Grass-based Systems Research Articles

Cultivation of forage maize in boreal conditions – Assessment of trade-offs between increased productivity and environmental impact

The cultivation of whole crop forage maize (Zea mays L.) for cattle feed has a potential for increased forage yield while reducing nitrogen (N) fertilisation compared to perennial grass-based systems. However, the possible environmental trade-offs of forage maize cultivation remain unknown in the boreal region due to the short growing season which limits cultivation practices. The aim of this study was to compare the environmental impact of forage maize with more widely cultivated forage crops in Finland that include perennial silage grass mixtures and whole crop spring cereal harvested as silage. The use of plastic mulch film in forage maize cultivation was included in the assessment as well. A life cycle assessment (LCA) was conducted including impact categories for global warming potential; marine and freshwater eutrophication; terrestrial acidification; freshwater, marine and terrestrial ecotoxicity; land use; and fossil resource depletion. Additionally, soil organic carbon (SOC) stock changes under long-term cultivation of the studied forage crops were simulated with the C-TOOL and Yasso20 models with methodological comparisons. The only clear differences between the studied crops were that the land use was lower (−26–48%) for forage maize, and the freshwater eutrophication (+59–67%) and terrestrial acidification (+10–57%) were higher for perennial grasses compared with other forages. A risk for decreased SOC stock under continuous forage maize cultivation was observed. Forage maize could be used to supplement perennial grass cultivation without major associated environmental risks. Future research shall be conducted on the effect of forage choices on the environmental impact of boreal dairy milk production and on decreasing the current high uncertainty associated with nitrous oxide (N2O) emission factors and SOC stock modelling choices.

Grass-based finishing of early- and late-maturing breed bulls within suckler beef systems: Performance, profitability, greenhouse gas emissions and feed-food competition

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 supplementation, 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 × 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 subcutaneous 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.

Contrasting effects of bioenergy crops on biodiversity.

Agriculture is driving biodiversity loss, and future bioenergy cropping systems have the potential to ameliorate or exacerbate these effects. Using a long-term experimental array of 10 bioenergy cropping systems, we quantified diversity of plants, invertebrates, vertebrates, and microbes in each crop. For many taxonomic groups, alternative annual cropping systems provided no biodiversity benefits when compared to corn (the business-as-usual bioenergy crop in the United States), and simple perennial grass-based systems provided only modest gains. In contrast, for most animal groups, richness in plant-diverse perennial systems was much higher than in annual crops or simple perennial systems. Microbial richness patterns were more eclectic, although some groups responded positively to plant diversity. Future agricultural landscapes incorporating plant-diverse perennial bioenergy cropping systems could be of high conservation value. However, increased use of annual crops will continue to have negative effects, and simple perennial grass systems may provide little improvement over annual crops.

Heat tolerance in Mashona beef cows in semi-arid rangelands: does conformation matter?

High temperatures and frequent heat waves raise concerns about heat stress in cattle in grass-based systems, especially in arid and semiarid areas. This study analysed the relationship between conformation traits and physiological parameters associated with heat stress in Mashona cattle. A total of 200 records from fifty cows were used to study the relationships between seven conformation traits and physiological parameters associated with heat stress. Body conformation traits were categorised into three principal components related to body capacity (body depth, flank circumference, chest girth), frame size (stature and body length), and loose skin fold (navel height and dewlap size). As the size of abdominopelvic and thoracic cavities increased, respiratory rate, heart rate, and rectal temperature decreased significantly, while blood triiodothyronine concentration increased. Cattle with deeper bodies, larger flanks, and larger chest girths had significantly lower heart rate, respiratory rate, and rectal temperature but higher blood triiodothyronine concentration than cattle with shallower bodies, smaller flanks, and smaller chest girths. Respiratory rate increased with increasing frame size. Large-framed cattle had significantly higher respiratory rate and lower blood thyroxine concentration. Small-framed cattle with larger chest girth, larger dewlap, and navel farther from the ground surface are better adapted to higher ambient temperatures.

