According to Bosma et al. (2011), transport of feed
ingredients contributed to about 20% of the total impact from the
feed production process in the toxicity categories. Contribution of
transport to the other emission categories, such as global warming,
was small. The remaining contribution of feed to the fossil
fuels category (15%) can be assigned to rice husk for the boiler
(2%), electricity use in the feed mill (8%) and additives to the feed
(5%)