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Global livestock production is expected to increase in future decades and expansion of the agricultural area for feed production is not desired Hence increasing livestock production per unit agricultural area is essential The bio-physical scope to increase production of livestock systems with the corresponding feed crop production feed-crop livestock systems could not be assessed generically at the start of this research In crop production however crop models based on concepts of production ecology are widely applied to assess the bio-physical scope to increase actual production The difference between the biophysical scope and actual production is referred to as the yield gap The objectives of this thesis were 1 to develop a generic framework to assess the scope to increase production in feed crop-livestock systems based on concepts of production ecology 2 to develop a generic livestock model simulating potential i e maximum theoretical and feed-limited livestock production and 3 to apply this framework and model to feed-crop livestock systems and conduct yield gap analyses Concepts of production ecology for livestock were specified in more detail Feed efficiency at herd level was a suited benchmark for livestock production only and production of animal-source food per hectare for feed-crop livestock systems Application of the framework showed that the yield gap was 79 of the potential beef production of a cow-calf system and 72 of a cow-calf-fattener system in the Charolais region of France The model LiGAPS-Beef Livestock simulator for Generic analysis of Animal Production Systems Beef cattle was developed to simulate potential and feed-limited production of beef cattle using input data about animals genotype climate and feed quality and availability The model consists of sub-models describing thermoregulation feed intake and digestion and energy and protein utilisation Model evaluation under different agro-ecological conditions indicated live weight gain was estimated fairly well 15 4 deviation from measured values LiGAPS-Beef was coupled with crop growth models to simulate potential and resource-limited production of twelve grass-based beef production systems in the Charolais region Resource-limited production combines feed-limited production of cattle and water-limited production of feed crops Yield gaps were on average 85 of potential live weight production per hectare and 47 of resource-limited production Yield gaps were attributed to feed quality and quantity limitation 41 of potential production water-limitation in feed crops 31 the combination of sub-optimal selling or slaughter weights culling rates calving dates age at first calving and stocking densities 9 and the combination of prolonged calving intervals and calf mortality 2 Improved grassland management and an earlier start of the grazing season may increase live weight production per hectare Furthermore the resource-limited production of bulls was simulated to increase by 6-14 from 1999-2006 up to 2050 due to climate change From the results of this thesis it can be concluded that 1 a generic framework using concepts of production ecology is available now to assess the bio-physical scope to increase production in feed-crop livestock systems per unit area 2 the mechanistic model LiGAPS-Beef simulates potential and feed-limited production of beef cattle fairly well 3 combining LiGAPS-Beef with crop growth models allows to quantify yield gaps in feed-crop livestock systems and to analyse these yield gaps The method described in this thesis can be used subsequently to identify options to mitigate yield gaps and to increase livestock production per unit area which may contribute to sustainable intensification of agriculture

A generic method to analyse yield gaps in feed-crop livestock systems

Ecology and biology of Rhamphicarpa fistulosa, a new parasitic weed of Rain-fed Rice (Oryza sativa) in sub-Saharan Afric...

Publication search with gewasecologie as keyword

A generic method to analyse yield gaps in feed-crop livestock systems

Ecology and biology of Rhamphicarpa fistulosa, a new parasitic weed of Rain-fed Rice (Oryza sativa) in sub-Saharan Afric...

Publication search
with gewasecologie as keyword