Beef produced originating from the dairy herd forms an integral part of beef supply chains globally. The objective of this study was to quantify the economic and environmental performance of three dairy-beef genotypes differing in beef genetic merit and managed under three contrasting pasture-based feeding treatments, using a farm-level systems model and data from an animal systems experiment. The three steer genotypes modelled were: 1) high beef-merit Angus sires (HA); 2) low beef-merit Angus sires (LA); and 3) Holstein-Friesian (HF) sires. Each genotype was evaluated across one of three feed treatments: 1) control (CTL), grass-only during both grazing seasons; 2) low concentrate (LC), supplemented with concentrate during the first grazing season, pasture only during the second grazing season; and 3) high concentrate (HC) supplemented with concentrate during the first and second grazing season; amounting to nine scenarios. High Angus steers were most profitable (& euro;424/animal, & euro;1362/ha), followed by LA (& euro;337, & euro;1126) and HF (& euro;188, & euro;659). There were no interactions between genotype and feed treatment, with the CTL treatment having highest profit per head due to lower concentrate input costs. High Angus scenarios had the lowest greenhouse gas emissions between genotypes, and concentrate use reduced emissions per kg of beef, but CTL had the lowest total emissions per ha and per farm due to greater forage use. In conclusion, this study demonstrates the financial and environmental benefits of high beef genetic merit sires in dairy herd for dairy-beef systems and producers.

Anaerobic digestion harnesses microbial processes to convert organic wastes into renewable biogas, offering a sustainable pathway for energy production. In agricultural settings, biogas plants often co-digest livestock manure with crop residues, yet seasonal variations in feedstock quality introduce fluctuations that challenge process stability and yield optimization. Mechanistic models such as the Anaerobic Digestion Model No. 1 (ADM1) provide detailed biochemical simulations but require extensive substrate characterization, limiting their practicality for full-scale operations. Here we show that a simplified ADM1, alongside machine learning approaches—random forest and long short-term memory (LSTM) networks—achieves comparable accuracy in predicting daily biogas and methane production from a full-scale plant over 2023–2024. All models yielded Nash-Sutcliffe efficiencies above 0.78, with random forest excelling when incorporating feedstock quantities and maize silage volatile solids. While LSTM proved effective even with minimal inputs, it incurred a training time 141 times greater than ADM1, highlighting critical trade-offs in computational efficiency. These findings advance hybrid modelling strategies for real-time monitoring, enabling operators to balance predictive precision with data requirements to enhance renewable energy integration and agricultural sustainability.

Genetic selection presents a long-term opportunity to reduce enteric methane emissions in beef cattle. This study evaluated the effect of incorporating an enteric methane production trait into the Irish Terminal Index, an index that is typical of global terminal-type indexes and quantified its impact on methane output and other economically important traits. At present, the Irish Terminal Index incorporates a Carbon sub-index based on life cycle assessment in an effort to reduce farm carbon emissions. Selection index scenarios were modelled to reflect an index with no environmental consideration, the current status quo, the inclusion of a direct enteric methane trait and finally the impact of changes in carbon pricing. Genetic parameters were derived from a national multi-breed dataset of 1508 beef animals with enteric methane phenotypes. Selection based on the current index which includes a lifecycle carbon weighting, increased daily enteric methane emissions by up to 2.14 g/day, while the inclusion of a direct enteric methane trait reversed the response, with predicted reductions of 0.22g/day and 4.20 g/day depending on carbon price. Associated changes included a 13.81 kg increase in carcass weight response and a 0.33 kg reduction in feed intake per animal under the highest environmental weighting (Carbon valued at 160/tonne and a direct enteric methane trait). Scaled to the national herd, this would equate to an annual reduction of approximately 27,400 tonnes of carbon dioxide equivalent and an opportunity cost of 1311 tonnes of carcass output. Selection direction remained favourable across all production traits, with minimal impact on calving, docility, and conformation traits. These results demonstrate that enteric methane can be incorporated into the national breeding goal with measurable reductions in emissions and limited trade-offs in economically relevant performance traits.

