The eating quality of meat of steers fed grass and/or concentrates

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<0.05) carcass growth rate (−0.31) but only a small proportion of the variation in meat quality between animals could be attributed to diet pre-slaughter or carcass fatness. It is concluded that high carcass growth can be achieved on a grass-based diet without a deleterious effect on meat quality.     

Meat quality of steers finished on autumn grass, grass silage or concentrate-based diets

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<0.05) subcutaneous and kidney/channel fat than all other treatments. There was an interaction (P<0.05) between ageing time and treatment with treatment GC having higher (P<0.05) tenderness, texture and acceptability values after 2 days ageing, but not after 7 or 14 days ageing. It is concluded that supplementing grass with low levels of concentrate produced the most tender and acceptable meat at 2 days post mortem, but that further ageing eliminated all treatment effects on eating quality of beef.     

Rate of carcass components gain, carcass characteristics, and muscle longissimus tenderness in lambs fed dietary protein sources with a low quality roughage diet

An experiment was conducted to examine the effects of infrequently fed (twice/week) protein supplements on rate of carcass components gain, carcass traits and tenderness of meat in lambs. Forty-three Dorset Horn×Merino wether lambs (aged 4 months) were assigned by stratified randomization (live weight basis) to five dietary treatments to compare the results with lambs fed very low quality (5.1 MJME/day) roughage diet. Lambs on control diet (BAS; treatment 1) and all other dietary treatment groups were offered ad libitum amounts of a mixed roughage diet (oat hay:lucerne hay) at the ratio of 85:15 throughout the 10-week experimental study. Supplements of barley grain with added urea and sulphate (USB, 226 g DM/day; treatment 2); lupins (LUP, 231 g DM/day; treatment 3); cottonseed meal (CSM, 152 g DM/day; treatment 4); fish meal (FM, 97 g DM/day; treatment 5) were offered at isonitrogenous amounts. Final live weight (FLW) and empty body weight (EBW) were greater (P<0.01) with FM, LUP, USB and CSM when compared with BAS. Rates of gain of carcass components observed during the experimental period resulted in lower carcass fatness (P<0.05) and greater muscle content (P<0.01) with FM; and higher (P<0.05) level of fat and muscle in the carcass with LUP compared to those on BAS diet. Other diets (USB and CSM) had less marked effects, but higher rate of daily fat gain in the carcass with LUP and CSM was indicated by greater carcass fat depth (P<0.05; the total tissue depth of muscle and fat at the twelfth rib, 110 mm from the midline; GR) and content of intramuscular fat (P<0.05), respectively. Energy gained as fat in the carcass was lowest with FM (P<0.05), highest with BAS and intermediate with all other treatments. The increase in carcass leanness and reduction in fatness with FM and USB compared to BAS and other treatments affected neither (P>0.1) meat tenderness (Warner-Bratzler shear force) nor sarcomere length of longissimus thoracis muscle. Feeding small amounts of protein supplements to lambs on very low quality forage diets during dry seasons may be a viable path to improve the carcass weight and leanness in lambs without changing the meat tenderness.     

Characterisation of young bulls of the Bruna dels Pirineus cattle breed (selected from old Brown Swiss) in relation to carcass, meat quality and biochemical traits

Seventy-four young bulls of the Bruna dels Pirineus beef cattle breed were reared in a typical production system and slaughtered at an average age of 381 days and live weight of 541 kg. The animals were evaluated for productive traits, carcass quality, meat quality, eating quality and biochemical characteristics of m. longissimus thoracis (LT). Biochemical measurements included intramuscular fat (IMF) and collagen proportion, haem pigment concentration, lactate dehydrogenase and isocitrate dehydrogenase activities and type I (MHC I) fibre percentage determined by ELISA. Bruna dels Pirineus bulls achieved high growth rates during the fattening period (1.63 kg/day) and showed good carcass quality, with a high dressing-out proportion (607 g/kg, hot carcass), a good conformation score (U; EUROP) and a moderate fatness score (3;1-5). Carcass composition was estimated from the sixth rib joint dissection (682 g/kg lean proportion, 127 g/kg total dissectable fat and 163 g/kg bone). IMF (24.3 g/kg) and MHC I (27.9%) showed high variabilities (CV>30%). Sensory analysis of LT included beef and livery odour and flavour intensity, and overall tenderness and juiciness assessment of loin samples (14-day ageing). Beef odour and flavour were slightly positively correlated with IMF and carcass fatness score (P<0.05). Fatness, MHC I, insoluble collagen and cooking losses tended to affect the livery flavour intensity positively. This variable was significantly higher in meat from bulls of lower carcass quality (i.e. lower conformation score, lower lean proportion; P<0.05) and higher type I fibre percentage. Loin overall tenderness and juiciness were not affected by the biochemical traits studied, however, they were negatively affected by cooking loss (P<0.05).     

