Effects of winter stocker growth rate and finishing system on: III. Tissue proximate, fatty acid, vitamin, and cholesterol content

Effect of residual feed intake on meat quality in fattening Charolais bulls fed two contrasting diets

The selection of more efficient animals for breeding is of both economic and environmental interest to the industry. The aim of this study was to evaluate the influence of the animals' residual feed intake (RFI) ranking in interaction with the type of diet on the meat quality of Charolais beef cattle. Indeed, several biological mechanisms are associated with RFI, especially when animals are fed high starch-diets. It is therefore possible that quality parameters may show greater changes due to RFI in the context of high starch diets compared to high forage diets. An 84-day feed efficiency trial followed immediately by a second 112-day feed efficiency trial was conducted with a total of 100 animals fed either maize- or grass-diets for 196-days. At the end of the 84-day period, the 32 most divergent RFI animals (16 extreme RFI animals per diet, 8 RFI+ and 8 RFI-) were identified. They were slaughtered after 112-days of finishing. The Longissimus thoracis was characterised in terms of nutritional and sensory quality. RFI had no effect on lab colour, muscle shear force, total fat, fatty acid ratios and most of the total fatty acid content (especially n-3) irrespective of the diet. However, more efficient animals (RFI-) showed higher CLA contents compared to less efficient animals (RFI+) regardless of the diet and also a lower n6/n3 ratio only in animals fed the maize diets. Diet also had a significant effect on lipid and FA content as well as on FA composition.

The Meat Standards Australia carcass grading site affects assessment of marbling and prediction of meat-eating quality in growing European beef cattle

The lack of consumer feedback on beef eating quality contributes to reduced beef consumption in Europe. The Meat Standards Australia (MSA) grading scheme can assess the palatability of beef carcasses usually graded at the 10th thoracic vertebrae. However, the European beef industry relies on late-maturing breeds usually cut at the 5th vertebrae due to commercial reasons. Data from 55 young bulls and heifers of late-maturing breeds were collected in an Italian slaughterhouse following the MSA guidelines at both carcass grading sites and sides. Intramuscular fat levels were assessed through two scores and used with other variables to feed the MSA model, which predicts the MSA index, the meat-eating quality scores (MQ4) for 5 muscles and for each carcass grading site × side combination. The scores were analyzed using a mixed linear model. A correlation analysis was conducted to predict the variables measured at the 10th site using their correspondent at the 5th carcass grading site. A stepwise regression was conducted to understand the weight of each measured variable on marbling and MQ4 scores measured both at 5th and 10th carcass grading sites. Results showed significantly higher value for the studied traits at the 5th carcass grading site, while carcass side had no significant impact. The equations had high predictive capability and MSA marbling score played a key role in explaining the variability across carcass grading sites. The differences in marbling and MQ4 scores between the carcass grading sites suggest considering this factor if the MSA grading system will be applied to Europe.

Effect of Post-Weaning Concentrate Feeding Prior to Forage Finishing on Intramuscular Fat Deposition

The objectives of this study were to examine the effects of feeding high-concentrate diets post-weaning (PW) prior to forage finishing on (1) changes in ultrasound intramuscular fat deposition and lipogenic/lipolytic gene expression during the post-weaning phase and (2) carcass characteristics and fatty acid composition after forage finishing to 487 kg. Steers were randomly assigned to one of four treatments (PW0, PW40, PW80, and PW120) at weaning to examine the time of high-concentrate feeding prior to forage finishing. The ultrasound intramuscular fat content was greater (p < 0.05) for PW120 compared to those for PW0, PW40, or PW80 at the end of the post-weaning phase. Feeding high concentrates (PW120) up-regulated (p < 0.01) the mRNA expression of fatty acid transporters and lipogenic genes and down-regulated lipolytic genes in the LM compared to PW0. Carcasses from PW120 were graded 83% Choice (p = 0.025), whereas carcasses from other post-weaning treatments (PW0, 40, or 80) were graded 25, 36, and 54% Choice, respectively, at the final harvest. The total fatty acid content of the muscle at slaughter was greater (p = 0.0004) for PW120 than PW0, PW40, and PW80. Feeding high-concentrate diets to steers post-weaning for 120 day enhanced early intramuscular fat deposition without causing major changes to the fatty acid composition of the longissimus muscle after forage finishing.

Effects of Dam and Sire Breeds on Lamb Carcass Quality and Composition in Pasture-Based Systems

This study explored the impacts of sire and dam breed on carcass quality and composition in a pasture-based system and the use of DXA to rapidly rank carcasses for leanness. Southdown (SD) and Suffolk (SF) ewes were mated to Texel (TX) or SD rams to produce seventy-nine lambs. Lambs were raised on pasture-based systems with limited grain supplementation. Lamb birth weight was greater (p < 0.01) for TX, regardless of dam breed. Lambing rate was lower (p < 0.01) for SD than SF ewes. Circulating myostatin concentrations were greater (p < 0.05) on d 42 than d 75 or d 110 but did not differ by sire breed. Texel-sired lambs had greater (p < 0.01) carcass weight, ribeye area and quality grade compared to SD-sired. Total and primal fat mass as predicted from DXA was higher (p < 0.05) in carcasses from SD than TX sires. Muscles from TX lambs had greater (p < 0.05) polyunsaturated fatty acid (PUFA) composition than SD-sired. Shear force values were influenced (p < 0.01) by dam breed, muscle cut and postmortem age but not by sire breed. The use of TX sires in pasture-based systems improved carcass leanness and muscle PUFA concentrations without altering tenderness.

Measuring the Phytochemical Richness of Meat: Effects of Grass/Grain Finishing Systems and Grapeseed Extract Supplementation on the Fatty Acid and Phytochemical Content of Beef

Grass-finished beef (GFB) can provide beneficial bioactive compounds to healthy diets, including omega-3 polyunsaturated fatty acids (n-3 PUFAs), conjugated linoleic acid (CLA), and secondary bioactive compounds, such as phytochemicals. The objective of this study was to compare fatty acids (FAs), micronutrients, and phytochemicals of beef fed a biodiverse pasture (GRASS), a total mixed ration (GRAIN), or a total mixed ration with 5% grapeseed extract (GRAPE). This was a two-year study involving fifty-four Red Angus steers (n = 54). GFB contained higher levels of n-3 PUFAs, vitamin E, iron, zinc, stachydrine, hippuric acid, citric acid, and succinic acid than beef from GRAIN and GRAPE (p < 0.001 for all). No differences were observed in quantified phytochemicals between beef from GRAIN and GRAPE (p > 0.05). Random forest analysis indicated that phytochemical and FA composition of meat can predict cattle diets with a degree of certainty, especially for GFB (5.6% class error). In conclusion, these results indicate that GFB contains higher levels of potentially beneficial bioactive compounds, such as n-3 PUFAs, micronutrients, and phytochemicals, compared to grain-finished beef. Additionally, the n-6:n-3 ratio was the most crucial factor capable of separating beef based on finishing diets.

