Understanding variability in carbon footprint of smallholder dairy farms in the central highlands of Ethiopia.

Indian dairy enterprise is dominated by smallholder dairy farms that contribute 72% of the country's total milk production. These smallholder dairy farms are often considered to emit substantial greenhouse gases (GHG) but are poor in productive performances. Therefore, it is crucial to estimate the carbon footprint (CF) of milk production of the smallholder Indian dairy farms. The primary objectives of the study were (1) Assessing the CF of milk production of smallholder dairy farms through life cycle analysis in south-interior Karnataka, India; (2) Identifying the hotspots of GHG emissions and significant factors influencing the CF of milk production in smallholder dairy production system. The study accounted GHG emissions from different sources and considered multiple functions of the smallholder production system. Estimations were made based on primary data collected from 47 farms and associated secondary data. For estimating the CF of milk production, the emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) on a CO2-equivalent (CO2-eq) basis from feed production, enteric fermentation, manure management, transport and energy usage were allocated to fat- and protein-corrected milk (FPCM) based on mass balance, price (crop byproducts and residues) and feed digestibility. Principal component analysis and stepwise linear regression analysis were performed to identify the major factors influencing the CF. The average total GHG emissions (kg CO2-eq yr-1 farm-1) attributable to milk production based on mass, economic, and digestibility allocations were 8,936, 8,641, and 8,759, respectively. The contributions of CH4, N2O, and CO2 to the total farm GHG emission were 70.6%, 20.5%, and 7.69%, respectively. The major emission hotspots were CH4 emission from enteric fermentation (66.8%) and GHG emission from feed production (23.0%). The average CF of cradle-to-dairy cooperative milk production varied from 1.45 to 1.81 kg CO2-eq kg FPCM-1. The CF of milk production was more than 2-fold greater, when milk yield was below 3,500 kg lactating cow-1 yr-1. The FPCM yield 100 kg body weight-1, dry matter intake, and CH4 emission from manure management were the strongest determinants of the CF and explained 83.4% of the observed variation. The study emphasized the importance of considering multiple functions of a mixed crop-livestock-based dairy production system for estimating CF per unit of product. The results suggest that maintaining high-yielding dairy animals and adopting appropriate feeding strategies for better feed utilization are the possible effective interventions for reducing the CF of milk production.

In recent years, the concept of life cycle assessment (LCA) has proven to be useful because of its potential to assess the integral environmental impacts of agricultural products. Developing countries such as India are good candidates for LCA research because of the large contribution of smallholder dairy system to the production of agricultural products such as milk. Therefore, the aim of the present study was to explore the carbon footprint of milk production under the multi-functional smallholder dairy system in Anand district of Gujarat state, western India. A cradle-to-farm gate LCA was performed by covering 60 smallholder dairy farms within 12 geographically distinct villages of the district. The average farm size was 4.0 animals per farm, and the average number of each category of animal was 2.5 lactating cows, 1.4 lactating buffaloes, 1.8 replacement cows, 1.6 replacement buffaloes, 2.0 retired cows, 1.3 retired buffaloes and 1.0 ox per farm. The emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) on CO2-equivalent (CO2-eq) basis from feed production, enteric fermentation and manure management were allocated to fat- and protein-corrected milk (FPCM) on the basis of mass balance, price and digestibility. Emissions of CO2, CH4 and N2O from cattle contributed 11.0%, 75.4% and 13.6%, respectively, to the total greenhouse gas (GHG) emissions. The contribution of CO2, CH4 and N2O from buffalo was 8.2%, 80.5% and 11.3%, respectively, to the total GHG emissions of farms. The average carbon footprint (CF) of cow milk was 2.3, 1.9 and 2.0 kg CO2-eq/kg FPCM on mass, economic and digestibility basis, respectively, whereas for buffalo, milk CF was 3.0, 2.5 and 2.7 kg CO2-eq/kg FPCM, respectively. On the basis of digestibility allocation, emissions from retired (>10 years of age and incapable of or ceased producing milk) cows and buffaloes were 1571.3 and 2556.1 kg CO2-eq/retirement year, respectively. Overall, the CF of milk production under the smallholder dairy system in Anand district was 2.2 kg CO2-eq/kg FPCM, which reduced to 1.7 kg CO2-eq/kg FPCM when milk, manure, finance and insurance were considered as economic functions of the smallholder system. The CF was lower by 65% and 22% for cow and buffalo milk, respectively, than were the estimates of FAO for southern Asia, and this was mainly attributed to difference in the sources of GHG emissions, manure management systems, feed digestibility and milk production data used by FAO.

