Feed Additives and Growth Promotants

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Feed Additivesand Growth Promotants
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Feed Additives

• Compounds that are added to the diet other than
  to supply nutrients to the animal
• Example Antibioticsno nutrient requirement
  for antibiotics
• Urea is not considered feed additive provides a
  source of dietary protein (in the form of
  nitrogen)
• Additives used to enhance production efficiency
  and improve health

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Feed Additives

• Feed additives used in small quantities
• eg MGA
• Toxicity and end-product residue.mixing,
  delivery and consumption critical
• Most feed additives are regulated for these
  reasons
• No onenot even a vetcan authorize use off label
• Feed industry developed premixes for effective
  and safe use

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Feed Additives

• Primary Effects
• Improve feed efficiency and/or daily gain
• Secondary Effects
• Reduce acidosis, coccidiosis, bloat, liver
  abscesses, suppress estrus and control foot rot.

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

Five main categories Antibiotics Ionophores Cocci
diostats Estrus suppressants Buffers
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Antibiotics

• Classified as antibacterial agents
• Limit growth of certain bacteria
• Bacteria can cause clinical sickness or
  subclinical reductions in health (morbidity) that
  reduces performance
• Generally approved for low-level use
• Animal response to antibiotics depends on feeding
  conditions at the time they are used
• Difficult to quantify actual response that can be
  expected

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Antibiotics

• Many antibiotics are normally produced in
  organisms found naturally in the soil other
  places
• People exposed for centuries
• Generally, used correctly results in healthier
  animals
• No risk to people or livestock?
• McDonalds and burger chains reducing the amount
  of usage

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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
• Control of liver abscesses is the primary reason
  to continuously feed antibiotics
• Cattle on high grain diets
• ? episodes of acidosis ? liver damage and
  infection

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• Chlortetracycline
• Aureomycin, Aureo S700
• Numerous recommendations based on production
  level of animal
• Receiving calf AS700 350mg of each
• 48 hour withdrawal time
• Aureomycin 5 days only
• AS700 28 days

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• Oxytetracyline
• Terramycin
• 75 mg/hd/d ? liver abscesses (cattle)
• 0.5 - 2.0 g/hd/d ? shipping fever complex
  (cattle)
• Feed 3 - 5 days before after arrival
• 7 day withdrawal time
• Tylosin
• Tylan
• 8 - 10 g/t or 60 - 90 mg/hd/d (cattle)
• Cleared for use with Rumensin and/or MGA

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Ionophores

• Ionophores selectively affect certain
  microorganisms by altering the passage of ions
  through pores on their outer cell membrane
• Originally used as a coccidiostat in poultry
  industrylater shown to enhance feed efficiency
  in cattle by altering the microbial fermentation
  of feed in the rumen

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Ionophores

• Results in selection of certain microorganisms in
  the rumen
• Inhibits or depresses certain MCO growth
• Alters rumen fermentation
• Usually ? propionate production
• Reduction in protein degradation in the rumen
• Propionate tends to enhance energetic efficiency
  of growth
• Reducing protein degradation increases amount of
  protein that bypasses rumen to lower digestive
  tract

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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

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• 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

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• 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

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• Use of ionophores in levels higher than approved
  is not only illegal but can be toxic to cattle
• Horses are especially susceptible to ionophore
  toxicity

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• Coccidiostats
• Protozoal organisms can invade and destroy the
  intestinal mucosa
• Present in most animals at subclinical
  numbers.generally do not affect performance or
  health
• Numbers increase to a point where production is
  impaired

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• Coccidiostats
• Cause irritation of the digestive tract.scours
  and bloody stools
• Stress (due to shipping), abrupt diet changes,
  weather changes can all cause episodes of
  clinical coccidiosis
• Interpretation of fecal coccidia is difficult,
  since a clinical problem can exist with low
  coccidia counts

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• Coccidiostats
• 4 additives are approved for prevention and
  treatment
• Amprolium (Corrid)
• Decoquinate (Deccox)
• Lasalocid (Bovatec)
• Monension (Rumensin)

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Estrus Suppressants

• Melengesterol Acetate (MGA)
• Synthetic hormone similar in structure and
  activity to progesterone
• Steroidal feed additive used to suppress estrus
  (cyclic sexual activity or heat)
• Results in improvements in growth rate and feed
  efficiency
• Breeding females
• Used to synchronize females for breeding

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Estrus Suppressants

• 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 (cattle)
• Cleared for use with Rumensin, Bovatec Tylan
• 48 hour withdrawal period

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Estrus Suppressants

• Response of feedlot heifers to MGA depends on
• The age of the heifer
• Number of sources of heifers being fed together
• Amount of space per heifer
• Implant effects
• Adequate mixing

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Buffers

• Added to the diet to aid in resisting pH changes
  of the rumen when acids are present
• Large quantities of organic acids produced in
  rumen by microbial fermentation
• Reduces incidence of acidosis on high grain diets
• SALIVA is principle source of rumen-buffering
  agents
• 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 in Ruminants

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

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Growth Promotants in Ruminants

• Given to cattle to improve
• Feed Efficiency 15 - 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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• ? cost of gain, ? choice carcasses (25), ?
  lean
• Altered or aggressive pen behavior (bullers)
• Estradiol implants reduce NEg requirement by 5
• 2 E2 implants 18 - 20 NEg requirement
  reduction

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• Most implants are effective from 50 to 100 days
• Selection for growing finishing cattle
• 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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• Estrogens
• Estradiol 17? (Compudose)
• Estradiol Benzoate (71 E17?) - Synovex
• Zeranol (produced from the production of mold)
  Ralgro
• Androgens
• Testosterone Propionate (Component)
• Trenbolone Acetate (TBA) Finaplix

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• Progesterones
• Progesterone (Component)
• Melengesterol Acetate (MGA)
• Combination implants
• Estradiol TBA RevS
• Estradiol benzoate TBA Synovex