Feed intake Flashcards
What factors affect digestibility of food?
Food composition
Diet/ration composition
Preparation - rolling, alkali, heating etc
Enzyme supplementation
Animal factors
Describe the animal factors that affect digestibility
Individual variation
Species variation:
- forages have higher digestibility for ruminants
- sheep digest grain better than cattle
- cattle digest low quality forage better than sheep
How does food ration affect digestibility?
More food eaten => faster passage time => less time for digestive action of enzymes => lower apparent digestibility
What effects grass digestibility?
Grass digestibility decreases as grass grows due to more structural carbs and less storage carbs
Describe the impact of lignin on digestibility
High in wood, straw and hay
High resistance to chemical degradation
Will reduce digestibility of closely associated structural polysacchrarides e.g., cellulose
Describe the fibre fractions of crude fibre
NDF - neutral detergent fibre
ADF - acid detergent fibre
MADF - modified acid detergent fibre
NDF:
- soluble in neutral detergent
- Cell contents: lipids, sugars, starch etc
ADF:
- insoluble in neutral detergent
- soluble in acid detergent
- cell wall constituents: hemicellulose
Cell wall constituents insoluble in neutral and acid detergents - cellulose, lignin, silica
what factors control food intake?
Physical factors:
- stomach, crop, rumen size
Chemical factors:
- glucose, CKK (non-ruminants
- VFAs (ruminants)
Hormonal control:
- leptin and ghrelin
Physiological factors:
- energy density
Sensory appraisal
Palatability
Deficiencies
Illness
Heat (hot eat less)
Obesity
Availability
Why do we need to predict/estimate food intake?
Diet formulation
Feed availability
Feed budgeting
Reducing feed wastage
Determining stock densities
Conservation management
How can you optimise voluntary food intake?
Clean troughs, enough trough space
Provide food at all times
Clean potable water
Good quality feed
Mixed forages
Short chop length
Increase palatability
