Effect of feeding treatment during the backgrounding phase of beef production from pasture on: I. Animal performance, carcass and meat quality

This research evaluated effects of feedlot backgrounding on 40, 70 or 100% alfalfa hay diets (40hay, 70hay; 100hay, respectively) or pasture grazing (Pasture) before pasture finishing, on performance and beef characteristics of Angus heifers. Ninety six female calves were allocated to the four feeding strategies. Backgrounding took place during 114 days and subsequent pasture finishing over 132 days. Heifers of each strategy were slaughtered after 114 days (end of the feedlot period) and at end of the study when all remaining animals were finished on pasture. Effects of backgrounding were associated with rate of gain. Backgrounding strategies 40hay and Pasture resulted in the best performance. Beef attributes were similar. At the end of the feedlot period, 100hay was smaller and leaner, less tender and less juicy. At the end of the study, Pasture and 40hay heifers had on average the largest back fat thickness and intramuscular fat measurements. No treatment effects were detected for Warner-Bratzler shear force, muscle pH, muscle color and sensory panel attributes.     

Fatty acids and tocopherol levels in M. Longissimus dorsi of beef cattle in Sweden - A comparison between seasonal diets

This study investigated the influence of Swedish outdoor feeding systems on the fatty acid composition and tocopherol content of M. Longissimus dorsi from beef. Dietary effects of pasture (PA), silage, and silage supplemented with grain (SIG) were compared. Each dietary group consisted of six animals. Higher levels (P < 0.05) of polyunsaturated fatty acids (PUFA) were found in the PA treatment. The n − 6/n − 3 fatty acid ratio of total lipids in the muscle tissue was in the range 1.2–1.5. The SIG treatment increased the n − 6/n − 3 ratio and decreased the total PUFA content of muscle tissue. The lipid class composition and the content of -tocopherol in the meat showed no differences among treatments.     

Quality of retail beef from two grass-based production systems in comparison with conventional beef

Seventy beef strip loins (Longissimus dorsi) were sampled, originating from labels prescribing pasturing (PS, suckler beef; PF, finished steers or heifers), from conventional production (CH, heifers; CB, young bulls), and from a label producing intensively fattened young bulls (LB) and prescribing specific husbandry conditions but not grazing. Samples were purchased in autumn and spring (1:1) from 33 retail stores in northeastern Switzerland. Colour was lightest in LB beef, while PS displayed the least intensive red. Shear force was low in pasture beef, with PF showing the lowest variability. Pasture beef was richer in n-3 fatty acids than beef of all other origins. The n-6/n-3 ratio was consistently below 2 in pasture beef, while it ranged above 5 in LB, and also in CH and CB when purchased in spring. Prescribing year-round feeding of grass products and the use of steers or heifers therefore guarantees n-3 enriched beef, which can be at least as tender as conventional beef.     

The relevance of methane emissions from beef production and the challenges of the Argentinean beef production platform

The livestock sector faces the challenge to respond to the growing demand for animal protein from an expanding population while reducing environmental impact through GHG emissions. Globally about 2.836 million tons of CO₂-eq were emitted by the beef production sector equivalent to 46,2 kg CO₂-eq per kg carcass weight (CW). From the 1.485 million cattle head spread out over the world, 82% are on extensive grazing systems while only 18% are on high productive intensive systems. Among the top ten beef exporter countries, five are located in Latin America accounting a quarter of the global stock and two of them, Argentina and Uruguay, produce on temperate pastures under grazing systems. In Argentina, the livestock area was reduced in favor of increasing the grain cropping area, which took place in the last two decades. Production systems were intensified to maintain cattle stock. Cattle programs changed from 100% pasture to pasture supplemented with cereal grains and conserved forages, and confinement on grain feeding for fattening was incorporated. Due to land sharing competition with cash crops, no increment of cattle stock is expected therefore improving production efficiency appears as the only way to increase beef production while reducing methane emissions intensity. Beef produced on intensive grazing systems on supplemented pastures maintained organoleptic, nutritional and lipid profile than that of beef produced on pure grazing systems.     