Nutrient recovery from wastewater is pivotal for sustainable development, particularly in mitigating resource scarcity and environmental pollution. This study investigated the potential of long-term electrodialysis (ED) for nutrient recovery from pig manure digestate with a focus on membrane fouling, which is often overlooked in short-term operations. ED reactors were operated over 1100 h using both heterogeneous and homogeneous ion exchange membranes (IEMs), with a treatment loading of 5000 L of digestate /m². The ED system demonstrated effective desalination, achieving over 80 % recovery of ammonium (NH₄⁺) and 90 % recovery of phosphate (PO₄³⁻), while maintaining high perm-selectivity (>95 %). Membrane analysis revealed significant color darkening and structural deterioration, particularly in heterogeneous anion exchange membranes (AM), which exhibited increased resistance and reduced ion exchange capacity (IEC) after a treatment loading of 3472 L/m². Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) confirmed the accumulation of organic matter and the formation of hydrogen bonds on fouled membranes. Cation exchange membranes (CM) demonstrated greater stability and resistance to fouling than AM, with homogeneous CM outperforming their heterogeneous counterparts in maintaining IEC and structural integrity. Despite the increased membrane resistance, the ED system led to efficient nutrient recovery, highlighting the resilience of membrane perm-selectivity. This study highlights the potential of ED for resource recovery and emphasizes the critical role of effective fouling mitigation strategies in ensuring its long-term feasibility in nutrient recovery from high-solid wastewater streams, thereby providing a strong foundation for its practical application.

There is little published research on dairy-beef heifer systems or comparisons of heifer and steer dairy-beef production. Furthermore, given its impact on the productivity and economics of dairy-beef systems, any comparison of gender must also consider potential interactions with stocking rate (SR). The objective of this study was to evaluate the variability of physical and economic performance, greenhouse gas emissions, feed-food competition and pasture land-use of dairy-beef production steer and heifer systems at differing stocking rates. Performance data from a two (gender: Steers and Heifers) x two (SR: Low and High) x two (breed-types: Early-maturing (EM) and Late-maturing (LM) factorial experiment was used to parameterize a bio-economic farm systems model. Low SR animals were heavier, had higher fat scores and better conformed at slaughter. High stocking rate resulted in greater carcass output per hectare and subsequently were, on average, 22 % more profitable than their Low SR counterparts. Late-maturing animals were found to be more profitable than early-maturing, and steers were more profitable than heifers. GHG emissions of the eight treatments investigated ranged from 10.7 to 17.7 kgs of carbon dioxide equivalents (kg CO2eq) per kilogram of carcass weight produced, with both High SR and heifer systems having lower GHG emissions per kg of product than their Low SR and steer counterparts. Human edible protein efficiency was only favorable for the steer systems. High SR systems had, on average, lower land use per kg of product than their Low SR counterparts. Results from this study indicate that no single treatment was optimal across the range of performance metrics considered.

