Grain-fed Cattle Research Articles

21 Trace mineral nutrition for grain-fed feedlot cattle

Abstract Trace minerals are essential dietary components for feedlot cattle diets. They are integral components for normal carbohydrate, lipid, and protein metabolism and have been shown to be involved in hormone production, immunity, oxidation/reduction reactions, and cellular homeostasis. The functions of trace minerals in metabolic processes are extremely complex. In general, trace minerals function primarily as activators or components of enzymes that assist with enzyme structural integrity and/or substrate binding. Enzymes involved in the protection of cells from oxidative stress, electron transport, oxygen transport, bone metabolism, gene expression, and nutrient metabolism all have been shown to require certain trace elements for proper function. Trace minerals typically supplemented to feedlot cattle diets are cobalt (Co), copper (Cu), iodine (I), manganese (Mn), selenium (Se), and zinc (Zn). Although chromium (Cr) is not considered an essential nutrient in the Nutrient Requirements of Beef Cattle: National Academies of Sciences, Engineering, and Medicine (NASEM, 2016) publication, it is currently being included in some feedlot diets. Absorption of trace minerals from the gastrointestinal tract and tissue distribution of trace minerals are tightly regulated. However, many factors can impact the response of an animal to trace mineral supplementation, such as the dose and duration of supplementation, physiological status of an animal, the absence or presence of dietary antagonists, basal diet trace mineral concentrations, environmental factors, microbial-mineral interactions, and stress. Several research groups have compared the impact of supplementing increased concentrations (greater than the NASEM requirements) of Co, Cu, Mn, Zn, I, Se, and Zn (concurrently) on feedlot cattle performance and carcass characteristics. Results of these experiments have been variable, and caution should be taken when comparing experiments. Increasing trace mineral concentrations above published requirements does not always improve feedlot performance and carcass characteristics but has been reported, in some studies, to increase dry matter intake and average daily gain during certain intervals of the feeding period. The variability in animal numbers, the inclusion or omission of a negative control treatment, dietary ingredients, growth technologies used, and basal diet availability of trace minerals make comparing these types of experiments difficult.

Bushfire exposure is associated with darker color of beef loin at grading

The effect of bushfires (also known as wildfires) on the Australian livestock industry extends beyond the direct loss of animals and farming assets, with anecdotal reports of increased incidence of dark meat color defects in beef carcasses at grading (AUSMEAT color score >3) from bushfire affected cattle. To understand the association between bushfire exposure and meat color, an investigation using historical MSA (Meat Standards Australia) grading data, pasture data and bushfire data over two bushfire seasons (2018–2019, 2019–2020) was conducted. For bushfire affected beef cattle (n = 451 299), predictive models were developed to estimate the association between bushfire exposure and (1) loin color at grading, and (2) the incidence of ‘dark color’ defects. Both models incorporated bushfire exposure, production, and animal variables, with hierarchical random effects specified as plant/processing date/consignment. For the two predictive models, distance of the animal's originating property from closest bushfire (km), the days the animal was exposed to bushfire, feed type (grass, grain), the use of hormone growth promotants (HGPs; no, yes), the interaction of distance of property from closest bushfire and feed type, and days of bushfire and HGP treatment, were all significant predictors of loin color outcomes (P < 0.05 for all). Model 1 indicated that as distance from closest bushfire decreased, loin from grain-fed animals had darker color (P < 0.001), and that as days of bushfire exposure increased, HGP treatment exacerbated dark color outcomes for grain-fed animals but had little effect on the consistently high color scores of grass-fed HGP treated animals (P = 0.001). For model 2, the highest predicted proportion of dark color defects (11.8 %) was for grass-fed, HGP treated cattle, 10 km from the closest bushfire and exposed to 150 days of bushfire. The lowest predicted proportion of dark colour carcasses (1.3 %) was for grain fed, non-HGP treated cattle, 30 km from the closest bushfire, with no change associated with increasing days of bushfire. Cattle can be categorized in order of increasing susceptibility to dark color defects as a result of being exposed to bushfires; grain-fed cattle with no HGPs were the least susceptible to dark color defects, and grass-fed cattle with HGP treatment were the most susceptible. Remediation strategies are discussed in relation to cattle susceptibility to adverse loin meat color outcomes associated with bushfire exposure.

