Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 403192
Title Effects of nutritional strategies on simulated nitrogen excretion and methane emission in dairy cattle
Author(s) Dijkstra, J.; France, J.; Ellis, J.L.; Kebreab, E.; Lopez, S.; Reijs, J.W.; Bannink, A.
Source In: Modelling Nutrient Digestion and Utilisation in Farm Animals / Sauvant, D., van Milgen, J., Faverdin, P., Friggens, N., Wageningen : Wageningen Academic Publishers - ISBN 9789086861569 - p. 394 - 402.
Department(s) Animal Nutrition
LEI SECT & OND - Duurzame Ontwikkeling Agrosectoren
LR - Backoffice
Publication type Peer reviewed book chapter
Publication year 2010
Abstract To assess the relation between emission of methane (CH4) and faecal and urinary losses of nitrogen (N) in dairy cattle, various dietary strategies were evaluated using a mechanistic model of fermentation and digestion processes. To simulate faecal and urinary composition, an extant dynamic, mechanistic model of rumen function and post-absorptive nutrient supply was extended with static equations that describe intestinal digestion and hindgut fermentation. The extended model predicts organic matter, carbon and N output in faeces and urine. Methane emissions were simulated using the same model including a mechanistic description of methanogenesis in the rumen and in the hindgut. Four different types of grass silage were explored at high and low N fertilization levels and early or late cutting. For each grass silage, 10 supplementation strategies that differed in level and type of supplement (no supplement, maize silage, straw, beet pulp, potatoes) and level of concentrate (20 or 40% of total diet DM) were studied. Simulated total N and CH4 excretion ranged from 211 to 588 g/d and 334 to 441 g/d, respectively, with a small, positive correlation (r2=0.15). When expressed per unit fat and protein corrected milk (FPCM), a reduced N excretion (g N/kg FPCM) was associated with increased CH4 emission (g CH4 / kg FPCM) although the coefficient of determination was small (r2=0.22). This relationship varied between different treatments. For example, reducing N fertilization level lowered N excretion per kg FPCM, but increased CH4 emission per kg FPCM, whereas supplementation with maize silage reduced both N excretion and CH4 emission per kg FPCM. The ratio of urea-N in urine to total N excretion was negatively related to emission of CH4 per kg FPCM (r2=0.54). This is of particular concern since urea in the urine, being quickly converted to ammonia, is susceptible to rapid volatilization. The present simulations indicate that measures to reduce N pollution from dairy cattle may increase CH4 emission and highlight an important area for experimental research.
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