Evaluation of a Saccharomyces cerevisiae Fermentation Product on the Feedlot Performance and Carcass Merit of Hair Lambs Offered an Annual Ryegrass-Hay-Based Finishing Diet: A Pilot Study

Hair sheep production has increased in recent years, which has resulted in an increased presence in feedlots. Additionally, grass-based finishing systems for ruminant animal production have increased. Data are limited for finishing hair lambs on diets based on cool-season hay. The objective was to evaluate a Saccharomyces cerevisiae fermentation product (SCFP) on the feedlot performance and carcass characteristics of Katahdin lambs offered an annual ryegrass (Lolium multiflorum)-hay-based diet. Twenty-four Katahdin lambs (21.5 ± 2.5 kg BW) were assigned to either the control (CON) or the yeast-supplemented group (SCFP) in a completely randomized design. Lambs were offered a 14% crude protein total mixed ration diet based on annual ryegrass hay. The SCFP group also received the yeast supplement in their diet. Lambs in the SCFP group had a higher final body weight (p < 0.01) and ADG (p = 0.01). Less maximum and total energy were required to cut SCFP lamb meat compared to CON lamb meat (p < 0.03). Results from this study indicated that SCFP supplementation may prove to be beneficial in hair lamb finishing diets. Future research will need to specifically evaluate the use of these products in hair lambs with a larger sample size.

Effects of Hay, Baleage, and Soybean Hulls Waste Used as Supplemental Feeds on the Nutritional Profile of Grass-Finished Beef

Grass-finished beef (GFB) has demonstrated wide nutritional variations with some GFB having a considerably higher n-6:n-3 ratio compared to grain-finished beef. To better understand these variations, the current study investigated the effects of commonly used supplemental feeds on the nutritional profile of GFB. This two-year study involved 117 steers randomly allocated to one of four diets: (1) grass+hay (G-HAY), (2) grass+baleage (G-BLG), (3) grass+soybean hulls (G-SH), and (4) baleage+soybean hulls in feedlot (BLG-SH). Feed samples were analyzed for their nutritional value, and beef samples underwent analysis for fatty acids (FAs), vitamin E, minerals, lipid oxidation, and shear force. FAs were measured by GC-MS, vitamin E was analyzed chromatographically, minerals were analyzed by ICP-MS, and lipid oxidation was measured via a thiobarbituric acid reactive substances (TBARS) assay. G-SH beef had the highest n-6:n-3 ratio (p < 0.001), while BLG-SH beef contained less vitamin E (p < 0.001) and higher TBARS values (p < 0.001) compared to the other groups. G-HAY beef contained more long-chain n-3 polyunsaturated FAs compared to the other groups (p < 0.001). In conclusion, G-HAY beef had the most beneficial nutritional profile, while soybean hulls increased the n-6:n-3 ratio of beef.

Fatty Acid and Micronutrient Profile of Longissimus Lumborum from Red Angus and Red Angus x Akaushi Cattle Finished on Grass or Grain

Cattle diet and breed modify the nutritional profile of beef. The objective of this study was to compare the fatty acid (FA) and micronutrient profiles of Red Angus (RA) and RA x Akaushi (AK) crossbreed steers fed either a grass or grain diet. This two-year study randomly assigned steers to the diets using a 2 × 2 factorial experiment. FAs and micronutrients were analyzed. Diet effect was the strongest with grass-finished beef being higher in n-3 polyunsaturated FAs (p < 0.001), conjugated linoleic acid (p < 0.05), vaccenic acid (p < 0.05), iron (p < 0.001), and vitamin E (p < 0.001) compared to grain-finished beef. Breed effects were observed for lauric and myristic acids (p < 0.05), selenium (p < 0.05), and zinc (p < 0.01) with AK containing more of these compounds than RA. Diet × breed effects were non-existent. These results indicate that diet has a stronger influence than breed on modifying the nutritional profile of beef. Because of a more favorable FA and antioxidant profile, consumption of grass-finished beef could benefit human health.

Consumer Perception of Beef Quality and How to Control, Improve and Predict It? Focus on Eating Quality

Quality refers to the characteristics of products that meet the demands and expectations of the end users. Beef quality is a convergence between product characteristics on one hand and consumers’ experiences and demands on the other. This paper reviews the formation of consumer beef quality perception, the main factors determining beef sensory quality, and how to measure and predict beef eating quality at scientific and industrial levels. Beef quality is of paramount importance to consumers since consumer perception of quality determines the decision to purchase and repeat the purchase. Consumer perception of beef quality undergoes a multi-step process at the time of purchase and consumption in order to achieve an overall value assessment. Beef quality perception is determined by a set of quality attributes, including intrinsic (appearance, safety, technological, sensory and nutritional characteristics, convenience) and extrinsic (price, image, livestock farming systems, commercial strategy, etc.) quality traits. The beef eating qualities that are the most valued by consumers are highly variable and depend mainly on the composition and characteristics of the original muscle and the post-mortem processes involved in the conversion of muscle into meat, the mechanisms of which are summarized in this review. Furthermore, in order to guarantee good quality beef for consumers in advance, the prediction of beef quality by combining different traits in scenarios where the animal, carcass, and muscle cuts can be evaluated is also discussed in the current review.

Attention to the Details: How Variations in U.S. Grass-Fed Cattle-Feed Supplementation and Finishing Date Influence Human Health

As the global population increases, so does meat consumption. This trend is accompanied by concerns regarding the meat industry, and consumers are demanding transparency on the environmental and health effects of the products they are purchasing. Many leading health organizations recommend reducing red meat consumption. Nevertheless, no differentiation is made among red meats and beef. The beef production system is generally ignored despite nutritional differences between grain- and grass-fed beef. Compared to grain-fed beef, grass-fed beef contains a healthier fatty acid profile, including more omega-3 polyunsaturated fatty acids and conjugated linoleic acid, and increased concentrations of phytochemicals desired by health-conscious customers. However, there is a lack of consistency among grass-fed beef in the United States regarding clear product labeling and cattle dietary components. Grass-fed beef labeling confusion has emerged, including misunderstandings between grass-fed and grass-finished beef. Along with this, previous studies observed significant nutritional variation among grass-finished beef from different producers across the country. Cattle diet has the strongest influence on the nutritional composition of beef. Therefore, understanding differences in feeding practices is key to understanding differing nutritional quality of grass-fed beef. Feeding cattle diverse pastures composed of multiple plant species including grasses and legumes managed in a rotational grazing fashion results in higher omega-3 polyunsaturated fatty acids and phytochemical levels in beef compared to feedlots and monocultures. Seasonal differences including changes in temperature, rainfall, grazing practices, and plant growth cycles affect the nutritional composition of feeds and ultimately meat. Additional feeds utilized in grass-fed beef production systems such as conserved forages may reduce or increase health-promoting nutrients in grass-fed beef, while supplements such as grape byproducts and flaxseed may improve its nutritional profile. Further research should measure the effects of individual feedstuff and the finishing period on the nutritional profile on grass-fed beef. A better understanding of these details will be a step toward the standardization of pasture-raised ruminant products, strengthening the relationship between grass-fed beef consumption and human health.