Allostasis as a consequence of high heat load in grain-fed feedlot cattle.

Heat wave intensity, frequency, and duration are increasing in many regions of the world, including locations where highly productive livestock are raised. There are animal health and welfare, as well as economic impacts from these events. In this study, the physiological responses of grain-fed steers during a high heat load challenge through to recovery in climate-controlled rooms (CCR) were intensively evaluated. Two cohorts of 12 Black Angus steers (BW, 615.4 ± 40.1kg) sequentially underwent a simulated heatwave event that consisted of 3 phases in the CCR: PreChallenge (5 d duration and temperature humidity index (THI) range of 65 to 71), Challenge (7-d duration and THI 66 to 95 with diurnal cycling), and Recovery (5 d duration and THI 65 to 70). The Challenge period was modeled on a severe heat wave, characterized by 3 very hot days. Individual rumen temperature (RumT, °C) was collected every 10min, and respiration rate (RR, breaths per minute), panting score (PS), and water usage (L·steer-1·day-1) were obtained at multiple time points daily, by trained observers. Individual animal daily DMI was also determined. Morning (0700 hours) rectal temperature (RecT, °C)was measured on days 3, 5, 7 to 13, 15, and 17. Not unexpectedly, RumT, RecT, RR, and PS rose during Challenge and fell rapidly as conditions eased. Conversely, DMI was reduced during Challenge. During the transition between PreChallenge and Challenge, there were abrupt increases in RumT, and RR. It was also very apparent that during Recovery the steers did not return to the baseline PreChallenge state. Compared to PreChallenge, Recovery was characterized by persistent lowered daily mean RumT (P = 0.0010), RecT (P = 0.0922), RR (P = 0.0257), PS (P ≤ 0.0001), and DMI (P ≤ 0.0001). These results provide evidence that these steers have undergone an allostatic response in response to high heat load, and the new adjusted physiological state post-heat event may not be transient.

Comparing the responses of grain-fed feedlot cattle under moderate heat load and during subsequent recovery with those of feed-restricted thermoneutral counterparts: blood cells and inflammatory markers

Given the climate projections for livestock rearing regions globally, understanding the inflammatory status of livestock under various heat loads will be informative to animal welfare and management. A survey of plasma inflammatory markers was conducted, and blood leucocyte counts followed to investigate the capacity of the ~ 500 kg grain fed Black Angus steer to respond to and recover from a moderate heat load challenge. Two sequential cohorts of 12 steers were housed in climate-controlled rooms (CCR) for 18 days. A thermally challenged (TC) group (n = 2 × 6) experienced five consecutive periods: PreChallenge, Challenge, and Recovery within the CCR, and 40 days in outdoor pens (PENS and Late PENS). PreChallenge (5 days) and Recovery (7 days) delivered thermoneutral conditions, whereas in Challenge the TC steers experienced a diurnal temperature range of 28–35 °C. A feed-restricted thermoneutral (FRTN) treatment (n = 2 × 6) was run concurrently to differentiate between responses to reduced feed intake alone and moderate heat stress. Blood neutrophil counts were particularly sensitive to moderate heat load with higher numbers during Challlenge and in PENs. The plasma concentrations of TNFα and IL-1β were depressed in the TC group compared to the FRTN counterparts and remained so for 40 days after Challenge. Linear relationships of the concentrations of IL-1β, IL-10, and haptoglobin with rumen temperature or dry matter intake detected in the FRTN group were altered or absent in the TC group. The findings suggest significant impacts of moderate heat load on the inflammatory status of feedlot cattle.

21 Intentionally Induced Barrier Dysfunction Causes Inflammation, Decreases Growth, and Alters Carcass Characteristics of Feedlot Cattle