Sustainable sheep production and consumer preference trends: Compatibilities,contradictions, and unresolved dilemmas

There are increasing concerns of society towards the consumption of animal products which have been produced and transformed in a sustainable manner. This trend influences consumer purchasing decision making, particularly in developed countries. On the other hand, in the next years, the pressure to increase the volume and efficiency of meat production will be much higher to cope with the expected unsatisfied demand. At least in part, current and future technologies could contribute to solve this challenge. However, the use of some of these innovations could have a negative effect on consumer preferences. There is no consensus in our society about this dilemma. The objective of this paper is to review the scientific evidence related to these topics and to analyze and discuss the effect of some of the extrinsic and intrinsic factors linked with the sheep industry which could affect the acceptability of lamb meat by consumers.     

Airborne Salmonella and Listeria associated with Irish commercial beef,sheep and pig plants

Air samples from lairage, hide/fleece pulling or dehairing/scraping, evisceration and chilling areas in commercial beef, sheep and pig plants were examined for Salmonella spp. and Listeria monocytogenes, by impaction or sedimentation onto selective (Brilliant Green Agar, BSA; Listeria Selective Agar, LSA) and non-selective (Plate Count Agar, PCA) media.     

The effect of production system and age on levels of iron, taurine, carnosine, coenzyme Q(10), and creatine in beef muscles and liver

Samples of longissimus (LL) and triceps brachii (TB) muscles from Angus-cross heifers finished either on a high-concentrate ration in Washington, USA, (US cattle, n = 15) or on pasture in New Zealand (NZ cattle, n = 16) were assessed for composition characteristics. Half of the NZ cattle were of a similar age to the US cattle (NZAge) and half were of a similar weight (NZWt). Iron concentration was higher in TB (20.9 vs. 17.5 μg g⁻¹; P < 0.001) and was higher for the NZWt group than the NZAge group or the US cattle. The proportion of iron as haem iron was highest for the NZWt group (87.3%; P < 0.01), but the proportion as soluble haem iron was highest for the US cattle. For a sub-group of 10 pasture-finished cattle, iron levels in cheek muscle were higher than for LL or TB, and liver levels were 66% higher than cheek muscle. The proportion of haem iron, however, was lowest in liver (55.3%) and was lower in cheek muscle (78.4%) than LL or TB. Relative to LL, TB had higher levels of taurine and coenzyme Q₁₀, but lower levels of carnosine, creatine and creatinine, as expected for a muscle with a more aerobic metabolism. These differences were magnified for the even more aerobic cheek muscle. Differences between the two NZ groups were small, but muscles from the US cattle contained less taurine, carnosine, coenzyme Q₁₀, and creatinine. Reasons for these differences in various meat components for similar cattle from different production systems are not clear.     

Effect of feeding treatment during the backgrounding phase of beef production from pasture on: II. Longissimus muscle proximate composition, cholesterol and fatty acids

This study evaluated effects of feedlot backgrounding strategies (40, 70 or 100% alfalfa hay diets) or pasture grazing on moisture, protein, total lipids, ash, cholesterol concentration, and lipid profiles of the longissimus dorsi muscle (LM) of pasture finished Angus heifers. Ninety six calves were allocated to the strategies over a 114-day period, followed by pasture grazing over 132 days. At the end of the backgrounding stage, the concentration of omega-3 (n-3) fatty acids was highest in the Pasture group and this difference persisted (P < 0.032) until the end of the 132 day pasture finishing phase. Similarly, the n-6/n-3 ratio was lowest in the Pasture group at the end of backgrounding and after pasture finishing. Backgrounding diets based on 70 and 100% hay or pasture grazing showed greater (P < 0.041) conjugated linoleic acid (CLA) concentration in the lipid fraction than 40% hay. Results suggested that residual effects of backgrounding strategies could be detected in intramuscular fat of pasture finished heifers.     

