New Zealand Dairy Farming: Milking Our Environment for All Its Worth

Sedimentary ancient DNA reveals the impact of anthropogenic land use disturbance and ecological shifts on fish community structure in small lowland lake

Freshwater fish biodiversity and abundance are decreasing globally. The drivers of decline are primarily anthropogenic; however, the causative links between disturbances and fish community change are complex and challenging to investigate. We used a suite of sedimentary DNA methods (droplet digital PCR and metabarcoding) and traditional paleolimnological approaches, including pollen and trace metal analysis, ITRAX X-ray fluorescence and hyperspectral core scanning to explore changes in fish abundance and drivers over 1390 years in a small lake. This period captured a disturbance trajectory from pre-human settlement through subsistence living to intensive agriculture. Generalized additive mixed models explored the relationships between catchment inputs, internal drivers, and fish community structure. Fish community composition distinctly shifted around 1350 CE, with the decline of a sensitive Galaxias species concomitant with early land use changes. Total fish abundance significantly declined around 1950 CE related to increases in ruminant bacterial DNA (a proxy for ruminant abundance) and cadmium flux (a proxy for phosphate fertilizers), implicating land use intensification as a key driver. Concurrent shifts in phytoplankton and zooplankton suggested that fish communities were likely impacted by food web dynamics. This study highlights the potential of sedDNA to elucidate the long-term disturbance impacts on biological communities in lakes.

Probabilistic monitoring of meteorological drought impacts on water quality of major rivers in South Korea using copula models

The impacts of drought range from water supply for humans to ecosystems. Drought affects river water quality by disturbing the hydrological regime in a variety of ways, and can degrade water quality by reducing surface and groundwater availability. In particular, drought-induced low flows, reduced nutrient dilution, and extreme increases in water temperature affect various water quality parameters in streams. Furthermore, the effects of drought on stream water quality may vary from season to season and from stream segment to stream segment, which requires careful investigation. In this study, Environmental Drought Condition Index - water quality (EDCI-wq) is proposed using a bivariate copula joint probability model between meteorological drought index and river water quality. Using this, environmental drought with respect to water quality is defined, and it is confirmed that environmental drought with respect to water quality can be routinely monitored through time series analysis and mapping of the proposed EDCI-wq. In addition, in order to express the environmental drought condition more explicitly to the general public, the environmental drought condition is graded into four classes based on the EDCI-wq. Furthermore, the sensitivity of river water quality to meteorological drought was estimated using the copula joint probability model, which allowed us to identify river segments that are relatively more sensitive to meteorological drought events.

Establishing riverine nutrient criteria using individual taxa thresholds

Nutrient enrichment is one of the most pervasive impacts on aquatic ecosystems globally. Approaches to establish nutrient criteria that safeguard aquatic ecosystem health are highly variable and, in many instances, criteria are derived from correlations between in-situ nutrient concentrations and biological indices. Summarising entire assemblages with a single index can result in a substantial loss of information and potentially weaker relationships. In this study, we compared the derivation of nutrient criteria using biological indices and those from individual taxa for rivers and streams in New Zealand. Random forest models, including nutrient concentrations, were built to predict two biological indices and individual taxa across New Zealand's river monitoring network. For all acceptable models, the response of the biological indices and individual taxa to increasing Dissolved Inorganic Nitrogen (DIN) and Dissolved Reactive Phosphorus (DRP) were then predicted for every river reach across the nation, and nutrient concentrations that protected 80% of taxa were then identified. Models for the biological indices were poor but were good for most of the taxa, with nutrient concentrations almost always being the most influential factor. To ensure persistence of at least 80% of the taxa within a river reach, we estimated that DIN (Dissolved Inorganic Nitrogen) concentrations would need to be below 0.57-1.32 mg/L, and DRP (Dissolved Reactive Phosphorus) concentrations below 0.019-0.033 mg/L, depending on the river type. In general, high order, low slope rivers and streams required more stringent nutrient criteria than steep, low order streams. The link between nutrient concentrations and biological indices were weak and likely suffer from the loss of information from summarising an entire assemblage into a single numeric. We consider that the derivation of nutrient criteria for waterways should also examine the individual relationships with the taxa in a river system to establish protection for a desired proportion of taxa.

On-farm investments into dairy cow health: evidence from 15 case study countries

Managing investments in dairy cow health at a national and global scale, requires an improved understanding of current on-farm expenses for cow health (e.g., expenditure for medicine and veterinary consultations). The aim of this study was to assess on-farm health investments for typical dairy farms in 15 case study countries, including Argentina, Australia, Bangladesh, Brazil, Canada, India, China, Colombia, Indonesia, Kenya, New Zealand, Uganda, UK, Uruguay, and USA. The study was conducted using a descriptive analysis of a secondary data set that was obtained from the International Farm Comparison Network (IFCN). The results suggest that health expenditures take up a relatively small proportion (<10%) of the annual total production costs per cow across all countries in the sample. The means of production costs (e.g., feed, machinery) can take up to 90% of the total production costs for highly intensive systems, while these costs can be as low as 9% for extensive systems. This study highlights the importance of understanding on-farm animal health investments as a contribution to improved national and global decision making about animal health in the dairy sector.

