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Water for livestock
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Introduction
Rainwater management is probably the most neglected and misunderstood aspect of
livestock production. An intelligent land planning and rainwater management is the key to everything.
These techniques will help farmers enlarge their flocks of
livestock to an extent which may now seem to be impossible.
Today, many thousands of hectares in Sub-Saharan Africa consist of impermeable paving, dreary detention basins, compacted soils, turf grass and landscaping that require an inordinate amount of money, energy and non-renewable resources to maintain. Where rainwater harvesting and sustainable ecosystems are the basis for the planning and design of livestock production systems, such systems and the native flora and fauna could flourish side by side.
Arid and semiarid areas are home to one-sixth of the world's population, most of
whom are poor agro-pastoralists who depend totally on renewable natural resources
for their livelihoods. The inhabitants of these regions are among the poorest people
in the world. Their poverty is partly caused by inadequate supplies of water for crop,
livestock and other enterprises. However, the shortage of water is not due to low rainfall,
as is commonly perceived, but rather by a lack of capacity for sustainable management
and use of available rainwater. The most critical management challenge is how to deal
with rainfall variability - short periods when there is too much water and long periods
of too little water. Better management of available rainwater could help to reduce the
occurrence, and mitigate the impact, of droughts during dry periods or in places with
low rainfall.
The current approach to food security considers self-sufficiency at the household level
and focuses on overcoming water limitations. Subsistence producers who lack water give
priority to minimizing risks at the expense of increasing productivity and profits. This
is a strategic survival mechanism but it denies people the opportunities of building the
capital resources required to:
Invest in new technologies;
- Participate in the market economy; and
- Protect against extremes of climatic and economic downturns.
The technologies and skills required to overcome the lack of water resources, and poor
and extremely variable rainfall, although well known, are not available and widely
used. As a consequence, water supplies for agriculture, drinking and sanitation, and the
environment are critically low. Poor access to water is among the leading factors hindering
sustainable development in semiarid and arid regions. Approaches to overcoming
this problem include technologies for enhancing the productivity of water in rainfed
production, rainwater harvesting and precision irrigation.
Techniques to improve rainwater management, such as bio-swales that allow rainwater
to seep into the ground as it flows away from parking lots, porous pavements, rain
gardens and perforated diffuser pipes to capture and slowly dissipate water, are all readily
available. However, people need to be made aware of them and educated about them.
How much water does livestock need?
Water consumption varies widely, depending upon physiological and environmental conditions, for example the type and size of the animal, whether or not it is lactating, how active it is, the type and amount of food it consumes and climatic conditions. The normal range of water consumption for adult animals has been summarized as follows:
| Livestock type | Water consumption in litres/day |
| Beef cattle | 35-60 per head |
| Dairy cattle | 30-80 per head |
| Horses | 24-36 per head |
| Swine | 15-25 per head |
| Sheep and goats | 5-20 per head |
| Chickens | 40-50 per 100 birds |
| Turkeys | 40-75 per 100 birds |
Water quality for livestock
Interpreting water analyses - Factors in water quality
As the origin of all waters is rain, most groundwater or surface water is satisfactory for livestock. Some water, however,is of poor quality resulting in poor performance and even death of animals.
- Excessive saline water, having a high concentration of dissolved salts, makes water unsatisfactory for livestock
- Nitrate content, alkalinity and other factors may also affect water quality for livestock
Salinity
Water is a very good solvent, and all natural waters contain dissolved substances. Most
of these are inorganic salts, calcium, magnesium and sodium chlorides, sulphates and
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Green water management handbook
bicarbonates. Occasionally the salts are present in such high concentrations that animals
do not thrive, become ill or even die. The various salts have slightly different effects, but
these differences are of no practical significance. Thus, while sulphates are laxative, and
may cause diarrhoea, their effect on animal seems no greater than that of chlorides,
and magnesium salts seem no more of a problem than calcium or sodium salts. Further,
the effects of the various salts seem to be additive, which means that a combination
of salts seems to have the same effect as that caused by a single salt at the same total
concentration.
Research on the effects of saline drinking water on livestock has shown that, at high (but
not toxic) salt concentrations, water consumption increases, although the animals may at
first refuse to drink for a short time when given saline water. On the other hand, at very
high salinities animals may at first refuse to drink for a few days, but then drink large
quantities in one go, leading to sudden sickness or even death. Older animals seem to be
more resistant to the harmful effects of salinity than younger animals.
Anything causing an increase in water consumption, such as lactation, high temperatures
or exertion, also increases the harmful effects of saline water. Animals seem to have the
ability to adapt to saline water quite well, but abrupt changes in salinity may be harmful,
while gradual changes are not. When they have an alternative source of water livestock
will avoid excessively saline water.