Abstract There are a variety of acute and chronic psychological and physical stressors associated with management practices used in beef production systems. Primary challenges in feedlot cattle include heat stress, acute and subacute acidosis, weaning, transportation, feed deprivation/restriction, and social mixing/crowding. These stressors disturb the homeostatic state of the host and microbiome and cause acute or chronic inflammation resulting in damage to the gastrointestinal tract (GIT) epithelial barrier that leaves the animal vulnerable to enteric pathogens and toxins. A breach of the small intestinal barrier (leaky gut) allows unwanted pathogens and toxins to infiltrate into blood, causing infection, depressed feed intake, and diverts nutritional resources away from anabolic processes. We have demonstrated that intentionally inducing GIT inflammation in feedlot cattle with aspirin, which is known to cause mucosal injury and increase GIT barrier dysfunction, provides a model system to better understand the metabolic cost of leaky gut in grain-fed feedlot cattle. Indeed, aspirin increased leakage of chromium-EDTA into urine, raised serum concentrations of lipopolysaccharide binding protein (LBP), decreased growth by 4.5 to 8.5%, and re-partitioned carcass components from lean tissue (rib-eye area) into fat. Thus, the chronic inflammatory effects of leaky gut have the potential to create a significant economic loss. Our work also shows that in-feed administration of monensin and tylosin have offered a solution to the non-specific immune response observed in grain-fed cattle by increasing jejunal villus height to crypt depth ratio, diminishing leaky gut, and decreasing serum LBP. Finally, we have observed that molasses based liquid supplements increase ruminal butyrate concentration, resulting in improved gut barrier function, decreased serum inflammatory markers, and greater DMI and ADG in newly received feedlot cattle fed a 30% roughage diet.

High-intensity ultrasound improves color and oxidative stability of beef from grain-fed and pasture-fed Nellore cattle

This research aimed to evaluate the influence of high-intensity ultrasound (HIU) levels (control: 0; high: 747.79; ultra-high: 1344.17 Wcm−2) on pH, instrumental color (redness, R630/580, hue angle and chroma) and oxidative stability (lipid and protein oxidation) of Psoas major (PM) muscle from Nellore cattle raised in two feeding systems: grain and pasture. Using a structural equation modeling (SEM) approach, the relations (P > 0.05) between exogenous (HIU levels) and endogenous (pH, color, lipid and protein oxidation) variables were observed. In beef from grain-fed animals the pH was directly and negatively related to lipid oxidation (γ = −0.321), hue angle (γ = −0.847) and chroma (γ = −0.442) and protein oxidation (γ = −0.752). In PM from pasture-fed HIU exhibited a negative relation with lipid (γ = −0.144) and protein (γ = −0.743) oxidation, suggesting a possible positive influence on the oxidative stability of meat and a positive relation with redness (γ = 0.197) and R630/580 (γ = 0.379). The HIU positively influenced the color and oxidative stability of beef from Bos indicus cattle, and a synergistic effect of HIU and feeding system on beef from pasture-fed animals.

Influence of harvest method on proximate composition, texture profile and protein oxidation of beef from grain-fed Nellore cattle

The influence of harvest method on proximate composition, protein oxidation, and texture profile of beef from Nellore cattle were investigated. Longissimus lumborum (LL) muscles were obtained from twelve grain-fed Nellore carcasses. The animals were slaughtered after stunning (STU; n=6) or without stunning (WST; n=6) and after 24 hours postmortem, the LL was sliced into 2.54-cm steaks, packed under aerobic conditions, and stored at 4°C for nine days. Proximate composition was analyzed on day 0, whereas protein oxidation (carbonyl content) and texture profile (hardness, chewiness, cohesiveness, and springiness) were evaluated on days 0, 3, 6, and 9. STU and WST steaks exhibited similar proximate composition, hardness, and chewiness (p &gt; 0.05). WST steaks exhibited greater protein oxidation and lower cohesiveness than their STU counterparts on day 0 (p &lt; 0.05). Concerning the storage period, WST steaks demonstrated a decrease in springiness and a more pronounced increase in cohesiveness than their STU counterparts (p &lt; 0.05). These results indicated that the harvest method influenced LL protein oxidation and texture profile from Bos indicus cattle.

Rumen Microbial Predictors for Short-Chain Fatty Acid Levels and the Grass-Fed Regimen in Angus Cattle.