Variation in the carbon footprint of milk production on smallholder dairy farms in central Kenya

In 2022, New York (NY) had over 620 000 dairy cows producing more than 7 million Mg (15 billion lb) of milk, ranking fifth in dairy producing states in the United States. The objectives of this work were to (1) estimate total farm-gate greenhouse gas (GHG) emissions and GHG emission intensity (GHGei) of 36 medium to large (>300 mature cows) commercial NY dairies, (2) determine the contribution of main GHGs (on-farm methane [CH4], nitrous oxide [N2O], and carbon dioxide [CO2], plus embedded emissions [CO2 equivalents; CO2eq]) and sources (enteric fermentation, feed production, manure management, grazing, fuel and energy) to farm-gate GHGei, and (3) identify key performance indicators (KPIs) driving farm-gate GHGei. Assessments were done for 2022 using The Cool Farm Tool. Farm size ranged from 345 to 6 350 head of predominantly Holstein cows with animal densities between 1.76 and 4.85 animal units ha-1 (0.71 to 1.96 AU ac-1) and heifer to cow ratios between 0.02 and 0.49. Herds produced an average fat and protein corrected milk (FPCM) yield of 12.7 Mg (29 000 lb) FPCM cow-1 per year using 64% homegrown feed. Total FPCM production was 873 000 Mg (1.92 billion lb), representing approximately 12% of total NY milk production in 2022. The GHGei ranged from 0.63 to 1.06 kg CO2eq kg FPCM-1 (mean GHGei = 0.86kg CO2eq kg FPCM-1). Methane was the biggest contributor, accounting for 60% of total GHG emissions on average, with enteric CH4 as the largest contributor (45% of total farm emissions). Among farms, feed production emissions accounted for about 25%, with approximately 7% from homegrown feed production. Manure management practices accounted for about 20% of emissions and explained the largest amount of variation in GHGei among farms. Potential KPIs for GHGei included manure management system, heifer to cow ratio, herd feed consumption intensity, percentage of homegrown feed, and crop nutrient source (fertilizer versus manure). Emission intensity reflected the high proportion of good quality homegrown feed, careful nutrient management and use of manure treatment systems (covered liquid slurry storages, anaerobic digesters) on several dairies. The influence of replacement rate and heifer to cow ratio on animal density, herd feed consumption intensity, and subsequent GHGei requires more detailed analysis. The farms in this study represent a considerable proportion of NY's 2022 FPCM production. Greater participation by smaller farms is necessary to draw conclusions for NY's dairy industry as a whole.

The objective of this study was to estimate the carbon footprint (CF) of milk production (in kg of CO2 equivalents (CO2e) per kg of fat and protein corrected milk (FPCM)) in dairy farms of the San Martín region, in the Peruvian Amazon. A cradle-to-farm gate characterization and analysis were carried out on eight representative dairy farms. Greenhouse gas (GHG) emissions were estimated using equations, following the 2019 refinement of the 2006 IPCC Guidelines. The results showed an average milk production of 9.7 ± 0.82 L milk/cow/day, Gyr x Holstein crosses as the predominant breed, use of cultivated grasses such as Brachiaria brizantha, living fences (Guazuma ulmifolia Lam) as the predominant silvopastoral arrangement, and low level of external inputs such as feed or grain additives. In relation to CF, an average value of 2.26 ± 0.49kg CO2e/kg FPCM was obtained, with enteric fermentation being the most important source (1.81 ± 0.51kg CO2e/kg FPCM), followed by manure management, land use, and energy/transport (0.26 ± 0.06, 0.14 ± 0.04, and 0.05 ± 0.04kg CO2e/kg FPCM, respectively). Differences were found between farmers, obtaining lower CF values (1.76 vs 3.09kg CO2e/kg FPCM) on farms with better feed quality, higher production levels, and a higher percentage of lactating animals compared to dry cows. It is concluded that dairy farms in the Peruvian Amazon region can reduce their emissions if they improve their current feeding practices.