Demand for beef is increasing but concerns about the environmental impact of ruminant-protein production and food security are also increasing. Animal performance, profitability, greenhouse gas (GHG) emissions and feed -food competition within spring-calving suckler grass-based systems in which the males, progeny of either early -(EM) or late-maturing (LM) breed sires, were finished from pasture-alone or pasture-plus-concentrate supple-mentation, at 19.5 months-of-age, were evaluated. Sixty yearling bulls, previously offered grass silage ad libitum and supplementary concentrates during a first winter 'store' period, were assigned within breed type (EM or LM) to a pasture-finishing strategy of grass only (G-G) or grass + 3.2 kg dry matter of a barley-based concentrate daily (G-GC). Bulls rotationally grazed Lolium perenne-based swards over a 192 day grazing season. Concentrates were offered to G-GC treatments for the final 95 days following which all animals were slaughtered. The experimental data produced were used to populate a whole-farm systems economic and environmental model to determine beef output, profit, GHG emissions and feed-food competition of spring-calving suckler calf-to-beef systems. There were no finishing strategy x breed type interactions. Supplementation increased slaughter weight (+37 kg), carcass weight (+27 kg), carcass fat score (+1.1 units, 15-point scale), and resulted in more yellow sub-cutaneous fat. The LM bulls were heavier at slaughter (+65 kg), had a heavier carcass (+45 kg), greater kill-out proportion (+14 g/kg), a greater lean meat proportion in the carcass (+35 g/kg), superior carcass conformation score (+1.4 units, 15-point scale), lower carcass fat score (-1.2 units), and more yellow subcutaneous fat than EM bulls. Compared to G-GC suckler calf-to-beef systems, G-G systems had lower beef output, were less profitable, had higher GHG emission intensities (kg CO2 eq) per kg live-(10.2 v. 10.1), carcass-(18.6 v. 18.1) and meat -weight (26.1 v. 25.5), but superior human-edible protein (HEP) and energy efficiencies. The LM-sired systems were more profitable, had lower GHG emission intensities, and superior HEP and energy efficiency than EM systems. The HEP efficiency ratios exceeded 1.0 (i.e. were net producers of protein) for the G-G treatments and ranged from 0.9 to 1.0 for the G-GC treatments, when offered the 'control' barley-soyabean meal based concentrate: alternatively, using by-product concentrate feedstuffs increased the HEP ratios to 3.9 or greater. In conclusion, the existence of synergies and trade-offs between sustainability metrics makes the selection of a beef production system that optimises all performance metrics difficult.

Objective: The objective of this study was to quantify the sustainability of representative dairy-beef farms in Ireland (AVE) and to compare these with dairy-beef farms participating in a farm improvement program (IMP) and research (RES) systems. The study aimed to determine the differences in technical performance and key sustainability indicators among these farm categories. Material and Methods: Within each farm category, dairy-beef systems differing in sire breed (early maturing, late maturing, and Holstein-Friesian), animal sex (steer and heifer), finishing age (ranging from 18 to 30 mo of age), and production system (finishing from grazing or indoor-based systems) were modeled using the Grange Results and Discussion: The average finishing age was 25.4, 23.8, and 20.6 mo on AVE, IMP, and RES, respectively. Results highlighted a wide range in net margins (from 185 to 806 per hectare; 1 = $1.05) for the systems modeled. Sex had the largest effect on profitability (steer greater than heifer), followed by finishing system (finishing from grazing systems greater than indoor systems) and breed type (late maturing greatest and Holstein-Friesian least). Greenhouse gas emissions of the 3 oxide equivalents (CO2eq) per kilogram of carcass weight ducers of human-edible protein, and all farms were net consumers of human-edible energy. economic, environment, labor, feed-food competition, and land-use perspective because none of the 3 farm categories investigated were without fault from a sustainable dairy- beef production perspective.

This study investigated whether plasma biomarkers of residual feed intake (RFI), identified under ad libitum feeding conditions in beef cattle, remained consistent during feed restriction. Sixty Charolais crossbred young bulls were divided into two groups for a crossover study. Group A was initially fed ad libitum (first test) and then restricted (second test) on the same diet, while Group B experienced the opposite sequence. Blood samples were collected from the 12 most divergent RFI animals in each group at the end of the first test and again after the second test. 12 plasma variables consistently increased, while three consistently decreased during feed restriction (FDR < 0.05). Only two metabolites, α-aminoadipic acid for Group A and 5-aminovaleric acid for Group B, were associated with RFI independent of feed intake level (FDR < 0.05), demonstrating moderate-to-high repeatability across feeding levels (intraclass correlation coefficient ≥ 0.59). Notably, both metabolites belong to the same metabolic pathway: lysine degradation. These metabolites consistently correlated with RFI, irrespective of fluctuations in feed intake, indicating a connection to individual metabolic processes influencing feed efficiency. These findings suggest that a portion of RFI phenotypic variance is inherent to an individual’s metabolic efficiency beyond variations in feed intake.

