Feed Additives for Ruminants

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Feed Additives for Ruminants
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Feed Additives

• Many commercially prepared additive products are
  included in animal diets
• By definition, these products do not supply
  nutrients
• Not listed in feed composition tables
• Since 1960, FDA has regulated feed additive
  incorporation into animal diets
• Prevention of cancer in human/animal

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Feed Additives

• More than 1000 products are approved by FDA for
  use in livestock/poultry feeds
• Include products intended to promote animal
  health
• Prevention/treatment of disease
• Growth promotion
• Both

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Feed Additives

• Some additives can leave residues in the muscle
  tissues
• Withdrawal times prior to slaughter
• Must choose correct additive for stage of
  production

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Feed Additives

• Antibiotics/Chemotherapeutics
• Ionophores
• Estrus suppressants
• Buffers

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Antibiotics/Chemotherapeutics

• Against life or destructive to life
• Natural compound synthesized by living organisms
  or chemically synthesized compounds
• AB are either
• Bacteriostatic
• Bactericidal
• or both

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Antibiotics/Chemotherapeutics

• For over 50 years antibiotics and
  chemotherapeutics have been used in the animal
  feed industry
• Approximately 60 of beef cattle and 75 of dairy
  cattle raised in U.S. are estimated to have been
  fed these at some point during production

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Antibiotics

• The primary reason to feed antibiotics to
  ruminants is to control liver abscesses, foot rot
  secondary infections/diseases as a result of
  shipping stress

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Antibiotics

• Control of liver abscesses is the primary reason
  to continuously feed antibiotics
• Cattle on high grain diets
• ? episodes of acidosis ? liver damage and
  infection
• The greater the severity of liver abscesses, the
  greater the reduction in growth performance

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Common Antibiotics

• Chlortetracycline
• Aureomycin
• Numerous recommendations based on production
  level of animal
• 48 hour withdrawal time
• Oxytetracyline
• Terramycin
• 75 mg/hd/d ? liver abscesses
• 0.5 - 2.0 g/hd/d ? shipping fever complex
• Feed 3 - 5 days before after arrival
• 7 day withdrawal time

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Common Antibiotics

• Tylosin
• Tylan
• 8 - 10 g/t or 60 - 90 mg/hd/d
• Cleared for use with Rumensin and/or MGA
• Feed to reduce incidence of liver abscesses

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Ionophores

• Results in selection of certain microorganisms in
  the rumen
• Inhibits or depresses certain microbe growth
• Alters rumen fermentation
• Usually ? propionate production

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Ionophores

• Mechanism of action Disrupts the ion gradient
  across the cell membrane cell death
• Destroys secondary transport processes and
  energy-conserving reactions

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Effects of Ionophores

• 1. Improve efficiency of energy metabolism
• by changing the VFA profile ? energy lost
  in fermentation
• ? energy retention
• 2. Decrease breakdown of feed protein may
  decrease microbial protein synthesis
• Impacts Growing cattle on high-roughage diets
• 3. Reduce digestive upsets reduced stress
  improved animal performance

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Ionophores

• Too high of a level of ionophore can reduce
  cellulolytic bacteria
• ? fiber digestion
• ? rumen protein ruminal protein shortage

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Ionophores

• Growing cattle high-roughage diets
• Improved daily gain (5 - 15) feed efficiency
  (8 - 12)
• Finishing cattle high-concentrate diets
• Improved feed efficiency (6 - 8) and subtle
  improvement in daily gain (1 - 3)
• Prevention or control of bloat and acidosis

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Common Ionophores

• Rumensin? (Monensin Sodium)
• 20 - 30 g/ton
• Bovatec? (Lasalocid Sodium)
• 10 - 30 g/ton
• 1 mg/2.2 lb. of BW control of coccidiosis
• Cattlyst? (Laidlomycin Propionate Potassium)
• 5 - 10 g/ton

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Estrus Suppressants

• Melengesterol Acetate (MGA)
• Synthetic hormone similar in structure and
  activity to progesterone
• Breeding females
• Used to synchronize females for breeding

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Estrus Suppressants

• Melengesterol Acetate (MGA)
• Feedlot heifers
• Suppress estrus ? growth performance
• 3 - 7 for ADG FE
• ? injury, ? dark cutters, ? energy expended by
  chasing heifers
• 0.25 - 0.50 mg/hd/d
• Cleared for use with Rumensin, Bovatec Tylan
• 48 hour withdrawal period

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Buffers

• Added to the diet to aid in resisting pH changes
  of the rumen when acids are present
• Reduces incidence of acidosis on high grain diets
• Improves fiber digestion in corn silage diets
• Performance is variable
• -2 - 5 improvement in ADG FE

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Buffers

• Sources
• Sodium Bicarbonate 0.75 - 1.5 diet DM
• Limestone 1.0 diet DM
• Sodium Bentonite 1 - 2 diet DM
• Magnesium oxide 0.5 - 0.75 diet DM

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Growth Promotants

• Redirection of nutrients from fat deposition to
  lean tissue deposition.
• ? Growth hormone secretion
• ? steroidal effect on growth of skeletal muscles
  through ? IGFs

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Growth Promotants

• Given to cattle to improve
• Feed Efficiency15 - 25 in growing cattle
• 10 - 12 in finishing cattle
• Daily Gain .33 lb./d in growing cattle
• 10 - 15 in finishing cattle
• 4 - 16 improvement in DMI

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Growth Promotants

• ? cost of gain, ? choice carcasses (25), ?
  lean
• Estradiol implants reduce NEg requirement by 5
• E2 implants 18 - 20 NEg requirement reduction
• Most implants are effective from 70 to 100 days

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Growth Promotants

• Most are cleared for use in confinement cattle
  and some are available for grazing cattle
• There are 6 individual component implants 10
  combination implants currently on the market
• Implant wars changing companies and products

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Common Growth Promotants

• Estrogens
• Estradiol 17?
• Estradiol Benzoate (71 E17?)
• Zeranol (produced from the production of mold)
• Androgens
• Testosterone Propionate
• Trenbolone Acetate (TBA)

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Common Growth Promotants

• Progestins
• Progesterone
• Melengesterol Acetate (MGA)
• Somatotropins (growth hormones)
• Bovine Somatotropin (BST)