In the context of global climate change, carbon footprint (CF) becomes an important sustainability indicator for dairy production systems. To mitigation the CF of the dairy sector, insight into greenhouse gases (GHG) emissions from individual farms is required. The objective of this study was to determine the primary contributors to GHG emissions at the farm-gate level, expressed as a carbon dioxide equivalents (CO2-eq), to produce one kg of fat-and protein corrected milk (FPCM). Primary data about farms’ management and feeding practices were collected from twelve dairy farms that belong to Gyeonggi-do province, which represent the most important region for milk production in South Korea. Allocation of GHG emissions between meat and milk was assessed as a physical allocation, 98% allocated to milk and 2% to meat (surplus of calves and culled cows). The CF of the evaluated farms averaged to 0.61 CO2-eq/kg of FPCM and ranged from 0.49 to 0.78 CO2-eq/kg of FPCM. Results indicated that the largest source of GHG comes mostly from enteric fermentation (83%), followed by manure management (6%), manure and fertilizer land application (8%) and energy consumption (3%). By type of gas emitted, methane accounted for 86% of total emissions, originating from enteric fermentation and manure management. Nitrous oxide and carbon dioxide accounted for 11.6 % and 2.8% of total GHG emissions, respectively. Lactating cows contributed by 70% of total GHG emissions, whereas dry cows, heifers and calves contributed by 5, 22 and 3%, respectively. Differences in GHG emissions from the evaluated farms could be explained by differences in feed quality and management practices through manure and fertilizers application on cropland. This study contributes to identify the main sources of GHG production in dairy farms, which can help to define mitigation strategies towards the transition to neutral carbon emissions of the dairy sector.

Greenhouse gas emission intensities of grass silage based dairy and beef production: A systems analysis of Norwegian farms

Greenhouse gas emissions from dairy production represent a major source of emissions especially in Western Europe where the sector has grown over the past decade. Different feeding strategies have evolved and there is a need to identify effective mitigation measures. Life cycle assessment (LCA) was used to examine carbon footprints (CFs) of milk production across 71 commercial dairy farms in Ireland, Northern Ireland, England, Spain (Galicia and Basque regions), Portugal and France based on monthly data collection over two years. Emissions up to the farm gate were calculated within a global boundary with both higher tier emission factors (HTEF) applicable in respective countries, and default emission factors (DEF). The global warming potential (GWP) used was the GWP100 metric, however results were also calculated using GWP20 for comparison. Functional units were: (i) one tonne fat and protein corrected milk (FPCM); (ii) 1 ha of on-farm agricultural area (FAA); (iii) 1 ha of global agricultural area (GAA). Farms were categorised based on the proportion of time that cows spent grazing. Mean CF per tonne FPCM (FPCM-CF) were 1,129, 1237 and 1519 kg CO2e for grazing (>220d grazing; n = 16), mixed (up to 219d grazing; n = 17) and housed farms (0d grazing; n = 38), respectively. housed had the widest range, from 884 to 2494 kg CO2e/tonne FPCM, and included the farm with the overall lowest FPCM-CF. housed also had the highest mean CF per ha FAA: 44.1 tonne CO2e, followed by mixed (15.2 tonne) and grazing (11.6 tonne). CF (tonne CO2e) per ha GAA followed the same ranking: housed (15.1), mixed (9.8) and grazing (9.2). There was no difference in ranking of the feeding strategies using DEF in comparison with HTEF. A stepwise regression analysis identified feed efficiency and age at first calving as important factors in determining FPCM-CF for all farms. Furthermore, N surplus was important for grazing &mixed farms. The proportion of uncovered slurry storage, milk yield per cow and the amount of bought in concentrate per cow were important for housed farms. Wide variation in CFs implies considerable potential for lowering emissions per tonne FPCM and per ha FAA and GAA, but it is imperative that mitigation measures are tailored to feeding strategy.

