Thacker Digestion and Energy

Question 1

Digestibility

Answer 1

The proportion of feed not in the feces which is assumed to be absorbed and used by the animal

Question 2

In vivo

Answer 2

in the animal

Question 3

in vitro

Answer 3

in the lab

Question 4

DM Digestibility formula (also works for nutrient digestibility

Answer 4

DM intake - DM output (need to subtract endogenous from this)
/
DM intake

Question 5

Apparent vs. true digestibility

Answer 5

Some of the components of the feces may be endogenous

Question 6

Types of endogenous secretions (3)

Answer 6

digestive (enzymes)
dead bacteria
sloughed off intestinal cells

Question 7

Problems with total digestibility (2)

Answer 7

need accurate intake

large amount of feces sometimes or diarrhea

Question 8

Properties of a good marker in the indicator method (7)

Answer 8

1. Not digested
2. no metabolic effect
3. uniform excretion
4. stable
5. inexpensive
6. readily available
7. easily detected

Question 9

Good markers (3) internally

Answer 9

Lignin, Acid soluble ash, beryllium

Question 10

Good external markers (5)

Answer 10

1. Chromic oxide
2. titanium oxide
3. carmine red
4. dysporium
5. Ruthenium

Question 11

DM digestibility =

Answer 11

100- (%indicator in feed)/% indicator in feces)*100

Question 12

Laboratory methods

Answer 12

1. Artificial rumen
2. Gas production
3. Enzymes
4. Chemical Analysis
5. Nylon Bag - in saccus - put a bag of feed in the stomach of the animal. What is left if indigestible
6. Mobile Nylon bag - inserted into the duodenum

Question 13

Joule

Answer 13

1 calorie = 4.184 joules

Question 14

Digestible Energy

Answer 14

considers what is lost in the feces (DE = GE - FE)

Question 15

Metabolizable Energy

Answer 15

considers what is lost in the urine and gaseous products of digestion (ME = DE - (UE +GPD).

Question 16

%s lost at each step from Gross to Net Energy for ruminants

Answer 16

50-70% left after Fecal loss, 4-5% and 3-10% losses from that because of Urine and GPD, then

Question 17

%s lost at each step from Gross to Net Energy for Monogastrics

Answer 17

80% left after fecal loss, 2-3% and >1% taken from the 80% for urine and GPD, then

Question 18

Formulae for measuring gas loss

Answer 18

ME = DE * 0.82
Methane = 2.41x + 9.8 where x is every 100 g digested

Question 19

Maintenance components of Net energy (3)

Answer 19

BMR, Heat (direct or indirect calorimetry), Voluntary activity

Question 20

TDN =

Answer 20

DCP + DCF + DNFE + (DEE*2.25) as a % of ration

Question 21

Ration of TDN and DE

Answer 21

1 kg TDN = 4.4 kcal DE