Consumer demand for grass-fed beef (GFB) is increasing due to its perceived advantages in food safety, healthfulness, animal welfare, and environmental stewardship, yet its sustainability remains contested. This PRISMA-guided systematic review synthesised evidence from 141 studies identified through Web of Science, Scopus, AGRICOLA, and supplementary grey-literature sources to evaluate GFB production, meat quality, and sustainability, and to provide actionable insights for future research, market governance, and policy. The currently inconsistent evidence is insufficient to confirm the sustainability of GFB. Although GFB can offer desirable quality attributes, including leaner carcasses, greater proportions of omega-3 and conjugated linoleic fatty acids, and elevated antioxidant levels, its darker colour and variable tenderness may affect consumer acceptance. Environmentally, reduced grain inputs and greater pasture biodiversity may promote ecological stewardship, but methane emissions and higher land requirements may offset these gains unless adaptive grazing and carbon sequestration are appropriately incorporated. Socially, animal welfare can be enhanced through regenerative grazing practices but can also be compromised when animals are exposed to adverse weather and parasites. Economic performance depends on productivity, certification costs, price premiums, and market access. Despite their growing social relevance, animal welfare, traceability, authenticity, and certification remain insufficiently integrated into sustainability assessments. Overall, the current evidence is fragmented and dominated by farmgate economic and greenhouse gas metrics. Multidimensional, value-chain-based, and context-sensitive sustainability assessment frameworks are proposed to guide credible standards, targeted incentives, and market development.
The metabolic status of periparturient dairy cows is highly heterogeneous, making it difficult for traditional assessment methods based on a single biomarker to comprehensively reflect systemic metabolic dysregulation. This study aimed to apply unsupervised clustering to identify distinct metabolic phenotypes using integrated blood physiological indicators and to evaluate the prepartum identifiability of metabolically compromised profiles. Venous blood samples were collected from 316 healthy Holstein cows (from − 7 to + 7 days relative to calving) across seven commercial farms in China for blood gas and electrolyte analysis. After data cleaning and variable selection, six key indicators—pH, PCO₂, HCO₃⁻, glucose, potassium, and sodium—were standardized and subjected to K-means clustering. The optimal number of clusters was determined to be three, yielding the following phenotypes: (1) a “metabolically compromised” group characterized by acidosis (low pH), hypercapnia (elevated PCO₂), hypoglycemia, and electrolyte imbalance; (2) a “normoacidemic–hyperkalemic” group with normal acid–base status but persistently elevated potassium; and (3) a “metabolically homeostatic” group exhibiting alkalotic tendencies, higher sodium and glucose levels, and stable electrolyte balance. A substantial proportion of cows already belonged to the metabolically compromised phenotype before calving, and its prevalence peaked during the mid-postpartum period (+ 4 to + 7 d). In unadjusted analyses, cows in this cluster exhibited modestly elevated postpartum β-hydroxybutyrate concentrations (P = 0.001) and significantly reduced milk protein percentage (P < 0.001); however, the BHBA association was not significant after adjusting for farm of origin in a mixed-effects model (P = 0.622), whereas the milk protein association remained robust. These findings indicate that impaired metabolic adaptation in this cluster is more consistently reflected by reduced milk protein than by elevated BHBA. Based on cluster centroids and validated by exploratory ROC analysis, prepartum thresholds for identifying the metabolically compromised profile were proposed: venous pH < 7.25 (AUC = 0.928), PCO₂ > 58.75 mmHg (AUC = 0.956), and glucose < 27.5 mg/dL (AUC = 0.876). Potassium was not retained as a discriminatory threshold because its AUC was only 0.577. These thresholds are exploratory and require validation in independent cohorts. These findings demonstrate that periparturient dairy cows segregate into three distinct metabolic states, and that a metabolically compromised acidotic profile can be identified antepartum. This provides a foundation for early risk stratification; future intervention studies are needed to determine whether targeting this profile improves clinical outcomes.