Accounting for diversity while assessing sustainability: insights from the Walloon bovine sectors

Livestock production is confronted with significant challenges across all dimensions of sustainability. There is an urgent need to identify sustainable livestock systems that are environmentally friendly, economically viable for farmers, and socially acceptable. To this end, diversity assessments and data-driven indicator-based sustainability assessments can be helpful tools. These two mutually reinforcing approaches each have their own dilemmas and strengths; however, their combination is not straightforward. In this paper, we propose a method that simultaneously assesses the diversity and sustainability of production systems within one agricultural sector, without compromising either aspect, while overcoming the dilemmas of diversity and sustainability assessments. We test our method on the Walloon dairy and beef sectors (Belgium) and base our assessment on data from the European Farm Accountancy Data Network (FADN). We apply relevant classification criteria to the sample farms to group them into production systems. The core data was complemented with calculated environmental indicators to perform a comprehensive sustainability assessment, including structural, socio-economic, and environmental indicators. Our results confirm the importance of complementing sustainability assessments with diversity assessments. Our case study results show that a diversity of livestock systems coexist and that it is possible to overcome trade-offs between economic and environmental performances. Extensive grass-based systems present the best combination of economic and environmental results, which highlights the importance of preserving grassland resources at the regional level. The proposed method proves effective to improve the relevance of FADN data and supports the ongoing call to transform the FADN into a more comprehensive database that satisfactorily covers all dimensions of sustainability.

Complexity, Crash and Collapse of Chaos: Clues for Designing Sustainable Systems, with Focus on Grassland-Based Systems

Terms such as system crash, collapse of chaos and complexity can help one understand change, also in biological, socio-economic and technical systems. These terms need, however, explanation for fruitful dialogue on design of sustainable systems. We start this paper on Grass Based (GB) systems, therefore, dwelling on these terms and notions as review for the insiders and to help interested ‘outsiders’. We also stress the need to use additional and/or new paradigms for understanding of the nature of nature. However, we show that many such ‘new’ paradigms were known for long time around the globe among philosophers and common men, giving reason to include quotes and examples from other cultures and eras. In the past few centuries, those paradigms have become hidden, perhaps, under impressive but short-term successes of more linear paradigms. Therefore, we list hang-ups on paradigms of those past few centuries. We then outline what is meant by ‘GB systems’, which exist in multiple forms/‘scapes’. Coping with such variation is perhaps the most central aspect of complexity. To help cope with this variation, the different (GB) systems can be arranged on spatial, temporal, and other scales in such a way that the arrangements form logical sequences (evolutions) of stable states and transitions of Complex Adaptive Systems (CAS). Together with other ways to handle complexity, we give examples of such arrangements to illustrate how one can (re-)imagine, (re-)cognize and manage initial chaotic behaviors and eventual ‘collapse’ of chaos into design and/or emergence of new systems. Then, we list known system behaviors, such as predator–prey cycles, adaptive cycles, lock-in, specialization and even tendency to higher (or lower) entropy. All this is needed to understand changes in management of evolving GB into multi-scapes. Integration of disciplines and paradigms indicates that a win-win is likely to be exception rather than rule. With the rules given in this paper, one can reset teaching, research, rural development, and policy agendas in GB-systems and other areas of life.

Evaluating net energy and protein feed conversion efficiency for dairy ruminant systems in France

