ch 3

Question 1

Aimed at giving information on the capacity of individual feeds to meet the nutritional requirement of the animal. Testing feed quality for animal consumption.

Answer 1

FEED EVALUATION

Question 2

CONTRIBUTING FACTORS TO
FEED INGREDIENT QUALITY

Answer 2

1. Genetic differences
2. Soil characteristics
3. Degree and type of processing
4. Dehulling process
5. Storage systems

Question 3

SAMPLING FEEDS FOR ANALYSIS

Considerations for sampling process:

Answer 3

1. Sampling size and sampling scheme
2. Sampling equipment
3. Sampling preparation and retention
4. Sampling purpose
5. Type of material to sample

Question 4

sampling equipment for samples in big containers

Answer 4

slotted grain probe

Question 5

sampling equipment for samples obtained in sacks

Answer 5

tapered bag trier or buriki

Question 6

sampling equipment with heaps of feed ingredients

Answer 6

pelican sampler

Question 7

sampling equipment for liquid ingredients

Answer 7

bomb sampler

Question 8

METHODS OF FEED EVALUATION

Answer 8

1. PHYSICAL METHODS
2. PROXIMATE ANALYSIS
3. MINERAL ANALYSIS
4. DETERGENT FIBER ANALYSIS
5. QUICK TEST KITS
6. BIOCHEMICAL TRIALS

Question 9

• Uses naked eye to physically evaluate feeds.
• Insect pests, molds, stones, and other extraneous substances may be observed for their presence.
• Simple stereo microscope can be used to detect Adulteration in feeds.
• Adulteration - the admixture of a pure substance with some cheaper and low quality substance.
• Adulteration = poor feed quality.

Answer 9

PHYSICAL METHODS

Question 10

• Also known as Weende method.
• Most common chemical method used to determine the amounts of dry matter, moisture, fat, protein, ash, and fiber.
• Nitrogen-free extract is obtained by difference.
• All values obtained in this method are termed “crude”.

Answer 10

PROXIMATE ANALYSIS

Question 11

*proximate analysis, for?

A known weight of sample is dried in an oven a 105oC
* Loss in weight in drying corresponds to the amount of water.

Answer 11

For the amount of water

Question 12

*proximate analysis, for?

May be directly analyzed using toluene distillation method.
* Sample is boiled with toluene in a flask.

Answer 12

For high moisture samples

Question 13

*proximate analysis, for?

Determined using Kjeldahl apparatus.

Answer 13

For protein content

Question 14

*proximate analysis, for?

Uses Soxhlet apparatus
* Fats are dissolved with organic solvent (petroleum ether).
* Non very reliable because it also dissolves the nonfat substances, hence crude fat.

Answer 14

For fat or lipid content

Question 15

*proximate analysis, for?

Analyzed by simulating the digestion process of stomach of monogastric animals
* Weak acid → weak alkali

Answer 15

For fiber content

Question 16

*proximate analysis, for?

Subjects the sample at 550-600oC.
* Solubilizes organic substances then leaving only the ash.

Answer 16

For inorganic components (ash)

Question 17

• Commonly used for analyzing calcium, phosphorus, salt.
• Ash from proximate analysis is used here.
• Calcium is determined by precipitating ash as calcium oxalate.
• Phosphorus is determined by converting the phosphorus into phosphoric acid.
• Salt is determined by using Volhard method.

Answer 17

MINERAL ANALYSIS

Question 18

• Active ingredients are detergent compounds.
• Two solutions: neutral detergent solution and acid-detergent solution

Answer 18

DETERGENT FIBER ANALYSIS

Question 19

✓ Dissolves starches and other soluble fractions of sample, hence leaving only the insoluble fractions (neutral detergent fiber or NDF).
✓ NDFs are cellulose, hemicellulose, lignin and ash.

Answer 19

Neutral detergent solution

Question 20

✓ Dissolves the hemicellulose from the NDF.
✓ Thus, leaving an insoluble fraction known as the ligno-cellulose plus ash.

Answer 20

Acid-detergent solution

Question 21

• Give fast and reliable results as compared to laboratory analysis which may take at least a day or two to get results.

Answer 21

QUICK TEST KITS

Question 22

*Common test kits:

determine the degree at which soybean and soybean meal have been to heat during processing.

Answer 22

Urease test kit

Question 23

*Common test kits:

for detecting adulteration of rice bran hulls.

Answer 23

Rice bran test kit

Question 24

*Common test kits:

indicate the amount of aflatoxin and other mycotoxins.

Answer 24

Mycotoxin test kit

Question 25

*Common test kits:

instantly measure moisture content.

Answer 25

Electronic moisture testers

Question 26

• Also known as metabolism trial.
• Used to determine the amount of nutrient digested, absorbed, and utilized.
• Uses proximate analysis and live animal.
• Three stages:
  o Adjustment
  o Preliminary
  o Collection

Answer 26

BIOCHEMICAL TRIALS

Question 27

*stage of biochemical trial

Feed is gradually presented to the animal, until feed intake stabilizes.

Answer 27

ADJUSTMENT

Question 28

*stage of biochemical trial

Feed intake should already be stable.
* Level of feeding is determined.
* Give allowances in feeding.

Answer 28

PRELIMINARY

Question 29

*stage of biochemical trial

Feed sample, refusal, feces, and urine are collected regularly.
* Total collection method.

Answer 29

COLLECTION

Question 30

In vivo means

Answer 30

inside/within the animal

Question 31

In vitro means

Answer 31

laboratory set up

Question 32

In vitro methods are more rapid and convenient. Also, more samples can be tested at a given time.
* In vitro methods:

Answer 32

o Gas production method – tests the rate of gas (C02 and CH4) production during fermentation process.

o Tilley and Terry two-stage method – rumen fermentation followed by enzymatic digestion.

o Nylon bag technique – also called as sacco fermentation trial. Sample in nylon or Dacron bag is placed inside rumen.

Question 33

Different values of feed nutrients:

Answer 33

➢“Fresh basis”
➢“Dry basis”
➢“As fed basis”
➢“Air-dry basis”