Elsevier

Journal of Cleaner Production

Volume 19, Issue 13, September 2011, Pages 1494-1505
Journal of Cleaner Production

Life cycle assessment of milk produced in two smallholder dairy systems in the highlands and the coast of Peru

https://doi.org/10.1016/j.jclepro.2011.04.010Get rights and content

Abstract

Life Cycle Assessment (LCA) was applied to two smallholder milk production systems in Peru in order to evaluate the environmental burden of milk produced in each. An Andean highland milk production system where livestock feeding is restricted to permanent pastures supplemented with on farm grown ryegrass-clover was opposed to a coastal system with dairy cows fed a diet consisting of fodder maize and purchased concentrate. Milk production levels (kg/cow day) differed considerably with 2.57 for the highland and 19.54 for the coastal system. A Life Cycle Inventory was calculated for the functional unit of 1 kg energy corrected milk (ECM) and the environmental impacts global warming, acidification and eutrophication were estimated for 1 kg ECM, 1 ha and 1 animal, considering the multi-functionality of the system. The highland system was characterized by a high land use (23.1 m2a/kg ECM vs. 1.71 m2a/kg ECM at the coast). Irrigation water and energy were on the other hand used to a much higher amount at the coast (7291 l/kg ECM and 8791 MJ/kg ECM, respectively) than in the highlands (848 l/kg ECM and 0.20 MJ/kg ECM). Global warming potential, acidification and eutrophication were higher for 1 kg ECM produced in the highlands than at the coast by 10.6 kg CO2 equivalents, 6.58 g sulfur dioxide equivalents and 10.63 g phosphate equivalents, respectively. Nevertheless, 5220 kg CO2 equivalents more were emitted per animal at the coast than in the highlands. Also acidification and eutrophication were estimated to be on average 6 and 4 times higher at the coast compared to the highlands when expressed for the functional units of 1 ha and 1 animal.

Results

Whereas livestock is mainly responsible for impacts on the environment in the highlands, at the coast both livestock related emissions and forage cultivation play an important role. Furthermore CO2 releases from soybean cultivations heavily contribute to total emissions. Sensitivity analysis indicates that for dairy systems relying on crop by-products as feed the choice of the allocation method is a crucial point in a LCA study. Based on the results of this study, strategies in order to reduce the environmental burden of milk production should focus on an increase of production levels and a reduction of methane emissions from enteric fermentation in the highlands and a modification of the concentrate components replacing soya as the protein source at the coast.

Introduction

Milk production is associated with environmental impacts such as acidification and eutrophication of soil and water bodies or global warming caused by the emission of greenhouse gases (De Vries and Boer, 2010). Interest in the development of methods in order to better understand such possible environmental impacts associated with the production and consumption of products has increased recently (ISO, 2006). Life cycle assessment (LCA) is a method developed in order to assess the environmental aspects and potential environmental impacts throughout a product’s life cycle and provides a widespread insight into the environmental burdens associated with a product or a human activity (ISO, 2006). Some studies have already applied LCA on typical regional (Hospido et al., 2003) or national (Chen et al., 2005, Basset-Mens et al., 2009) milk production systems or focussed on comparisons of conventional with organic production systems (Thomassen et al., 2008, Boer, 2003) or different production scenarios (Basset-Mens et al., 2009, Casey and Holden, 2005). No LCA on milk production has so far been elaborated for a tropical region.

Milk production in Peru has grown quickly during the last 15 years (up to 60% between 1990 and 2003; (FAOSTAT, 2008)) and the sale of milk is an important source of income especially for smallholder farmers. Most of the studies mentioned above have identified the production and use of feed to be the main contributor to the total environmental impact of milk. Furthermore the production level significantly influences the environmental performance if the impact is expressed per unit of milk produced (Thomassen et al., 2009). Dairy feed and milk production levels vary considerably between the smallholder milk production systems in the Peruvian highlands and the coastal region. In the Peruvian highlands, smallholder milk production is based on local Criollo cattle on permanent pastures supplemented with ryegrass-clover (Bartl et al., 2009) whereas dairy cows at the coast are Holstein-Friesian breed and are fed a diet consisting of fodder maize and concentrate (Gómez, 2008).

The hypothesis tested in this study was that typical Peruvian smallholder dairy systems in the Andean highlands and at the coast have different potential environmental impacts mainly due to different feeding systems and milk production levels.

Section snippets

Material and methods

In this project we applied an attributional LCA (Rebitzer et al., 2004), which analyses the resource inputs and the emissions within a defined system attributed to the production of 1 kg energy corrected milk (ECM). According to ISO 14044 (ISO, 2006) the study includes a goal and scope definition, inventory analysis, impact assessment and interpretation of results.

Life cycle inventory for 1 kg ECM

Permanent pastures contribute to 84.5% of all land used in the highlands and 96.7% of the water is consumed for the irrigation of forages. The land use for milk production at the coast is distributed between production of forages (58.3% of total land used) and concentrate ingredients (41.7%). Most of the water (77.8%) and energy (76.9%) used at the coast are spent for the production of the concentrate ingredients (Table 5).