Natural heavy metal concentrations in seawater as a possible cause of low survival of larval mussels

BACKGROUND

A period of seismic activity starting in 2010 coincided with a decline in commercial catches of wild seed mussels in a major aquaculture production region of New Zealand. Analyses of over 40 years of mussel seed catch data from in the Pelorus and Kenepuru Sounds, confirmed a marked decline since 2010 in catches of the preferred, green-lipped mussel (Perna canaliculus), the larvae of which is known to have low tolerance of heavy metals in seawater.

METHODS

Heavy metal mean concentrations were measured throughout the Pelorus and Kenepuru Sounds. The concentrations ranged from < 0.60-3.24, < 16.94-74.35, < 1.47-4.00, 2.23-19.02, 1.86-3.29 and 0.12-0.52 µg L^-1 for Cr, Fe, Cu, Zn, As, and Cd, respectively. Seawater from six locations in the Sounds, historically associated with high commercial catches of settling mussel larvae, was used for experimental rearing of green-lipped mussel larvae.

RESULTS

No mussel embryos survived when incubated in these seawater samples. The mean concentrations of Cr, Fe, As, and Cd were significantly higher in the seawater from the Sounds than in the hatchery seawater. A higher concentration of one or a combination of these heavy metals could be the cause of the poor larval survival. These findings could be crucial for the sustainability of mussel farming in the area.

Dairy Cattle Density and Temporal Patterns of Human Campylobacteriosis and Cryptosporidiosis in New Zealand

Public health risks associated with the intensification of dairy farming are an emerging concern. Dairy cattle are a reservoir for a number of pathogens that can cause human illness. This study examined the spatial distribution of dairy cattle density and explored temporal patterns of human campylobacteriosis and cryptosporidiosis notifications in New Zealand from 1997 to 2015. Maps of dairy cattle density were produced, and temporal patterns of disease rates were assessed for urban versus rural areas and for areas with different dairy cattle densities using descriptive temporal analyses. Campylobacteriosis and cryptosporidiosis rates displayed strong seasonal patterns, with highest rates in spring in rural areas and, for campylobacteriosis, summer in urban areas. Increases in rural cases often preceded increases in urban cases. Furthermore, disease rates in areas with higher dairy cattle densities tended to peak before areas with low densities or no dairy cattle. Infected dairy calves may be a direct or indirect source of campylobacteriosis or cryptosporidiosis infection in humans through environmental or occupational exposure routes, including contact with animals or feces, recreational contact with contaminated waterways, and consumption of untreated drinking water. These results have public health implications for populations living, working, or recreating in proximity to dairy farms.

Coupled steroid and phosphorus leaching from cattle slurry at lysimeter scale

Water quality degradation can be caused by excessive agricultural nutrient transfers from fertilised soils exposed to wet weather. Mitigation measures within the EU Nitrates Directive aim to reduce this pressure by including 'closed' fertiliser spreading periods during wet months. For organic fertilisers such as slurry and manure, this closed period requires sufficient on-farm winter storage and good weather conditions to relieve storage at the end of the period. Therefore, robust scientific evidence is needed to support the measure. Incidental nutrient transfers of recently applied organic fertilisers in wet weather can also be complicated by synchronous transfers from residual soil stores and tracing is required for risk assessments. The combination of nutrient monitoring and biomarker analyses may aid this and one such biomarker suite is faecal steroids. Accordingly, this study investigated the persistence of steroids and their association with phosphorus during leaching episodes. The focus was on the coupled behaviour of steroids and total phosphorus (TP) concentrations in sub-surface hydrological pathways. Cattle slurry was applied to monolith lysimeters either side of a closed period and concentrations of both steroids and TP were monitored in the leachate. The study showed no significant effect of the treatment (average p = 0.17), though tracer concentrations did significantly change over time (average p = 0.001). While the steroidal concentration ratio was validated for herbivorous faecal pollution in the leachate, there was a weak positive correlation between the steroids and TP. Further investigation at more natural scales (hillslope/catchment) is required to confirm tracer behaviours/correlations and to compliment this sub-surface pathway study.

Voisin Rational Grazing as a Sustainable Alternative for Livestock Production

Current livestock practices do not meet current real-world social and environmental requirements, pushing farmers away from rural areas and only sustaining high productivity through the overuse of fossil fuels, causing numerous environmental side effects. In this narrative review, we explore how the Voisin Rational Grazing (VRG) system responds to this problem. VRG is an agroecological system based on four principles that maximise pasture growth and ruminant intake, while, at the same time, maintaining system sustainability. It applies a wide range of regenerative agricultural practices, such as the use of multispecies swards combined with agroforestry. Planning allows grazing to take place when pastures reach their optimal resting period, thus promoting vigorous pasture regrowth. Moreover, paddocks are designed in a way that allow animals to have free access to water and shade, improving overall animal welfare. In combination, these practices result in increased soil C uptake and soil health, boost water retention, and protect water quality. VRG may be used to provide ecosystem services that mitigate some of the current global challenges and create opportunities for farmers to apply greener practices and become more resilient. It can be said that VRG practitioners are part of the initiatives that are rethinking modern livestock agriculture. Its main challenges, however, arise from social constraints. More specifically, local incentives and initiatives that encourage farmers to take an interest in the ecological processes involved in livestock farming are still lacking. Little research has been conducted to validate the empirical evidence of VRG benefits on animal performance or to overcome VRG limitations.