Fatty Acid Composition of Grain- and Grass-Fed Beef and Their Nutritional Value and Health Implication

Beef contains functional fatty acids such as conjugated linoleic acid and long-chain fatty acids. This review summarizes results from studies comparing the fatty acid composition of beef from cattle fed either grass or grain-based feed. Since functional lipid components are contributed through dietary consumption of beef, the fatty acid composition is reported on mg/100 g of meat basis rather than on a percentage of total fat basis. Beef from grass-fed contains lesser total fat than that from grain-fed in all breeds of cattle. Reduced total fat content also influences the fatty acid composition of beef. A 100 g beef meat from grass-fed cattle contained 2,773 mg less total saturated fatty acids (SFA) than that from the same amount of grain-fed. Grass-fed also showed a more favorable SFA lipid profile containing less cholesterol-raising fatty acids (C12:0 to C16:0) but contained a lesser amount of cholesterol-lowering C18:0 than grain-fed beef. In terms of essential fatty acids, grass-fed beef showed greater levels of trans-vaccenic acid and long-chain n-3 polyunsaturated fatty acids (PUFA; EPA, DPA, DHA) than grain-fed beef. Grass-fed beef also contains an increased level of total n-3 PUFA which reduced the n-6 to n-3 ratio thus can offer more health benefits than grain-fed. The findings signify that grass-fed beef could exert protective effects against a number of diseases ranging from cancer to cardiovascular disease (CVD) as evidenced by the increased functional omega-3 PUFA and decreased undesirable SFA. Although grain-fed beef showed lesser EPA, DPA, and DHA, consumers should be aware that greater portions of grain-fed beef could also achieve a similar dietary intake of long-chain omega-3 fatty acids. Noteworthy, grain-fed beef contained higher total monounsaturated fatty acid that have beneficial roles in the amelioration of CVD risks than grass-fed beef. In Hanwoo beef, grain-fed showed higher EPA and DHA than grass-fed beef.

Chemical Characteristics of Limousine Beef Depending on Finishing Diets and Muscle Type of Meat

The goal of this study was to compare the chemical properties of three muscle types of beef cattle fed using different finishing diets compositions. Four finishing feeding models for bulls based on different proportions of concentrates, maise silage, grass silage and hay were evaluated. Muscles chemical composition was evaluated in m. infraspinatus (ISB), m. longissimus thoracis (LTC) and m. longissimus lumborum (LLS). The chemical composition of meat was influenced by muscle type. ISB was characterised by higher moisture, collagen content, lower protein and ash content, and net energy concentration than LTC and LLS. The differences between diets in dry matter and fat content in each of the muscle groups studied were stated. Furthermore, a difference in the collagen content in LLS and protein content in ISB was noted. High correlations (P ≤ 0.05) were found between the concentrate content in the finishing diet and protein content (r = 0.59) in ISB, and dry matter both in LLS (r = 0.69) and LTC (r = 0.58). The lowest fat content of beef was noted for all muscles obtained from animals fed with a diet composed of grass silage, hay, and concentrates (D1).

Influence of Grain- and Grass-Finishing Systems on Carcass Characteristics, Meat Quality, Nutritional Composition, and Consumer Sensory Attributes of Bison

The objective of this study was to determine the influence of two finishing systems (grain- or grass-finishing) on carcass characteristics, meat quality, nutritional composition, and sensory attributes of bison. Bison heifers were assigned to either a grain- or grass-finishing treatment for 130 days prior to slaughter. Carcass measurements, lean color and fat color were recorded. Striploins (M. longissimus lumborum) were collected for analysis of pH, fatty acid profile, cholesterol, proximate analysis, Warner-Bratzler shear force, cook loss, and consumer sensory evaluation. Grain-finished bison heifers had greater (p < 0.01) hot carcass weights, dressing percentage, ribeye area, backfat, and marbling scores compared to grass-finished heifers. Instrumental color values (L*, a*, b*) of the ribeye and a* value of backfat opposite the ribeye were greater (p < 0.01) for grain-finished heifers. Steaks from grain-finished heifers had increased (p < 0.05) crude protein and fat content and decreased (p < 0.01) moisture compared to grass-finished heifers. The grain-finishing system produced steaks with increased (p < 0.01) cholesterol and total fatty acids (mg/g of wet tissue). The grain-finished system produced more tender (p < 0.05) steaks, but consumer sensory ratings did not differ (p > 0.10) between treatments. These data indicate that finishing systems influence bison carcass characteristics, nutritional composition, and meat quality, but do not translate to differences in consumer preferences.

Enhancing the Nutritional Value of Red Meat through Genetic and Feeding Strategies

Consumption of red meat contributes to the intake of many essential nutrients in the human diet including protein, essential fatty acids, and several vitamins and trace minerals, with high iron content, particularly in meats with high myoglobin content. Demand for red meat continues to increase worldwide, particularly in developing countries where food nutrient density is a concern. Dietary and genetic manipulation of livestock can influence the nutritional value of meat products, providing opportunities to enhance the nutritional value of meat. Studies have demonstrated that changes in livestock nutrition and breeding strategies can alter the nutritional value of red meat. Traditional breeding strategies, such as genetic selection, have influenced multiple carcass and meat quality attributes relevant to the nutritional value of meat including muscle and fat deposition. However, limited studies have combined both genetic and nutritional approaches. Future studies aiming to manipulate the composition of fresh meat should aim to balance potential impacts on product quality and consumer perception. Furthermore, the rapidly emerging fields of phenomics, nutrigenomics, and integrative approaches, such as livestock precision farming and systems biology, may help better understand the opportunities to improve the nutritional value of meat under both experimental and commercial conditions.

The Effect of Grazing Level and Ageing Time on the Physicochemical and Sensory Characteristics of Beef Meat in Organic and Conventional Production

This study investigated the influence of the production system (conventional vs. organic), the grass consumption level and the ageing period (7 and 14 days) on beef quality. Three groups of samples from Limousin × Avileña calves were analysed: F100, formed by animals fed 100% on forage; F74, formed by animals fed on an average amount of forage of 74%; and F35, formed by animals fed on straw fodder (35%) and concentrate (65%). The results showed that the higher the grass content, the lower the fat oxidation and the higher the n-3 content, but also the higher the SFA level, the initial Warner-Bratzler shear force (WBSF), and the more residue it leaves on chewing. As for the effect of production system, organic samples showed higher intramuscular fat content and lower moisture and MUFA content. These samples were darker and showed lower values for flavour quality. Among the organic samples, F100 had higher n-3 and CLA content and higher values for colour, hardness, odour and flavour quality. Increased ageing time may improve the sensory characteristics of the meat, especially in the case of the F100 samples. The results pointed out that F100 samples aged at least 14 days showed the best physico-chemical, nutritional and sensory characteristics.