Managing meat tenderness

This paper discusses the management of meat tenderness using a carcass grading scheme which utilizes the concept of total quality management of those factors which impact on beef palatability. The scheme called Meat Standards Australia (MSA) has identified the Critical Control Points (CCPs) from the production, pre-slaughter, processing and value adding sectors of the beef supply chain and quantified their relative importance using large-scale consumer testing. These CCPs have been used to manage beef palatability in two ways. Firstly, CCPs from the pre-slaughter and processing sectors have been used as mandatory criteria for carcasses to be graded. Secondly, other CCPs from the production and processing sectors have been incorporated into a model to predict palatability for individual muscles. The evidence for the importance of CCPs from the production (breed, growth path and HGP implants), pre-slaughter and processing (pH/temperature window, alternative carcass suspension, marbling and ageing) sectors are reviewed and the accuracy of the model to predict palatability for specific muscle×cooking techniques is presented.     

Effects of feeding intensity and time on feed on performance, carcass characteristics and meat quality of Simmental bulls

Seventy two Simmental bulls, weighing 489 kg and approximately 15 months old fed extensively or intensively on maize silage and concentrate mixture for 100 or 138 days, were divided into four groups to assess the effect of time on feed and feeding intensity on the performance, carcass and meat quality traits. Bulls intensively fed for 138 days before slaughter had higher final body weight (673.7 kg) compared with the other three groups (610.6 kg, as overall mean). Intensive feeding significantly increased the average daily gain (1371 g/day) and improved the feed efficiency (6.95 kg DM/kg gain) compared with extensive feeding (943 g/day and 7.97 kg DM/kg gain). No significant differences were detected by time on feed. Hot carcass and kidney fat weights were significantly higher for intensively fed bulls compared with extensive ones. Dressing percentage significantly increased for 138 day groups compared with 100 day groups. Carcass conformation and fatness scores significantly improved by intensive feeding. L and b(*) values were not affected by time on feed or feeding intensity. Slaughtering after 138 days on feed significantly elevated the meat redness value (a(*)). Intensive feeding significantly decreased moisture and increased fat content of the longissimus dorsi muscle. Shear force, collagen content, juiciness, flavour and sarcomere length did not differ by time on feed or feeding intensity, while inconsistent effects were observed on tenderness and solubility of collagen.     

Effect of supplemental concentrate type on milk production and metabolic status in early-lactation dairy cows grazing perennial ryegrass-based pasture