Pasture-based beef systems can provide cattle slurry and grass silage for anaerobic digestion (AD). However, sustainable production of these feedstocks within a livestock farm presents challenges. This study examined the farmland area required to provide slurry and grass silage for a 40 GWh biomethane plant, quantified greenhouse gas (GHG) emissions reduction and analyzed digestate management. Results indicated that 130 farms of 50 ha and a livestock unit (LU) of 2.1 LU/ha were required to meet the feedstock requirements of the AD plant. Assigning 15 % of the farmland to produce grass silage for AD decreased GHG emissions by 24 % compared to conventional beef farming. Depending on soil nutrient status, returning digestate to the farmland reduced the application of nitrogen, phosphorus and potassium fertilizers by up to 65 %, 33 % and 56 %, respectively. Future research should analyze the economic implication of biomethane production from these feedstocks at farm and supply chain scales.

This study evaluates nutritional and management strategies aimed at exploiting compensatory growth (CG) in weanling-to-beef systems in Uruguay. The evaluation encompassed productivity, economic viability, and environmental impact. The Grange Beef System Model, augmented with Uruguayan national technical coefficients, was used. Four weanling-to-beef systems were modeled: 1) forage only with no CG (FNC), 2) forage only with management improvements to exploit CG (forage with CG; FWC), 3) forage with concentrate supplementation during two winter feeding periods (forage with supplementation; FWS), and 4) forage with supplementation during the first winter followed by feedlot finishing (forage with feedlot; FWF). The systems purchased spring-born Angus calves at 8 months of age and 180 kg live weight (LW) and finished with a slaughter weight of 550 kg. FWS system was used as reference with the performance parameters obtained during 5 years of systems experimentation. FNC used the performance parameters of FWS but during winter periods, LW gain was lower due to the absence of concentrate supplementation. FWC used the previous FNC performance parameters, but increased LW gain after the first and second winter restriction period due to improved grazing management practices thereby exploiting CG. FWF is based on the FWS system but instead of moderate supplementation during the second winter (concentrate: 3.0 kg/d/head), steers are feedlot finished (concentrate: 9.5 kg/d/head) exploiting CG due to previous summer-autumn restriction period. FNC and FWC increased age at slaughter, reducing net beef production by 21 and 11% relative to FWS, respectively. In contrast, FWF reduced age at slaughter, increasing beef production by 93% compared to FWS. FWS and FNC had similar profitability expressed in net margin; however, FWC and FWF increased net margin by 33 and 107% compared to the FWS, respectively. FNC and FWC increased greenhouse gas (GHG) emissions intensity per beef produced by 17 and 3% relative to FWS, respectively; meanwhile, FWF reduced GHG intensity by 10% relative to FWS. Due to the inclusion of concentrates in the diet for FWS and FWF systems, the only net producers of human edible energy and protein were the forage-only systems (FNC and FWC). In summary, strategically harnessing CG in both pasture and feedlot finishing stages within a weanling-to-beef system in Uruguay successfully increased profitability. Feedlot finishing reduced GHG emissions per beef produced. However, the forage-only farm systems emerged as the only net producers of human-edible energy and protein.

