Stretching Forages with Alternative Feedstuffs

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Stretching Forages with Alternative Feedstuffs
John K. Bernard Animal Dairy Science
Department University of Georgia Tifton
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How long a minute is depends on what side of the
bathroom door youre on.
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If Wal-Mart is lowering prices everyday, how
come nothing is free yet??
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Situation

• Reduced supply of locally produced forage
• Short term options for growing forage are limited
  without irrigation
• Increased demand for available forage or forage
  extenders
• Livestock producers are (will) experiencing
  higher purchased feed cost

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Options

• Reduce animal numbers or contract growth of
  animals to a second party
• Purchase hay to supplement forage inventories
• Modify diets to reduce amount of forage fed using
  alternative feeds - forage extenders or
  non-forage fiber sources

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Challenge

• Formulate diets that provide adequate effective
  fiber levels to maintain a healthy rumen.
• Optimum DMI
• Optimum chewing activity
• Normal ruminal fermentation
• Ruminal pH gt 6.0
• Normal milk fat percentage
• Attempt to optimize returns with increased
  purchased feed cost so producer does not get into
  credit problems.

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Note

• Substituting NFFS for forage may result in
  different responses to those expected when
  substituted for concentrate
• Dilution of starch
• Increased ruminal NDF digestion
• Improved microbial N synthesis

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NRC Recommendations
NRC, 2001
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Roughage value of select feeds

• Few feeds have adequate roughage value to allow
  a simple replace forage directly
• Stimulate chewing
• Contribute to the rumen mat
• Provide buffering

Note Long stem grass hay considered as 100
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Ruminal NDF digestibility
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NDF Digestibility

• Rate of passage varies among NFFS
• Particle size
• Specific gravity
• Forage source and particle size
• Passage rate is often assumed to be 0.4 to 0.6/h,
  but is often higher for high producing dairy cows
  (0.058 vs. 0.76/h)
• Potential for a shift in NDF digestion to hindgut
  with increased passage rate, thus actual ruminal
  digestibility is less than predicted by in vitro
  or in situ trials.

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NDF digestibility

• NDF digestibility and NFC concentration are
  inversely related
• Total tract NDF digestibility ( )
• 2.1 1.79(FNDF) 0.0332(NFC x NNDF)
• As FNDF decreases, the relationship becomes more
  important.
• For NFC and NNDF of 40 and 10, term 400
• Change to 35 NFC and 15 NNDF, term 525
• NNDF is 2/3 as effective as forage NDF in
  increasing (maintaining) total tract NDF
  digestibility

Firkins, 1997. JDS 801426 1437.
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Forage factors

• Type, amount, and particle size
• Grasses provides more effective fiber than
  legumes.
• As the amount of forage in the diet decreases,
  the particle size and NFC content are more
  critical for maintaining normal ruminal function.
• Course forage improves rumen mat consistency
  trapping small particles and increasing ruminal
  NDF digestion.

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Low forage or small particle size High nonforage
fiber
Low pH
-
Less entrapment
Rate of fiber digestion


Rate of fiber passage
-
Higher pH
Entrapment
High forage or large particle size Low nonforage
fiber
Grant. 1997. JDS 801438-1446.
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Other dietary factors to consider

• Supplemental dietary buffers
• Feeding method
• Variation in nutrient content of NFFS

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Variation in NDF concentrations in NFFS
DePeters et al. 2000. PAS 1669-99.
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General observations and guidelines

• DMI decreases and the rumen is negatively
  impacted when forage NDF is less than 15
• General guidelines for optimal DMI
• Total dietary NDF 25 to 35
• Forage NDF gt15
• NFC 33 to 40
• If forage NDF is less than 15, NFC should be
  diluted with NDF from NFFS even more

Firkins, 1997. JDS 801426 1437.
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Variation between multiple and single sources

• Variation is higher for industry averages
  compared with that of a single source supplier
• Reasons
• Type of brew
• Different adjuncts
• Method of processing

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Forage Extenders

• Provide bulk
• Nutrient content and digestibility are low
• Examples
• Cottonseed hulls
• Cotton byproducts
• Crop residues
• Peanut hulls
• Rice hulls
• Cardboard
• Wood chips

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Cottonseed Hulls

• More commonly used in diets to replace or extend
  forage.
• Rate of NDF digestion is slow and extent of
  digestion is low
• Passage rate is relatively fast compared to most
  NFFS.
• Does not stimulate chewing
• Good buffering capacity
• Maintains or improves ruminal pH
• DMI typically increases by 15 to 20.
• Feeding rates up to 40