Forty-four early-lactation dairy cows of mixed parity were used to examine the effect of 4 supplemental concentrate types (n=11) on milk production and metabolic status. Animals were blocked by parity and calving date, and blocks were balanced for previous milk yield and milk protein yield. Cows received grazed pasture plus 5.17 kg of DM/d of 1 of the following isoenergetic (1.1 units of energy for lactation) concentrates: 1) high crude protein (CP) with rolled barley (HP, 19% CP); b) low CP with rolled barley (LP, 15% CP); c) low CP with barley and a supplemental methionine hydroxy analog (HMBi; LP + HMBi, 15% CP); and d) low CP with ground corn (LP-corn, 15% CP). Milk yield was recorded from d 1 to 100 postpartum, with weekly milk sampling, body weight, and body condition score (BCS) measurements. Blood and rumen sampling were conducted weekly from wk 2 to 6 postpartum. Milk yield was lower for cows in the LP treatment compared with those offered other concentrate types (25.2 vs. 27.5 ± 0.39 kg/d). Animals in the HP group had a higher milk yield than those in the LP + HMBi group (28.2 vs. 26.8 ± 0.39 kg/d). Milk fat yield was lower from animals in the LP-corn group compared with those in the LP + HMBi group (0.94 vs. 1.03 ± 0.03 kg/d). Milk protein yield was lower in the LP group compared with those in the HP group (0.88 vs. 0.97 ± 0.02 kg/d). Animal body weight, BCS, and BCS loss were not affected by concentrate type. However, nonesterified fatty acids were higher from animals in the HP group than for those in the LP + HMBi group (0.41 vs. 0.33 ± 0.03 mmol/L), and β-hydroxy butyric acid was higher from animals in the HP group than for those in the other treatments (0.71 vs. 0.59 ± 0.03 mmol/L). Glucose was higher from animals in the LP-corn group than for those in the HP and LP groups (3.3 vs. 3.2 ± 0.05 mmol/L). Blood urea-N was higher from animals offered HP compared with those offered the other treatments (5.49.6 vs. 4.21 ± 0.44 mmol/L). However, rumen NH(3)-N and volatile fatty acid concentration in the rumen were not affected by supplemental concentrate type. Reducing supplemental concentrate CP reduced milk yield. However, milk fat production and energy-corrected milk were not different, reducing the likelihood of an improved energy balance or a more favorable blood metabolic profile in early-lactation dairy cows grazing perennial ryegrass. Offering HMBi with low-CP concentrates or replacing rolled barley with ground maize improves milk production relative to low-CP concentrates and metabolic status relative to high-CP concentrates.     

Influence of age at slaughter, rearing technique and pre-slaughter treatment on some quality traits of lamb meat

The influences of rearing technique and age on muscle fibre type, and of rearing technique, age and pre-slaughter transport on the meat quality characteristics of sheep were investigated using thirty lambs of a Bulgarian coarse-fleeced breed (Karakatchanska). The animals were reared on pasture or in barns and slaughtered at 22 or 30 weeks of age. Muscle fibre type and meat quality were studied in three muscles of different metabolic type—Longissimus dorsi (LD), Supraspinatus (SS) and Rectus abdominis (RA). Fibre type distribution was influenced by age but not by rearing technique. Pigment content of muscles was higher in older animals. Water binding capacity (WBC) increased—and cooking loss decreased—with age. There was an interaction between muscle and pre-slaughter stress with respect to pH, the latter being increased in SS muscle, as was WBC. Cooking loss was decreased by transport stress in the three muscles and by pre-slaughter stress. However, meat organoleptic characteristics (flavour, tenderness and juiciness, as judged by a taste panel) were not influenced by age, rearing technique or pre-slaughter treatment.     

不同屠宰方式对新疆多浪羊肉品质的影响

以新疆多浪羊为研究对象,对比分析传统屠宰（对照）和3 个不同电压（90、127 V和220 V）击晕屠宰 （分别计作EST 90、EST 127、EST 220）对多浪羊肉品质的影响。结果表明：EST 90处理组成熟过程中pH值下降 速率最快,血液中的皮质醇浓度、肌酸激酶和乳酸脱氢酶活力最高,羊应激反应最剧烈,宰后1、7 d的蒸煮损失率 最高（P＜0.05）;EST 127处理组的持水力最好;电击晕对多浪羊肉嫩度有一定影响,宰后7 d各处理组嫩度显著 改善,而EST 127处理组表现最佳;EST 220处理组放血不充分,且胴体表皮有多处血斑形成;电击晕屠宰对多浪羊 肉色泽无显著影响（P＞0.05）。综合分析实验结果,EST 127处理组持水力与嫩度较优,羊应激反应较小,肉品质 相对较好,因此EST 127处理适合应用于多浪羊的屠宰加工。     

Live weight and sex effects on carcass and meat quality of "Borrego terrincho-PDO" suckling lambs

Fifty seven suckling lambs (28 males and 29 females) of the Churra da Terra Quente breed were used to evaluate the effects of live weight and sex on carcass composition and meat quality traits. Lambs were slaughtered at three weight classes (<8 kg, 8–11 kg and >11 kg) according to “Borrego Terrincho–PDO” specifications. The left sides of the carcasses were totally dissected. The longissimus thoracis and lumborum muscle was used for meat quality determination. Dressing proportion and carcass fatness were not affected by weight class or sex. Muscle proportion was similar in all carcass joints for the three weight classes. The percentage of bone decreased at the higher weight class, while that of subcutaneous and intermuscular fat increased. Female lambs had higher muscle proportions and greater muscle/bone ratios in the carcass side than males. Muscle pH, colour, cooking losses and tenderness were not affected by gender and weight class. Female lambs and weight classes 8–11 kg and >11 kg had higher proportions of intramuscular fat.     