Health-Promoting Phytonutrients Are Higher in Grass-Fed Meat and Milk

While commission reports and nutritional guidelines raise concerns about the effects of consuming red meat on human health, the impacts of how livestock are raised and finished on consumer health are generally ignored. Meat and milk, irrespective of rearing practices, provide many essential nutrients including bioavailable protein, zinc, iron, selenium, calcium, and/or B12. Emerging data indicate that when livestock are eating a diverse array of plants on pasture, additional health-promoting phytonutrients—terpenoids, phenols, carotenoids, and anti-oxidants—become concentrated in their meat and milk. Several phytochemicals found in grass-fed meat and milk are in quantities comparable to those found in plant foods known to have anti-inflammatory, anti-carcinogenic, and cardioprotective effects. As meat and milk are often not considered as sources of phytochemicals, their presence has remained largely underappreciated in discussions of nutritional differences between feedlot-fed (grain-fed) and pasture-finished (grass-fed) meat and dairy, which have predominantly centered around the ω-3 fatty acids and conjugated linoleic acid. Grazing livestock on plant-species diverse pastures concentrates a wider variety and higher amounts of phytochemicals in meat and milk compared to grazing monoculture pastures, while phytochemicals are further reduced or absent in meat and milk of grain-fed animals. The co-evolution of plants and herbivores has led to plants/crops being more productive when grazed in accordance with agroecological principles. The increased phytochemical richness of productive vegetation has potential to improve the health of animals and upscale these nutrients to also benefit human health. Several studies have found increased anti-oxidant activity in meat and milk of grass-fed vs. grain-fed animals. Only a handful of studies have investigated the effects of grass-fed meat and dairy consumption on human health and show potential for anti-inflammatory effects and improved lipoprotein profiles. However, current knowledge does not allow for direct linking of livestock production practices to human health. Future research should systematically assess linkages between the phytochemical richness of livestock diets, the nutrient density of animal foods, and subsequent effects on human metabolic health. This is important given current societal concerns about red meat consumption and human health. Addressing this research gap will require greater collaborative efforts from the fields of agriculture and medicine.

Effects of grass- and concentrate-based finishing systems on the quality of meat from the M. longissimus thoracis of young Sarda bulls

Context Recent heightened interest of consumers in the origins of their food, together with broader general awareness of environmental matters, has led to an increase in the demand for meat obtained from grazing systems. The importance of local breeds adapted to medium- and low-input production is fully recognised as a means of guaranteeing the sustainability of these farming methods. A finishing system based on pastures and the use of local breeds could both meet the demands of consumers and increase economic returns for Sardinian farmers. Aims The work evaluated the effects of different finishing treatments (pasture PAS-0C vs hay–concentrate-based diets HAY-C) on the quality of meat from young Sarda bulls and the usefulness of meat chemicals as markers to discriminate between finishing systems. Methods Twenty-eight young Sarda bulls were assigned randomly to the following two treatments: finished on natural pasture (PAS-0C group, n = 7), and fed on natural pasture hay ad libitum and concentrate (HAY-C group, n = 21). The latter group comprised three levels characterised by an increasing daily dose of concentrates, as follows: 2.5 kg/animal (HAY-2.5C), 3.3 kg/animal (HAY-3.3C), and ad libitum (HAY-ALC). After slaughter at a fixed age (416 ± 25 days), carcass yield, pH of the Longissimus thoracis (LT) muscle, colour parameters, cooking loss, proximate analysis, α-tocopherol and cholesterol concentration, and fatty acid composition of intramuscular fat of LT were all determined. The discriminating power of the meat chemicals between the two main finishing systems (PAS-0C vs HAY-C) and among the three groups receiving concentrates and hay (HAY-2.5C, HAY-3.3C and HAY-ALC) was assessed using linear discriminant analysis. Key results Pasture-based treatment decreased the intramuscular fat and increased the α-tocopherol concentration of meat and the proportion of some desirable fatty acids (α-linolenic acid and its derivatives eicosapentaenoic acid, docosapentaenoic acid), and improved the value of the ratio of n-6:n-3, without affecting the ultimate pH, colour parameters, and cooking loss. The discriminant procedure was able to discriminate accurately between the two main finishing systems and among the three groups receiving concentrate and hay (P &lt; 0.0001 and P &lt; 0.005 of the Hotelling’s T-squared test respectively). The concentration of α-tocopherol was key to the discrimination of the two main finishing systems, whereas the content of C17:0 and C18:0i were particularly effective in discriminating among the three groups fed with hay concentrate. Conclusions Grazing improves some of the meat traits of young Sarda bulls compared with the effects of a hay-concentrate-based finishing diet. The concentration of α-tocopherol in meat is an effective marker for discriminating the effects of pasture from those of a concentrate-based finishing diet Implications The results highlight the role of pasture-based diet in finishing young Sarda bulls, and could provide a wealth of knowledge for Sardinian beef farmers for delivering meat produce that stands out in the market and meets the demand of consumers more concerned about food origin and its healthiness.

Influence of Genotype and Slaughter Age on the Content of Selected Minerals and Fatty Acids in the Longissimus Thoracis Muscle of Crossbred Bulls

Simple Summary

In some European countries, including Poland, beef production is based mostly on dairy cattle herds. Beef quality can be improved by the commercial crossbreeding of dairy cows with beef bulls. The offspring are characterized by higher fattening performance and more desirable carcass characteristics. The experiment was performed on 72 bulls produced by crossing Polish Holstein-Friesian (PHF) cows with bulls of three most popular beef breeds: Hereford (HH), Limousin (LM), and Charolais (CH), to determine the effects of genotype and age at slaughter on the content of selected minerals (K, Na, Mg, Zn, and Fe) and fatty acid profile in beef. The meat of PHF × LM crosses had a lower content of K and Mg, compared with the remaining crossbred bulls. The Fe content per kg of meat was higher in bulls slaughtered at 21 months of age than in those slaughtered at 15 months of age. The best sire breed for crossing with dairy cows cannot be clearly indicated based on the present findings. However, the results of this study suggest that bulls should be slaughtered at 21 months of age to achieve the optimal values of most analyzed traits and parameters, in particular the fatty acid profile.

Abstract

The aim of this study was to determine the effects of genotype and slaughter age on the mineral content and fatty acid profile of beef. The experiment was performed on 72 crossbred bulls produced by crossing Polish Holstein-Friesian (PHF) cows with bulls of three beef breeds: Hereford (HH), Limousin (LM), and Charolais (CH), slaughtered at 15, 18, and 21 months of age. Samples of the longissimus thoracis muscle were collected to determine their mineral (potassium—K, sodium—Na, magnesium—Mg, zinc—Zn, and iron—Fe) and fatty acid composition. The meat of PHF × LM crosses had a lower (p ≤ 0.01) content of K and Mg, compared with the remaining crossbred bulls. The Fe content per kg of meat was 4 mg higher (p ≤ 0.01) in bulls slaughtered at 21 months of age than in those slaughtered at 15 months of age. The content of monounsaturated fatty acids (MUFAs) in intramuscular fat was 2.77% higher in bulls slaughtered at 21 months of age than in those slaughtered at 15 months of age. The n-6/n-3 polyunsaturated fatty acids (PUFA) ratio did not exceed 4.0, and it was most desirable in PHF × LM crosses (2.84) and in the oldest bulls (2.92).