Dairy farming plays a critical role in Kenya's agricultural economy but also contributes significantly to greenhouse gas (GHG) emissions. Smallholder mixed crop-livestock systems dominate the sector and face challenges related to feed quality and manure management. This study aimed to assess the economic and environmental impacts of improved feeding strategies on smallholder dairy farms in the Lake Victoria Basin region of Western Kenya. Data were collected from 160 farms across Vihiga, Siaya, Kakamega, and Homabay counties and analyzed using economic modeling and IPCC Tier I and II methods to evaluate profitability and GHG emissions. Results indicated that replacing low-quality crop residues with high-quality forages improved milk yields and farm profitability, with a 9% increase in returns and a 6% reduction in production costs per kilogram of fat and protein-corrected milk (FPCM). GHG emission intensity per kilogram of FPCM decreased by 11%, mainly due to enhanced feed efficiency and increased milk production. Manure management practices, particularly the use of covered solid storage, also contributed to reduced methane and nitrous oxide emissions. The study concludes that adopting high-quality feed and proper manure management enhances both farm productivity and environmental sustainability. Policymakers are encouraged to support access to quality forage and promote climate-smart practices among smallholder farmers. Further research should explore genetic improvements and precision feeding as additional mitigation strategies.

Greenhouse gas emissions and land use from confinement dairy farms in the Guanzhong plain of China – using a life cycle assessment approach

The development of the carbon footprint (CF) of raw cow milk over time has been scarcely researched. The objectives of this study are (1) to determine the annual raw cow milk CF in the Netherlands between 1990 and 2019 and (2) to identify the factors explaining the development of the raw cow milk CF over time. We applied Life Cycle Assessment (cradle to farm gate) to the average Dutch dairy system and used data collected from national statistics and from the farm accountancy data network.The CF of raw cow milk produced in the Netherlands in 2019 was 992 g CO2-eq. per kg Fat and Protein Corrected Milk (FPCM), while in 1990 it was 1522 g CO2-eq. (kg FPCM)−1. This represents a reduction of 35%. The reduction rate of the CF is affected by the scope of the CF study, i.e. reduction rate is smaller if direct land use change (dLUC) (32%) and soil organic carbon (SOC) balance (29%) are included in the total CF. Methodological choices affect the absolute level of the CF by up to 27%, but the impact on the reduction rate over time is negligible. The results show that continuous improvement in agricultural practices (increased milk and roughage yields, improved feed efficiency and decreased nitrogen application) has played an important role in reducing the CF of milk over the years. Along with this process, the Dutch dairy system has evolved into less grazing and less land devoted to permanent grasslands which decreased carbon sequestration. In order to achieve climate targets, the annual reduction rate needs to be increased and additional efforts are required if the Dutch dairy sector is to play its part in limiting global warming to 1.5 °C. Special attention is needed for the reduction of greenhouse gas (GHG) emission from enteric fermentation and manure storage. However, the main challenge for the future is to find a balanced set of measures to integrally reduce all the sources of GHG emission within the carbon footprint of milk.

Dairy and livestock sector is a significant contributor of anthropogenic greenhouse gas emissions. Carbon footprint (CF) is commonly used to indicate the greenhouse gas (GHG) emissions (CO2 equivalent) at various life cycle stages of a product. Studies undertaken globally on CF of dairy products were reviewed, reported CF values for various products are summarized and important contributing factors are discussed. In various studies undertaken globally, CF of dairy products has been calculated by using different international standards and methodologies like ISO 14040, 14044 and 14067, publicly available specification (PAS 2050). Most of the studies have used functional units such as kilogram greenhouse gas emissions per kilogram of fat-and-protein-corrected-milk (FPCM) and energy correlated milk (ECM). Direct emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from on-farm livestock production and indirect CO2 and N2O emissions related to inputs on the farm have generally been considered in various studies. Enteric methane (CH4) has been reported as the major source of dairy farm emissions, followed by manure management, fertilizer production and its application. Processed milk products were found to have higher CF value as compared to the unprocessed milk. Various mitigation strategies have been suggested for emission reduction from dairy farms for example balanced feed rations and concentrates according to animal body requirements during lactation period, reducing use of nitrogen based fertilizers and increasing efficiency in application during crop production, use of biogas in place of cow dung, anaerobic digestion (AD) and efficient manure management.