The health benefits of grass-fed beef are well documented. However, the rumen microbiome features in beef steers raised in a grass-fed regimen have yet to be identified. This study examined the rumen microbiome profile in the feeding regimes. Our findings show that the rumen microbiome of the grass-fed cattle demonstrated greater species diversity and harbored significantly higher microbial alpha diversity, including multiple species richness and evenness indices, than the grain-fed cattle. Global network analysis unveiled that grass-fed cattle's rumen microbial interaction networks had higher modularity, suggesting a more resilient and stable microbial community under this feeding regimen. Using the analysis of compositions of microbiomes with a bias correction (ANCOM-BC) algorithm, the abundance of multiple unclassified genera, such as those belonging to Planctomycetes, LD1-PB3, SR1, Lachnospira, and Sutterella, were significantly enriched in the rumen of grass-fed steers. Sutterella was also the critical genus able to distinguish the two feeding regimens by Random Forest. A rumen microbial predictor consisting of an unclassified genus in the candidate division SR1 (numerator) and an unclassified genus in the order Bacteroidales (denominator) accurately distinguished the two feeding schemes. Multiple microbial signatures or balances strongly correlated with various levels of SCFA in the rumen. For example, a balance represented by the log abundance ratio of Sutterella to Desulfovibrio was strongly associated with acetate-to-propionate proportions in the rumen (R2 = 0.87), which could be developed as a valuable biomarker for optimizing milk fat yield and cattle growth. Therefore, our findings provided novel insights into microbial interactions in the rumen under different feed schemes and their ecophysiological implications. These findings will help to develop rumen manipulation strategies to improve feed conversion ratios and average daily weight gains for grass- or pasture-fed cattle production.

Feedlot Factors Influencing the Incidence of Dark Cutting in Australian Grain-Fed Beef.

Simple SummaryThis study was conducted to investigate feedlot factors that influence the incidence of dark cutting in Australian grain-fed beef. Awareness of factors influencing dark cutting within the supply chain will enable the implementation of management strategies to manage dark cutting risk and reduce incidence. The reduction of dark cutting incidence will increase feedlot productivity as well as profitability across the entire supply chain.It has been well-established that dark cutting (DC) is a multifactorial issue that is associated with numerous animal and management factors. However, there is limited understanding of the feedlot-based factors that contribute to the influence of DC. The aim of this study was to evaluate the effect of climate, animal, and feedlot factors on the incidence of pH non-compliance in Australian grain-fed cattle. For this study, feedlot and abattoir records from 142,228 individual cattle over a 1-year period were investigated. These data incorporated records from seven feedlots that consigned cattle to three abattoirs. The average incidence of DC in these carcasses was 2.8%. The production factors that were associated with increased risk of DC included feedlot, sex, hormone growth promotants (HGP), cattle health, and days on feed (DOF). Additionally, DC also increased by reduced solar radiation (SR, W/m2), lower wind speeds (WS, m/s), increased ambient temperature (TA, °C), higher rainfall, a higher average temperature–humidity index (THI), and increased duration of time above heat-load-index threshold of 86 (HLI ≥ 86) during the 7 days prior to feedlot departure. This study identified the feedlot factors that increase the risk of DC from a feedlot-management perspective.

PSIX-4 Comparison of water footprint in roughage-fed and grain-fed beef cattle finishing systems

Abstract Beef cattle production has been argued to represent a massive player on water usage given the high-water footprint (WF) attributed to the livestock sector. From a water usage mitigation standpoint, at the animal level, manipulation of drinkable water is possible since major differences in water utilization are highly related to diet composition and feed quality. The objective of this study was to evaluate the effects of two cattle finishing systems, grain-finished versus roughage-finished on dry matter intake (DMI), water intake (WI), WF and water use efficiency (WUE) of Angus cattle. Twenty-four steers (385 ± 10.80 kg) were fed either alfalfa only (roughage-finished) or predominantly whole grain (80% corn and 20% alfalfa). Individual DMI and WI were measured for 105 days. Water footprint was expressed as amount of green (rainwater; WFg), blue (surface and groundwater; WFb), and grey (waste; WFgy) water used for feed production and WI of animals, and the sum of all three represents the total WF (TWF). The WUE was calculated as the integral between water used during the experimental period, and then converted into water efficiency as divided by cold carcass weight (CCW). Differences amongst treatments were compared via orthogonal contrast using the GLIMMIX procedure of SAS (version 9.4) with treatment as fixed effect and animals as a random effect. Roughage-fed animals presented significantly higher WI and DMI (P = 0.0005 and P &amp;lt; 0.0001, respectively), 80 kg lighter CCW (P = 0.0005) when compared to grain-finished animals. Grain-finished animals had a lower WFb WFgy, and TWF (P &amp;lt; 0.0001), but a higher WFg (P &amp;lt; 0.0001). Water use efficiency was twice as high for roughage-fed animals. Therefore, for the finishing phase, steers finished on a grains had a lower WF when compared to roughage-fed animals.