Feedlot performance of Tanzanian Shorthorn Zebu finished on local feed resources

A study was conducted in Hanang District to assess potential for on-farm feedlot finishing of Tanzanian Shorthorn Zebu (TSHZ) in dry season using locally available feed resources. A total of 65 (2-3 years old, 150-250 kg LWT) steers were randomly distributed into two dietary treatments in three villages. The steers were finished either in feedlots using compounded diets or under free grazing in accordance with farmers' practice. Following 90 days of feeding, all steers were slaughtered for detailed carcass and meat quality assessment. Growth performance, carcass and meat quality of experimental animals were assessed to determine feedlot performance of TSHZ. Results show that average daily gain of feedlot-finished animals (620 g/day) was nearly three-fold higher (P = 0.042) than that of grazed steers (223 g/day). Feedlot-finished steers produced 28 kg (P = 0.001) heavier carcasses than grazed ones. Carcasses from feedlot-finished steers cooled slowly as they had higher (P = 0.001) temperatures than that of grazed ones at 45 min (33.1 vs. 30.5 °C) and 6 h (21.0 vs. 19.5 °C) post-mortem. Feedlot-finished steers produced beef with higher (P = 0.003) marbling scores (3.4) than grazed ones (2.4). As a result, beef from the feedlot-finished steers was more tender (P = 0.016) than that from grazed ones, and it required 13 N less force to shear. It is concluded that TSHZ responds positively to improved feeding with significant enhancement on carcass gain and meat quality. Use of diets compounded using agro-processing by-products, instead of whole grain, can lower the cost of finishing TSHZ steers significantly.

Fatty Acid Characterization of Beef Longissimus from Steers Finished on Fodder Beet or Traditional Winter Forages in New Zealand Compared to US Grain-Fed Beef

Fatty acids were evaluated to characterize lipid profiles of beef from 3 feeding programs: New Zealand (NZ) fodder beet (FB), NZ grass/non-FB (NFB), and United States grain. Strip loins were selected within each program based on expected eating quality focusing on marbling, ossification, and pH. Selection resulted in 6 treatments: FB high quality, FB low quality, NFB high quality, NFB low quality, US Top Choice, and US Select. Samples were aged 21 d or 35 d postmortem. A subset of 152 samples (12–13 per treatment combination) were used for fatty acid characterization. Within the polar lipid fraction, US treatments had lower monounsaturated fatty acid (MUFA) and greater polyunsaturated fatty acid (PUFA) than NZ treatments (P &lt; 0.05). Within the neutral lipid fraction, concentrations of total neutral lipids and proportions of saturated fatty acid, MUFA, and PUFA were affected by treatment (P &lt; 0.05). Total neutral lipids were greatest in Top Choice (P &lt; 0.05) and greater in FB high quality than all other treatments (P &lt; 0.05). Proportions of satu- rated fatty acid in the neutral lipid fraction were greater in NFB treatments than US treatments (P &lt; 0.05); FB treatments were intermediate. Proportions of MUFA were greatest in Top Choice (P &lt; 0.05). Proportions of PUFA were greatest (P &lt; 0.05) in Select, greater in Top Choice than all NZ treatments (P &lt; 0.05), and greater in NFB treatments than FB treatments (P &lt; 0.05). No interactions occurred for any groups of fatty acids in either fraction ( P &gt; 0.05), and aging did not affect fatty acid composition. Lipid profiles were impacted by finishing diet; however, most differences were between US grain-fed beef and NZ treatments—with limited differences between FB and NFB samples—when product was selected based on quality descriptors. Therefore, FB could be substituted for grass forages to sustain the NZ beef industry through winter months and limit seasonality without detrimental effects on product quality.

Effect of Diet on the Vitamin B Profile of Bovine Milk-Based Protein Ingredients

The influence of diet on the water-soluble vitamin composition of skim milk powder and whey protein ingredients produced from the milk of cows fed pasture or concentrate-based diets was examined. Fifty-one Holstein-Friesian cows were randomly assigned into three diets (n=17) consisting of outdoor grazing of perennial ryegrass (GRS), perennial ryegrass/white clover (CLV), or indoor feeding of total mixed ration (TMR) for an entire lactation. Raw mid-lactation milk from each group was processed into skim milk powder and further processed to yield micellar casein whey and acid whey. Sweet whey was also produced by renneting of pasteurised whole milk from each system. The water-soluble vitamin profile of each sample was analysed using a combination of direct injection mass spectrometry and reverse-phase liquid chromatography-mass spectrometry. Vitamin B3 and B3-amide concentrations were significantly higher (p < 0.05) in TMR-derived samples than in those from CLV and GRS, respectively. Vitamin B1, B2, and B7 concentrations were significantly higher in GRS and CLV-derived samples than those from TMR. Significant differences in vitamins B1, B2, and B3-amide were also observed between protein ingredient types. This study indicates that bovine feeding systems have a significant effect on B vitamin composition across a range of protein ingredient types.

Drivers of Consumer Liking for Beef, Pork, and Lamb: A Review

Tenderness, juiciness, and flavor have been associated with consumer acceptance of beef, lamb, and pork. Drivers of consumer liking are interrelated across these species, but there are differences in consumer preferences. Animal age, animal diet, and subsequent marbling impact consumer liking across species. For beef, consumer research prior to the 1990s showed that tenderness was the main driver of liking. Consumer tenderness and juiciness liking are highly correlated. More recent research has shown that as overall tenderness improved and tenderness variation decreased, flavor has become a more important driver of beef consumer liking. Flavor is affected by consumer preparation methods, familiarity with different flavor presentations, and animal production systems. Animal diet impacts consumer perception of beef tenderness and flavor, especially when comparing forage-fed versus grain-fed beef. Flavor preferences vary across countries more so than preferences for beef based on consumer tenderness preferences and are most likely influenced by the consumption of locally produced beef and the flavor-derived type of beef traditionally consumed. Drivers of pork consumer liking have been shown to be affected by pH, color, water holding capacity, animal diet, and the presence of boar taint compounds. While tenderness and juiciness continue to be drivers of consumer liking for pork, flavor, as impacted by animal diet and the presence of boar taint compounds, continues to be a driver for consumer liking. For lamb, the flavor, as affected by diet, and animal age continue to be the main drivers of consumer liking. Lamb consumers vary across countries based on the level of consumption and preferences for flavor based on cultural effects and production practices.

Biology, strategies, and fresh meat consequences of manipulating the fatty acid composition of meat

The utility and attractiveness of adipose tissue within meat products vary based on species, cut, and consumer preference. In beef, producers are rewarded for producing carcasses with greater visual marbling at the 12th and 13th rib juncture, while pork producers are either not rewarded or penalized for producing carcasses with too much adipose tissue. Some consumers prefer to purchase leaner meat cuts, while other consumers pay premiums to consume products with elevated fat content. While no clear consumer adipose tissue preference standard exists, advances in beef and swine nutrition have enabled producers to target markets that enable them to maximize profits. One niche market that has increased in popularity over the last decade is manipulating the fatty acid profile, specifically increasing omega-3 fatty acid content, of beef and pork products to increase their appeal in a healthy diet. While much research has documented the ability of preharvest diet to alter the fatty acid profile of beef and pork, the same studies have indicated both the color and palatability of these products were negatively affected if preharvest diets were not managed properly. The following review discusses the biology of adipose tissue and lipid accumulation, altering the omega-3 fatty acid profile of beef and pork, negative fresh meat color and palatability associated with these studies, and strategies to mitigate the negative effects of increased omega-3 fatty acid content.

