lecture quiz 17: feedstuffs

Question 1

oats

Answer 1

• grain
• cool climate crop
• limit in swine & poultry b/c of ↑ fiber (9-11% CF) & low energy value
  - ↑ CF b/c hard to remove husk/hull from bran
• most popular & “safest” grain to feed horses b/c of ↑ CF ➞ less likely to cause colic
• can be fed whole or processed (ground, rolled, or steam-rolled)
• hulled known as oat grouts (oatmeal) = to corn (more palatable & low in CF but generally too expensive for routine feeding
  
  • more expensive b/c of low yield

Question 2

barley

Answer 2

• grain
• cool climate crop
• majority is grown in north central, far east, canada, & Ca
• limit in swine & poultry b/c higher fiber content (5-6% CF)
  
  • don’t exceed 20%
  • high in β-glucans → reduces absorption of other nutrients & makes sticky feces in poultry
• higher in protein than corn (10-12%)
  
  • not necessarily good thing: higher in protein = lower in energy
• ususally processed in some way prior to feeding (ground, dry-rolled, steam-rolled)
• used to make beer

Question 3

grain sorghum (milo)

Answer 3

• drought-intolerant ∴ grown in drier climate (texas, kansas, Ca)
• grain is exposed aka naked seed ➞ not covered by husk or hull
• small hard seed ∴ must be processed (grinding or rolling)
• high tannin (bird-resistant) for ruminants & low tannin varieites for swine & poultry
  
  • tannins are polyphenolic compounds found on unripened fruits that give dry sensation
  • make grain astringent (unpalatable) & reduce protein digestibility

Question 4

tannins

Answer 4

• polyphenolic compounds found on unripened fruits that give dry sensation
• make grain astringent (unpalatable) & reduce protein digestibility
• high tannin (bird-resistant) varieties for ruminants
• low tannin varieites for swine & poultry

Question 5

grain quality

Answer 5

• diff for human & animal consumption
• for human consumption:
  1. no foreign material (only 1 ingredient)
  2. low % of discolored, broken, & heat damaged kerbels
  - broken rice discounted for animal feed
  - heat-damaged kernels from maillard rxn btwn carbs & proteins turn corn brown ∴ not acceptable
  3. high milling yield
  4. no insects/molds
  5. no mycotoxins (or below certain levels
• for animal consumption
  
  1. foreign material okay depending on what
  2. starch content important
  3. digestibility/availability of nutrients
  4. molds/mycotoxins must be below certain levels (ruminants are more tolerant)

Question 6

main factor involved in grain storage

Answer 6

moisture

Question 7

grain storage

Answer 7

• high moisture breeds mold
• need to have dry grains for bin or shed storage
  
  • small grains - whole: <12% moisture
    
    • smaller grains have larger SA that can be used for mold growth
    • as size gets smaller, SA gets bigger & become more sensitive to mold ∴ moisture content has to be lower
  • corn - whole <14% moisture
    
    • as particle size gets bigger, moisture storage can go up b/c less SA
  • ground grains (or w/ >12% broken kernels): <11% moisture

Question 8

high moisture in storage causes

Answer 8

• heating
• caking = grains get stuck together b/c of combination of moisture & mold so gets stuck in dispensing system → wasted
• mold that produces poisonous myotoxins that cause
  
  • reduced performance
  • poor feed efficiency
  • diarrhea
  • liver disease
  • infertility or abortion

Question 9

aspergillus flavis

Answer 9

• most common mold in corn grain
• greenish/olive color
• aflatoxins = mycotoxin that causes:
  
  • liver damage
  • impaired reproductive efficiency
  • reduced growth & prod performance
• max levels:
  
  • feed for dairy, immature poultry, & stressed animals = 20 ppb or 0.00002%
  • human consumption = 20 ppb
  • for breeding cattle, breeding swine, & mature poultry = 100 ppb (can cause abortion)
  • for finishing swine >100 lbs = 200 ppb
  • for finishing beef cattle = 300 ppb

Question 10

steps to prevent molds/mycotoxins

Answer 10

1. moisture test: reject any grain which is too wet or that you can’t dry (can use grain dryers)
2. obtain a sample & analyze any suspect grains for mycotoxins
3. keep equipment clean & mold-free (don’t contaminate clean grain)

Question 11

grain processing

Answer 11

• main reason: ↑ digestibility
• physical interrupts seed coat & ↓ particle size that ↑ SA exposed to digestive enzymes
• thermal (steam or moist heat) → starch swells & gelatinizes
  
  • gelatinization = starch gel
  • gelatinized = more digestible

Question 12

grinding: hammer mills

Answer 12

• hammer mills can be portable or stationary
• steel shaft w/ hammers that swing
• feed is battered
• screens set size