Colombia’s water buffalo dairy market has experienced significant growth in recent years, emerging as the industry’s leading sector in milk quality and favorable prices. Buffaloes are renowned for their early maturity and ability to produce high-quality meat. Two key characteristics stand out when considering animals for dual- purpose systems: excellent milk quality suitable for sale, calf rearing and strong maternal abilities. A yield gap analysis was conducted to assess the potential for greenhouse gas emissions mitigation in Colombian buffalo systems to identify achievable buffalo milk productivity. This study is adapted to the standards for life cycle assessment, focusing specifically on greenhouse gas emissions from the International Organization for Standardization. Two functional units were used for measurement: tons of CO 2 -equivalents (CO 2e ) per hectare (ha) and kilograms of CO 2e per kilogram of fat-and-protein-corrected milk (FPCM). Greenhouse gas emissions were calculated using the 2019 Refinement to the 2006 IPCC guidelines, with emission factors sourced from databases. Emissions were categorized into those associated with animals, feces, and soils, with the corresponding sequestration or assimilation accounted in soils, forage biomass, trees, shrubs, and milk production. The simulations were conducted for 550 kg live-weight buffaloes, with a dry matter intake of 11 kg per day alongside 2 kg of balanced feed, under two milk production scenarios: 1500 liters and 3000 liters per lactation. Herd gross energy (GE) intake was calculated using IPCC Tier 2 equations, considering daily gross energy intake per animal category, diet digestibility, and daily net energy requirements for pregnancy, lactation, growth, activity and maintenance. Dry matter intake (DMI) was determined by dividing gross energy intake values by 18.45 MJ of metabolizable energy per kg dry matter, representing the feed’s energy density. These greenhouse gas emissions encompassed methane (CH4) from enteric fermentation and excretions left in paddocks, nitrous oxide (N 2 O) from excretions deposited on pastures and fertilizer application, and carbon dioxide (CO2 ) from lime and urea application, as well as the burning of fossil fuels. The global warming potential indices GWP100 and GWP* were employed to calculate the impact of emissions. Milk carbon footprints (CFs) ranged from 0.7 to 1.41 kgCO2 -eq kg FPCM-1, but when calculated with the GWP* index, they decreased by nearly 35% for both scenarios.

A survey on 61 dairy farms in the Po Valley was carried out using an LCA approach to identify milk production's carbon footprint (CF) at the farm gate, with 1 kg of fat and protein corrected milk (FPCM) as a functional unit. Data were collected and grouped into five main categories: feed purchase, in farm feed production, energy & resources, enteric fermentation, and livestock manure. The CF calculation was conducted according to IPCC guidelines 2006. Dairy herds were classified into three groups according to quartiles for the number of lactating dairy cows: small (< 87), medium (between 87 and 270), and large herds (> 270). The overall CF was 1.19 kg CO2-eq kg−1 FPCM, and the major contribution was from enteric fermentation (43.3%), feed purchase (29.1%), and manure handling (14.6%). Small farms have shown a higher CF (1.35 kg CO2-eq kg−1 FPCM) than medium and large herds (1.13 kg CO2-eq kg−1 FPCM, on average). A Monte Carlo simulation analysis showed a high contribution to the variance of CF due to feed purchase, mainly from proteic extra EU and cereals. Results could help plan mitigation initiatives in less performing herds.

In order to explore the effective management measures of increasing yield and reducing non-CO2 greenhouse gas (CH4 and N2O) emission in the cold black soil paddy field, field experiments were carried out.This paper analyzed the impact of straw returning and different irrigation methods on rice field yield, greenhouse gas emissions, global warming potential (GWP) and greenhouse gas emission intensity (GHGI).The results showed that compared with the treatment without straw returning, the yield of straw returning treatment increased by 11.79% annually, CH4 emissions increased by 62.71% annually, N2O emissions decreased by 1.28% annually, GWP and GHGI increased by 60.90% and 45.58% annually, respectively.Compared with conventional flooding treatment, the yield of controlled irrigation treatment increased by 2.68% annually, the difference was not significant, CH4 emissions decreased by 56.42% annually, N2O emissions increased by 133.41%,GWP and GHGI decreased by 54.89% and 55.93% annually, respectively.Straw returning and controlled irrigation had significant interaction on GWP and GHGI, but not significant interaction on yield.The GHGI values of the four treatments were as follows: KFH0< KFHS< CFH0< CFHS.Therefore, controlled irrigation is an irrigation method with stable rice yield and good greenhouse gas emission reduction effect.Straw returning and controlled irrigation can achieve the double goals of increasing yield and reducing greenhouse gas emissions of rice fields in cold regions.