The impact of weather on the incidence of dark cutting in Australian feedlot cattle.

This study conducted a retrospective analysis of historical Meat Standard Australia (MSA) carcass data in combination with Bureau of Meteorology (BOM) weather data, to evaluate the relationship between climatic conditions prior to feedlot departure on the incidence of dark cutting grain-fed beef. Data records for 2,795,754 carcasses from 17 commercial feedlots over a 6-year period were evaluated within this study. Carcasses were consigned to 16 abattoirs. Weather data from BOM were recorded at 30-min intervals and were obtained from weather stations with the closest proximity to each feedlot. These data were used to calculate the Temperature Humidity Index (THI). Climatic data were amalgamated into daily observations and a series of predictors including ambient temperature (TA, °C), relative humidity (RH, %), wind speed (WS, m/s), rainfall (mm) and THI. In addition, lag interactions from 24h out to 28days prior to exiting the feedlot were generated. The incidence of dark cutting was determined as percentage per cohort with an ultimate pH > 5.7. Data were analysed using three models: model 1 included feedlot, abattoir, hormone growth promotant status and sex as fixed effects. Model 2 incorporated the fixed effects within model 1 and minimum, maximum and standard deviation (SD) of TA and RH, daily range in TA, average WS and rainfall as random effects. Model 3 incorporated minimum, maximum, range and SD of THI, average WS and rainfall as random effects in addition to the fixed effects of model 1. The incidence of dark cutting within feedlot had a 10.1% range in estimated means with the lowest incidence was observed at feedlot 17 (0%) and highest incidence at feedlot 10 (10.1%). The inclusion of the climatic variables in model 2 and model 3 accounted for an additional 0.1 to 0.2% of the incidence of dark cutting carcasses. Higher maximum TA, RH and THI in the 3 to 28days prior to consignment were all associated with an increased incidence of dark cutting (P < 0.05), but not in the 48h preceding consignment (P > 0.05). Low minimum TA and low THI were also associated with an increase the incidence of dark cutting across all lag periods (P < 0.05). Increased variation in THI and TA in the 48h prior to consignment increased dark cutting (P < 0.05) while increased standard deviation (SD) of temperature and THI range also increased dark cutting in the 14 and 28day prior to feedlot exit (P < 0.05). Smaller minimum ranges in TA in the 28days prior to consignment also reduced dark cutting (P < 0.05). Climatic conditions accounted for a further 0.1 to 0.2% of the incidence of dark cutting, whereas animal management factors, feedlot and abattoir were able to account for 21% of dark cutting. These data suggest that climatic conditions appear to have an inherent role in the incidence of dark cutting, albeit a small impact. Regardless, understanding the influence of climatic conditions on dark cutting allows for the implementation of management strategies within the supply chain to further reduce the impact of climatic conditions on grain-fed cattle.

Authenticating common Australian beef production systems using Raman spectroscopy

Australian grain-fed and grass-fed beef products garner premium market prices and many beef processors market branded beef supported by production system claims. Given beef cattle nutrition alters the fatty acid composition of subcutaneous fat and grass and grain-fed cattle can be differentiated using Raman spectra of the fat, this study aimed to evaluate if Raman spectroscopy and chemometric modelling can differentiate grass fed cattle from a variety of production systems. To this end, subcutaneous fat from a total of 520 beef carcases with 130 from long term grain-fed, short term grain-fed, grass-fed and supplemented grass-fed beef cattle were measured. Classification of carcases using Partial Least Squares Discriminant Analysis (PLS-DA) demonstrated spectra were able to correctly classify long term grain-fed (96%), short term grain-fed (85%), grass-fed (83%) and supplemented grass-fed (83%) carcases based on the test dataset. Spectral patterns including peaks that characterise fatty acids have been shown to underpin this classification. Overall, this study demonstrates Raman spectroscopy is a useful tool for the authentication and discrimination of beef carcases from different production systems.