Examining the Environmental Impacts of the Dairy and Baby Food Industries: Are First-Food Systems a Crucial Missing Part of the Healthy and Sustainable Food Systems Agenda Now Underway?

Food systems are increasingly being understood as driving various health and ecological crises and their transformation is recognised as a key opportunity for planetary health. First-food systems represent an underexplored aspect of this transformation. Despite breastfeeding representing the optimal source of infant nutrition, use of commercial milk formula (CMF) is high and growing rapidly. In this review, we examine the impact of CMF use on planetary health, considering in particular its effects on climate change, water use and pollution and the consequences of these effects for human health. Milk is the main ingredient in the production of CMF, making the role of the dairy sector a key area of attention. We find that CMF use has twice the carbon footprint of breastfeeding, while 1 kg of CMF has a blue water footprint of 699 L; CMF has a significant and harmful environmental impact. Facilitation and protection of breastfeeding represents a key part of developing sustainable first-food systems and has huge potential benefits for maternal and child health.

Exploring Text Mining for Recent Consumer and Sensory Studies about Alternative Proteins

Increased meat consumption has been associated with the overuse of fresh water, underground water contamination, land degradation, and negative animal welfare. To mitigate these problems, replacing animal meat products with alternatives such as plant-, insect-, algae-, or yeast-fermented-based proteins, and/or cultured meat, is a viable strategy. Nowadays, there is a vast amount of information regarding consumers’ perceptions of alternative proteins in scientific outlets. Sorting and arranging this information can be time-consuming. To overcome this drawback, text mining and Natural Language Processing (NLP) are introduced as novel approaches to obtain sensory data and rapidly identify current consumer trends. In this study, the application of text mining and NLP in gathering information about alternative proteins was explored by analyzing key descriptive words and sentiments from n = 20 academic papers. From 2018 to 2021, insect- and plant-based proteins were the centers of alternative proteins research as these were the most popular topics in current studies. Pea has become the most common source for plant-based protein applications, while spirulina is the most popular algae-based protein. The emotional profile analysis showed that there was no significant association between emotions and protein categories. Our work showed that applying text mining and NLP could be useful to identify research trends in recent sensory studies. This technique can rapidly obtain and analyze a large amount of data, thus overcoming the time-consuming drawback of traditional sensory techniques.

Nutrient criteria to achieve New Zealand's riverine macroinvertebrate targets

Waterways worldwide are experiencing nutrient enrichment from population growth and intensive agriculture, and New Zealand is part of this global trend. Increasing fertilizer in New Zealand and intensive agriculture have driven substantial water quality declines over recent decades. A recent national directive has set environmental managers a range of riverine ecological targets, including three macroinvertebrate indicators, and requires nutrient criteria be set to support their achievement. To support these national aspirations, we use the minimization-of-mismatch analysis to derive potential nutrient criteria. Given that nutrient and macroinvertebrate monitoring often does not occur at the same sites, we compared nutrient criteria derived at sites where macroinvertebrates and nutrients are monitored concurrently with nutrient criteria derived at all macroinvertebrate monitoring sites and using modelled nutrients. To support all three macroinvertebrate targets, we suggest that suitable nutrient criteria would set median dissolved inorganic nitrogen concentrations at ~0.6 mg/L and median dissolved reactive phosphorus concentrations at ~0.02 mg/L. We recognize that deriving site-specific nutrient criteria requires the balancing of multiple values and consideration of multiple targets, and anticipate that criteria derived here will help and support these environmental goals.

Consistent trade-offs in ecosystem services between land covers with different production intensities

Sustaining multiple ecosystem services across a landscape requires an understanding of how consistently services are shaped by different categories of land uses. Yet, this understanding is generally constrained by the availability of fine‐resolution data for multiple services across large areas and the spatial variability of land‐use effects on services. We systematically surveyed published literature for New Zealand (1970–2015) to quantify the supply of 17 non‐production services across 25 land covers (as a proxy for land use). We found a consistent trade‐off in the services supplied by anthropogenic land covers with a high production intensity (e.g. cropping) versus those with extensive or no production. By contrast, forest cover was not associated with any distinct patterns of service supply. By drawing on existing research findings, we reveal complementarity and redundancy (potentially influencing resilience) in service supply from different land covers. This will guide practitioners in shaping land systems that sustainably support human well‐being.

Globalization, first-foods systems transformations and corporate power: a synthesis of literature and data on the market and political practices of the transnational baby food industry

BACKGROUND

The global milk formula market has 'boomed' in recent decades, raising serious concerns for breastfeeding, and child and maternal health. Despite these developments, few studies have investigated the global expansion of the baby food industry, nor the market and political practices corporations have used to grow and sustain their markets. In this paper, our aim is to understand the strategies used by the baby food industry to shape 'first-foods systems' across its diverse markets, and in doing so, drive milk formula consumption on a global scale. We used a theoretically guided synthesis review method, which integrated diverse qualitative and quantitative data sources.