Modern systems of animal production are facing increasing challenges on issues such as animal welfare, product quality, and environmental impact. Ruminants in particular are often regarded as being inefficient with respect to feed conversion for both protein and energy. Efficiency is defined as the ratio between resources and production; when applied to dairy production systems, it corresponds to the total amount of feed (kg of dry matter of roughages and concentrates) consumed per kg of milk and meat produced. This ratio underlines the biological ability of dairy cows, ewes, and goats to convert feed into products that are edible by humans while maintaining other physiological functions. Feeds consumed by animals can be “human-edible”, i.e. directly usable for human nutrition (cereals, legumes, maize silage), or not (grasslands, wild grass areas). Calculations of livestock efficiency are strongly influenced by whether or not they consider, and distinguish between, the consumption of human-edible or -inedible plant resources (roughages and concentrates) as well as the production of edible and/or inedible animal products (e.g., milk, meat, wool, leather). An improved understanding of the inedible fraction of both energy and protein in animal feed will be invaluable in analyses of feed-food competition, especially in ruminants. In this study, we investigated the feed conversion efficiency (FCE) of dairy ruminant systems in France (cow, goat, ewe) with respect to both energy and protein. We hypothesized that FCE would be influenced by the composition of the diet and its grass content, as well as, by animal type. Data from a French database (Diapason) provided information on land, labor, herds, and production from 2012 to 2016 for 274 dairy goat farms, 108 dairy ewe farms, and 498 dairy cow farms. These herds consumed feeds that were human-edible (cereals, legumes, maize silage) as well as -inedible (grasslands, wild grass areas). We estimated that French dairy systems are, on average, net consumers of energy and net producers of protein, with higher efficiencies for grass-based systems compared to maize-based systems. At the national scale, average net protein efficiencies were 1.16, 1.12, and 1.88 for ewes, goats, and cows, respectively. These results on the net FCE in dairy systems will promote a more objective quantification of their contribution to food security, which should be taken into account in assessments of feed-food competition and its impact on human nutrition. When combined with other factors such as greenhouse gas emissions and land and resource use, such considerations will help to inform discussions of the future of livestock production.

A Qualitative Study of Irish Dairy Farmer Values Relating to Sustainable Grass-Based Production Practices Using the Concept of ‘Good Farming’

Ireland’s grass-based dairy system is relatively unique in industrialised countries in its focus on producing milk from grazed grass rather than increasing yields through non-forage feed. The environmental benefits of a grass-based dairy system have been promoted within Ireland and abroad. However, the means by which grass is produced is important. There have been environmental concerns about water pollution from nutrient leaching and increasing greenhouse gas emissions from the increased number of cows and higher fertiliser application in the Irish dairy sector. This paper uses qualitative interviews with Irish dairy farmers to assess: (1) how can we understand Irish farmer attitudes towards the grass-based system within a ‘good farmer’ theoretical framework? (2) How do concepts of extensive and intensive production fit with good farming norms within the grass-based system? (3) How could cultivation of multispecies swards, including legumes, fit with existing notions of good farming? The research finds that there had been a concerted efforts by researchers, advisory bodies and other actors to foster a definition of good farming to mean good grass management. This definition of good farming excluded the use of feed inputs over a certain level to increase yields but included the use of fertiliser to maximise grass production. There is scope to change the definition of good farming within the industry to include minimal use of fertiliser, for instance through the cultivation of multispecies swards including legumes and the skills and knowledge this involves. In terms of policy implications, the paper identified three strategies for government and industry to facilitate a definition of good farming which involves low fertiliser use: emphasising the cost-saving aspect of reducing fertiliser; identifying visible symbols of ‘good farming’ using multispecies swards; and co-producing the definition of good farming with a diverse range of stakeholders including farmers.

Effects of Age at First Joining and Ewe Genotype on the Performance of Two-Tooth Ewes and That of Their Progeny to Slaughter.

Simple SummaryEwe replacements are a major cost in prime-lamb production. Many producers do not join replacements at 7 months as they believe that it has a negative effect on two-tooth performance. The effect of age at first joining on the reproductive performance of two-tooth ewes, representing three genotypes, was evaluated as well as the performance of their progeny. Whilst joining at 7 months reduced ewe body weight when joined at 19 months and immediately post joining, body weight at the subsequent lambing was increased, and ewe productivity and progeny performance were unaffected. Ewe genotype significantly influenced litter size and the number of lambs reared per ewe joined but had no effect on progeny performance. The probability of rearing at least one lamb (PR1L) is an indicator of overall efficiency. In the current study, whilst there was no relationship between ewe body weight when joined at 19 months and PR1L, there was a positive relationship between body weight at 7 months and PR1L at 2 years. It is concluded that joining replacements at 7 months does not have a negative impact on the performance of two-tooth ewes. The effects of first-joining age (7 or 19 months) and genotype on ewe performance when joined to lamb at 2 years, and the performance of their progeny, were evaluated using 424 ewes, representing 3 genotypes: Belclare (Bel), Suffolk × Belclare (Suf × Bel) and Suffolk-type (≥75% Suffolk ancestry (Suf75)). Ewes were managed in a grass-based system. Ewes first joined at 7 months were lighter (p < 0.01) at 19 months and immediately post lambing; otherwise, age at first joining had no effects (p > 0.05) on ewes or their progeny and there were no important interactions with genotype. Bel and Suf × Bel had larger litters (p < 0.001) and reared more lambs per ewe joined (p < 0.01) than Suf75. Ewe genotype had no effect (p > 0.05) on proportion failing to lamb, incidence of lambing assistance, lamb mortality, ewe survival to 31 months, or progeny performance. Increasing the body weight of ewes at 7 months of age increased the probability (p < 0.02) of rearing 1 or more lambs at 2 years and there was no interaction with genotype. It is concluded that age at first joining had no negative impact on the performance of ewes or their progeny.

