NEWS
realistic and justifiable assumptions, it
was calculated that the water require-
ment for red meat production was 18L
to 540 L/kg, and 80L to 320 L/kg. The
significant variation is due to differenc-
es in production systems and manage-
ment efficiency. The water requirement
for the production of total milk solids in
whole milk, and in skim milk powder, is
respectively 14.4 L/kg and 15.8 L/kg.
In extensive conditions (such as those
found in Sub-Saharan Africa) the water
need of the animal itself is a major con-
tributor to the total requirement, which
amounts to about 4 L per kg feed dry
matter intake, with a 50% increase in hot
weather.
The argument is sometimes advanced
that the water used in livestock pro-
duction should rather be channelled to
crop and vegetable production which
requires less water, but this is not true
for areas where crop and vegetable
production is not viable. In South Af-
rica, agriculture takes up 74.5% of the
rainfall. From this, 60% is utilised by the
natural vegetation, 12% by dryland crop
production and 2.5% by irrigation.
However, natural vegetation (range-
lands) and dryland crop production
uses only ‘green’ water, which is rain
water stored in the soil after precipita-
tion. It is called ‘green’ water because
only green plants growing in the soil uti-
lise this water. It cannot be used by, or
for, anything else. In extensive grazing
systems the natural vegetation, which is
the food source of livestock, uses only
‘green’ water.
This water cannot be used for crop pro-
duction. It is often in areas unsuitable
for crop production because of inad-
equate rainfall and/or the poor quality
of soils. The quantity of water used for
livestock production (e.g. kgs meat) in
the extensive rangeland areas is there-
fore irrelevant in the calculation of wa-
ter consumption for beef production.
Natural rangelands not utilised by live-
stock or game would result in water be-
ing wasted.
In terms of food production, it means
that green water can only be used for
the production of meat or other animal
produce under extensive grazing sys-
tems on natural rangelands, as is the
case in South Africa. These systems are
critical for the provision of food security
in such areas, which dominate almost
all less-developed countries. Natural
rangelands in these areas do not use
‘blue’ water (runoff water to streams,
dams etc.) or water stored in under-
ground aquifers.
This is completely different from the
Grassroots
Vol 19
No 1
intensive systems of Europe and North
America. Since only the rain that infil-
trated the soil is used, there is no water
cost for the production of the range-
land. Nothing needs to be done to
capture or extract this water other than
applying good rangeland management
to ensure a dense basal vegetation cov-
er, thus avoiding excessive runoff that
would lead to damaging floods, erosion
and silting up of dams.
A balance between food and nutri-
tion needs
In addition to the formulation of strat-
egies aimed at greener food environ-
ments, health considerations (such as
nutrient-density), in addition to carbon
footprint calculations, should be consid-
ered. Choosing nutrient-rich foods and
reducing the intake of nutrient-poor, en-
ergy dense foods is one way of reducing
the amount of food (and resources) re-
quired to meet nutritional needs.
Food systems should produce more
nutritious food, not just more food,
and guarantee an adequate supply of
animal source foods. Any reduction
in the consumption of meat and dairy
products may compromise the dietary
intakes of those nutrients that meat and
dairy products supply in relatively large
proportions.
The risk is greatest where those nutri-
ents are already in short supply or where
there is evidence of low nutrient status.
For children in South Africa this includes
energy, protein, vitamin A, vitamin C,
thiamine, riboflavin, niacin, vitamin B6,
folate, Vitamin B12, iron, zinc and cal-
cium.
The lower bio-availability and quality of
these nutrients from plant-based sourc-
es should also be taken into consid-
eration when comparing different food
sources. In terms of protein produced
per unit of water, animal products are
more efficient than fruit and other food
crops such as grains and vegetables. It
is therefore important not to overlook
the importance of animal products in
providing bio-available mineral nutri-
ents.
Differences in production systems be-
tween countries and regions can af-
fect the carbon and water footprint of
livestock products. Current methods
to estimate these footprints are largely
based on generic values from northern
hemisphere countries, that do not make
provision for different production sys-
tems. – Prof Michiel Scholtz, ARC.
For more information, contact Prof
Michiel Scholtz at [email protected].
za.
March 2019
34