A comparison of the meat properties of pasture-fed steers, heifers, pregnant heifers and spayed heifers

Mean ultimate pH values, sarcomere lengths, cooking losses, Warner-Bratzler peak shear values and compression values for the M. longissimus dorsi (LD) did not differ significantly between heifers, spayed heifers, heifers fitted with a HEIGRO^TM device^* pregnant heifers (2 to 6 months pregnant) and steers, killed at 18 or 22 months of age, with mean carcass weights of 189 and 221 kg, respectively. This result, from animals grazed at pasture, agrees with those of others who used LD samples from lot-fed animals. It would appear that carcasses of non-pregnant heifers, spayed heifers, pregnant heifers, heifers fitted with a HIEGRO^TM device and steers of similar age and subcutaneous fat depth, do not need to be differentiated on grounds of tenderness.     

Have we underestimated the impact of pre-slaughter stress on meat quality in ruminants?

Stress is the inevitable consequence of the process of transferring animals from farm to slaughter. The effects of chronic stress on muscle glycogen depletion and the consequent dark cutting condition have been well documented. However, there has been little examination of the consequences of acute stress immediately pre-slaughter on ruminant meat quality. New evidence is emerging to show that non pH-mediated effects on meat quality can occur through pre-slaughter stress in cattle and sheep. This paper reviews the general aspects of pre-slaughter stress in the pre-slaughter context. It then examines the impacts of pre-slaughter stressors on ruminant carcass and meat quality and considers remedial strategies for remediating and preventing pre-slaughter stress. Further quantification of the biological costs of pre-slaughter stress and the consequences to meat quality is required.     

Meat quality of wether lambs grazed on either saltbush (Atriplex nummularia) plus supplements or lucerne (Medicago sativa)

The meat quality of 42, 8 month-old cross-bred wether lambs that had been grazed on either predominantly saltbush (Atriplex nummularia) and supplemented with pasture hay (n=14) or oat grain (n=14) for 68 days was compared to lambs grazed predominantly on lucerne (Medicago sativa; n=14). The lambs used in the study ranged in un-fasted liveweight from 44.5 to 63.6kg pre-slaughter. There was no significant (p>0.05) difference between the treatments for liveweight, but there was a significant (p<0.05) treatment effect on hot carcass weight with those from the saltbush/hay group (SH) being lighter than those from the lucerne group. When the carcass measures of fatness or m. longissimus thoracis et lumborum area were adjusted to a common carcass weight of 22.4kg there was no difference between groups. There were no significant differences (p>0.05) between groups for pH or colour values (where L* indicates relative lightness, a* indicates relative redness and b* indicates relative yellowness). There was no significant difference (p>0.05) between groups for b(2)* values of subcutaneous fat. Treatment had a significant effect on aroma strength (p<0.05), samples from lambs in the SH group (n=10) and those in saltbush/grain (SG) group (n=10) having a stronger aroma than those from lambs grazed on lucerne (L; n=10). No treatment effect for liking of aroma was found. Flavour strength was not significantly (p>0.05) stronger for samples from groups SH and SG than for samples from group L. There was no effect of treatment on tenderness or juiciness and overall panellists ranked the samples similarly for acceptability. Finishing lambs on saltbush and either supplemented with hay or grain as used in this experiment did not present any apparent meat quality problems compared to lucerne fed lambs.     

Effects on quality attributes of commercial veal pieces under different ageing treatments

The objective of this study was to assess the effect of freezing on quality attributes of four commercial beef pieces of the ‘pistola’ under three ageing treatments: only refrigeration (T1), and refrigeration before (T2) and after (T3) freezing. Eight young calves with a low fatness score from the ‘Galician Blond’ × ‘Holstein‐Friesian’ breed cross were studied. Six steaks from each piece were allocated to treatments. Water–holding capacity (refrigeration and thawing expressible juice, and cooking losses), tenderness (shear force) and chemical composition (fat, moisture, ash and protein) were measured. Freezing produced higher total juice losses than only refrigeration; however, freezing did not improve the tenderness of beef with low fat content. Sequential order of freezing and refrigeration (T2 and T3) did not affect juice losses. The ribeye piece was the most tender veal piece and produced the lowest juice loss. Veal fat content was inversely related to juice losses and directly related to tenderness. Commercial pieces with low fat content are suggested not to be overcooked because of higher juice losses which reduce tenderness.     