However, animals suffering the effects of saline water are known make a rapid and
complete recovery when given water with a low salt content. Plus, salt is sometimes added
to animal feed to regulate water intake. Special care to provide drinking water with a low
salt content should be taken in these instances.Nitrates
Nitrate-poisoning in cattle was first observed around 1900 and, since then, there have
been many cases. As a rule, poisoning results from eating forages with a high nitrate
content. The nitrates are not very toxic in themselves, but bacteria in the rumen reduce
the nitrates to nitrites, which then get into the bloodstream. There the nitrites convert
the red pigment, haemoglobin, which is responsible for carrying oxygen from the lungs
to the tissues, to a dark brown pigment, methaemoglobin, which will not carry oxygen.
When this conversion is about 50% complete, animals become distressed and short of
breath, and when conversion reaches 80% or more, they usually die of suffocation.
Non-ruminants may convert small amounts of ingested nitrate to nitrite in their intestines,
but the amount so converted is not harmful. Under some circumstances nitrates in the
diet may also interfere with the conversion of carotene to vitamin A, but an impressive
amount of experimental data shows this to be of no practical significance. Further, the
experimental evidence suggests that chronic nitrate poisoning does not occur in livestock,
and that the young are no more susceptible to acute nitrate poisoning than are older
animals. Nitrates are occasionally found at toxic levels in water. Nitrites are also often
present, but not at levels dangerous to livestock. As a rule, water analyses include data on
both nitrites and nitrates.
Sulphates
Experimental data on the effects of large amounts of sulphates in livestock drinking
water are limited. Both sodium and magnesium sulphates are well-known laxatives. In
humans, a sulphate content of over 250-600 ppm may have a temporary laxative effect,
while over 700 ppm may have a persistent laxative effect. Research in South Dakota
(USA) showed that water containing up to 3,000 ppm sulphates had no harmful effects
on the rate or efficiency of weight gain or on faecal consistency, in gestating or lactating
sows or on their litters up to 28 days of age. In weaning pigs, 3,000 ppm added sulphates
did cause more scouring and less firm faecal consistency than in pigs receiving water
without added sulphates, but the rate of weight gain and efficiency was essentially the
same. Sulphates in drinking water should seldom be a problem for livestock if rations
are adequately formulated. However, copper deficiency might be a problem with high
sulphate levels in drinking water.Alkalinity
Most waters are alkaline, which is fortunate since, if they were acid, they would corrode
pipes and plumbing. Only in a very few instances has water been found to be too alkaline
for livestock. Alkalinity is expressed either as pH or as titratable alkalinity in the form of
bicarbonates and carbonates. A pH of 7.0 is neutral, below that is acid, and above that
is alkaline. Most waters have pH values between 7.0 and 8.0, which means that they are
very mildly alkaline and, also, that they contain only bicarbonates and no carbonates. As
the pH goes up, the waters become more alkaline, and at values of around 10, waters are
very highly alkaline and contain carbonates. Most waters have alkalinities of less than 500
ppm, and are not harmful. Excessive alkalinity in water can cause physiological problems
and digestive upsets in livestock. The level at which alkalinity becomes a problem and
its precise effects have not been thoroughly studied. Therefore, the establishment of
guidelines for levels of alkalinity in livestock drinking waters is difficult.Waters with alkalinities of less than 1,000 ppm are considered satisfactory for all classes of livestock and poultry. Above that, they are probably unsatisfactory, although adults may not be harmed at concentrations of less than about 2,500 ppm unless the concentration of carbonates exceeds the concentration of bicarbonates.
Bacterial contamination
Bacterial contamination in livestock drinking water does not usually cause problems. Most
water consumed by livestock has some degree of contamination from being impounded
in depressions, tracks, dugouts or ponds. However, producers should be concerned if
farm water supplies become contaminated by bacteria. The source of contamination
should be determined and eliminated, particularly if humans also consume water from
the system. While there is no meaningful laboratory method to measure contamination
in water for livestock, it should obviously be avoided. A reasonable effort should always
be made to provide animals with a clean and sanitary water supply.Other factors
On rare occasions, water may contain or become contaminated with toxic elements such
as arsenic, mercury, selenium and cadmium, or with radioactive substances. While these
toxic elements may harm animals, the major concern is that an accumulation in meat,
milk or eggs is unsafe for human consumption. Water needs to be analyzed for toxic
elements if there is good reason to suspect that they are present in excessive levels.
Persistent organic pesticides contaminate most surface waters. However, the concentration
is small (because of their low solubility in water) and they are not a problem for
livestock.
Occasionally, heavy algal growths occur in stagnant or slowly flowing water bodies.
Under some circumstances, a few of these species can be toxic. As there are no tests for
these toxins at present, stagnant water should not be used for livestock.
Information Source Links
- Malesu, M.M., Oduor, A. and Odhiambo, O. J. (Eds) (2008). Green Water Management Handbook. Rainwater harvesting for agricultural production and ecological sustainability. Technical Manual No.8. World Agroforestry Centre. Nairobi, Kenya. ISBN 978 92 9059 219 8
- Teyssier, A. (2000). Establishing and managing waterpoints for village livestock. A guide for rural extension workers in the sudano-sahelian zone. Agrodok-Series No. 27. CTA. ISBN 9907246-90-2
