Extruded Protein concentrates in the nutrition of high
producing Dairy Cows
Distinctive features of digestion in ruminants
>>>FRANCAIS
Dairy cows, as well as sheep, goat or buffalo, are ruminant animals.
This means that ruminants are herbivores that chew their feeds during
their meal, but also between their meals. After being swallowed, feeds
come anew in their mouth (regurgitation process), where they are mixed
with and finely ground to small pieces. This process of rumination is
one of the characteristics adaptation which allows the ruminants to extract
their energetic needs from vegetal cell walls, i .e. dietary fiber.
Ruminants’ stomach is constituted of 4 reservoirs : paunch (or rumen),
reticulum, omasum and abomasum. In dairy cows, the rumen is a big reservoir
containing about 250 liters where the feeds are fermented by bacterias
and protozoa without oxygen . The environment in the rumen is an ideal
one (temperature, water content) with the supply of big quantities of
plants for the growth and the multiplication of those microbs.
The lack of oxygen of the rumen content favor the development of some
types of baterias able to digest vegetal fibre. They ferment the complex
sugars of cell walls to obtain their energy needs and produce volatile
fatty acids (VFA), a waste of no use for them, but the main energy source
for the ruminant cells.
In monogastrics, the nitrogen must come from amino-acids enclosed in
the proteins of the diet. Ruminants can also take advantage of the proteins
of their diet, but can digest the proteins of microbs after their death
in the abomasum and small intestine, many of them being elaborated from
non proteic sources (urea, non proteic nitrogen) by the micro-organisms.
Those microbial proteins are the main source of amino-acids in the ruminant
diet.
Some feed proteins are non soluble protein, after heat, formalin or tannins
application. Those insoluble protein cannot be degraded by rumen microorganisms
and " by-pass " the rumen to be digested in the small intsetine.
Fatty acids of oils and fats included in the feeds undergo important
modifications in the rumen, in particular the poly-unsaturated fatty acids
(PUFA) , some of them being undesirable, some of them on the contrary
being highly interesting for the consumers of milk products.
To sum up :
Ruminants have the ability to digest more feed ingredients than monogastric
animals. The micro-organisms in their rumen allow them to transform fiber
of grass, silage, forrages, crop residues and industrial by-products ,
as well as non protein nitrogen (ammonia, urea). The end products of this
transformations are volatile fatty acids and the micro-organims themselves
utilised by the ruminants for traction, field works and food production.
The milk of dairy cows (ewes, goats.. ) is used to manufacture highly
desirable products for humans, as such or as a raw material te produce
" cream, butter and a wide variety of cheeses.
Fiber is essential to the good health of dairy cows, necessary to the
rumination and saliva secretion, both indispensable to keep the rumen
in good working order.
Cows can also ingest concentrates, generally high in energy contzent.
However, addition of big quantities of concentrates in the diet must be
adjusted progressively in order for the micro-organisms to adapt to the
new diet.
Feces of dairy cows are very good fertilisers, rich in organic matters
(undigested micro-organisms) and in minerals (calcium, phosphorus, potasium)
.
Where do the milk components come from ?
The udder is not a straightforward filter that would let pass through
water and some nutrients of the blood to the milk. The udder is a true
glandular tissue, made up by the cells of the acinis. Theese cells draw
water and nutrients from the blood, modify some of them to synthetise
specific milk molecules (casein, lactose, fatty acids, enzymes, etc…)
and store them in the apex (the portion of the cells that is located at
the opposite site of its base close to blood and lymph capillaries). The
apex of the cells litterally melt inside the milk ducts and the secretion
produced is stored inside the ducts beetween two milking operations.
Therefore, milk is a complex mix of different substances : it is at the
same time a true solution (moles of lactose, urea, sodium, potassium,
calcium, chlorides, phosphates, soluble protein, enzymes), a colloid solution
( casein and various protein micelles), an emulsion of fats, and also
a suspension of microbes and macrophages.
The main organic elements of milk are synthetised in the cells of the
udder which is a true gland pouring out its secretion towards the outside
of the organism (exocrine gland), as do for instance digestive glands.
Milk proteins are manufactured from amino-acids of the blood. 90% are
synthetised in the udder, apart from lactoglobulins that are blood proteins
modified in the udder. 10% of milk protein originate from the blood (lactalbumines,
immunoglobulins).
Milk fat synthesis is very complex. Some fatty acids are synthetised
de novo in the udder. Short and medium chain fatty acids, which amount
up to 50% of total fatty acids in the milk, are synthetised de novo in
the udder out of acetate and beta-hydroxybutyrate produced by micro-organism
fermentation in the rumen. Some other are brought by blood and reconditionned
as triglycerides specific to the milk.
Long chain fatty acids are extracted from the lipoproteins of the blood,
essentially coming from the cow’s diet. They generally are less saturated
than the fatty acids of blood lipoproteins. In the udder, a desaturase
enzyme change stearic acid on to cis-oleic acid The same enzyme can also
desaturate C14 and C16 saturated fatty acids, as well as oleic acid (C18.1),
giving C18cis9-trans11 Conjugated Linoleic Acids (CLA).
It seems that there is a balance beetween the different groups of fatty
acids in the milk fat, so that the melting temperature of the milk fat
be under the cow’s body temperature (39°C).
Most of the 400 (+) differents fatty acids identified in the milk fat
are produced by the microbes’ metabolism in the rumen. The kind of
feeds and physico-chemical conditions in the rumen can modify the nature
of fatty acids produced, their amount , their potential influence on milk
fat synthesis ant their possible biological effects.