Diet-induced changes in bacterial communities in the jejunum and their associations with bile acids in Angus beef cattle

BackgroundThe small intestine, while serving as the main absorption organ, also possesses a unique bacterial environment and holds the critical function of conversion of primary bile acids. Bile acids are, in turn, able to regulate bacterial composition and promote the growth of bacteria that convert primary bile acids to secondary bile acids. However, in beef cattle, few studies have explored the influence of diets on jejunal bacterial communities and examined its relationships with bile acids. Here, we examined the impact of grain- and grass-based diets on jejunal and fecal bacterial communities’ composition and investigated possible association of bacterial features with bile acids.ResultsWe demonstrated that the influences of diets on intestinal bacteria can be observed in young beef cattle after weaning. A significantly higher level of microbial diversity was documented in feces of grass-fed cattle comparing to grain-fed cattle. Top 20 important genera identified with random forest analysis on fecal bacterial community can be good candidates for microbial biomarkers. Moreover, the jejunal bacteria of adult Angus beef cattle exhibited significant differences in microbial composition and metabolic potential under different diets. Global balances and bacteria signatures predictive of bile acids were identified, indicative of the potential association of bacterial features with bile acids.ConclusionsThe findings from this study provided novel insights into the relationships between jejunal bacteria and bile acids under different diets in Angus beef cattle. Our results should help us gain a better understanding of potential health benefits of grass-fed beef.

Flavor Characterization of Grass- and Grain-Fed Australian Beef Longissimus Lumborum Wet-Aged 45 to 135 Days

The study objective was to evaluate the effects of extended postmortem wet aging of Australian beef, cattle diet, and their interaction on objective and subjective measures of beef flavor of the longissimus lumborum. Beef strip loins were collected from grass- and grain-fed cattle (n = 50 total) at a commercial abattoir near Brisbane, Australia. Beef longissimus lumborum were portioned and assigned randomly to one of 3 postmortem aging periods (45, 70, or 135 d). As each section reached its respective postmortem aging designation, that section was fabricated into 2.5-cm steaks, individually vacuum packaged, and frozen (−21°C). Trained panelists evaluated cooked steaks for numerous flavor attributes, tenderness, and juiciness; volatile compounds were also evaluated. Sensory scores differed (P &amp;lt; 0.05) due to diet, whereby grain-fed samples were rated more intense (P &amp;lt; 0.05) for beef flavor identity, fat-like, liver-like, and sweet but grass-fed samples were more intense (P &amp;lt; 0.05) for green-hay and bitter. Juiciness, tenderness, and 4 flavor attributes (bloody/serumy, metallic, umami, and rancid) were similar (P &amp;gt; 0.05) between diets. Extending postmortem aging from 45 to 135 d resulted in decreased beef and umami flavors (P &amp;lt; 0.05), along with concurrent increased detection of off-flavors, such as liver-like, rancid, bitter, and sour (P &amp;lt; 0.05). Volatile flavor compounds were more influenced by postmortem aging than diet. Increased postmortem aging time increased concentration for both lipid oxidation and Maillard-reaction–derived volatiles, resulting in the concentration of negative flavor volatile compounds rather than the absence of positive flavor compounds. Based on these results, differences existed in the flavor profile of longissimus lumborum from grass- and grain-fed beef, regardless of postmortem aging. However, aging beef strip loins 135 d is not recommended based on reduced beef flavor and increased off-flavor detection compared to samples aged 45 or 70 d postmortem.

Assessment of atherogenic index, long-chain omega-3 fatty acid and phospholipid content of prime beef: a survey of commercially sourced New Zealand Wagyu and Angus beef cattle