RESULTS

Global milk formula sales grew from ~US$1.5 billion in 1978 to US$55.6 billion in 2019. This remarkable expansion has occurred along two main historical axes. First, the widening geographical reach of the baby food industry and its marketing practices, both globally and within countries, as corporations have pursued new growth opportunities, especially in the Global South. Second, the broadening of product ranges beyond infant formula, to include an array of follow-up, toddler and specialized formulas for a wider range of age groups and conditions, thereby widening the scope of mother-child populations subject to commodification. Sophisticated marketing techniques have been used to grow and sustain milk formula consumption, including marketing through health systems, mass-media and digital advertising, and novel product innovations backed by corporate science. To enable and sustain this marketing, the industry has engaged in diverse political practices to foster favourable policy, regulatory and knowledge environments. This has included lobbying international and national policy-makers, generating and deploying favourable science, leveraging global trade rules and adopting corporate policies to counter regulatory action by governments.

CONCLUSION

The baby food industry uses integrated market and political strategies to shape first-foods systems in ways that drive and sustain milk formula market expansion, on a global scale. Such practices are a major impediment to global implementation of the International Code of Marketing of Breastmilk Substitutes, and other policy actions to protect, promote and support breastfeeding. New modalities of public health action are needed to negate the political practices of the industry in particular, and ultimately to constrain corporate power over the mother-child breastfeeding dyad.

Quantifying National-Scale Changes in Agricultural Land Exposure to Fluvial Flooding

This study quantifies the exposure of agricultural land in Aotearoa-New Zealand's (A-NZ) flood hazard zones (FHZs). We developed a spatio-temporal flood exposure framework to quantify the extent of the area and yearly earnings before income and tax (EBIT) for arable, forestry, horticulture, sheep and beef, and dairy land in FHZs between 1990 and 2016. In 1990, ~1.57 million hectares of agricultural land were exposed, decreasing slightly to ~1.50 million hectares by 2016. However, there was a change in the lower-value types of agricultural land uses being exposed, such as for sheep and beef farming and forestry, toward dairy farming (from ~364,000 hectares in FHZs in 2008 to ~471,000 hectares in 2016). Dairy farming is more intensively staffed with larger amounts of fixed assets, making them less resilient to flood impacts. Despite this, conversion to dairy farming even within the identified FHZs has been driven by the increasing profitability of the enterprise. As a result of both the production value change and land area increases, the dairy EBIT values within FHZs rose rapidly from NZD 382 million to NZD 1.25 billion between 2008 and 2012, creating significantly more economic exposure for A-NZ. This trend is particularly evident in the Southland, Canterbury, and Waikato regions. Similarly, in the Marlborough, Tasman, and Hawke's Bay regions, there was an increase in high-value horticultural land-predominantly viticulture-in FHZs (a increase of NZD 321 million in annual EBIT for exposed horticulture across the three regions). Identifying sub-national trends in agricultural flood exposure allows for a detailed analysis of the likely impacts in high-risk areas, which can inform emergency management plans and mitigative actions that diminish the economic impacts from flood events.

The influence of nutrient enrichment on riverine food web function and stability

Nutrient enrichment of rivers and lakes has been increasing rapidly over the past few decades, primarily because of agricultural intensification. Although nutrient enrichment is known to drive excessive algal and microbial growth, which can directly and indirectly change the ecological community composition, the resulting changes in food web emergent properties are poorly understood. We used ecological network analysis (ENA) to examine the emergent properties of 12 riverine food webs across a nutrient enrichment gradient in the Manawatu, New Zealand. We also derive Keystone Sensitivity Indices to explore whether nutrients change the trophic importance of species in a way that alters the resilience of the communities to further nutrient enrichment or floods. Nutrient enrichment resulted in communities composed of energy inefficient species with high community (excluding microbes) respiration. Community respiration was several times greater in enriched communities, and this may drive hypoxic conditions even without concomitant changes in microbial respiration. Enriched communities exhibited weaker trophic cascades, which may yield greater robustness to energy flow loss. Interestingly, enriched communities were also more structurally and functionally affected by species sensitive to flow disturbance making these communities more vulnerable to floods.

Does land use affect pathogen presence in New Zealand drinking water supplies?

