds (VOC). Seven heifers grazed pasture for twelve months (group P); 8 heifers received grass silage ad libitum indoors for six months and then were switched to pasture for six months (group SiP); 8 heifers received grass silage ad libitum indoors for six months and then switched to pasture and also offered 0.5 of the diet dry matter of concentrate for six months (group SiPC); 8 heifers received concentrate for twelve months (group C). The muscle longissimus dorsi was sampled at slaughter and subjected to VOC analysis by SPME-GC-MS. Some aldeyhdes, ketones and furans deriving from lipid oxidation were affected by the treatments. Skatole, 3-undecanone, cuminic alcohol and 1-butanol, 2-methyl allowed the discrimination between animals fed concentrate from animals fed non-concentrate diets. Germacrene D, a terpenoid, was a marker of grass feeding.

The objective was to determine, relative to animals expressing their full potential for carcass growth, the impact on meat quality of increasing carcass growth of grazing steers by supplementing with concentrates or by increasing grass supply. Sixty-six continental (Limousin and Charolais) crossbred steers (567 kg) were assigned to one of six diets: (1) 18 kg grass dry matter (DM); (2) 18 kg grass DM grass and 2.5 kg concentrate; (3) 18 kg grass DM and 5 kg concentrate; (4) 6 kg grass DM and 5 kg concentrate; (5) 12 kg grass DM and 2.5 kg concentrate; or (6) concentrates daily. Animals were slaughtered after an average of 95 days. Samples of the M. longissmus dorsi (LD) were collected at the 8–9th rib interface and subjected to sensory analysis and to other assessments of quality following 2, 7, or 14 days aging. Carcass weight gain averaged 360, 631, 727, 617, 551 and 809 g/day for treatments 1 to 6, respectively. There was no difference between diets for colour, Warner–Bratzler shear force (WBSF) or any sensory attribute of the LD. WBSF was negatively correlated with (P

The objective of this experiment was to determine the effect of varying the proportions of autumn grass and concentrates and grass silage and concentrates on the quality of meat from cattle with similar rates of carcass growth. Fifty continental crossbred steers were assigned to five treatments. The experimental diets offered were (1) grass silage ad libitum plus 4 kg concentrate (SC), (2) 1 kg hay plus 8 kg concentrate (CO), (3) 6 kg grass dry matter (DM) plus 5 kg concentrate (CG), (4) 12 kg grass DM plus 2.5 kg concentrate (GC) and (5) 22 kg grass DM (GO). The experiment lasted 85 days after which all animals were slaughtered. The right side m. longissmus dorsi was excised from all animals 24 h post slaughter for assessment of meat quality. Treatments SC and CO resulted in animals with whiter (P