The chemical composition of muscles from steers which experienced compensatory growth

The psoas major and semitendinosus muscles from ten Hereford Shorthorn steers were analysed. Five of the steers had been severely restricted in their diet during an Irish winter period (temperature range 3–13°) of 20 weeks. The remaining five were used as controls and were adequately fed throughout their lives. After the restriction period the five diet-restricted animals were adequately fed for 22 weeks. All ten steers were then slaughtered at the age of 20 months. Within each type of muscle there were no significant differences between treatments in the components, moisture, intramuscular fat, total protein, ash, intramuscular collagen, hexosamine hydrochloride, or in Warner Bratzler shear values. The correlations between intramuscular fat and shear values, and between hexosamine hydrochloride and shear values were low and not significant. Collagen contents correlated significantly with shear values at the 10% level of significance. There was no evidence that variation in tenderness (as measured by shear values) could be attributed to the pre-slaughter treatment or that any deterioration in meat quality was caused by this treatment.     

Dual X-ray absorptiometry accurately predicts carcass composition from live sheep and chemical composition of live and dead sheep

Fifty merino wethers (liveweight range from 44 to 81kg, average of 58.6kg) were lot fed for 42d and scanned through a dual X-ray absorptiometry (DXA) as both a live animal and whole carcass (carcass weight range from 15 to 32kg, average of 22.9kg) producing measures of total tissue, lean, fat and bone content. The carcasses were subsequently boned out into saleable cuts and the weights and yield of boned out muscle, fat and bone recorded. The relationship between chemical lean (protein+water) was highly correlated with DXA carcass lean (r(2)=0.90, RSD=0.674kg) and moderately with DXA live lean (r(2)=0.72, RSD=1.05kg). The relationship between the chemical fat was moderately correlated with DXA carcass fat (r(2)=0.86, RSD=0.42kg) and DXA live fat (r(2)=0.70, RSD=0.71kg). DXA carcass and live animal bone was not well correlated with chemical ash (both r(2)=0.38, RSD=0.3). DXA carcass lean was moderately well predicted from DXA live lean with the inclusion of bodyweight in the regression (r(2)=0.82, RSD=0.87kg). DXA carcass fat was well predicted from DXA live fat (r(2)=0.86, RSD=0.54kg). DXA carcass lean and DXA carcass fat with the inclusion of carcass weight in the regression significantly predicted boned out muscle (r(2)=0.97, RSD=0.32kg) and fat weight, respectively (r(2)=0.92, RSD=0.34kg). The use of DXA live lean and DXA live fat with the inclusion of bodyweight to predict boned out muscle (r(2)=0.83, RSD=0.75kg) and fat (r(2)=0.86, RSD=0.46kg) weight, respectively, was moderate. The use of DXA carcass and live lean and fat to predict boned out muscle and fat yield was not correlated as weight. The future for the DXA will exist in the determination of body composition in live animals and carcasses in research experiments but there is potential for the DXA to be used as an online carcass grading system.     

Effect of feeding pasture-finished cattle different conserved forages on Escherichia coli in the rumen and faeces