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In situ digestibility
Gu et al. 1997. JDS 80 (Suppl. 1)272. (Abstr.)
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Corn silage or 35 pelleted CSH
Harris and Staples. 1991.
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30 Regular or Pelleted CSH
Harris and Staples. 1991.
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10, 20 or 30 CSH with low or high RUP
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10, 13 CP
10
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Gu and Moss. 1996. JDS 79(Suppl. 1)152. (Abstr.)
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Substituting CSH for Forage
CSH 7 of DM
Moss et al. 2002 PAS 18324-331.
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Substituting CSH for Forage
CSH 7 of DM
Moss et al. 2002 PAS 18324-331.
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Substituting forage or CSH for corn silage in
diet with either high or low RUP
Substitutions 10 of DM
Moss et al. 1996 JDS 79 (Suppl. 1)151. (Abstr.)
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Substituting forage or CSH for corn silage in
diet with either high or low RUP
Substitutions 10 of DM
Moss et al. 1996 JDS 79 (Suppl. 1)151. (Abstr.)
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Cotton motes, textile waste, and gin trash

• Nutrient content similar to low quality hay
• Performance of growing animals is similar to that
  obtained when cottonseed hulls are fed.
• Concerns Contaminants from pesticides and
  defoliants (arsenic) or mycotoxins

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Non-forage Fiber Sources

• Low to moderate nutrient content
• Digestible fiber with low starch content
• Examples
• Whole cottonseed
• Soybean hulls
• Wheat middlings
• Corn gluten feed
• Brewers grains
• Distillers grains
• Citrus pulp
• Beet pulp

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Whole Cottonseed

• Most effective non-forage fiber source available
  for replacing forage.
• Stimulates rumination and chewing
• Rate of passage is not as fast as other NFFS
• Maintains DMI, milk yield, and composition
• Can be used to decrease forage NDF to 15 of
  total NDF
• When used to replace forage, the amount and
  source fat provided by other ingredients should
  be taken into consideration to avoid any negative
  effect on ruminal fermentation.

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Replacing forage with whole cottonseed
Firkins et al. 2002. JDS 852662-2668.
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Replacing forage with WCS
abWCS versus Easiflo (P lt 0.01).
Firkins et al. 2002. JDS 852662-2668.
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Soyhulls

• Small particle size
• Increased passage rate if rumen mat consistency
  is not adequate to entrap
• Typically supports increased NDF intake and
  improved milk yield, but results are influenced
  by proportion of forage in the diet

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Soyhulls

• Average response
• NDF intake increased 11.9
• FCM increased 2.8
• High forage diets (60 to 70 of NDF)
• NDF intake 0.8 less
• FCM was 0.1 less
• Low forage diets (40 to 50 of NDF)
• NDF intake increased 22
• FCM increased 5.2

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Replace forage with SH
Yes
Are cow gt 28 DIM?
No
Yes
Is dietary forage gt 50 of DM?
Do not feed SH until 28 DIM
Yes
No
Small particle size?
Yes
Yes
No
No
Do not feed SH
Add SH at lt10 of DM
Add SH at lt25 of DM
Add SH at lt15 of DM
Expect no change or a small decrease in DMI and
FCM
Expect no change in DMI or FCM
Expect increase in DMI or FCM
Grant. 1997. JDS 801438-1446.
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Low vs high fill

• Combinations of NFFS that provide similar NDF
  content (34), but are digested rapidly in the
  rumen
• High fill
• 0.034 h-1
• 32.8 RD
• Low fill
• 0.077 h-1
• 51.5 RD

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Low vs. High Fill Diets

• Forage intake were well below NRC recommendations
  
• High NSC concentrations reduces ruminal pH, AP
  ratio, and microbial protein synthesis compared
  to low NSC diets (39 vs. 29 NSC).
• Digestible NDF from NFFS compliments lower NSC
  concentrations to maintain a health ruminal
  environment

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Application

• Management ability of the operator or limits of
  the setup
• Forage type and particle size
• Economics of using purchased forage versus
  alternative feeds
• Short term vs long term

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Summary

• Alternative feeds can be successfully substituted
  for forage to extend supplies
• Lactating cow diets should be formulate with a
  minimum of 15 NDF from forage and use a
  combination of alternative feeds.
• As the amount of forage in the diet decreases or
  if forage particle size is less than ideal, the
  starch content of the diet should be reduced and
  fiber from NFFS or coarse forage added.

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Thank you!
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Summary

• Caution should be used when feeding low forage
  diets to fresh cows
• Monitor DMI, cud chewing, and milk fat content to
  evaluate any change in ruminal fermentation.