Warm-season annual forages in forage-finishing beef systems: II. Animal performance and carcass characteristics

More information on expected animal performance and carcass traits of forage-finished steers grazing warm-season annual forages is needed. To achieve this objective, a grazing trial was conducted in 2014, 2015, and 2016 (70, 63, and 56 d, respectively), with variation in length of grazing based on forage availability. Sixteen pastures (0.81 ha) were assigned to 1 of 4 forage treatments in a randomized complete block design. Forage treatments were brown midrib sorghum × sudangrass (BMR; Sorghum bicolor var. bicolor*bicolor var. sudanense), sorghum × sudangrass (SS), pearl millet [PM; Pennisetum glaucum (L.)R.Br.], or pearl millet planted with crabgrass [PMCG; Digitaria sanguinalis (L.) Scop.]. Each year, British-cross beef steers (n = 32; 3 y average: 429 ± 22 kg) were stratified by weight and randomly assigned to 1 of the 16 pastures for forage finishing. Each pasture was subdivided into two 0.405-ha paddocks for rotational stocking and a put-and-take stocking method was used to maintain a forage allowance of 116 kg forage dry matter/100 kg body weight (BW). Shrunk body weight and ultrasonically measured carcass composition were recorded at the initiation, middle, and end of each grazing season. Steers were harvested once forage availability became limited and chilled carcasses (24 h) were evaluated for yield grade and quality grade attributes. Statistical analysis was conducted using the GLIMMIX procedure in SAS 9.4 (Cary, NC) with main effects of treatment, year, and the interaction. Pasture and block were considered random effects while date was assessed as a main effect when applicable. Daily stocking densities were greater (P < 0.04) for SS than PMCG in the first 20 d of 2014 and 2015. Forage treatment did not affect (P > 0.17) total gain, total average daily gain, or body weight at any time point. Ultrasound composition traits of loin muscle area, 12th rib fat thickness, intramuscular fat, and rump fat were impacted (P < 0.01) by scanning date. No differences (P > 0.08) in forage treatments were observed for carcass characteristics associated with yield grade or quality grade. The findings suggest that forage-finished cattle during the summer months on BMR, SS, PM, and PMCG perform similarly, giving producers the option to use the most economical or practical forage type for their production system.

Physicochemical properties of whole milk powder derived from cows fed pasture or total mixed ration diets

This study examined the effect of dietary factors on compositional and functional properties of whole milk powder (WMP) produced from bovine milk. Raw milk samples were obtained from 3 groups of 18 Holstein Friesian spring-calving cows randomly assigned to diets based on perennial ryegrass (GRS), perennial ryegrass/white clover sward (CLV), and total mixed ration (TMR). Raw milks obtained in late lactation were subsequently standardized for fat, heat-treated (90°C for 30 s), evaporated, and homogenized before spray drying. The WMP produced from each diet were analyzed to determine differences in color, particle size distribution, heat coagulation time, yogurt gelation, texture profile, and protein profile due to each diet. Significant differences in heat coagulation time were observed between the CLV and TMR samples, whereas color values were significantly different between GRS and TMR samples. No significant differences in gross composition, protein profile, or whey protein nitrogen index were found between the 3 WMP samples. Average D₉₀ values (the particle size at which 90% of the particles were smaller than the specified size) for fat globules were significantly lower in the TMR sample compared with the GRS and CLV samples. Yogurts produced from GRS- and CLV-derived WMP had significantly higher elastic moduli (G') than those produced from TMR-derived WMP. Similarly, texture profile analysis revealed significantly higher firmness values in yogurt samples derived from CLV compared with TMR samples. Our data characterize the effect of these diets on the composition and functional properties of fat-standardized WMP, suggesting better yogurt functionality and thermal stability in WMP derived from pasture-based bovine diets.

Postweaning Exposure to High Concentrates versus Forages Alters Marbling Deposition and Lipid Metabolism in Steers

Angus-cross steers (n = 20; 261 ± 21.5 kg BW) were used to examine how early exposure to high concentrates or high quality forages altered marbling deposition and lipid metabolism. Steers were randomly assigned to high concentrate diet (CONC) or high quality forages (FOR) at 30-d postweaning, fed for 127 d, and slaughtered. Data were analyzed using a mixed model that included fixed effect(s) of dietary treatment (CONC vs. FOR), time (for plasma levels, ultrasound measures, and postmortem aging time) and two-way interaction (when appropriate). Steers fed CONC had greater (P < 0.01) ADG and heavier (P < 0.001) body weight at 127 d. Ultrasound measures over time showed greater (P < 0.001) intramuscular fat deposition at d 98 and 126 for CONC than FOR steers. Steers fed CONC had elevated (P < 0.05) plasma glucose and insulin concentrations from d 57 to 127 compared to FOR. Early exposure to CONC increased (P < 0.01) dressing percent, HCW, LM area, 12th rib fat thickness, and marbling scores compared to FOR. Total lipid content of the LM was greater (P < 0.01) for CONC than FOR; however, moisture, protein, and ash content was lower (P < 0.01) for CONC than FOR. Concentrate fed steers had greater (P < 0.01) MUFA content and lower (P < 0.01) polyunsaturated fatty acids PUFA n-3 content than FOR. The n-6:n-3 ratio was greater (P < 0.01) for CONC due to decreased (P < 0.01) in n-3 fatty acid content with CONC. Gene expression was up-regulated (P < 0.05) for key lipogenic genes and downregulated for glucose transporter 4 in steers fed CONC vs. FOR. Early exposure to CONC diets for 127 d at 30 d postweaning stimulated marbling deposition and resulted in these carcasses grading 80% Choice when slaughtered at 13 mo of age and 248 kg HCW.

Warm-season annual forages in forage-finishing beef systems: I. Forage yield and quality

The demand for a year-round supply of fresh, locally grown, forage-finished beef products has created a need for forage-finishing strategies during the summer months in the southeast. A 3-yr study was conducted to evaluate four warm-season annual forages in a southeastern forage-finishing beef production system. Treatments were four forage species and included brown-midrib sorghum × sudangrass (Sorghum bicolor var. bicolor*bicolor var. sudanense; BMR), sorghum × sudangrass (SS), pearl millet [Pennisetum glaucum (L.) R. Br.; PM], or pearl millet planted with crabgrass [Digitaria sanguinalis (L.) Scop.; PMCG]. Treatments were distributed in a randomized complete block design with four replicates. Pastures (0.81 ha, experimental unit) were assigned to one of four forage treatments, subdivided, and rotationally stocked with a variable stocking density. British-cross beef steers (n = 32; 3-yr average: 429 ± 22 kg) grazed for 70, 63, and 56 d in 2014, 2015, and 2016, respectively. Put-and-take animals were used to maintain a forage allowance of 116 kg forage dry matter /100 kg body weight. Forage mass was measured by clipping a 4.3-m² area in triplicate on d 0 and on 14-d intervals. Hand grab samples for forage nutritive value determination and quadrat clippings for species compositions were measured on d 0 and on 34-d intervals until termination of the trial. Forage mass was lowest (P < 0.01) for PMCG at the initiation of the grazing trial, whereas BMR was greater (P < 0.01) than SS at wk 6. Total digestible nutrients in 2014 were greater for SS compared to BMR and PM at the middle harvest (P < 0.01) and BMR, PM, and PMCG at the final harvest (P < 0.01). At the middle and final harvests in both 2015 and 2016, PM and PMCG contained greater (P < 0.01) concentrations of crude protein than SS. These results suggest that BMR, SS, PM, and PMCG may all be used in southeastern forage-finishing beef production systems, as long as the producer strategically accounts for the slight growth and nutritive value differences throughout the season.

