Download Importance of phosphate supplementation in farm animals

Importance of Phosphorous Supplementation in farm animals
Phosphorous is the essential element involved in energy and nutrient metabolism. The
deficiency of this mineral negatively affects animal performance, fertility and bone
mineralization in all farm animals (Swiatkiewicz et al., 2008).
Introduction
The importance of phosphorous (P) supplementation for optimal animal health and
production cannot be over emphasized. Most pastures and ingredients used in animal
nutrition cannot supply the grazing and housed animal with enough P to sustain a high level
of performance in terms of reproductive rate, milk production and growth.
The supplementation of phosphorous is a costly practice, but the repercussions of not
supplying P in situations where animals have either an acute or even a sub- clinical P
deficiency, could be even more costly.
The importance of Phosphorous
Phosphorous is the second most abundant element in the animal’s body and plays a major
metabolic role – it has more known physiological functions in the animal body than any
other element. Eighty percent of the phosphorous in the animal’s body is found in the
skeleton where it acts as a reservoir for phosphorous. By far the greatest proportion of P is
devoted to maintaining and supporting the skeleton.
Phosphorous, together with other minerals, also plays a major role in maintaining the
osmotic pressure, buffer capacity and acid-base balance in the animal body.
Phosphorous further plays a vital part in energy utilization and transfer. Phosphorous
compounds are both directly and indirectly involved in all major physiological functions
and are also a component of a large number of co-enzymes and the structure of nucleic acids
(DNA).
Lastly, phosphorous also plays an important role in appetite control, efficiency of feed
utilization and the fertility of all farm animals.
Phosphorous deficiency
A phosphorous deficiency will develop in farm animals without an adequate supply of P, or
if the P is supplied in a form which the animal cannot utilize (use of P sources with a low
“digestible” or “available” P content). The consequences of a P deficiency vary between the
different types of farm animal, but in all cases affect the physical well being of the animals,
as well as their economic performance.
Some of the deficiency symptoms include:
Sows – fertility is reduced and the sows can develop posterior paralysis (Downer Syndrome)
and osteomalacia.
Fattening pigs – Growth rate and feed efficiency is reduced. Pigs also develop rickets,
which can lead to piglet mortalities, while bone breakages during transport and processing
affects meat quality and results in economic losses.
Ruminants – Reduction in feed intake and lower feed utilization. Reduced fertility, irregular
or suppressed ovulation and lower conception rates. Other symptoms may include reduced
milk production, lameness, stiffness of gait and in severe instances, enlarged and deformed
joints and bones.
Phosphorous requirements
The production phase of the animal will influence its requirement for phosphorous. Animals
need a basic amount of P for maintenance and this will increase as the size of the animal
increases. Growing animals have an additional demand for P and the amount they need is
directly related to the rate of weight gain. Pregnancy also increases the demand for P,
especially for the development of the fetus and placenta. Lactation imposes a heavy
demand for P because of the relatively high content of P in milk (e.g. 0,95 - 1 g P/ liter of
cow’s milk). Table 1 shows the P requirements of pigs, cattle and dairy.
Table 1
Piglets
P requirements for pigs and ruminants
P requirements for pigs
Digestible P in the
feed
(% as fed)
0.4
P Requirement for Ruminants
Daily P
requirement (g)
Dairy cow, 600 kg,
35kg milk /day
Beef stock 400 kg
1.4 kg gain/day
84.6
Fattening pigs
36.0
0.3
 < 50 kg
0.24
 50-100 kg
Sows:
0.32
 Lactating
0.25
 Pregnant
Sources: 1) CEFIC
2) WCF Bulletin, April 1986; Mineral Nutrition of Ruminants, F Meschy
Supplementation of Phosphorous
Phosphorous can be supplied to animals by sources from plant and animal origin as well as
inorganic sources. The phosphorous content of plant materials typically used in animal
nutrition ranges from 0.09 % to 1.09 % (CEFIC). Most of the phosphorous in plants are in
phytate form and is approximately 60 % available to ruminants and 10 to 39 % available to
pigs (CEFIC).
Animal sources providing P includes meat, fish and bone meals. The available P from these
sources varies between 59 and 74 %, depending on the source and production process. The
Animal Feed Act currently bans the feeding of meat and bone meal to any ruminant.
As a result of the problems with P sources of plant and animal origin, it became common
practice to use inorganic feed phosphates to supply animals with P. When using inorganic
feed phosphate, one must be aware that not all inorganic P sources are the same in terms of
quality. It is therefore vital to have a sound knowledge of the differences between the
sources in order to make a well informed choice.
Differences between inorganic sources
Chemical Composition – Use a product of which the chemical composition is not only
according to the correct specification, but is also consistent and can be guaranteed by the
manufacturer.
Physical appearance – Products should be dust and lump free, free flowing and easy to
handle.
Undesirable elements – De-fluorinated phosphoric acid should be used in the
manufacturing processes to ensure a low content of fluorine and cadmium, as well as other
undesirable element.
Bioavailability - describes to what extent an animal can utilise a given nutrient. Knowing
the bioavailability of a P source is important, as this makes it possible to optimise feed
formulation according to the animal’s requirements for digestible P, instead of formulating
for total P.
Conclusion
Phosphorous is one of the most important minerals in animal nutrition. A deficiency of this
mineral will negatively affect the health as well as economic performance of an animal.
Inorganic sources are widely used to supplement P, but one must be aware of the differences
between these sources.
The improvement in animal performance concerning general health, growth rate, milk yield,
weaning weight and rate of reproduction, will outweigh the cost of supplying a high quality
phosphate.