A comparison of solid-phase microextraction (SPME) with simultaneous distillation-extraction (SDE) for the analysis of volatile compounds in heated beef and sheep fats

A comparison has been made on the application of SPME and SDE for the extraction of volatile compounds from heated beef and sheep fats with separation and measurement by gas chromatography-mass spectrometry. As far as we know, this report represents the first time that such a comparison has been made for the measurement of volatile compounds in heated sheep fat. Approximately 100 compounds (in relatively high abundance) were characterised in the volatile profiles of heated beef and sheep fats using both techniques. Differences were observed in the volatile profiles obtained from each technique, independent of compound class. Rather than rate one technique as superior to another, the techniques can be regarded as complementary to each other.     

Selenium,copper, zinc,iron and manganese content of seven meat cuts from Hereford and Braford steers fed pasture in Uruguay

Tenderloin (T), eye of rump (E), striploin (S), eye round (ER), tri-tip (TT), rib-eye roll (RR) and three rib plate-flank on (RP) meat cuts were evaluated. Selenium contents ranged between 0.42 and 1.20 mg/kg wet tissue (wt) in Hereford (H) breed and between 0.49 and 1.3 mg/kg wt in Braford (B) breed. In H and B breeds, T, TT and RP, and TT and RP were the richest cuts in selenium, respectively. Copper contents ranged between 0.25 and 1.04 mg/kg wt in H, and between 0.19 and 1.09 mg/kg wt in B. In H breed, RP had significantly more Cu than ER, TT, and RR. In B breed, ER and RR show a significant lower Cu level in comparison to the other meat cuts. Zinc contents ranged between 23 and 72.7 mg/kg wt in H, and between 23 and 63.9 mg/kg wt in B. RP is the richest cut in Zn compared to the other cuts in the two breeds. Iron contents ranged between 16.4 and 48.2 mg/kg wt in H, and between 14.2 and 47.9 mg/kg wt in B. In H breed, RR shows a lower content compared to the other cuts, except RP and S. In B breed, RR had the lowest level of Fe compared to the other cuts, except RP and T. Manganese contents ranged between 0.05 and 0.17 mg/kg wt in H, and between 0.04 and 0.48 mg/kg wt in B. In H no differences were detected between cuts. In B breed, ER cut shows the highest level of Mn.     

Eating quality of beef, from different production systems, assessed by German, Spanish and British consumers

The acceptability of beef from Uruguay (UY), based on eating quality, was compared with beef produced in different European countries (Germany, DE, Spain, ES and United Kingdom, UK). Consumer tests were conducted in DE, ES and UK (each comprising 200 consumers) using 'Hall Tests'. In each country four samples were evaluated, two from Hereford steers from UY (finished at 2 and 3 years) and two from local meat (the same meat sample aged 7 or 20d). Consumers evaluated tenderness, flavour and overall acceptability using 8-point category scales. Hierarchical cluster analysis, highlighted the existence of different clusters of consumers. Two main clusters were identified in DE and UK. The main cluster identified in DE, was labelled as Prefer foreign-imported beef (n=128). These consumers preferred (P<0.05) the samples from UY_2y in terms of tenderness and overall acceptability. The other cluster was labelled as Prefer local beef in terms of flavour and overall acceptability (P<0.05) and comprised the majority of consumers from ES (n=176) and UK (n=153) and the cluster 2 from DE (n=69). UK, cluster 2 (n=33) that did not discriminate between origin and ageing time of beef. These results indicate that consumers did not prefer the same type of meat within the same country and it is possible that there are individual preferences that could lead to the concept of market segmentation being based on taste preferences. It would appear that Uruguayan beef would be very acceptable in Germany and to a lesser extent in Britain and Spain, although further studies are required that include labelling information.     

