Agricultural Economy

Determination of animal husbandry and pasture production

The production of animal products (from LEITAP) forms the basis of further simulations on animal husbandry, resulting in number of animals and the desired pasture production.

The intensification of livestock production systems influences the composition of the animal feed required by livestock production systems. In general, intensification is accompanied by decreasing dependence on open range feeding and increasing use of concentrate feeds, mainly feed grains, to supplement other fodder. At the same time, improved and balanced feeding practices and improved breeds in ruminant systems enable more of the feed to go to meat and milk production than to maintenance of the animals. IMAGE simulates the production of livestock products, the animal stocks, productivity per animal, feed conversion and the use of different feedstuffs.

IMAGE 2.4 distinguishes the following categories of animal feed:

• Seven food crops (i.e. the six basic products and oilcrops)
• Grass
• Crop residues and fodder crops
• Livestock products (mainly milk)  
• Scavenging (road-side grazing, wastes, etc.)    

The demand for animal feed is computed on the basis of the production of meat and milk. For cattle, the total feed demand is calculated on the basis of the energy requirements for maintenance, obtaining feed, growth, lactation, animal traction and calving. Feed requirements for dairy and non-dairy cattle increase along with increasing animal productivity. For the other animals the total feed requirement is calculated from feed efficiencies (i.e., the amount of feed required to produce 1 kg product).

The composition of the feed depends on the animal category considered and the production system. Grazing animals such as cattle, goats and sheep depend mainly on pasture and fodder species, while pigs and poultry rely primarily on crops. For the historical period, the composition of the feed was calibrated against data from the literature for various regions.

Future shifts in feed composition are taken from the IMAGE implementation of the FAO projection up to 2030 (Bruinsma, 2003), as described in Bouwman et al. (2005). The grazing intensity is assumed to change additionally on the basis of LEITAP results for intensification or extensification (see above).

• to  Land Allocation – production systems   

Agricultural economy links:

• to  Demand for wood products
• to  external references
• to  MNP references