CONTEXT: Demand for efficient sustainably-produced 'grass-fed' beef is increasing. Steers predominate in pasture-based systems. Bulls are inherently more efficient than steers but are usually produced indoors on concentrate-based rations rather than at pasture. OBJECTIVE: Evaluate the animal productivity, meat quality, financial performance, greenhouse gas (GHG) production and human-edible protein (HEP) efficiency of suckler calf-to-beef systems, in which male progeny were finished as bulls or steers at pasture, with or without concentrate supplementation, at 19.5 months-of-age. METHODS: Weaned suckler male cattle, produced as either bulls or steers, were offered grass silage and sup-plementary barley-soybean meal-based concentrates during a 'backgrounding' phase, and then assigned to one of two finishing strategies: grazed pasture-only for 192-days (G-O) or pasture-only for 95 days followed by pasture supplemented with 3.2 kg concentrate dry matter daily for 97 days (G-C). The experimental data generated were used to parameterise a whole-farm systems model and the productivity, profitability and GHG production of suckler calf-to-beef systems (encompassing cows, replacement heifers, female and male -bulls vs. steers -progeny) were evaluated. RESULTS AND CONCLUSIONS: Bulls had a heavier carcass (+44 kg), greater kill-out proportion (+14 g/kg) and carcass conformation score (+1.6 units, scale 1-15), a lower carcass fat score (-2.3, scale 1-15), darker muscle and less yellow subcutaneous fat than steers. Concentrate supplementation increased daily live-weight gain (+0.36 kg), carcass weight (+37 kg), kill-out proportion (+12 g/kg), carcass conformation score (+1.1 units) and fat score (+1.0). Meat tenderness, texture and acceptability were lower for bulls than steers. Profitability of suckler calf-to-beef systems was greater where male progeny were finished as bulls rather than steers, and for G-C than G-O. The GHG emissions (CO2 eq) per cow were lower for steer compared to bull systems, and for G-O than G-C; however, when expressed per kg live-, carcass-and meat-weight, the opposite was found. Half of the GHG emissions within the calf-to-beef systems were attributed to the cow. The HEP ratio for G-O exceeded 1.0, but for G-C declined to 0.9 for steers and 1.0 for bulls: replacing cereal and soya-bean meal with by-products resulted in all systems having HEP efficiencies >1.0. Bull systems had lower meat eating quality, greater profit, lower GHG emissions intensity, and superior HEP efficiency than steers. Concentrate supplementation did not affect meat quality, increased profitability, and reduced GHG emission intensity and HEP. SIGNIFICANCE: Consideration of unavoidable trade-offs in sustainability-related metrics between suckler beef systems is necessary.

The objective was to evaluate steer performance, meat nutritional value, land-use, food–feed competition and both economic and environmental sustainability within temperate pasture-based suckler weanling-to-beef systems with or without (forage-only) concentrates. Post-weaning, 8-month-old, late-maturing breed steers (333 kg) were assigned to one of three systems: (1) grass silage + 1.2 kg concentrate DM (148 days), followed by pasture (123 days) and finished on ad libitum concentrates (120 days) – slaughter age, 21 months (GRAIN); (2) as per (1) but pasture (196 days) and finished on grass silage ad libitum + 3.5 kg concentrate DM (124 days) – slaughter age, 24 months (SIL + GRAIN); and (3) grass silage-only (148 days), pasture (196 days), silage-only (140 days) and finished on pasture (97 days) – slaughter age, 28 months (FORAGE). The mean target carcass weight was 390 kg for each system. Data generated were used to parameterize a farm-level beef systems model. Concentrate DM intake was 1187, 606 and 0 kg/head for GRAIN, SIL + GRAIN and FORAGE, respectively. The forage-only (FORAGE) system offers several advantages, including improved farm profitability, enhanced meat fatty acid profile and only utilized inedible human feed. Consequently, associated greenhouse gas (GHG) emissions per net human edible food produced were more favourable for FORAGE. However, compared to GRAIN, the FORAGE system had an older age at slaughter and associated increased pasture land-use and GHG emissions per animal, meat weight gain and essential amino acids gain. There are therefore inevitable trade-offs, as one beef system does not improve all sustainability and GHG emission metrics.