Gas‐producing and spoilage potential of Enterobacteriaceae and lactic acid bacteria isolated from chilled vacuum‐packaged beef

This study aimed to enumerate and identify lactic acid bacteria and Enterobacteriaceae from spoiled and nonspoiled chilled vacuum‐packaged beef and determine their potential to cause blown pack spoilage. These microbial groups were also enumerated in nonspoiled samples and detected in abattoir samples. The potential of isolates to cause ‘blown pack’ spoilage of vacuum‐packaged beef stored at chilled temperature (4 °C) and abuse temperature (15 °C) was investigated. Populations of lactic acid bacteria in exudate of spoiled and nonspoiled samples were not significantly different (P > 0.05), whereas the number of lactic acid bacteria on the surface was significantly higher (P < 0.05) in spoiled samples as compared to nonspoiled samples. The population of Enterobacteriaceae species in exudate and on the surface of samples were significantly higher (P < 0.05) in spoiled packs in comparison with nonspoiled packs. Results of the deterioration potential showed that ‘blown pack’ spoilage was noticeable after 7 days at 15 °C and after 6 weeks at 4 °C for samples inoculated with Hafnia alvei.     

Prediction of methane production from dairy and beef cattle

Methane (CH₄) is one of the major greenhouse gases being targeted for reduction by the Kyoto protocol. The focus of recent research in animal science has thus been to develop or improve existing CH₄ prediction models to evaluate mitigation strategies to reduce overall CH₄ emissions. Eighty-three beef and 89 dairy data sets were collected and used to develop statistical models of CH₄ production using dietary variables. Dry matter intake (DMI), metabolizable energy intake, neutral detergent fiber, acid detergent fiber, ether extract, lignin, and forage proportion were considered in the development of models to predict CH₄ emissions. Extant models relevant to the study were also evaluated. For the beef database, the equation CH₄ (MJ/d) = 2.94 (± 1.16) + 0.059 (± 0.0201) × metabolizable energy intake (MJ/d) + 1.44 (± 0.331) × acid detergent fiber (kg/d) - 4.16 (± 1.93) × lignin (kg/d) resulted in the lowest root mean square prediction error (RMSPE) value (14.4%), 88% of which was random error. For the dairy database, the equation CH₄ (MJ/d) = 8.56 (± 2.63) + 0.14 (± 0.056) × forage (%) resulted in the lowest RMSPE value (20.6%) and 57% of error from random sources. An equation based on DMI also performed well for the dairy database: CH₄ (MJ/d) = 3.23 (± 1.12) + 0.81 (± 0.086) × DMI (kg/d), with a RMSPE of 25.6% and 91% of error from random sources. When the dairy and beef databases were combined, the equation CH₄ (MJ/d) = 3.27 (± 0.79) + 0.74 (± 0.074) × DMI (kg/d) resulted in the lowest RMSPE value (28.2%) and 83% of error from random sources. Two of the 9 extant equations evaluated predicted CH₄ production adequately. However, the new models based on more commonly determined values showed an improvement in predictions over extant equations.     

Polyunsaturated fats in meat from Merino, first- and second-cross sheep slaughtered as yearlings

This study examined the level of long chain omega-3 and omega-6 polyunsaturated fats, the ratio of polyunsaturated fat to saturated fat (PUFA/SFA) and the ratio of omega-6 to omega-3 (n-6/n-3) fat in sheep grown under grazing conditions in Australia. The sheep genotypes used were Poll Dorset_growth × Border Leicester Merino (PDg × BLM), Poll Dorset_growth × Merino (PDg × M), Poll Dorset_muscling × Merino (PDm × M), Border Leicester × Merino (BL × M) and Merino × Merino (M × M). Loin muscles (Longissimus lumborum) collected from 40 ewe and wether sheep slaughtered at 14 months of age were processed for fatty acid determination. After frozen storage, 20 g samples were minced and a 7 g homogenate was processed for muscle lipid extraction using a chloroform:methanol (2:1) procedure. There was an increase in PUFA/SFA as the proportion of Merino genetics increased in the progeny (second-cross < first-cross < Merino), but this was not shown in the n-6/n-3 ratio. The PUFA/SFA trend appeared to be associated with an increase in the level of total polyunsaturated fats, but not a decrease in the level of total saturated fats. The results demonstrate that there is a need to improve the PUFA/SFA content in first- and second-cross animals which are mainly used for meat production in Australia so as to maintain the healthy lipids in meat. Nutritional manipulation through feeding systems or selection of sires for greater heritability of omega-3 fat deposition may be suitable pathways to elevate the ratio of polyunsaturated fatty acids, and in particular omega-3.     