Context There is increasing interest in the composition of lipids in beef from pasture-fed Wagyu-cross cattle and how they compare to beef from traditional beef breeds. Aim The present study aimed to investigate the differences in fatty acid and phospholipid content of the ribeye, striploin and tenderloin obtained from commercially sourced beef. Hypothesis We hypothesised that long-chain omega-3 fatty acid and phospholipid concentrations would be higher in Wagyu beef sourced from pasture-based production systems than in those sourced from grain-finished Wagyu. Methods Beef was either derived from commercial cattle exclusively fed pasture (Angus, Wagyu × Angus and Wagyu × Dairy (Friesian × Jersey); n = 10 per breed) or finished on grain (Angus and Wagyu; n = 10 per breed). Key results Phosphatidylcholine was the predominant phospholipid observed in beef surveyed, followed by phosphatidylethanolamine and sphingomyelin. All classes of phospholipid measured were affected by where the commercial beef was obtained, with the concentrations of total phospholipids being highest (P < 0.05) in the ribeye, striploin and tenderloin from pasture-fed beef compared with grain-fed beef. The fatty acid composition also varied among the commercial cuts; typically total saturated fatty acid and monounsaturated fatty acid concentrations were highest in beef finished on grain, whereas the concentrations of long-chain omega-3 fatty acids were two-fold higher (P < 0.05) in striploin and tenderloin derived from pasture-fed Wagyu × Dairy cross cattle than in those from grain-fed cattle. Despite different fatty acid concentrations among the commercial beef breeds surveyed, the calculated atherogenic index was similar for ribeye and striploin. In contrast, the tenderloin obtained from pasture-fed Wagyu × Dairy had the lowest (P = 0.017) atherogenic index. Conclusions Depending on the cut of meat studied, pasture-fed Wagyu × Angus and Wagyu × Dairy have different lipid compositions, including lipids that have been associated with both health benefits and risks in human. Implications These results show that a serving of meat obtained from non-traditional beef breeds such as pasture-fed Wagyu × Dairy may contribute significantly to the recommended daily intake of long-chain omega-3 fatty acids.

Muscle from grass- and grain-fed cattle differs energetically

Insufficient acidification results in dark, firm, and dry beef. While this defect is often indicative of a stress event antemortem, muscle tissue may change in response to feeding regime. Longissimus dorsi muscle samples from 10 grain-fed and 10 grass-fed market weight, angus-crossbred beef cattle were collected postmortem. Lower (P < .05) L* and a* values were recorded for steaks from grass-fed cattle. Higher (P < .05) ultimate pH values were noted in lean of grass-fed cattle compared to grain-fed cattle, yet differences in lactate, glycogen and glucose were not detected. Further, increased (P < .05) ultimate pH values and lower (P < .05) lactate accumulations were noted when samples from grass-fed cattle were subjected to an in vitro glycolysis system. Muscle from grass-fed beef possessed nearly two-fold more (P < .05) succinate dehydrogenase and (P < .001) myoglobin than that of grain-fed cattle. These data show lean from grass-fed beef has greater enzymes reflective of oxidative metabolism and suggest dark lean from grass-fed cattle may be a function of more oxidative metabolism rather than a stress-related event antemortem.

An eight-year retrospective study of hydatid disease (Echinococcus granulosus sensu stricto) in beef cattle slaughtered at an Australian abattoir

A retrospective study was conducted on 1,178,329 cattle slaughtered at an eastern Australian abattoir between 2010 and 2018. The data were searched for records in which a diagnosis of hydatid disease was made by routine meat inspection and apparent prevalence was calculated. True prevalence of hydatid disease in any organ was then estimated using previously reported sensitivity and specificity for diagnosis of hepatic hydatid disease by routine meat inspection. Mixed effects logistic regression was conducted to assess putative associations between dentition (age), sex, and feed-type (grass- or grain-fed), and hydatid disease reported at slaughter, with origin (Property Identification Code [PIC] region) included as a random effect. Regression was also conducted on subsets stratified by dentition and feed-type to account for measurement bias resulting from differences in sensitivity and specificity between groups of cattle. Discrete-Poisson models (SaTScan, v.9.5) were used to detect spatio-temporal clustering of hydatid-positive cattle within PIC regions.The apparent prevalence of hydatid disease reported in any organ was 8.8% (n = 104,038; 95% confidence interval [CI] 8.8–8.9%). The liver, lungs, heart, spleen, and kidneys were reported infected with hydatid cysts. Of cattle reported infected with hydatid cysts, 75.6% had both the liver and lungs reported infected. True prevalence was estimated to be 33.0% (95% CI 24.4–44.4%). Significant interaction between dentition and feed-type was identified. Risk of reported hydatid disease was highest in both eight-tooth grass- and eight-tooth grain-fed cattle (OR 17.5, 95% CI 17.0–18.1, reference level [ref] zero-tooth; OR 4.8, 95% CI 4.4–5.2, ref zero-tooth, respectively). Sex was also significantly associated with reported cases of hydatid disease at slaughter, with the highest odds in females (two-tooth group, OR 1.2, 95% CI 1.1–1.2, ref male). Three spatio-temporal clusters of hydatid-positive regions were identified. The most likely cluster was located in north eastern New South Wales from June 2012 to September 2015 (log likelihood ratio 4774, P < 0.001).This study indicates a higher prevalence of hydatid disease than previously recognised and demonstrates that an effect of sex cannot be ruled out. The identification of clusters could indicate periods when hosts of Echinococcus were more abundant, or localised climatic events that facilitated transmission to cattle. Given the high prevalence, the financial impact of hydatid disease on the Australian beef industry and risk factors associated with variation in spatial distribution should be determined to target interventions.