The Use of Temperate Tannin Containing Forage Legumes to Improve Sustainability in Forage–Livestock Production

Greenhouse gas emissions from ruminant livestock production systems contribute significantly to the environmental footprint of agriculture. Emissions are lower for feedlot systems than for grass-based systems primarily because of the extra time required for grass-finished cattle to reach slaughter weight. In contrast, legume forages are of greater quality than grasses, which enhances intake and food conversion efficiencies, leading to improvements in production and reductions in environmental impacts compared with forage grasses. In addition, the presence of certain bioactives in legumes such as condensed tannins (CT) enhance the efficiency of energy and protein use in ruminants relative to grasses and other feeds and forages. Grazing tannin-containing legumes also reduce the incidence of bloat and improve meat quality. Synergies among nutrients and bioactives when animals graze diverse legume pastures have the potential to enhance these benefits. Thus, a diversity of legumes in feeding systems may lead to more economically, environmentally, and socially sustainable beef production than grass monocultures or feedlot rations.

Dairy farmer practices and attitudes relating to grass-based, high-feed-input, and indoor production systems in Ireland

Grazing has become a less common dairy farming practice in most European countries. Ireland is an exception with its predominantly grass-based system. After the removal of European milk quotas, farmers were encouraged to expand within a grass-based paradigm rather than pursuing yield increases through feeding more concentrate. This research assessed Irish dairy farmer attitudes toward grass-based, higher-feed-input, and indoor paradigms. A paradigm of agriculture is a shared understanding about how agriculture should be carried out. Grass-based, higher-feed-input, and indoor paradigms propose different solutions to economic, environmental, and animal-welfare challenges facing dairy farming. An online survey was distributed to Irish dairy farmers in August 2018, which received 396 responses. There was support among respondents for the grass-based paradigm of maximizing milk from forage and minimizing concentrate use, with 73% of respondents strongly agreeing or agreeing this was the best option for Irish dairy farmers. The results suggest there were not significant ideological disagreements among respondents about the economic, environmental, and animal-welfare merits of different paradigms. Rather, the results showed respondents supported grass-based or higher-feed-input paradigms for different reasons as follows: profitability and lifestyle for the former, and the ability to expand production without access to additional land and less dependence on weather for the latter. These findings could be of interest in countries where grazing is less widely practiced, but where there is a desire to increase the uptake of grazing practices. Messaging about the profitability and simplicity of the grass-based system clearly resonated with respondents, and could be replicated in other countries. There is a desire within the Irish government, industry, and advisory bodies to keep dairy expansion within a grass-based paradigm. The results suggested individuals may diverge from this paradigm not because they disagree with messaging about its benefits, but rather if difficulties with land access or managing weather variability lead them to expand through feeding more concentrate. To maintain production within the grass-based paradigm, more opportunities could be created for farmers who are restricted from further expansion, such as alternative supply chains or payments for environmental services.

Energy Requirements of Beef Cattle: Current Energy Systems and Factors Influencing Energy Requirements for Maintenance.