Meat quality of Nguni, Bonsmara and Aberdeen Angus steers raised on natural pasture in the Eastern Cape, South Africa

The current study compared meat quality of Nguni, Bonsmara and Angus steers raised on natural pasture. Fifteen seven-month-old weaners of each breed were kept at the University of Fort Hare Farm for 12 months till slaughter. Monthly weights of the steers were recorded. Carcasses were electrically stimulated. The m. longissimus thoracis et lumborum was sampled for the measurement of meat colour, pH, drip loss, sarcomere length, myofibrillar fragmentation length and Warner Bratzler (WB) shear force. The Nguni had the highest (P < 0.05) average daily gain. Bonsmara and Angus steers had higher (P < 0.05) carcass weight and dressing percentage than the Nguni steers. Meat quality characteristics were similar among all the breeds except that Nguni meat was darker (L^∗) (P < 0.05) than meat from the other two breeds. The respective L^∗ values for Nguni, Bonsmara and Angus steers were 36.5, 38.6 and 39.9. There were significant (P < 0.05) correlations among some meat quality traits. There were significant (P < 0.05) correlations between WB values of meat aged for 2 and 21 days in Nguni and Bonsmara, but not in Angus. Meat quality from Nguni compares favourably with that from established breeds, when raised on natural pasture.     

Conventional freezing plus high pressure-low temperature treatment: Physical properties, microbial quality and storage stability of beef meat

Meat high-hydrostatic pressure treatment causes severe decolouration, preventing its commercialisation due to consumer rejection. Novel procedures involving product freezing plus low-temperature pressure processing are here investigated. Room temperature (20 °C) pressurisation (650 MPa/10 min) and air blast freezing (−30 °C) are compared to air blast freezing plus high pressure at subzero temperature (−35 °C) in terms of drip loss, expressible moisture, shear force, colour, microbial quality and storage stability of fresh and salt-added beef samples (Longissimus dorsi muscle). The latter treatment induced solid water transitions among ice phases. Fresh beef high pressure treatment (650 MPa/20 °C/10 min) increased significantly expressible moisture while it decreased in pressurised (650 MPa/−35 °C/10 min) frozen beef. Salt addition reduced high pressure-induced water loss. Treatments studied did not change fresh or salt-added samples shear force. Frozen beef pressurised at low temperature showed L, a and b values after thawing close to fresh samples. However, these samples in frozen state, presented chromatic parameters similar to unfrozen beef pressurised at room temperature. Apparently, freezing protects meat against pressure colour deterioration, fresh colour being recovered after thawing. High pressure processing (20 °C or −35 °C) was very effective reducing aerobic total (2-log₁₀ cycles) and lactic acid bacteria counts (2.4-log₁₀ cycles), in fresh and salt-added samples. Frozen + pressurised beef stored at −18 °C during 45 days recovered its original colour after thawing, similarly to just-treated samples while their counts remain below detection limits during storage.     