The present study was conducted to investigate the supplementation of a mixture of plant hydroalcoholic extract in drinking water and its effect on performance, carcass, jejunal morphology, and ileum microbiota in broiler chickens. A total of 240 one-day-old male Ross 308 chicks with similar initial body weights (44 ± 2 g) were used in a completely randomized design with four treatments, six replicates, and 10 chicks per replicate over a 42-day period. The experimental treatments includes T-1 (control, no supplementation), T-2 (supplementation of 1 L of hydroalcoholic extract per 1000 L), T-3 (supplementation of 2 L of hydroalcoholic extract per 1000 L), and T-4 (supplementation of 3 L of hydroalcoholic extract per 1000 L). Body weight gain was not significantly affected by the treatments throughout the experimental period (P > 0.05). Feed intake differed among treatments during 1–10, 25–42, and 1–42 days of age, with T-2 and T-3 showing higher feed intake than the other treatments during some periods (P < 0.05). Feed conversion ratio differed among treatments during 11–24 and 25–42 days of age, but no significant difference was observed over the total experimental period (P > 0.05). Carcass yield and the proportions of breast and thigh meat were significantly affected by the treatments (P < 0.05). Breast meat pH, malondialdehyde concentration, and cooking loss also differed among treatments (P < 0.05). In addition, the extract-supplemented groups (T-2, T-3, and T-4) showed higher ileal Lactobacillus populations than T-1 (P < 0.05). Overall, supplementation of the plant hydroalcoholic extract mixture in drinking water influenced several carcass and gut health parameters but did not consistently improve growth performance under the conditions of this study.
Typically, true protein sources are the most expensive ingredients in feed formulations for feedlot cattle. However, low-protein diets can limit animal performance. This study aimed to use the mechanistic NASEM model to formulate diets with similar metabolizable protein levels while varying crude protein content and evaluating the impact of these adjustments on performance and nutrient digestibility in feedlot Nellore bulls. A total of 120 Nellore bulls (initial body weight = 386.18 ± 23 kg; 24 ± 1 months of age) were allocated to 15 pens (8 bulls/pen). A randomized complete block design was used, with bulls stratified into five blocks according to their initial body weight. Within each block, pens were randomly assigned to one of three dietary treatments differing in crude protein (CP) concentration: High CP (HCP), Medium CP (MCP), and Low CP (LCP), while maintaining the same metabolizable protein (MP) level across all diets. The CP and MP concentrations were as follows: HCP: 140 g CP/ kg dry matter (DM) and 86 g MP/kg DM; MCP: 125 g CP/kg DM and 86 g MP/kg DM; LCP: 110 g CP/kg DM and 86 g MP/kg DM. Final BW (P < 0.001) and ADG (P = 0.003) as well as dry matter intake (DMI) (P < 0.001) increased linearly with higher dietary CP concentrations. Similarly, both hot and cold carcass weights (P = 0.002) and carcass gain (P < 0.001) increased linearly with increasing CP levels in the diets. Comparing the NASEM model predictions with observed data, the predicted DMI from the model was approximately 15
Cinnamon and its derivatives (bark powder, essential oil, extract, and nanoparticles) were used as phytogenic feed additives (PFAs) in the modern poultry industry possibly due to their antioxidant, antimicrobial, anti-inflammatory, and gut-promoting properties. The present review pools recent studies on the effects of cinnamon supplementation on broiler and laying hen performance, focusing on growth performance, carcass and meat quality, egg production, egg quality, and hatchability. Cinnamon bioactive compounds, particularly cinnamaldehyde, has been show to improve nutrient utilization through multiple mechanisms of action: direct stimulation of digestive enzymes, enhancement of intestinal morphology, and selective suppression of pathogenic bacteria and proliferation of non-pathogenic bacteria. In broilers, cinnamon supplementation has been indicated to enhance body weight gain (BWG), feed conversion efficiency (FCE), carcass yield, and meat quality traits, including water holding capacity (WHC), meat tenderness, oxidative capacity, and sensory attributes. In laying hens, studies suggest that cinnamon improve egg production, egg mass, internal egg quality, shelf life, and reduce cholesterol content in egg yolk. Supplementation doses are highly form-and context-dependent: 0.2–0.5
