Feeding and energy

what are feed stuffs

an ingredient in a diet or ration that has one or more purposes

what is apparent digestibility

extent to which a nutrient or feed component is absorbed and utilized by an organism after feeding. It is calculated by measuring the difference between the amount of a nutrient consumed and the amount excreted in feces.

what are six classes of nutrient

1. water (the aqueous medium of life)
2. protein
3. carbohydrates (structural & energy)
4. lipids
5. vitamins (indispensable components elements
6. inorganic elements of diverse cellular processes)

three factors affecting digestibility

1- gut transit time

2- fibre content

3- feed preparation factors

what is gross energy

Sample dried
• Known quantity of DM combusted (completely oxidised) in sealed chamber
• Energy released by oxidation of covalent bonds warms surrounding water

what is digestible energy

amount of energy digested

calculated from faeces lost

GE-faecal energy loss = digestible energy

what is metabolizable energy

the energy assimilated by the animal & available to fuel metabolism

GE - FL = DE

DE- other losses = ME

6 factors effecting metabolisable energy

1) digestibility

2) diet quality

3) species

4) nitrogen balance

5) food prep

6) feeding levels

what is net energy

all of the dietary energy available to the animal when the costs of digestion, metabolism & wastage have been accounted for

Thermic energy loss must be subtracted from the
ME to give the Net Energy (NE) of foods

how do you calculate DM from FW

fresh weight (Kg) X dry matter proportion

how do you calculate FW from DM

dry matter weight (Kg) / dry matter proportion