Research project CG/DD1/29 (Research action CG)
Context
During fermentation in the gut, ruminants produce methane, which reacts as a greenhouse gas after being expelled into the atmosphere. For Belgium, dairy cattle are estimated to contribute 60% of total methane production. Tackling the problem at source, through optimisation of pasture management and adapted supplementary feeding, appears advisable since the processing of methane into fuel is not widely acceptable in practice.
Objectives
During this project, we intend to quantify the methane emission of grazing ruminants. Moreover, this methane emission will be evaluated in terms of the N-fertilization rate, herbage growth stage, sward composition and supplementation rate. Finally, strategies to reduce methane emission through a better grassland management and adapted supplementation will be proposed. Indeed, the protein rich grass of current production systems causes an unbalanced protein/energy supply for the rumen microbes. Hence, maize, supplying increased energy levels compared to N, is supplemented regularly. In this way, N utilization would be optimized. Moreover, methane production can be expected to be influenced through changed N, energy and fiber content as well as through the energy supplementation system.
Methodology
Description of the experimental design:
The experiments take place during two successive grazing seasons. During the first experimental year, the effect of N fertilization rate and sward composition will be studied, utilizing two objects with ryegrass/clover and N fertilization rate of 0 and 150 kg/ha.year. During the second experimental year, N-fertilization rate on ryegrass pastures (200 and 400 kg N/ha.year) and maize silage supplementation will be taken into account. An integrated evaluation of plant yield and chemical composition, total and rumen digestibility of the ration, microbial utilization of the available N and N excretion, methane excretion and fermentation pattern will be carried out. This extended data collection is necessary for an objective evaluation of the methane excretion and finally, to propose optimal, integrated production systems: maximal plant production in relation to maximal utilization and hence minimal excretion by the animal.
Description of the methodology used:
Animals, nutrition and housing :
Fistulated sheep, housed in metabolic cages during the experimental period, are used, as ruminant model according to the advices of the Ethical Commission of the University of Ghent. The amount of daily mowed grass represents 1.5 times maintenance requirements and is fed to the animals four times a day (10 am, 4 pm, 10 pm, 4am)
Plant production :
Weekly sampling for production calculations, evaluation sward composition (first experimental year: ryegrass/clover). Daily sampling for evaluation of chemical composition.
Rumen degradability :
Weekly evaluation in sacco degradability and outflow rate (Cr hay)
Digestibility:
Apparent digestibility: collection and chemical analysis of faeces
Partners
In this project, both of partners are collaborating intensively on the completion of animal trials (grazing period: May-October). Chemical analyses and preparations for the trials (November- April) are spread among the two partners by mutual agreement.
- Department of Crop Husbandry and Ecophysiology
Agricultural Research Center - Gent
DG6 Council for Research and Development
Ministry of Small Enterprises, Traders and Agriculture
Responsible for plant production: laying and tending of trial fields, preparing maize silage, fertilisation, soil sampling (N-residue), daily mowing of the grass during the trial period, and chemical and botanical analyses of plant production
- Department of Animal Production
Faculty of Agricultural and Applied Biological Sciences - University of Gent
Responsible for monitoring animal production parameters: preparatory literature study + development of in vivo methane measurements using ethane as a tracer gas; carrying out of in vivo methane measurements; total and ‘in gut’ digestibility; monitoring of fermentation pattern and efficiency of N-utilisation.
Responsible valorisation (reports and scientific publications) and co-ordination of the project.
Expected end products and results
Via an integrated interpretation and evaluation of plant and animal production parameters and environmental criteria in terms of pasture management and supplementary feeding of practically applicable or already applied ruminant rations, this project should offer the possibility of providing an insight into the sustainability of achievable alternatives for grazing cattle. Consequently, project results may be used by government bodies to place Belgian possibilities for methane reduction within the European or world contexts. In view of the very limited amount of knowledge in this sphere today and the world-wide distribution of grazing ruminants, Belgium might set the example within the international community as regards a general reduction in methane emissions from grazing cattle.
Effet de la composition botanique et la supplémentation sur les émissions de méthane par du bétail sur pâturage: rapport final
Demeyer, Daniel - Carlier, L. Bruxelles: SSTC, 2001 (SP0734)
[To download]
[Exhausted]
Effect van wisselende grassamenstelling en bijvoedering op de methaanemissie bij grazend rundvee: samenvatting
Brussel: DWTC, 2001 (SP0745)
[To download]
Effect of sward composition and quality and supplementation on methane emission by grazing cattle: summary report
Brussels: OSTC, 2001 (SP0746)
[To download]