Mathematical modeling of anaerobic digestion is a powerful tool to predict gas yields and optimize the process. The Anaerobic Digestion Model No. 1 (ADM1) is a widely implemented model for this purpose. However, modeling full-scale biogas plants is challenging due to the extensive substrate and parameter characterization required. This study describes the modification of the ADM1 through a simplification of individual process phases, characteristic components and required parameters. Consequently, the ability of the simplified model to simulate the co-digestion of grass silage and cattle slurry was evaluated using data from a full-scale biogas plant. The impacts of substrate composition (crude carbohydrate, protein and lipid concentration) and variability of carbohydrate degradability on simulation results were assessed to identify the most influential parameters. Results indicated that the simplified version was able to depict biogas and biomethane production with average model efficiencies, according to the Nash-Sutcliffe efficiency (NSE) coefficient, of 0.70 and 0.67, respectively, and was comparable to the original ADM1 (average model efficiencies of 0.71 and 0.63, respectively). The variability of crude carbohydrate, protein and lipid concentration did not significantly impact biogas and biomethane output for the data sets explored. In contrast, carbohydrate degradability seemed to explain much more of the variability in the biogas and methane production. Thus, the application of simplified models provides a reliable basis for the process simulation and optimization of full-scale agricultural biogas plants.

CONTEXT: Agriculture and food systems contribute significantly to climate change. Greenhouse gas (GHG) emissions intensity from beef production are high when compared to other livestock production systems and, therefore, mitigation of these emissions is urgently required. In many countries dairy-beef is making a large and growing contribution to total beef output thereby reducing net emissions given the lower emissions intensity of beef originating from the dairy herd when compared to specialized beef-cow systems. GHG emissions from dairy beef systems can be further reduced by adopting best practice and mitigation technologies. OBJECTIVES: The objectives of this study were to (1) evaluate a range of management practices to reduce GHG emissions for pasture-based beef cattle production systems, (2) model the individual and combined impacts of these management practices on GHG emissions from dairy-beef systems, and (3) identify any trade-offs between GHG emissions mitigation, farm profitability, food security and land use.METHODS: A farm level bioeconomic systems model was modified to evaluate spring-born, steer production systems finishing cattle at differing slaughter ages and from contrasting forage-based finishing diets (grazed grass or grass silage, each supplemented with concentrates). Mitigation measures included earlier slaughter age, optimal slurry management, urease inhibitors for nitrogen (N) fertilizers, replacing cereals with 'by-products' in concentrate feed rations and incorporating clover in grassland pastures.RESULTS AND CONCLUSIONS: Combining mitigation strategies reduced dairy-beef systems GHG emissions intensity by an average of 21%. Incorporating clover in grassland pastures was found to be the most profitable stand-alone mitigation strategy increasing net margin by an average of 18%. Substituting by-products for barley in a concentrate ration converted all systems into net producers of human edible protein; otherwise, steer systems finishing at pasture during the third grazing season were the only net producers of human-edible protein. However, finishing at pasture during the third grazing season increased GHG emissions per animal and per kilogram of beef carcass.SIGNIFICANCE: Within a grass-based dairy-beef system, such as that modelled in this study, a number of complementary GHG emissions mitigation strategies can be implemented, without making substantive changes to the production system, while simultaneously improving farm profitability.

CONTEXT.Global demand for grass-based beef systems is increasing with a growing proportion of beef output in many countries originating from the dairy herd. Concurrently, concerns around the environmental impact of food, particularly that derived from ruminants, and food security is growing in prominence. Therefore, a compre-hensive analysis of the sustainability of dairy-beef systems is required.OBJECTIVES: The objectives of this study were to (1) augment an existing farm-level bioeconomic model to permit greenhouse (GHG) emissions and feed-food analysis of dairy-beef systems and (2) use this model to asses the performance of grass-based dairy-beef steer production systems.METHODS: The developed farm-level model was used to evaluate production systems finishing males as steers on three contrasting soil types and differing with respect to sire breed (early-maturing, late-maturing and dairy), age at slaughter (20, 24 and 28 months of age) and finishing diet (grazed grass or grass silage, each supplemented with concentrates).

Unlabelled Image