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Humboldt Universität zu Berlin (2013)

Energy efficiency in dairy cattle farming and related feed production in Iran

Maysami, Mohammadali

Titre : Energy efficiency in dairy cattle farming and related feed production in Iran

Auteur : Maysami, Mohammadali

Université de soutenance : Humboldt Universität zu Berlin

Grade : Doctor rerum agriculturarum (Dr. rer. agr.) 2013

Résumé
Dairy farming is increasing and becoming more intensive, attendant on higher energy inputs, also in Iran. The aim of this study was to estimate and assess the energy efficiency of dairy farming and the related feed production in north-western Iran. Data were gained from a company producing feeds in north-western Iran, and from 24 dairy farms, also in north-western Iran for a period of three years. A method of investigation was devised based on the cumulative energy demand (CED) method introduced by VDI guideline 4600 and ISO standard 14044, which is used in life cycle assessment (LCA). The energy intensity (EI) in the feed production (in MJ kg-1 DM) was 2.92 for alfalfa, 6.76 for barley grain, 9.19 for maize corn, 12.36 for rapeseed, 2.45 for spring maize silage, 4.45 for summer maize silage and 4.35 for wheat grain. The EI for the energy corrected milk (ECM) was 5.84±0.69 MJ kg-1 with a ECM yield of 6,585±1,221 kg cow-1 yr-1 . Feedstuff was the main source of energy input in milk production, with approximately 79% of the total energy input. The EI was decreasing with an increasing milk yield (-0.36 MJ kg-1 ECM per +1,000 kg ECM cow-1 yr-1 ), within the range of the milk yield found in the investigated farms (3,860-8,320 kg ECM cow-1 yr-1 ). The energy input was allocated to milk (83%), manure (15%) and meat (2%). The EI for boneless meat produced by bulls up to 400 kg body mass was 75.4±9.1 MJ kg-1 and produced by bulls up to 700 kg was 103.8±11.4 MJ kg-1 . The allocated EI for meat of the replacing slaughtered cows was 16.3 MJ kg-1 of meat. By calculating the EI for milk production on the basis of the higher heating value (HHV) of feeds, it yielded in a mean EI of 23.7±3.37 MJ kg-1 ECM and an EI of 314±25 MJ kg-1 bull meat (400 kg body mass). Energy output input ratio (OIR) ranged between 2.03 MJ MJ-1 for maize corn and 7.75 MJ MJ-1 for spring maize silage production. While, in milk production OIR was 0.55 MJ MJ-1 and in meat production 0.12 MJ MJ-1

Mots Clés : Cumulative Energy Demand, Dairy, Energy Intensity, Feedstuff, Iran, LCA

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