Simple SummaryThe accurate estimation of energy requirements for present-day genotypes under current feeding conditions is crucial for improving profitability and reducing the environmental impact of the beef industry. Equations for predicting energy requirements of beef cattle according to the Agricultural and Food Research Council (AFRC) are outdated and require an urgent update. The results from literature review confirmed previous reports on the under prediction of energy requirements for maintenance by the AFRC, especially for growing animals. This may have consequences on the efficiency of use of the dietary energy on productive functions. Although much less research has been conducted over the last decade on energy metabolism for suckler cows, the existing data appears to be relevant as a valid reference for updating AFRC recommendations. The present review also revealed the lack of data on the contribution of both animal and diet-related factors influencing on energy requirements for beef cattle and thus conclusions on this regard are difficult to draw.The present review compared features of the UK system for predicting energy requirements in beef cattle with a number of feeding systems developed from research institutes consortiums around the world. In addition, energy requirements for maintenance calculated from studies conducted at the Agri-Food and Biosciences Institute (AFBI) in Northern Ireland since the 1990s were compared with compiled data from recent peer-review papers published over the last decade (2009–2020). The mean metabolisable energy requirement for the maintenance (MEm) of growing cattle was 0.672 MJ/kg0.75 according to values obtained from calorimetry studies conducted at AFBI. This value is respectively 8.2 and 19.5% greater than the MEm values obtained by the Agricultural and Food Research Council (AFRC), and the National Academies of Sciences, Engineering and Medicine (NASEM) equations, but it is in close agreement with the Institut National de la Recherche Agronomique (INRA) approach, when assuming a Bos taurus bull (300 kg LW) and an efficiency for converting energy for maintenance (km) of 0.65. Most of the literature data on energy requirements for the maintenance for this animal category were obtained from studies conducted with Bos indicus animals and their crossbreds in Brazilian conditions with this confirming lower requirements of these animals when compared to pure Bos taurus cattle. A simulation of the total ME requirements calculated for an Angus × Friesian steer (LW = 416 kg) offered good quality grass silage, indicated that both AFRC and NASEM systems overestimate (38.5 and 20.5%, respectively) the observed efficiency of converting ME for growth (kg). When the total ME requirements (maintenance + growth) were assessed, both systems underpredicted total ME requirement in 15.8 and 22.1 MJ/d. The mean MEm requirements for suckler cows obtained from the literature (0.596 MJ/kg0.75) is on average 19.1% greater than predictions given by both AFRC and INRA (lactation) equations when considering a 550 kg cow and a km value of 0.72. Although no differences in net energy requirements for maintenance (NEm) were detected between dry and lactating suckler cows, as expected the later displayed greater variation as a result of differences in milk production. On this regard, the INRA model recognise increased NEm requirements for lactating animals compared to dry cows. The re-evaluation of the concept of diet metabolisability and the analysis of existing data on compensatory growth responses are recommended for future updates of the British system (AFRC) having in to account the particularities of grass-based systems in the UK.

Economics and Feasibility of Legume Inclusion in Southeastern Perennial Grass-Based Systems

Abstract Perennial grass pastures provide the basis for beef production systems across the Southeast United States. One common management practice that is widely recommended among agronomists is interseeding cool-season legumes. Legumes can serve as a complementary resource for filling in production gaps, reducing supplemental feedstuffs, reducing the need for nitrogen fertilization, increasing the nutritional quality of forage available, increase biomass production, improve animal performance, and can reduce the toxic effects of endophyte-infected tall fescue through dilution. A simulated economic analysis was developed to further the economic understanding of the cost of implementation, the subsequent animal and forage performance benefits, and net returns from the inclusion of legumes over many research trials and years. Data from 15 peer-reviewed papers was used to simulate the economic benefits of implementing this production practice. Cost of production and revenue for each paper were calculated using the 10-year average from 2010 to 2019. This analysis provides users with a further understanding of the net returns, critical breakeven areas, and return on investment that is necessary in order to successfully implement the inclusion of cool-season legumes in perennial grass-based systems.