Four microbes (Campylobacter spp., Escherichia coli, Cryptosporidium spp. and Giardia spp.) were monitored in 16 waterways that supply public drinking water for 13 New Zealand towns and cities. Over 500 samples were collected from the abstraction point at each study site every three months between 2009 and 2019. The waterways represent a range from small to large, free flowing to reservoir impoundments, draining catchments of entirely native vegetation to those dominated by pastoral agriculture. We used machine learning algorithms to explore the relative contribution of land use, catchment geology, vegetation, topography, and water quality characteristics of the catchment to determining the abundance and/or presence of each microbe. Sites on rivers draining predominantly agricultural catchments, the Waikato River, Oroua River and Waiorohi Stream had all four microbes present, often in high numbers, throughout the sampling interval. Other sites, such as the Hutt River and Big Huia Creek in Wellington which drain catchments of native vegetation, never had pathogenic microbes detected, or unsafe levels of E. coli. Boosted Regression Tree models could predict abundances and presence/absence of all four microbes with good precision using a wide range of potential environmental predictors covering land use, geology, vegetation, topography, and nutrient concentrations. Models were more accurate for protozoa than bacteria but did not differ markedly in their ability to predict abundance or presence/absence. Environmental drivers of microbe abundance or presence/absence also differed depending on whether the microbe was protozoan or bacterial. Protozoa were more prevalent in waterways with lower water quality, higher numbers of ruminants in the catchment, and in September and December. Bacteria were more abundant with higher rainfall, saturated soils, and catchments with greater than 35% of the land in agriculture. Although modern water treatment protocols will usually remove many pathogens from drinking water, several recent outbreaks of waterborne disease due to treatment failures, have highlighted the need to manage water supplies on multiple fronts. This research has identified potential catchment level variables, and thresholds, that could be better managed to reduce the potential for pathogens to enter drinking water supplies.

Towards a bioeconomic vision for New Zealand - Unlocking barriers to enable new pathways and trajectories

•

New Zealand has existing primary sector growth and a low carbon economy commitment.

•

It has no clearly defined bioeconomic vision and has yet to develop a national strategy.

•

Key barriers hinder development of the emergent bioeconomic transition pathways.

•

We examine the emerging bioeconomy approach, and growing a bioeconomic environment.

There has been significant national interest and movement towards bioeconomic policy over the past decade. Through an examination of the current bioeconomic pathways in New Zealand, this paper outlines key barriers that transition pathways will need to overcome and factors needing development within the country’s bioeconomic environment. New Zealand’s strength in primary production, coupled with a market-led economy and recent green growth with low carbon policies, provide an excellent platform for bioeconomic development. However, the strength in established biological industries and lack of clearly defined vision or cohesive support for bioeconomic development provide sufficient inertia to realising the full potential. For a bioeconomy in New Zealand to flourish, a primary sector model that is cohesive and more integrated is needed to develop new niche industries and attract finance, while providing an overarching governance system to the primary industries.

Political ecology of milk: Contested futures of a lively food

This article advances thinking on the political ecology of food and agriculture by reviewing research on milk and dairy. As increasingly contested foods, milk and dairy provide a window onto inter-linked social and environmental crises and attempts to solve them through adjustments to food production and consumption. We critically assess three trajectories of change (more milk, better milk, and less milk) that are representative of broader efforts to fix social-environmental crises through food. Arguing that these efforts eschew systemic change, we discuss how ideas from food studies, agrarian political economy, and development studies can be united in a potentially transformative research agenda on the political ecology of milk (as well as other foods).We reflect on how concepts of justice, power, and care might inform a political ecology of food and agriculture that can help envision and enact more democratic food futures.

Efficiency of Crude Protein Utilisation in Grazing Dairy Cows: A Case Study Comparing Two Production Systems Differing in Intensification Level in New Zealand

Simple Summary

Improving the dietary crude protein utilisation in dairy cows is a key aspect of agronomically and environmentally sustainable production systems. The intensification process of grazing dairy systems identified with the increase of milking cows linked with the addition of supplementary feed along with the increasing use, and particularly inefficient use, of nitrogen fertiliser, has led to increasing pressure on the environment. However, feeding solely on pasture could result in an excess of crude protein intake relative to nutritional requirements, and this could reduce the dietary crude protein utilisation. In this study, we modelled the dietary crude protein utilisation, along with nitrogen excreta partitioning of milking cows, of two contrasting spring-calving pasture-based herds differing in intensification level in New Zealand. We found that feeding diets with higher fresh pasture proportions, such as those employed in low-intensification dairy systems, led to an excess of crude protein intake with greater nitrogen partitioned towards urine, which is sensitive in terms of body water eutrophication. In the high-intensity production system, the inclusion of low-crude protein supplements resulted in better dietary crude protein utilisation, along with less urinary nitrogen losses.

Abstract

In this study, we modelled and compared lactation curves of efficiency of crude protein utilisation (ECPU) and the nitrogen (N) excreta partitioning of milking cows of two contrasting spring-calving pasture-based herds to test some aspects of farming intensification practices on cow performance and N partition. In the low-intensity production system (LIPS), 257 cows were milked once-daily and fed diets comprised of pasture with low supplementary feed inclusion during lactation (304 kg pasture silage/cow). In the high-intensity production system (HIPS), 207 cows were milked twice-daily and fed pasture with higher supplementary feed inclusion (429 kg pasture silage and 1695 kg concentrate/cow). The dietary crude protein (CP) utilisation was calculated for each cow at every herd test date as the ECPU as a proportion of protein yield (PY) from the CP intake (CPI) derived from intake assessments based on metabolisable energy requirements, and the CP balance (CPB) calculated as the difference between CPI and PY. Total N excreta partitioned to faeces (FN) and urine (UN) was estimated by back-calculating UN from FN, considering dietary N, and from N retained in body tissues, taking into account live weight change during the lactation. The higher CPI (2.7 vs. 2.5 kg CP/day), along with the reduced milk yield (1100 kg milk/cow less), of the LIPS cows led to a lower ECPU (23% vs. 31%) and to a higher CPB (2.1 vs. 1.8 kg CP/day) when compared to the HIPS cows. Mean N excreta, and particularly UN, was significantly higher in LIPS cows, and this was explained by higher dietary CP and by the reduced PY when compared to the HIPS cows. Reducing the low-CP supplementation in the “de-intensified” herd lessened the ECPU, resulting in higher UN, which is sensitive in terms of body water eutrophication.

