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Living plant and animal tissue form the food and fibre that we give our animals as food.

A simple outline of nutrition classification:
FOOD or FIBRE constituents:

1. Water
2. Dry Matter [Carbon & Minerals]
A. Organic Compounds
1. Carbohydrates
2. Lipids [Fats] & fat-like substances
3. Proteins or nitrogenous compounds
4. Higher organic compounds: Vitamins, Enzymes & Hormones.
B. Mineral Matter [Inorganic]


  • Water is probably the most important constitutent of plant and animal life -
  • Water represents 60-80% of their physical structure and gives them shape.
  • Water is a feed stuff
  • It is the main constituent of milk
  • Remember that the constant supply of good clean water should be the first concern of any dairy farmer.
When did you last test your water supply?
What nasties / goodies could be in your water?

Dry Matter


Carbohydrate contains 3 elements: [remember]

Carb Carbon
o Oxygen
hydrate* Hydrogen as the name implies

[* Derived from hydor, Greek for "water". Note the proportion of hydrogen to oxygen in carbohydrates is always 2:1 just like water H20, hence carbo-hyrate means, "watered carbon".

1. Carbohydrate is an inclusive term for

Sugars are soluble chemical units
[Types of sugars: milk sugar, fruit sugar]
Starch is insoluble in water and composed of many sugar units which are readily broken
Cellulose or fibre is an even more complex combination of sugar units, highly insoluble and very difficult to break down chemically

3/4 of an animal's food contains Carbohydrates.


Carbohydrates are the most important source of energy.
Carbohydrates are "energy," "fat"[see next section] & "milk" producing foods.

A few points to consider on energy:

  • Energy is the number one limitation to milk production [if water is plentiful].
  • The BIGGEST limitation or shortage of energy is in early lactation.
  • When the cows' feed intake lags behind milk yield, then it comes off their backs.
  • As body reserves drop this can contribute to metabolic diseases.
  • Feed heavy after calving and into mating.
  • Cows putting on weight [within reason] have better conception rates.
  • Maximise dry matter high-energy intake in early lactation.
  • A cow can literally not get enough energy in very early lactation.
  • Stem your cows up to a peak - use energy to do it.
  • Cows generally need about 10-12% crude protein.
  • During early lactation protein levels can go to 16-18 % if it contains undegradable protein [UDP].
  • Old pasture can be deficient in P x2: Deficient in protein and phosphorous.
  • Don't get SOLD on protein. Everything in its place.

Fats are the reserve carbohydrates in the animal Proteins

Proteins differ from carbohydrates & fats for they contain nitrogen
They are composed of chemical units called amino-acids
For each different protein there are specific amino acids

Have you wondered why:

  • Different foods with the same protein values may have different nutritive values.
  • A major reason is that there are essential and non-essential amino acids.
  • An animal can use some and others they cannot.
  • It is necessary to balance the correct amino acids to suit individual situations.
  • Cattle and sheep are ruminants and they require less specific amino acids than other animals due to the synthesis of protein by bacteria in the rumen. This happens when bacteria use the ingested food in the rumen to make their own bodies. The high-grade bacteria protein is digested later in the stomach and intestine.
  • Cows digest and milk well off bacteria that they themselves have bred up.
  • You are not so much feeding a cow but a multitude of bacteria [housed in the cow]!!
  • A deficiency of food protein and hence of nitrogen can be a limiting factor for growing animals on dry feed.
  • Is the protein/nitrogen that goes into a cow the same as what she digests? [bacteria change it for you].
  • This is why a little urea and other non-protein nitrogen sources can be utilised to supply part of the protein needs of ruminants.
Gilbert [1957] suggests that all proteins contain from:
  • 50 - 54 % carbon
  • about 7 % hydrogen
  • 20 - 25 % oxygen &
  • 16 -18 % nitrogen
  • <2 % sulphur [some animal proteins don't contain sulphur]
  • Phosphorous is also part of some plant proteins.

Vitamins will be considered in greater detail than normal, as this will be the only section where they will be discussed prior to their inevitable association with minerals in the next section.

Vitamin A:

  • It is easily lost from feed with time or weather damage.
    For example old hay can be low in V A, or animals grazing dry pasture for over six months get low in V A.
  • Hay or silage that has been damaged by weather [as it gets leached out??]
  • Remember: "Green Hay A ok! Grey hay needs A".
In humans excess Vitamin A can stunt bone growth. Vitamin E:
High levels of Nitrate can cause Vitamin E deficiency.
Vitamin E works with Selenium and they need each other.
Remember: VE = Se [Vitamin E = Selenium]

Vitamin D:

  • It is the sun vitamin.
  • A deficiency can occur in housed cattle.
  • Generally not a problem in its own right.
  • Remember:"Grey skies vitamin D goes into disguise"
In humans excess Vitamin D can cause hardening of the bones [hyper-calcification].

Vitamin B12:

This vitamin is essential to cattle and microorganisms in the rumen use cobalt to form the B12. Because it is produced from cobalt, if cobalt is deficient, B12 will also be deficient. Cattle store cobalt, which is used in times of seasonal deficiencies.

Can we get a rhyme for Vitamin B12?

Minerals - Minerals are the inorganic ash residues of food.

Their general Fuctions Are:
A]. To enter into the structure of the body, not only of the skeleton, but also of the softer tissues such as muscles, glands, and of the fluids such as blood. B]. To regulate many body processes such as the passage of materials into and out of cells and normal growth.

Mineral Supplements

  • As higher production levels are achieved there will be a greater need for possible supplements. This is good thinking for high production cows are getting closer to the knife edge of production versus fertility and critical and essential nutrition needs to be fully understood.
  • It could be argued that it is difficult to define the mineral requirements for cattle due to the variation in absorption efficiencies on minerals due to dietary intake, age and the physiological state of the animals.
The use of any stock lick that contains trace elements is hazardous due to the spasmodic and very uncertain consumption by grazing animals.


One of the most deficient elements in livestock production is salt.

Warning on SALT - It can KILL! - if it is feed in large amounts

The information contained in this publication has been formulated in good faith, the contents do not take into account all the factors which need to be considered before putting that information into practice. Accordingly, no person should rely on anything contained herein as a substitute for specific professional advice.
S.O.S. Rev 9.2 All rights reserved. Contact: www.healthyag.com © Gwyn Jones 2001

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