Analysis: water intake of young Afrikaner and Nauni bulls

A study by Georgette Pyoos, junior researcher, and Prof Michiel Scholtz, specialist researcher in animal breeding and genetics, both at the Agricultural Research Council's Animal Production Institute, counters the popular argument that the water intake of beef cattle is so high that it is harmful to the environment.

With the media often reporting alarming figures on the water use of farm animals, without putting the methods and context of the calculations into perspective, many consumers have the perception that meat consumption is harmful to the environment. However, it is important to consider the wider context of animal production under extensive conditions.

Figures quoted about the water footprint of farm animals are unrealistic. For example, it is claimed that the volume of water used meat. The problem with these figures is that they are based on incorrect assumptions. The example below demonstrates this.

If 10mm of rain falls on 1ha, this will total 100kł (kilolitres). If 10mm of rain falls on a 3000ha farm, the total will be 300 000kt. If the average rainfall is 450mm/year, the total amount of water that will fall on the farm is 135 million kilolitres.

If its carrying capacity is 6ha/LSU, the farm can support 500 LSUs. This equates to 270 000kl of water per livestock unit per year. (An LSU is the equivalent of a 450kg ox that gains 500g/day.)

These are the type of calculations that are made to support the claim that 15 500l of water are used to produce 1kg of meat. The reality is that cattle use only a fraction of this water, and this brings us to the concepts of ‘green’ and ‘blue’ water. Green water is that which is absorbed by the soil and used by plants to grow; it cannot be used for anything else.