Cymraeg

Feeds and Feeding
Session 2 - Components of Feed

This resource is suitable to support Level 2 Agriculture courses.

Introduction

Feeds are made up of six main components:

graphic of 6 main components - minerals, vitamins, protein, carbohydrates, fats and oils

Water Content of Feeds

The water content of common feeds can range from 10% - 90%.

graphic of water content showing 10% - 90%

Water Content in a Range of Feeds

Table with title ‘Water (H2O) The water content of common feeds can range from 10% - 90%’. Table has 3 rows: ‘Feed’, ‘Dry Matter %’, and ‘Water %’. Columns below are as follows: ‘Turnips, 10.5, 89.5’; ‘Barley, 86.0, 14.0’; ‘Brewers Grains, 23.0, 77.0’; ‘Soya Bean Meal (Hipro), 90.0, 10.0’; ‘Fresh Grass, 20.0, 80.0’; ‘Silage - Clamp, 25.0, 75.0’; ‘Silage - Big Bale, 35.0, 65.0’; and ‘Hay, 85.0, 15.0’.

Water Requirement of Farm Animals

Water is needed by the body for all chemical reactions to take place so it is essential that livestock have a good supply of water. The requirement for drinking water will increase if:

  • Animals are fed on rations with high levels of dry matter.
  • The conditions are hot.
  • Livestock are lactating (producing milk).
    • image of skull in the dirt

    Carbohydrates

    These are made of carbon, oxygen and hydrogen.

  • Carbohydrates are a source of energy for animals; they are the main source of energy in most ruminant rations.
  • The smallest units of carbohydrates are single sugars (monosaccharides) such as glucose. For carbohydrates to be absorbed in the gut they need to be broken down from complex sugars to simple sugars.
    • image of cows eating

    Types of Carbohydrates : Simple Sugars

  • E.g. glucose and dextrose.

    • Characteristics

  • Taste sweet.
  • Soluble in water.
  • Rapid uptake because they are very small molecules.
    • graphic of chemical buildup of Glucose

    Types of Carbohydrates : Starch


    Characteristics

  • Made of long chains of sugar units.
  • Not sweet to taste.
  • Does not dissolve in water.
  • Found in feeds such as wheat and barley (in the endosperm).
  • Ferments in rumen, needs to be broken down before it can be absorbed by the animal.
    • graphic of chemical buildup of Starch

    Types of Carbohydrates : Fibre


    Characteristics

  • Made of long chains of sugar which are bonded together so they are difficult to break down.
  • Does not dissolve in water.
  • Broken down by the ruminant digestive system, but not by single stomached animals.
  • High levels found in feed such as straw.
    • graphic of chemical buildup of Fibre

    Protein

    Proteins contain carbon, oxygen, hydrogen and nitrogen.

  • Proteins are made of units called amino acids. There are twenty five amino acids that make up proteins and all contain nitrogen.
    • graphic of chemical buildup of Amino Acids

    Types of Protein in Farm Animal Feeds

    There are two main types of amino acids:

  • Essential amino acids have to be included in an animal’s diet. Single stomached animals such as pigs need amino acids such as lysine, methionine and tryptophan in their diets.
  • Non essential amino acids can be produced by the animal from other amino acids in the feed; they do not have to be provided in the diet.
    • image of piglets suckling

    Why Do Animals Need Protein?

    Protein is needed for muscle growth, tissue repair, milk production, metabolic activity, enzyme production, reproduction and the production of blood.

  • Feeds such as soya are high in plant proteins and are added to diets to increase the protein level.
    • image of piglets suckling

    Non-Protein Nitrogen

    Ruminants are able to use nitrogen in their diets even if it is not fed to them in the form of protein, this is known as non-protein nitrogen (NPN).

  • Urea is an example of non-protein nitrogen that may be found in ruminant feeds.
    • Chemical buildup of Urea

    Feeding Protein to Livestock

    When feeding pigs it is important to have the correct amount of essential amino acids in the feeds.

  • Feed labels will indicate the levels of certain important amino acids such as lysine and tryptophan. If the diet is short of particular (limiting) amino acids the pigs will not grow well even if the diet contains enough protein in total.
  • The amount of protein in the dry matter may be shown in two ways: Grams of protein per kilogram of dry matter g/kg, or as a percentage.
    • image of pigs feeding

    Microbes

    Microbes in the ruminant digestive system can break down protein: they can also form protein if there is enough nitrogen and energy available in the rumen.

    graphic of microbes

    Types of Protein

    There are several measures related to protein:

  • Crude protein – an estimate the amount of protein in the feed if all of the nitrogen was in protein molecules.
  • Non protein nitrogen – the amount of nitrogen in chemicals other than protein (ruminants may be able to use this instead of protein, so chemicals such as urea may be used as a source of nitrogen in feed blocks).
  • Rumen degradable protein (RDP) – can be broken down and used by the rumen microbes. If high levels are fed, it may be wasted.
  • Protected proteins – these are not broken down in the rumen but can be digested further along the digestive system. They may be included in rations for high yielding animals.
    • Graphic with text of the types of proteins

    Fats and Oils (Lipids)

    Lipid is the term that describes both fats and oils. These are made of carbon, oxygen and hydrogen. Fats and oils are not water soluble.

  • Some rations for highly productive stock such as dairy cows may include ‘protected’ fats as a source of energy which can be digested in the small intestine.
    • Image of cows

    Why Do Animals Need Fats and Lipids?

    Lipids are a source of energy for animals; weight for weight they contain about twice as much energy as carbohydrates.

  • However, only a limited amount can be included in livestock rations without causing digestive upsets.
  • Fats are solid at room temperature.
  • Oils are liquid at room temperature.
    • graphic of lacteal

    Lipids

    Many lipids are made up of two types of chemical; fatty acids and glycerol.

  • For fats to be absorbed by the animal the links between the fatty acids and the glycerol must be broken by enzymes.
    • Graphic of text showing 3 fatty acid coming off glycerol
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