Benefits Are Limited with High Nitrogen Fertiliser Rates in Kikuyu-Ryegrass Pasture Systems

Nitrogen (N) fertiliser is applied to pastures in dairy farming systems to ensure productivity, but it is an expensive input that could be damaging to the environment if used excessively. In the southern Cape region of South Africa, N fertilisation guidelines for pastures were developed under conditions different to current management practices, yet dairy producers still base fertiliser programmes on these outdated guidelines. This study aimed to determine the efficiencies of N fertilisation. Various N fertiliser rates (0, 20, 40, 60 and 80 kg ha−1 applied after grazing), as well as a variable rate according to the nitrate concentration in the soil water solution, were assessed on a grazed pasture. Dairy cows returned to a pasture approximately 11 times per year. Pasture production showed a minimal response to fertilisation within each season. The most responsive parameters to fertilisation were the herbage crude protein content, soil mineral N content and urease activity. Reduced microbial activity was observed when more than 40 kg N ha−1 was applied. When considering the soil total mineral N content, N is used inefficiently at rates above 40 kg N ha−1. The results are indicative of an N saturated system that provides a rationale for reducing N fertiliser rates.

Can technology help achieve sustainable intensification? Evidence from milk recording on Irish dairy farms

This article explores the potential of a farm technology to simultaneously improve farm efficiency and provide wider environmental and social benefits. Identifying these 'win-win-win' strategies and encouraging their widespread adoption is critical to achieve sustainable intensification. Using a nationally representative sample of 296 Irish dairy farms from 2015, propensity score matching is applied to measure the impact of milk recording on a broad set of farm sustainability indicators. The findings reveal that the technology enhances economic sustainability by increasing dairy gross margin and milk yield per cow. Furthermore, social sustainability is improved through a reduction in milk bulk tank somatic cell count (an indicator of animal health and welfare status). Conversely, milk recording (as it is currently implemented) does not impact farm environmental sustainability, represented by greenhouse gas emission efficiency. While the study shows that milk recording is a 'win-win' strategy, ways of improving current levels of utilisation are discussed so that milk recording achieves its 'win-win-win' potential in the future.

A Review of Potential Public Health Impacts Associated With the Global Dairy Sector

Strong demand for dairy products has led to a global increase in dairy production. In many parts of the world, dairy systems are undergoing rapid intensification. While increased production may contribute to food security, higher dairy stocking rates in some regions have resulted in increased pressure on natural resources with the potential to affect public health and wellbeing. The aim of this review was to identify and describe the potential health harms and benefits associated with dairy production and consumption. Electronic databases Medline, Embase, Scopus, Web of Science, PubMed, and Google Scholar were searched for published literature that investigated human health impacts of dairy production and consumption. Occupational hazards, environmental health impacts, ecosystem health impacts, foodborne hazards, and diet-related chronic diseases were identified as potential public health hazards. Some impacts, notably climate change, extend beyond directly exposed populations. Dairy production and consumption are also associated with important health benefits through the provision of nutrients and economic opportunities. As the global dairy sector increases production, exposure to a range of hazards must be weighed with these benefits. The review of impacts presented here can provide an input into decision making about optimal levels of dairy production and consumption, local land use, and identification and management of specific hazards from this sector. Future research should consider multiple exposure routes, socioeconomic implications, and environmental factors, particularly in regions heavily dependent on dairy farming.

Dairy intensification: Drivers, impacts and alternatives

Dairy production systems have rapidly intensified over the past several decades. Dairy farms in many world regions are larger and concentrated in fewer hands. Higher productivity can increase overall economic gains but also incurs site-specific social and environmental costs. In this paper, we review the drivers and impacts of dairy intensification. We identify in the literature four prominent concerns about dairy intensification: the environment, animal welfare, socioeconomic well-being, and human health. We then critically assess three frameworks-sustainable intensification, multifunctionality, and agroecology-which promise win-win solutions to these concerns. We call for research and policy approaches that can better account for synergies and trade-offs among the multiple dimensions of dairy impacts. Specifically, we suggest the need to (1) consider dairy system transitions within broader processes of social-environmental change and (2) investigate how certain framings and metrics may lead to uneven social-environmental outcomes. Such work can help visualize transformations towards more equitable, ethical, and sustainable food systems.