The effects of eight different pre-slaughter diets on gut microflora, pH and dry matter were evaluated in 112 slaughter-weight, pasture-finished heifers. Hide dirtiness at slaughter, plasma cortisol, meat pH and stickiness, and liveweight loss, were also examined. The pre-slaughter diets were: 48 h of 100% meadow hay, lucerne hay, red clover hay, perennial ryegrass hay, haylage, haylage supplemented with maize silage, pasture, or 24 h fasting before transport. Fasted animals had the highest counts of rumen Escherichia coli and Enterobacteria compared to other treatments (P<0.001), while red clover hay and haylage had the lowest (P<0.05). Faecal E. coli counts were also highest for fasted animals (P<0.05). Rumen E. coli and Enterobacteria counts were positively correlated with rumen pH (P<0.001), and negatively correlated with fibre intake (P<0.001). Diet significantly affected the pH of both the rumen and faeces (P<0.001), with fasted animals having the highest rumen pH and haylage and red-clover hay-fed animals the lowest. Dry matter (%) of the rumen contents was also significantly affected by diet (P<0.001). The mean carcass weight of fed heifers was 5 kg heavier than that of the fasted heifers (P<0.05). A pH/volatile fatty acid (VFA) dependent mechanism is suggested as the major mode for E. coli suppression by feeds used in the study. Coumarins may have contributed to lower ruminal and faecal E. coli counts with E. coli counts negatively correlated with expected coumarin ingestion (P<0.01). Feeding pasture-fed cattle conserved herbaceous forages, in preference to fasting, before transport for slaughter may prove beneficial in reducing the risk of carcass contamination with E. coli and other bacteria of digesta and/or faecal origin, and in protecting carcass weight.     

Meat production characteristics of Egyptian Baladi and Angora goats

Fifteen Baladi and 20 Angora intact males raised together from birth until 8 months of age were grown on a commercial concentrate mixture fed at the rate of 0·6 kg/head/day with chopped wheat straw fed at 0·5 kg/head/day for 14 weeks. Body measurements were taken before slaughter and carcass measurements and offal weights after it. The right sides of all carcasses were dissected into cuts, weighed and deboned. Fat was separated from the 9-10-11 rib joints and estimated. The two breeds did not significantly differ in birth weight, weaning weight, carcass weight, dressing percentage, most body measurements, all carcass measurements and most offal weights. Sigmificant differences were only found in body length, height at withers, weights of spleen and kidney fat. However, the Baladi had significant heavier loin and shoulder (P < 0·05) and breast and flank (P < 0·05) than the Angora which had heavier legs (P < 0·05). The carcasses of the two breeds had very similar percentage of edible meat (68·38 versus 68·65), lean (57·47 versus 57·38) and fat in the rib joint (10·91 versus 11·27).     

Effect of concentrate feeding pattern in a grass silage/concentrate beef finishing system on performance, selected carcass and meat quality characteristics

Steers were offered grass silage ad libitum and 6.4 kg concentrates daily for 126 days or silage ad libitum for 35 days, followed by concentrates ad libitum (Experiment 1). Steers were offered grass silage ad libitum and 6 kg concentrates daily for 154 days, concentrates ad libitum or grass silage ad libitum for 112 days followed by concentrates ad libitum (Experiment 2). All treatments received the same total concentrate allowance. In Experiment 1, there was no difference in any measurement of meat quality. In Experiment 2, ad libitum concentrate feeding per se, decreased redness and increased shear force of muscle at 2 days post-mortem. Delaying concentrate feeding decreased fat yellowness, decreased shear force at 7 and 14 days post-mortem and increased muscle redness at 14 days post-mortem. Modifications of the beef production system examined had minor effects on beef quality which are unlikely to be of commercial significance.     

The effect of supplementation with expanded sunflower seed on carcass and meat quality of lambs raised on pasture

The use of conventional concentrates in the supplementation of grass-based fed lambs may induce improvements in growth performance and/or carcass quality but may be disadvantageous in fatty acid profile of tissues, with a negative impact in some nutritional indexes. The objective of this trial was to evaluate the effects on growth performance, carcass and meat quality of using unprotected, unsaturated fat as a supplement for grass-fed based lambs. Twenty-four Merino Branco ram lambs raised on pasture, were supplemented with corn whole grain plus sunflower meal or corn whole grain plus expanded sunflower seed, from 20 to 30 kg live weight. The supplement had no effects on growth performance, carcass quality traits, or meat pH, colour estimates (L^*, a^*, b^*), water-holding capacity, shear force and sensorial attributes. However, lambs supplemented with expanded sunflower seed showed higher proportions of cis-9, trans-11 octadecadienoic acid and trans-vaccenic acid in intramuscular and subcutaneous fat, showing that the inclusion of unprotected lipids in lambs diet was effective in preventing the reduction of rumenic acid (C18:2 cis-9, trans-11) that occurs when conventional concentrates are used as a supplement.