Evaluation of the contribution of 16 European beef production systems to food security

ContextLivestock production, and more particularly ruminants, is criticized for its low conversion efficiency of natural resources into edible food. ObjectiveThe objectives of this paper are to propose an evaluation of the contribution to food security of different European cattle farms through three criteria: 1) food production assessed by the amount of human-edible protein (HEP) and energy (HEE) produced at farm level, 2) feed-food competition at the beef production scale estimated in terms of net human-edible protein and energy and in terms of land used, and 3) food affordability assessed by the production cost of meat, protein and energy. MethodsThe analysis is based on 16 representative beef production systems in France, Belgium, Ireland, Italy and Germany and covers cow-calf systems, finishing systems, dairy and mixed dairy- finishing systems, with or without cash crops. Results and conclusionsThe results show that, at the farm level, systems producing both beef and milk or cereals have higher HEP and HEE production per hectare (up to 370 kg of HEP and 60,000 106J.ha−1) than specialized beef systems (up to 50 kg of HEP and 1600 106J.ha−1) and have lower production costs (approximately €6 kg−1 of HEP in mixed beef system and €29 kg−1 of HEP in a specialized cow-calf-fattener system). Beef systems are almost all HEE net consumers. Results are more variable concerning net HEP efficiency. The cow-calf enterprises are mostly net producers of HEP but, in order to produce human edible meat, these systems need to be combined with finishing systems that are mostly net consumers of HEP. In most cases, cow-calf-finishing systems are net consumers of HEP (between 0.6 and 0.7) but grass-based systems using very little concentrates or systems using co-products not edible by humans are net HEP producers. The grass-based systems use more land area per kilogram of carcass but a major part of this area is non-tilled land, thus these systems are not in direct competition with human food production. The lowest meat production costs are the finishing systems producing the most live weight per livestock unit (LU) per year and dairy systems in lowland which share the costs between milk and meat. SignificanceAlthough most of HEE and HEP efficient farms typically have higher meat production costs, some grassland based systems stand out positively for all indicators. These results pave the way for improvements of the contribution of beef production systems to food security.

An environmental assessment of grass-based dairy production in the northeastern United States

Demand for grass-based dairy production, which relies heavily on grazing and use of forage crops, is growing in the United States, primarily due to reported human health benefits of the milk produced as well as perceived environmental and animal welfare benefits. We used a whole-farm model to evaluate environmental footprints of all-grass, grass supplemented with grain, and confinement dairy production systems in the temperate climate of the northeastern U.S. Model results were depicted per unit of farmland and per unit of milk produced to provide alternate perspectives from the viewpoint of land management and commodity production. For most environmental indicators, the grass-based systems had smaller environmental impacts per unit of farmland but larger impacts per unit of milk produced compared to confinement fed systems. To verify the simulation of grass-based operations, eight dairy farms - ranging from herds that were grazed and fed only forage to herds that received some grain supplementation - were surveyed and modeled. Due to variation in climate, soil characteristics and management practices, a comparison of the two grass-based farm types showed no significant differences in environmental impacts. Farms of the same size using each production strategy along with a more traditional confinement production system were then simulated using the same climate and soil conditions for a better comparison. Predicted nitrogen and phosphorus losses to the environment, fossil energy use, water use, and greenhouse gas emissions were less from the grass-based farms compared to the confinement operation. Due to lower milk production on the grass-based dairies, nutrient losses and greenhouse gas emissions expressed per unit of milk produced were generally greater than those of the confinement system. Within the grass-based dairy systems, the system that supplemented with grain had slightly lower nitrogen and phosphorus losses per unit of farmland compared to the grass-only system, and much lower losses and emissions when expressed per unit of milk produced. Total production cost was less for the all-grass dairy than the grass with grain dairy. With a greater milk price, the all-grass system provided greater profitability per unit of land used and per unit of milk produced compared to the confinement farm of similar size. These data indicate that grass-based dairy farms can provide environmental benefits to a local watershed, but due to a lower efficiency in milk production, they may increase the aggregate environmental impacts of regional and global supply chains.