Palatable disruption: the politics of plant milk

Plant-based milk alternatives-or mylks-have surged in popularity over the past ten years. We consider the politics and consumer subjectivities fostered by mylks as part of the broader trend towards 'plant-based' food. We demonstrate how mylk companies inherit and strategically deploy positive framings of milk as wholesome and convenient, as well as negative framings of dairy as environmentally damaging and cruel, to position plant-based as the 'better' alternative. By navigating this affective landscape, brands attempt to (re)make mylk as simultaneously palatable and disruptive to the status quo. We examine the politics of mylks through the concept of palatable disruption, where people are encouraged to care about the environment, health, and animal welfare enough to adopt mylks but to ultimately remain consumers of a commodity food. By encouraging consumers to reach for "plant-based" as a way to cope with environmental catastrophe and a life out of balance, mylks promote a neoliberal ethic: they individualize systemic problems and further entrench market mechanisms as solutions, thereby reinforcing the political economy of industrial agriculture. In conclusion, we reflect on the limits of the current plant-based trend for transitioning to more just and sustainable food production and consumption.

Digestion and nitrogen excretion by Holstein-Friesian cows fed grasses with lucerne or lucerne and plantain

Forages and forage mixtures with greater tolerance of dry conditions than perennial ryegrass (Lolium perenne L.) are desirable for dairy farming in New Zealand, and a low urinary nitrogen (N) excretion is desirable to lessen pollution of waterways and ground water, and nitrous oxide emissions. Measurements were undertaken with late-lactation Holstein-Friesian cows (5/treatment) fed tall fescue (Festuca arundinacea Schreb.) with a substantial incursion of weed grasses, as either a sole diet (Grass), or with lucerne (Medicago sativa L.) or lucerne and plantain (Plantago lancelota L.), in metabolism stalls. Approximate ratios (DM basis) of Grass with lucerne (GL) were 55:45, and Grass with lucerne and plantain (GLP) were 55:25:20. Measurements included intakes, production, digestion, rumen function, and urinary excretion, including the circadian patterns of metabolite excretion with a focus on nitrogenous aspects. The DM intakes (kg/day) of cows fed Grass, GL and GLP were 14.9, 12.7 and 15.0 (P = 0.006), and DM digestibility (%) was 58.0, 59.8 and 61.9 (P = 0.006), respectively. Milk yields (kg/day) were Grass, 9.0; GL, 8.7 and GLP, 11.7 (P = 0.003) but composition was not affected by diet. Rumen digesta weight was greatest in cows fed Grass, averaging 23.4% of liveweight after morning feeding. The microbial growth (g/kg organic matter digested) was 16.8 in cows fed Grass and ~24.0 in the other diets. Dietary crude protein concentrations (g/100 g DM) were Grass, 15.4, GL, 20.1 and GLP, 18.3 and urinary N excretion (g/day) was lowest with the Grass diet but urinary N concentration was lowest from cows fed GLP. Daily creatinine excretion was unaffected by diet but there was a 2-fold range in excretion rates within 24 h and values from cows fed fresh forages are lower than published values from cows fed dry diets. Results showed that supplementation of poor quality pasture with lucerne or lucerne with plantain had minor effects on digestibility, and measurements of urinary N suggest a need for caution when predicting urinary N excretion from spot urine sampling in grazing trials.

Strategic grazing management towards sustainable intensification at tropical pasture-based dairy systems

Agricultural systems are responsible for environmental impacts that can be mitigated through the adoption of more sustainable principles. Our objective was to investigate the influence of two pre-grazing targets (95% and maximum canopy light interception during pasture regrowth; LI_95% and LI_Max, respectively) on sward structure and herbage nutritive value of elephant grass cv. Cameroon, and dry matter intake (DMI), milk yield, stocking rate, enteric methane (CH₄) emissions by Holstein × Jersey dairy cows. We hypothesized that grazing strategies modifying the sward structure of elephant grass (Pennisetum purpureum Schum.) improves nutritive value of herbage, increasing DMI and reducing intensity of enteric CH₄ emissions, providing environmental and productivity benefits to tropical pasture-based dairy systems. Results indicated that pre-sward surface height was greater for LI_Max (≈135 cm) than LI_95% (≈100 cm) and can be used as a reliable field guide for monitoring sward structure. Grazing management based on LI_95% criteria improved herbage nutritive value and grazing efficiency, allowing greater DMI, milk yield and stocking rate by dairy cows. Daily enteric CH₄ emission was not affected; however, cows grazing elephant grass at LI_95% were more efficient and emitted 21% less CH₄/kg of milk yield and 18% less CH₄/kg of DMI. The 51% increase in milk yield per hectare overcame the 29% increase in enteric CH₄ emissions per hectare in LI_95% grazing management. Thereby the same resource allocation resulted in a 16% mitigation of the main greenhouse gas from pasture-based dairy systems. Overall, strategic grazing management is an environmental friendly practice that improves use efficiency of allocated resources through optimization of processes evolving plant, ruminant and their interface, and enhances milk production efficiency of tropical pasture-based systems.

