Water in Livestock – Biological Role and Global Perspective on Water Demand and Supply Chains

Abstract

This chapter describes issues related to the use of water in agriculture, especially in livestock production, which is the major water consumer in the world. Water is found in every cell of the body, as well as in the intercellular spaces. There is a difference between biological (bulk) water and cellular (nonbulk) water. Biological water is any water surrounding biomolecule that has distinct properties compared to those in the water mass. Cellular water is an ordered molecular structure that is surrounded by the molecules mediating its transfer inside the cells. The amount of water in the individual body depends on the species, gender, age, and body structure. At cellular level, water mediates and modulates intermolecular forces, controls the rate of substrate diffusion and conformational changes. In animal physiology, water influences all bodily functions, such as thermoregulation, fluid balance, and salt concentration. The level of water consumption in livestock varies between animal species. As much as 99% of the water footprint in animal production comes from feed that animals consume, rather than water that they drink. Therefore, water productivity in livestock farming depends to a large extent on selection of the diets and fodder production. There is a vast difference between use of water by different species to produce the same amount of meat or other products (e.g., eggs or milk). Among meat products, beef has the largest water footprint compared to meat obtained from other farm animals. It is related to the high feed efficiency of the beef cattle. Monogastric animals (e.g., pigs and poultry) farmed in intensive, industrial conditions, have lower total water footprint. Since agriculture is the most water-consuming branch of the human activity, the global supply chains are also taken into account when considering food security. The agriculture might be supplied with water in two ways: rainfed or irrigated. Over the last 50 years the global irrigated area has doubled. Irrigated water competes with water intended for human consumption, as well as producing crops and pulses for human feed. Water is the primary medium which will be affected by the climate change. To conserve the limited resource of freshwater, the agriculture and livestock farming in particular, should be taken into scrutiny.