A Nutritional Survey of Commercially Available Grass-Finished Beef

Consumer interest in the source of their food, its environmental footprint, and the impact of diet on health has supported the growth of the grass-finished beef (GFB) industry. Studies have concluded that GFB has distinct nutritional differences from conventionally-finished beef. As the GFB industry continues to expand, it is vital to continue to explore the nutritional complexities and variation in the product. To achieve this, a survey of grass-finishing production systems throughout the USA was conducted, and beef finished on the participating farms was analyzed for its nutritional composition, including fatty acid (FA), mineral and fat-soluble vitamin contents. Samples were analyzed from 12 producers and annual production capacity of farms ranged from 25 to 5,000 cattle, with a mean age of cattle at harvest of 26.8 ± 2.30 mo. An array of finishing diets included grazing exclusively in perennial pasture, incorporating annual forage crops, and feeding a variety of harvested forages with supplementation of non-starch feed byproducts. Beef muscle tissue FA content was analyzed by gas chromatography-mass spectrometry (GC–MS). The mean ratio of omega-6 (n-6) to omega-3 (n-3) FA in samples varied significantly by producer, ranging from 1.80 to 28.3 (P < 0.0001), with an overall sample set median of 4.10. A selection of minerals including iron, magnesium, and potassium were analyzed by ICP emission spectroscopy and mineral content significantly differed by producer for all minerals (P < 0.001). Mean α-tocopherol and β-carotene content was 610.6 µg/100 g beef and 32.2 µg/100 g, respectively. The amount of these antioxidants also varied between producers (P < 0.0001), but tended to be greater in beef finished solely on fresh forages. This survey indicates that commercially available GFB can vary in nutritional composition due to the diverse practices used to grass-finish cattle.

Timing of Exposure to High-Concentrates versus High-Quality Forages on Growth and Marbling Deposition in Steers

Forty Angus-cross steers (280 ± 21.4 kg BW, 8 mo.) were used to examine the effects of exposure to 2 diets [high concentrate diets (CONC) versus high quality forages (FOR)] during 2 time periods [early (EARLY; at 30-d post weaning) or late (LATE; just prior to slaughter)] on animal growth, marbling deposition and tenderness. Steers were blocked by weight and randomly assigned to four dietary treatments: 1) CONC-FOR, 2) CONC-CONC, 3) FOR-CONC, or 4) FOR-FOR. Exposure to CONC during the EARLY or LATE period increased (P < 0.05) growth and fat deposition compared to FOR-FOR. Hot carcass weight was greater (P < 0.05) for CONC-CONC and FOR-CONC steers than FOR-FOR and CONC-FOR due to changes in dressing percent. Marbling score was greater (P < 0.05) for CONC-CONC and CONC-FOR compared to FOR-FOR. Exposure to CONC during the EARLY period (CONC-FOR and CONC-CONC) increased (P < 0.05) n-6 polyunsaturated fatty acids (PUFA) deposition in longissimus muscle (LM) and subcutaneous adipose tissue (SQ); whereas, exposure to CONC during the LATE period (CONC-CONC and FOR-CONC) reduced (P < 0.05) n-3 PUFA, trans-11 octadecenoic acid and cis-9 trans-11 isomer of conjugated linoleic acid (CLA). Warner-Bratzler shear force at d 2 and 7 of postmortem aging in ribeye steaks from CONC-CONC and FOR-CONC was greater (P < 0.05) than FOR-FOR and CONC-FOR. Lipogenic gene expression was up-regulated (P < 0.05) and lipolytic gene expression was downregulated (P < 0.06) in SQ from CONC-CONC and FOR-CONC compared to FOR-FOR. Overall, exposure to CONC in both periods increased growth rate and marbling deposition but LATE exposure had the greatest impact on adipose lipogenesis and lipolysis, fatty acid composition, and tenderness.

Ruminant meat flavor influenced by different factors with special reference to fatty acids

Ruminant meat flavor is an important quality and sensory parameter which relays mainly on the organoleptic characteristics of meat. Meat flavor is vital factor for the palatability and acceptability of meat by the consumers. There are various intrinsic and extrinsic factors that influence eating quality of meat. Among these factors, flavor is the major contributor. Fat and low-molecular-weight water-soluble compounds are the most important precursor components in meat, responsible for the meat flavor. The present review focus on the different pre and post-harvest factors that influences the ruminant meat flavor. Raw meat has little flavor but cooking adds value in flavor due to different temperature and cooking methods. The volatile flavoring compounds which are responsible for cooked meat flavor are produced thermally by the Maillard's reaction itself or interaction with lipid oxidation products and vitamin degradation. In nutshell, this review provides perception into previous literature on flavor that affected by various factors particularly the fatty acids and cooking methods.

Case studies of packaging and processing solutions to improve meat quality and safety

A significant amount of the meat is wasted due to spoilage or safety risks. Active packaging systems have a great potential to reduce waste through chemical and microbial control of the product and/or the storage environment. Although commercial products are already available, active packaging is far from being fully developed. In contrast, passive packaging, such as modified atmosphere packaging (MAP) and vacuum packaging, have been fully implemented. Research conducted at the Danish Meat Research Institute (DMRI), demonstrates that it is possible to create new opportunities for the meat industry by modifying MAP or combining microwave treatment with vacuum packaging. Predictive shelf life models can be used to estimate the shelf life in MAP or vacuum under dynamic temperature conditions. Using the tri-gas guidelines, the industry can benefit from the increased eating quality, and the in-package decontamination process using vacuum packaging in combination with 5.8 GHz microwaves eliminates C. botulinum spores, resulting in increased food safety and an extended shelf life.

Carcass characteristics of grass-fed crossbred bulls and steers slaughtered at two different ages

The aim of this study was to evaluate beef production potential and meat quality in young crossbred bulls and steers raised indoors and fed grass-based diets. One half of 96 bull calves were castrated at 2–3 wk of age. The calves were fed standard diets, and starting at 7 mo of age, they received grass silage supplemented with concentrates. At the end of the fattening period (18 and 21 mo of age), the animals were slaughtered, carcass quality was evaluated, and samples of musculus longissimus thoracis were collected to determine the proximate composition and meat quality. The semi-intensive feeding system contributed to higher daily gains (0.835 kg) in Holstein-Friesian (HF) × Hereford (HH) crosses. In comparison with steers, bulls were characterized by a higher dressing percentage (+1.33%), higher weight of five most valuable primal cuts (+6.7 kg), and higher lean meat content of three-rib cuts (+7.54%). Meat from steer carcasses, which had higher fat content was more tender and had desirable aroma, juiciness, and flavor. In semi-intensive production systems, steers performed better than bulls, and HF × HH crosses were more suitable than HF × Limousin (LM) and HF × Charolais (CH) crosses. Dairy-beef crosses should be slaughtered at 21 mo of age to improve carcass quality.