Colour Classification of 1486 Lakes across a Wide Range of Optical Water Types

Remote sensing by satellite-borne sensors presents a significant opportunity to enhance the spatio-temporal coverage of environmental monitoring programmes for lakes, but the estimation of classic water quality attributes from inland water bodies has not reached operational status due to the difficulty of discerning the spectral signatures of optically active water constituents. Determination of water colour, as perceived by the human eye, does not require knowledge of inherent optical properties and therefore represents a generally applicable remotely-sensed water quality attribute. In this paper, we implemented a recent algorithm for the retrieval of colour parameters (hue angle, dominant wavelength) and derived a new correction for colour purity to account for the spectral bandpass of the Landsat 8 Operational Land Imager (OLI). We used this algorithm to calculate water colour on almost 45,000 observations over four years from 1486 lakes from a diverse range of optical water types in New Zealand. We show that the most prevalent lake colours are yellow-orange and blue, respectively, while green observations are comparatively rare. About 40% of the study lakes show transitions between colours at a range of time scales, including seasonal. A preliminary exploratory analysis suggests that both geo-physical and anthropogenic factors, such as catchment land use, provide environmental control of lake colour and are promising avenues for future analysis.

Grazing management: setting the table, designing the menu and influencing the diner

Pastoral livestock-production systems are under increasing environmental, social and consumer pressures to reduce environmental impacts and to enhance biodiversity and animal welfare. At the same time, farmers face the challenge of managing grazing, which is intimately linked with profitability. Recent advances in understanding grazing patterns and nutritional ecology may help alleviate such pressures. For instance, by managing grazing to (1) manipulate links between ingestive–digestive decisions and temporal patterns of nutrient excretion, (2) provide phytochemically diverse diets at appropriate temporal (the menu) and spatial (the table) scales and (3) influence the behaviour of animals (the diners) on the basis of their specific ‘personalities’ and needs, to overcome or enhance animal differences, thereby enhancing their and farm productivity and welfare, as well as our health. Under pastoral systems, synergies between animals’ and farmers’ grazing decisions have the potential to offer greater benefits to the animal, the environment and the farm than does simple and parsimonious grazing management based on a single component of the system. In the present review, we look at grazing and its management through an alternate lens, drawing ideas and hypotheses to stimulate thinking, dialogue and discussions that we anticipate will evolve into innovative research programs and grazing strategies. To do so, we combined experimental and observational studies from a wide range of disciplines with simulation-modelling exercises. We envisage a more holistic approach to manage grazing based on recent advances in the understanding of the nutritional ecology of grazing animals, and propose management practices that may enable pastoral livestock-production systems to evolve continually as complex creative systems.

The effects of climatic fluctuations and extreme events on running water ecosystems

Most research on the effects of environmental change in freshwaters has focused on incremental changes in average conditions, rather than fluctuations or extreme events such as heatwaves, cold snaps, droughts, floods or wildfires, which may have even more profound consequences. Such events are commonly predicted to increase in frequency, intensity and duration with global climate change, with many systems being exposed to conditions with no recent historical precedent. We propose a mechanistic framework for predicting potential impacts of environmental fluctuations on running-water ecosystems by scaling up effects of fluctuations from individuals to entire ecosystems. This framework requires integration of four key components: effects of the environment on individual metabolism, metabolic and biomechanical constraints on fluctuating species interactions, assembly dynamics of local food webs, and mapping the dynamics of the meta-community onto ecosystem function. We illustrate the framework by developing a mathematical model of environmental fluctuations on dynamically assembling food webs. We highlight (currently limited) empirical evidence for emerging insights and theoretical predictions. For example, widely supported predictions about the effects of environmental fluctuations are: high vulnerability of species with high per capita metabolic demands such as large-bodied ones at the top of food webs; simplification of food web network structure and impaired energetic transfer efficiency; and reduced resilience and top-down relative to bottom-up regulation of food web and ecosystem processes. We conclude by identifying key questions and challenges that need to be addressed to develop more accurate and predictive bio-assessments of the effects of fluctuations, and implications of fluctuations for management practices in an increasingly uncertain world.

Thinking beyond the Bioreactor Box: Incorporating Stream Ecology into Edge-of-Field Nitrate Management

Around the world, artificially drained agricultural lands are significant sources of reactive nitrogen to stream ecosystems, creating substantial stream health problems. One management strategy is the deployment of denitrification enhancement tools. Here, we evaluate the factors affecting the potential of denitrifying bioreactors to improve stream health and ecosystem services. The performance of bioreactors and the structure and functioning of stream biotic communities are linked by environmental parameters like dissolved oxygen and nitrate-nitrogen concentrations, dissolved organic carbon availability, flow and temperature regimes, and fine sediment accumulations. However, evidence of bioreactors' ability to improve waterway health and ecosystem services is lacking. To improve the potential of bioreactors to enhance desirable stream ecosystem functioning, future assessments of field-scale bioreactors should evaluate the influences of bioreactor performance on ecological indicators such as primary production, organic matter processing, stream metabolism, and invertebrate and fish assemblage structure and function. These stream health impact assessments should be conducted at ecologically relevant spatial and temporal scales. Bioreactors have great potential to make significant contributions to improving water quality, stream health, and ecosystem services if they are tailored to site-specific conditions and implemented strategically with land-based and stream-based mitigation tools within watersheds. This will involve combining economic, logistical, and ecological information in their implementation.