Nutrition Test 2

What does the PDIN value indicate? [MC]

Truly digestible protein when nitrogen is limiting

What does the acronym RED refer to in the feeding system? [MC]

Required Energy Density

How does the addition of concentrates affect the voluntary intake of forage in ruminants? [OPEN]

Reduces voluntary intake of forage in ruminant by decreasing rumen fill (due to faster digestion) and increasing energy density, which leads to earlier ‘fullness’ and lower forage consumption

Which unit is used to express net energy for meat production? [MC]

UFV

What does ‘KAL’ represent in the IRNA system? [MC]

Efficiency of metabolizable energy (ME) utilization for lactation

What does the acronym PDIM stand for? [MC]

Microbial Protein Digestible in the Intestine

What is the main goal of using the Fill Unit system in ruminant nutrition? [MC]

To balance forage and concentrate intake

What does the term ‘fill unit’ represent in the context of forage intake? [OPEN]

Measure of a forage’s physical bulk or fibre content that limits voluntary dry matter intake by occupying space in the rumen

What factors influence the voluntary dry matter intake (VDMI) of a ruminant? [OPEN]

Influenced by:

• feed’s physical fill (how filling it is)

• Energy density (UFL)

• Animal size

• Production level

• Physiological status

If PDIN = 274 and PDIE = 373, what is the limiting factor? [MC]

Nitrogen (bc PDIN is lower than PDIE)

How many kcal NEL are equivalent to 1 UFL? [MC]

1700 kcal NEL

The actual PDI value of a diet is: [MC]

The lower of PDIN or PDIE

Which of the following is used to characterize the energy available for microbial protein synthesis? [MC]

PDIME

Which fraction of dietary protein escapes rumen degradation but is digestible in the intestine? [MC]

PDIA

What is the reference feedstuff for calculating feed units? [MC]

Barley

Which value expresses protein available under nitrogen limitation? [MC]

PDIN

Which unit defines feed intake capacity in dairy cows? [MC]

LFU (Lait Feed Unit)

Which energy value is the highest in the IRNA classification? [MC]

Gross energy (GE)

How is the FED (forage energy density) of a feed calculated? [OPEN]

Calculated by dividing the total digestable nutrients (TDN) by the dry matter (DM) content, often expressed as FED = TDN/DM (kg) or as a percentage reflecting the energy available per unit of forage dry matter

Why is it important to calculate both PDIN and PDIE for a feed? [OPEN]

PDIN

• estimates rumen-undegradable protein evailabel for intestinal digestion

PDIE

• accounts for protein supplied by microbial synthesis plus rumen-undegradable protein, ensuring a balanced assessment of total protein supply for ruminant nutrition

What is the difference between PDIN and PDIE? [OPEN]

PDIN = PDIA + PDIMN

• represents the digestable protein in the small intestine when microbial protein synthesis is LIMITED by NITROGEN availability

PDIE = PDIA + PDIME

• represents the digestable protein in the small intestine when microbial protein synthesis is LIMITED by ENERGY availability

What is the significance of the kl, km and kf coefficients in net energy calculations? [OPEN]

Represent the efficiency of using metabolizable energy (ME) for different physiological functions in ruminants:

• kl — efficiency of ME use in lactation (milk production)

• km — efficiency of ME use for maintenance

• kf — efficiency of ME use for fattening

Used to convert ME into net energy (NE) for specific functions in IRNA system

What is the energy value of 1 UFV? [MC]

1820 kcal

Which animal category uses the UFL unit? [MC]

Dairy cows

What could happen if a ration provides excessive energy but insufficient protein for microbial synthesis? [OPEN]

Microbial growth in the rumen would be limited, reducing microbial protein producing and leading to a deficiency in digestable protein available to the animal

What role does microbial protein synthesis play in the INRA protein system? [OPEN]

Supplies digest able protein in the small intestine and helps determine a feed’s protein value based on the balance of energy and nitrogen in the rumen

Which of the following is a true statement about PDIA? [MC]

It is undegrated in the rumen and digestable in the intestine