Biomarkers and biosensors for the diagnosis of noncompliant pH,dark cutting beef predisposition,and welfare in cattle

Meat quality can be affected by stress, exhaustion, feed composition, and other physical and environmental conditions. These stressors can alter the pH in postmortem muscle, leading to high pH and low-quality dark cutting (DC) beef, resulting in considerable economic loss. Moreover, the dark cutting prediction may equally provide a measure for animal welfare since it is directly related to animal stress. There are two needs to advance on-site detection of dark cutters: (1) a clear indication that biomarker (signature compounds) levels in cattle correlate with stress and DC outcome; and (2) measuring these biomarkers rapidly and accurately on-farm or the abattoir, depending on the objectives. This critical review assesses which small molecules and proteins have been identified as potential biomarkers of stress and dark cutting in cattle. We discuss the potential of promising small molecule biomarkers, including catecholamine/cortisol metabolites, lactate, succinate, inosine, glucose, and β-hydroxybutyrate, and we identify a clear research gap for proteomic biomarker discovery in live cattle. We also explore the potential of chemical-sensing and biosensing technologies, including direct electrochemical detection improved through nanotechnology (e.g., carbon and gold nanostructures), surface-enhanced Raman spectroscopy in combination with chemometrics, and commercial hand-held devices for small molecule detection. No current strategy exists to rapidly detect predictive meat quality biomarkers due to the need to further validate biomarkers and the fact that different biosensor types are needed to optimally detect different molecules. Nonetheless, several biomarker/biosensor combinations reported herein show excellent potential to enable the measurement of DC potential in live cattle.     

Verocytotoxigenic Escherichia coli O157 in beef and sheep abattoirs in Ireland and characterisation of isolates by Pulsed-Field Gel Electrophoresis and Multi-Locus Variable Number of Tandem Repeat Analysis

This study aimed to investigate verocytotoxigenic Escherichia coli O157 in the largest beef and sheep slaughter plants in Ireland over a one-year period. Samples consisted of pooled rectal swabs (n = 407) and pooled carcass swabs (n = 407) from 5 animals belonging to the same herd or flock and minced meat (n = 91) from the same sampling date. E. coli O157 isolates were characterised using PCR for a range of genes, i.e. 16S, rfbE, fliC, vtx1, vtx2, eaeA and confirmed VTEC O157 isolates were tested for antimicrobial susceptibility and typed using Pulsed-Field Gel Electrophoresis (PFGE) and Multi-Locus Variable Number of Tandem Repeat Analysis (MLVA). VTEC O157 was isolated from 7.6% and 3.9% of bovine rectal and carcass swab samples and from 5.8% and 2.9% of ovine rectal and carcass swab samples respectively. None of the bovine minced meat samples (n = 77) and only one of the 14 ovine minced meat samples was positive for VTEC O157. Following PFGE and MLVA, cross contamination from faeces to carcasses was identified. While PFGE and MLVA identified the same clusters for highly related strains, MLVA discriminated better than PFGE in addition to being more rapid and less labour intensive. Results showed that cattle and sheep presented for slaughter in Ireland harbour VTEC O157, and although the levels entering the food chain are low, this should not be overlooked as possible sources of zoonotic infection; molecular typing was able to demonstrate relationships among strains and could be used to elucidate the sources of human infection.     

CT scanning carcases has no detrimental effect on the colour stability of M. longissimus dorsi from beef and sheep

This study investigated the effect of computerised tomography imaging (CT scan), for carcase composition determination, on the oxy/metmyoglobin ratio, hue and L^∗, a^∗ and b^∗ scores of M. longissimus dorsi from both beef and lamb. Beef and lamb M. longissimus dorsi were divided into four proportions and randomly allocated to one of the following treatments; CT 30 day aged; CT fresh; control 30 day aged; control fresh. Colour measurements were made over a 96 h retail display period. CT scan had little effect on the colour of both lamb and beef across all colour parameters. There was a small negative affect observed in CT aged samples (P < 0.05) for ratio, hue, a^∗ and b^∗ values, however these differences were so small that they are unlikely to impact upon the commercial shelf-life of the product. Other factors such as aging, species and vitamin E concentration play a much greater role in colour stability than CT. Aged M. longissimus dorsi clearly had a worse colour stability than the fresh packaged samples, while beef was a lot more colour stable than lamb. It appears that CT scan for the purpose of body composition determination will not have any commercially relevant impact on colour stability of both beef and lamb.