Ammonia, N2O and CH4 emissions to the air are higher by 144, 70 and 477%

Method and data availability

When interpreting the LCA results it has to be considered that due to the lack of real farm data regarding emissions, the environmental impact calculated with an LCA differs from the actual environmental impact (Thomassen et al., 2008). Especially when comparing different systems producing the same product the accuracy of data has to be high and a large amount of data has to be available (Basset-Mens and Werf, 2005). Thanks to detailed data collection for other purposes sufficient accurate on

Conclusions

The environmental burden of 1 kg energy corrected milk (ECM) produced in two typical smallholder Peruvian production systems in the highlands and at the coast were shown to differ considerably with impacts being higher by 333, 87 and 219% in the highland than in the coastal system for global warming potential, acidification and eutrophication, respectively. The highland system was characterized by a high land occupation and a high emission of methane per kg ECM. On the other hand, emissions per

Acknowledgements

We gratefully acknowledge the participation of the farmers in Chalhuas, Sallahuachac and San Felipe and of the administration personnel of the Asociación de Ganaderos de la Irrigación San Felipe. The provision of data by Fabia Parola is very much appreciated. This work was supported by ETH Research Grant CH1-03 08-3.

References (81)

  • G. Rebitzer et al.

    Life cycle assessment. Part 1: framework, goal and scope definition, inventory analysis, and applications

    Environment International

    (2004)
  • B. Reidy et al.

    A new Swiss inventory of ammonia emissions from agriculture based on a survey on farm and manure management and farm-specific model calculations

    Atmospheric. Environment.

    (2008)
  • S.G. Sommer et al.

    Algorithms determining ammonia emissions from buildings housing cattle and pigs and from manure stores

    Advances in Agronomy

    (2006)
  • M.A. Thomassen et al.

    IJM: Evaluation of indicators to assess the environmental impact of dairy production systems

    Agriculture Ecosystems and Environment

    (2005)
  • M.A. Thomassen et al.

    IJM. Life cycle assessment of conventional and organic milk production in the Netherlands

    Agricultural Systems

    (2008)
  • M.A. Thomassen et al.

    IJM. Relating life cycle assessment indicators to gross value added for Dutch dairy farms

    Ecological Economics

    (2009)
  • H.H. Van Horn et al.

    Components of dairy manure management systems

    Journal of Dairy Science

    (1994)
  • H.M.G. Van der Werf et al.

    Environmental impacts of farm scenarios according to five assessment methods

    Agriculture Ecosystems and Environment

    (2007)
  • Fütterungsempfehlungen und Nährwerttabellen für Wiederkäuer

    (2006)
  • Official Methods of Analysis

    (1990)
  • K. Bartl et al.

    Agronomic performance and nutritional value of traditional and alternative forage plants in the Peruvian highlands

    Grass and Forage Science

    (2009)
  • De Boer

    IJM. Environmental impact assessment of conventional and organic milk production

    Livestock Production Science

    (2003)
  • C. Cederberg

    Life Cycle Assessment of Milk Production – a Comparison of Conventional and Organic Farming. SIK, Report No. 643

    (1998)
  • Chen, G., Orphanti, S., Kenman, S.J., Chataway, R.G. Life cycle assessment of a representative dairy farm with limited...
  • PRé Consultants

    SimaPro 7.1.8 (Software). Amersfoort

    (2008)
  • A.S. Dahlin et al.

    Nutrient management in low input grazing-based systems of meat production

    Soil Use and Management

    (2005)
  • R. Dalgaard et al.

    LCA of soybean meal

    International Journal of Life Cycle Assessment

    (2008)
  • J.L. Ellis et al.

    Prediction of methane production from dairy and beef cattle

    Journal of Dairy Science

    (2007)
  • J. Eriksen et al.

    Nitrate leaching and N2-fixation in grasslands of different composition, age and management

    Journal of Agricultural Sciences

    (2004)
  • FAOSTAT (FAO Statistics Division). FAOSTAT. http://faostat.fao.org/ (accessed...
  • Fineli (National Institute for Health and Welfare). Fineli ® - Finnish Food Composition Database....
  • E. Flores et al.

    Utilización de praderas cultivadas en secano y praderas naturales para la producción lechera

    (2005)
  • S. Foster et al.

    Protección de la calidad del agua subterránea - guía para empresas de agua, autoridades municipales y agencias ambientales

    (2002)
  • R. Freiermuth

    Modell zur Berechnung der Schwermetallflüsse in der Landwirtschaftlichen Ökobilanz, SALCA-Schwermetall

    (2006)
  • R. Frischknecht et al.

    Implementation of life cycle impact assessment methods: data v2.0, ecoinvent report

    Dübendorf, Switzerland: Swiss Centre for Life Cycle Inventories

    (2007)
  • F.B. Fritschi et al.

    Seasonal nitrogen concentration, uptake, and partitioning pattern of irrigated Acala and Pima cotton as influenced by nitrogen fertility level

    Crop Science

    (2004)
  • C.A. Gómez

    Valor nutricional y utilización de alimentos. Presentation at the conference “Avances en alimentación de vacunos lecheros”

    (May 2002)
  • Gómez, C.A. Informe de línea base: Subproyecto de capacitación – Capacitación estratégica de ganaderos de la irrigación...
  • J.B. Guinée et al.

    Handbook on Life Cycle Assessment: Operational Guide to the ISO Standards

    (2002)
  • R.M. Harrison
  • Cited by (0)

    View full text