Feed Additives in Ruminants

1
Feed Additives in Ruminants

• Primary Effects
• Improve feed efficiency and/or daily gain
• Secondary Effects
• Reduce acidosis, coccidiosis, bloat, liver
  abscesses, suppress estrus and control foot rot.
• Four main categories
• Ionophores
• Antibiotics
• Estrus suppressants
• Buffers

2

• It is essential to abide by recommended feeding
  levels with any feed additive
• Violation of FDA guidelines
• Reduced animal performance

3
Ionophores

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

4
Effects of ionophores

• Improve efficiency of energy metabolism by
  changing the VFA profile ? energy lost in
  fermentation
• ? energy retention
• Reduce digestive upsets reduced stress
  improved animal performance

5

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

6

• Common ionophores on the market
• 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

7
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
• 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

8

• Chlortetracycline
• Aureomycin, Aureo S700
• 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
• Tylosin
• Tylan
• 8 - 10 g/t or 60 - 90 mg/hd/d
• Cleared for use with Rumensin and/or MGA

9
Estrus Suppressants

• Melengesterol Acetate (MGA)
• Synthetic hormone similar in structure and
  activity to progesterone
• 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

10
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
• 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