Towards Regional Synergy: Reconciling Rangeland Ecological Functioning with Forage Production of Cultivated Pasture

Animal husbandry and crop farming are specialized for development in separate areas on the Tibetan Plateau. Such a pattern of isolation has led to current concerns of rangeland and farming system degradation due to intensive land use. The crop-livestock integration, however, has been proven to increase food and feed productivity thorough niche complementarity, and is thereby especially effective for promoting ecosystem resilience. Regional synergy has emerged as an integrated approach to reconcile rangeland livestock with forage crop production. It moves beyond the specialized sectors of animal husbandry and intensive agriculture to coordinate them through regional coupling. Therefore, crop-livestock integration (CLI) has been suggested as one of the effective solutions to forage deficit and livestock production in grazing systems. But it is imperative that CLI moves forward from the farm level to the regional scale, in order to secure regional synergism during agro-pastoral development. The national key R & D program, Technology and Demonstration of Recovery and Restoration of Degraded Alpine Ecosystems on the Tibetan Plateau, aims to solve the problems of alpine grassland degradation by building up a grass-based animal husbandry technology system that includes synergizing forage production and ecological functioning, reconciling the relationship between ecology, forage production and animal husbandry, and achieving the win-win goals of curbing grassland degradation and changing the development mode of animal husbandry. It is imperative to call for regional synergy through integrating ecological functioning with ecosystem services, given the alarming threat of rangeland degradation on the Tibetan Plateau. The series of papers in this issue, together with those published previously, provide a collection of rangeland ecology and management studies in an effort to ensure the sustainable use and management of the alpine ecosystems.

Feed-derived iodine overrides environmental contribution to cow milk

Diets worldwide are deficient in iodine, leading to a range of undesirable health effects at the population level. Dairy products are a primary source of iodine in diets for those populations in which iodized salt is not systematically used or available. However, the flows of iodine through dairy agroecosystems are not well understood. The aim of this research was to investigate iodine flows though the dairy agroecosystem, including the influence of atmospheric depositional inputs, environmental variables, season, husbandry, and diet. Three farm-based sampling campaigns were carried out in this investigation, with milk, soil, silage, grass, and feed iodine determined by inductively coupled plasma mass spectroscopy, and nonparametric statistical analysis tests were conducted on data sets obtained. Natural iodine inputs into the environment are dominated by atmospheric deposition, which mainly from sea spray, and thus the location of farms relative to the coast and prevailing wind direction. Herbage and silage produced from grass-based systems strongly correlated with soil iodine, yet there was a strong disconnect between soil, forage, and feed and the milk that results. This was due to the levels of iodine in supplemental feeds being approximately 10-fold higher than those in forage-derived feeds. The practice of feed supplementation, accentuated by summer housing of cows, led to elevated milk iodine.

The effect of digestate and mineral fertilisation of cocksfoot grass on greenhouse gas emissions in a cocksfoot-based biogas production system

BackgroundClimate mitigation is a major consideration when choosing bioenergy systems. Anaerobic digestion of biomass is a bioenergy system, which is normally used for the treatment of manure or other residues, but cultivated energy crops may also provide a potential feedstock. One of the main crops for biogas production is still maize, but it may be desirable to replace it by perennial grasses, which also have high yields, but do not require as much management. The aim of this study was to analyse greenhouse gas (GHG) emissions in a biogas production system based on a perennial grass, cocksfoot, grown under different fertiliser application systems.MethodsField and laboratory experiments were carried out over a 7-year period to evaluate the influence of mineral nitrogen and digestate fertiliser application on cocksfoot biomass and biogas productivity. The obtained data were used to calculate GHG emissions and emission savings for the whole biogas production cycle, by use of the SimaPro v.8 software with the IMPACT 2002+ model, based on the climate change environmental impact category.ResultsProductivity of cocksfoot (Dactylis glomerata L.) was influenced by the annual rate of nitrogen applied as fertiliser, the fertiliser type and year, as influenced by the weather conditions. The biomass yield of cocksfoot fertilised with 180 kg nitrogen ha−1 year−1 was similar regardless if the nitrogen was applied as digestate or mineral fertiliser. At higher rates of nitrogen application (360–450 kg ha−1 year−1), higher yields and lower net GHG emissions could be obtained from the biogas production cycle when the nitrogen was applied as digestate compared to mineral fertiliser, especially in dry years. Energy input over the whole cycle was mainly influenced by the type of fertiliser and the biomass yield. Mineral fertiliser generally caused higher levels of GHG emissions than organic digestate fertiliser, when the same amount of energy is produced.ConclusionsThe cocksfoot grass-based biogas production system showed that a significant GHG emission saving potential exists, if nitrogen is added as digestate instead of mineral fertiliser, for similar yields of biomass and energy from biogas. Cocksfoot grass fertilised with digestate is thus a promising feedstock for biogas production.