In practice, the amoount of the differents componants of milk can vary
according to the breed of the animals, the period of lactation, the season,
the diet, the daily quantity produced, that is per liter :
from 30 to 48 grams of fat;
from 47 to 54 grams of lactose;
from 27 to 33 gramqs of caséin;
from 4 to 6 grams of albumin.
Those caracteristics are closely related to the genetic potential of
the animals.
Feeding high producing cows
In the wild and in traditionnal agriculture, grass and forrages are sufficient
for the cow to produce enough meal to feed his calf, from vegetals which
are of no use for other monogastric animals. But man has domesticated
wild animals non only to dispose of their meat, but also for their milk.
Very soon, in the palafittes (small villages built over the lake surface,
men learned how to produce differents products to preserve and store milk
for longer periods (fermented milk, yoghourts, cream, butter, cheese).
Theese products were very searched for by our ancestors, because of their
feeding value and their palatability.
Through selection, the individual cows started to produce more and more
milk. To feed those cows, it was necessary to use concentrates. Protein
nutrition was particularly difficult to achieve and led to utilisation
of animal proteins (fish meal, meat meal) in ruminant feeding by the late
1880s.
Feeding concentrates to milking cows is aiming to a triple goal :
Allow to the rumen microorganisms the possibility to produce, as much
as possible, volatile fatty acids and aminoacids, that is favour growth
and multiplication of cellulolytic bacterias and protozoa, supplying enough
soluble nitrogen (soluble proteins, NPN, urea, ammonia) and energy (starh,
sugars) to digest fibrous feeds ;
Supply the small intestine with digestible proteins that bring amino-acids
to produce enough milk protein for the high productions hoped for. In
practice, this can be achieved only by through high quality " by-pass
" proteins, which cannot be fermented by rumen microorganisms
Alter the characteristics of some milk components to cope with the demands
of the milk industry to manufacture better milk products asked for by
consumers (protein %, casein %, fatty acids profile, poly-unsaturated
fatty acids, etc). This is more and more important both from a nutritionnal
side (omega-3, CLA) and to achieve some specifications (soft butter to
be spread just after being taken from the fridge, raw milk cheese, etc).
Modifications achieved in the extruder to manufacture concentrates and
feeds for milk production
Extruder operation achieves on some raw vegetal ingredients which, either
single or combined, gives a wide variety of finished feeds for ruminants.
Starch gelitinisation
Temperature, steam and pressure drop at the oulet of the extruder induce
the explosion of the starch granules. Extrusion of cereals, peas, field
beans improve the digestibility of their glucids. Steam preconditionning
increase the outpout and decrease the energy needed to achieve a good
gelatinisation.
Destruction of the cell walls
Improve digestibility of energy and amino-acids through a better penetration
of digestive enzymes in the extruded ingredients . The very short time
to which the raw material is subjected inside the barrel of the extruder
does not lead to any browning action on the proteins (High Temperature-Short
Time treatment).
3) Protein insolubilisation
Very interesting for dairy cows. Extrusion produce insoluble by-pass
protein from soluble ative protein of proteaginous ingrédients
an oilseeds (soja, rapeseed, cotton meal, etc)
Inactivation of thermolabiles anti nutritionnal factors
Antitryptic fators and urease in soya beans, faba beans and field peas.
Enzymes in the ingredients : myrosinase in rapeseeds that transform glucosinolates
into nitrile, peroxydases that oxyde the oils and fats during storage,
gossipol in cottonseedmeal.
Aflatosins in peanut meals and moded ingredients.
5) Ingredients stérilisation
High temperatures an high pressures inside the barrel of the extruder
lead to thedestruction of microbs, mold spores and eggs of the insects.
6) Shaping
Give the possibility to increase levels of fat in the finished feed (up
to 20-25<%)
7) Texturisation
Single screw Inotec Extruders to manufacture extruded feeds and concentrates
for high producing dairy cows
In the aftermath of the ban of animal by-products put by European Union
in the formulation of the animal feeds following the mad cow disease (BSE)
epidemic and the possible transmission of BSE agent to humans through
meat consumption, vegetal heat treated protein have proved to be a useful
material in most high energy dairy cattle feeds.
Fat and by-pass protein mix (RUMIPRO*)
Rapeseed and field beans are two crops which suit european climatic conditions
and are grown successfully by aour farmers. They make an excellent alternative
crop to cereals and reduce european dependance on imported proteins.
Nutritional problems associated with the feeding of both rapeseed and
beans to animals are the glusosinolate content of rapeseed and trysin
inhibitor in raw beans. Both antinutritional factors are alleviated through
the extrusion process and 5 to 10% of RUMIPRO* can be incorporated in
both dairy and beef feeds without any problems. Protein content of the
milk will go up balancing the fat content which will fall down (1or 2
points less). Omega-3 and Conjugated Linoleic Acids will be up in milk,
cream butter and cheese made out of the milk.
Rumipro composition
Mixture of 50% rape seed and 50% field beans extruded
Crude protein 23,00
Oil 22,00
Crude fiber 8 ,00
Starch 19,00
Calcium 0,27
Phosphorus 0,60
Ash 5,00
Moisture 8,50
M.E. Ruminants 16,30 M.J./kg
Urea, insoluble protein and fat extruded cake (PROTEX ou EXTRUPRO)
Formulated to balance corn silage based diets, mixed and extruded
Extruded concentate to manufacture cakes for starting lactation in HPDC
(DEBUCAKE)
Bringing nergy (fat) and amino-acids to the gut (by-pass amino-acids)
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