DNA methylation, microRNA expression profiles and their relationships with transcriptome in grass-fed and grain-fed Angus cattle rumen tissue.

Rumen is an organ for supplying nutrients for the growth and production of bovine, which might function differently under grass-fed and grain-fed regimens considering the association of gene expression, DNA methylation, and microRNA expression. The objective of this study was to explore the potential mechanism influencing rumen function of grass-fed and grain-fed animals. Methylated DNA binding domain sequencing (MBD-Seq) and microRNA-Seq were respectively utilized to detect the DNA methylation and microRNA expression in rumen tissue of grass-fed and grain-fed Angus cattle. Combined analysis revealed that the expression of the differentially expressed genes ADAMTS3 and ENPP3 was correlated with the methylation abundance of the corresponding differentially methylated regions (DMRs) inside these two genes, and these two genes were reported to be respectively involved in biosynthesis and regulation of glycosyltransferase activity; the differentially expressed microRNA bta-mir-122 was predicted to possibly target the differentially expressed genes OCLN and RBM47, potentially affecting the rumen function; the microRNA bta-mir-655 was exclusively detected in grain-fed group; its targets were significantly enriched in insulin and TGF-beta signaling pathways, which might worked together to regulate the function of rumen, resulting in different characteristics between grass-fed and grain-fed cattle. Collectively, our results provided insights into understanding the mechanisms determining rumen function and unraveled the biological basis underlying the economic traits to improve the productivity of animals.

Preliminary investigation into the use of Raman spectroscopy for the verification of Australian grass and grain fed beef

Australian grass and grain-fed beef products attract premium prices at sale and several beef processors market beef underwritten by production system claims. This preliminary investigation assessed the feasibility of using Raman spectroscopy to detect differences in the chemical composition of subcutaneous fat from cattle raised in extensive and intensive production systems. Raman spectra, fatty acid composition, β-carotene composition and objective colour measurements were measured on 150 grass and 150 grain-fed cattle. Spectral differences at peaks including 1069 cm−1, 1127 cm−1, 1301 cm−1 and 1445 cm−1 suggest that Raman spectra is able to detect differences in saturated fatty acids, which were significantly higher in carcases from grain-fed cattle. Differences in spectra at 1658 cm−1 were observed, however further research is required to investigate the cause of this spectral feature. Overall, this study indicated that Raman spectroscopy is a potential tool for the authentication of beef carcases from grass and grain-fed production systems.

Muscle-specific color stability in fresh beef from grain-finished Bos indicus cattle.

ObjectiveTo investigate the color and oxidative stabilities of longissimus lumborum (LL) and psoas major (PM) muscles from grain-finished Bos indicus cattle in Brazil.MethodsThe LL and PM muscles were obtained 24 h post-mortem from eight (n = 8) Nellore bull carcasses, fabricated into 1.5-cm steaks, aerobically packaged, and stored at 4°C for nine days. Steaks were analyzed for myoglobin concentration, pH, instrumental color, metmyoglobin reducing activity (MRA) and lipid oxidation.ResultsThe LL steaks exhibited greater (p<0.05) redness, color stability, and MRA than their PM counterparts on days 5 and 9. The LL and PM steaks demonstrated similar (p>0.05) lightness and yellowness on days 0, 5, and 9. On the other hand, PM steaks exhibited greater (p<0.05) myoglobin concentration, pH, and lipid oxidation than their LL counterparts.ConclusionThese results indicated that muscle source influenced the color and oxidative stabilities of beef from grain-finished Bos indicus animals. These results highlighted the necessity of muscle-specific strategies to improve the color stability of beef from grain-fed Bos indicus cattle.