Managing the transition from purebred to rotational crossbred dairy cattle herds: three technical pathways from a retrospective case-study analysis

The growing interest in rotational crossbreeding in Western countries is due to its potential to improve reproductive and health performances of cows. Although a large amount of research focuses on assessing crossbred cows’ performances, how to manage the transition from purebred to rotational crossbred herds is under-explored. Based on a retrospective analysis of French dairy herd case studies, we aimed to identify and characterise technical pathways to make such a transition. In 2018, we performed semi-directive interviews on 26 commercial dairy farms. Data were collected to describe changes in breeding, replacement and culling management practices from the first crossbred mating with purebred cows to the management of a mainly crossbred herd in 2018. Based on a multivariate analysis, we identified two main guidelines structuring technical pathways to move towards rotational crossbred herds: (i) the depth and scale of change (i.e. farm v. herd) associated with the introduction of rotational crossbreeding in the whole-farm dynamics and (ii) the changes in herd replacement and breeding practices to adapt to the evolution of herd demographics induced by the evolution of the dairy crossbred mating rate over time (high from the beginning v. distributed over time). Hierarchical clustering discriminated three groups of farmers differing in their technical pathway to move towards a rotational crossbred herd. In pathway 1, farmers customised one or several rotational crossbreeding schemes to support whole-farm transition towards an organic or grass-based system. Once the scheme stabilised, they quickly implemented it and had to readjust replacement and culling practices to regulate imbalance in herd demographics induced by the improvement in cow fertility. In pathway 2, farmers also customised one or several rotational crossbreeding schemes to support whole-farm redesign but they implemented it more gradually in the herd, which induced no major imbalance in herd demographics. In pathway 3, farmers predefined a relatively well-known rotational crossbreeding scheme to correct fertility issues of purebred cows without any changes at the farm level. They implemented it quickly from the beginning and had to adapt herd replacement and culling to regulate imbalance in herd demographics induced by the improvement in cow fertility. These first empirical evidences on how dairy farmers manage the transition from a purebred to rotational crossbred herd provide original scientific and operational contributions.

Scenarios to limit environmental nitrogen losses from dairy expansion

Increased global demand for dairy produce and the abolition of EU milk quotas have resulted in expansion in dairy production across Europe and particularly in Ireland. Simultaneously, there is increasing pressure to reduce the impact of nitrogen (N) losses to air and groundwater on the environment. In order to develop grassland management strategies for grazing systems that meet environmental targets and are economically sustainable, it is imperative that individual mitigation measures for N efficiency are assessed at farm system level. To this end, we developed an excel-based N flow model simulating an Irish grass-based dairy farm, to evaluate the effect of farm management on N efficiency, N losses, production and economic performance. The model was applied to assess the effect of different strategies to achieve the increased production goals on N utilization, N loss pathways and economic performance at farm level. The three strategies investigated included increased milk production through increased grass production, through increased concentrate feeding and by applying a high profit grass-based system. Additionally, three mitigation measures; low ammonia emission slurry application, the use of urease and nitrification inhibitors and the combination of both were applied to the three strategies. Absolute N emissions were higher for all intensification scenarios (up to 124 kg N ha−1) compared to the baseline (80 kg N ha−1) due to increased animal numbers and higher feed and/or fertiliser inputs. However, some intensification strategies showed the potential to reduce the emissions per ton milk produced for some of the N-loss pathways. The model showed that the assessed mitigation measures can play an important role in ameliorating the increased emissions associated with intensification, but may not be adequate to entirely offset absolute increases. Further improvements in farm N use efficiency and alternatives to mineral fertilisers will be required to decouple production from reactive N emissions.