ANN 111: Principles of Animal Nutrition and Feed Technology (2+1)

PHYSICAL TREATMENT

Soaking:

• Chopped straw is soaked in water overnight. Softens the straw leading to increased intake.
• Disadvantage is mould growth.

Chaffing:

• Decreasing particle size. Increases surface area for action of rumen microbes and hence increase digestibility.

Grinding:

• Particle size is reduced still further. (0.1 to 0.3 cm ).
• Disadvantage is that it increases rumen flow rate, decreases retention time in the rumen leading to decreased production of acetate causing a condition of low milk fat syndrome.
• Steam pressure – Straw treated with Steam at pressure of 21.1 kg/cm² for 10 to 30 seconds. Causes rupture of ligno celluosic bonds to a certain extent and makes cellulose available for microbial action.

Explosion:

• Chopped or ground straw is treated with steam at pressure of 22.5 kg/cm² for two minutes and pressure is suddenly released.
• Causes rupture of ligno celluosic bonds to a certain extent and makes cellulose available for microbial action.

Irradiation:

• Straw is treated with γ irradiation.
• Causes rupture of ligno celluosic bonds and makes cellulose available for microbial action.

Pelleting:

• Particle size is reduced to 0.1 to 0.3 cm and pelleted through 1-2 cm die.
• Retention time in the rumen increases and the disadvantage of only grinding is overcome.