Muscle profiling to improve the value of retail meat cuts

Nutrition and meat quality are always important to consumers, but vary by individual muscle or muscle groups in retail meat cuts. Muscle profiling of nutrient content and palatability for all retail beef cuts is necessary to suggest healthy and tasty beef cuts and to inform consumers of the benefits of beef consumption. The current paper reviews numerous studies that provide muscle profiles for nutrients and palatability attributes of muscles or muscle groups in retail beef cuts. The composition of nutrients including protein, fat, moisture, vitamins, and minerals in beef cuts is documented as well as the nutritive role as a part of a healthy diet. In addition, this review presents knowledge in relation to innovative carcass fabrication and value-added cuts to improve the value of beef carcass. Finally, the current work emphasize the palatability assessment of individual beef muscles, and concludes that all retail beef cuts should be merchandised for proper cooking according to the palatability profiles of beef muscles.

Adaptive traits of indigenous cattle breeds: The Mediterranean Baladi as a case study

Generally taken, breeds of Bos taurus ancestry are considered more productive, in comparison with Bos indicus derived breeds that present enhanced hardiness and disease resistance, low nutritional requirements and higher capability of feed utilization. While breeds of B. taurus have been mostly selected for intensive production systems, indigenous cattle, developed mostly from indicine and African taurines, flourish in extensive habitats. Worldwide demographic and economic processes face animal production with new challenges - the increasing demand for animal food products. Intensification of animal husbandry is thus a desired goal in stricken parts of the world. An introduction of productive traits to indigenous breeds might serve to generate improved biological and economic efficiencies. For this to succeed, the genetic merit of traits like efficiency of feed utilization and product quality should be revealed, encouraging the conservation initiatives of indigenous cattle populations, many of which are already extinct and endangered. Moreover, to overcome potential genetic homogeneity, controlled breeding practices should be undertaken. The Baladi cattle are a native local breed found throughout the Mediterranean basin. Purebred Baladi animals are rapidly vanishing, as more European breeds are being introduced or used for backcrosses leading to improved production. The superiority of Baladi over large-framed cattle, in feedlot and on Mediterranean pasture, with respect to adaptability and efficiency, is highlighted in the current review.

Omega 3 and omega 6 fatty acids in human and animal health: an African perspective

Lipids are essential for plant and animal development, growth and nutrition and play critical roles in health and reproduction. The dramatic increase in the human population has put increasing pressure on human food sources, especially of those sources of food which contain adequate levels of polyunsaturated fatty acids (PUFAs) and more importantly, sources of food which have favorable ratios of the n-3 (18-carbon, α-linolenic acid, ALA) to n-6 (18-carbon linoleic acid, LA) PUFAs. Recent studies have demonstrated the beneficial effects of the n-3 PUFAs in diets as well as potentially negative effects of excessive levels of n-6 PUFAs in diets. This review discusses these human health issues relating to changes in diets based on environmental and industrial changes as well as strategies in East Africa for improving lipid composition of food using indigenous sources.

Nutritional milieu of isolated stromal vascular cells determines their proliferative, adipogenic, and lipogenic capacity in vitro

The objective was to determine the effect of nutritional milieu of isolated stromal vascular (SV) cells on proliferative capacity of preadipocytes, and adipogenic and lipogenic capacity in adipocytes in vitro. Proliferation of the preadipocytes increased over time with 48 and 72 h being greater than 24 h; however, preadipocytes from steers supplemented with corn (LC) had lower proliferation rates compared with those without corn grain supplementation (L) at 72 h. Adipocyte cultures isolated from LC group had higher mean diameter on d 4 and 6, and higher mean volume on d 0, 4, 6, and 12 of culture. Adipocytes from steers supplemented with corn grain (LC) had lower expression of key adipogenic genes during extended days in culture. The results show that prior nutritional treatment of the donor animal used to isolate SV cultures alters their proliferative, adipogenic, and lipogenic capacity in culture. These differences may be related to lower induction/expression of AP2 gene in the adipose cultures from corn supplemented group. Corn grain supplementation to steers grazing legumes could have stimulated more active adipogenic progenitor cells to differentiate, which would leave fewer behind in the SV pool for subsequent isolation.

Trace element distribution in selected edible tissues of zebu (Bos indicus) cattle slaughtered at Jimma, SW Ethiopia

The amount of trace elements present in edible bovine tissues is of importance for both animal health and human nutrition. This study presents data on trace element concentrations in semitendinosus and cardiac muscles, livers and kidneys of 60 zebu (Bos indicus) bulls, sampled at Jimma, Ethiopia. From 28 of these bulls, blood samples were also obtained. Deficient levels of copper were found in plasma, livers, kidneys and semitendinosus muscles. Suboptimal selenium concentrations were found in plasma and semitendinosus muscles. Semitendinosus muscles contained high iron concentrations. Trace elements were mainly stored in the liver, except for iron and selenium. Cardiac muscles generally contained higher concentrations of trace elements than semitendinous muscles except for zinc. A strong association was found between liver and kidney concentrations of copper, iron, cobalt and molybdenum. Liver storage was well correlated with storage in semitendinosus muscle for selenium and with cardiac muscle for cobalt and selenium. Plasma concentrations of copper, selenium, cobalt were well related with their respective liver concentrations and for cobalt and selenium, also with cardiac muscle concentrations. The data suggest multiple trace element deficiencies in zebu cattle in South-West Ethiopia, with lowered tissue concentrations as a consequence. Based on the comparison of our data with other literature, trace element concentrations in selected edible tissues of Bos indicus seem quite similar to those in Bos taurus. However, tissue threshold values for deficiency in Bos taurus cattle need to be refined and their applicability for Bos indicus cattle needs to be evaluated.

Impact of grass/forage feeding versus grain finishing on beef nutrients and sensory quality: the U.S. experience

Studies of forage and/or grass feeding of cattle versus grain finishing have been conducted in varying regions throughout the world but generalization of these results to beef from U.S. cattle may not be appropriate. In particular, available grass/forage variety and form as well as cattle breed have a significant impact on the nutritional profile of beef. The current review summarizes the nutritional characteristics of beef as reported from the limited number of studies comparing U.S. grass/forage-fed versus grain-finished cattle and estimates the intake of key nutrients that might be expected from consumption of U.S. beef from either feeding system. In addition, many studies report changes in fatty acids solely as a percentage of total fatty acids. Since grass/forage feeding typically results in a leaner product; the current review compares the fatty acid profile of beef from grass/forage feeding to that of grain-finished cattle on a mg/100 g of meat basis.