High-Selenium Beef and Lamb Production: Animal Productivity and Tissue Concentrations

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High-Selenium Beef and Lamb Production Animal
Productivity and Tissue Concentrations

• J. Bret Taylor
• USDA-Agricultural Research Service
• US Sheep Experiment Station
• Dubois, ID

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Historical BackgroundDeficiency

• Reported and assumed events
• Regions of limited forage selenium
• Low Se soils or acidic soils
• Management
• Clinical Se-salt injections or drenches
• Marginal feed supplements

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Current OutlookDeficiency

• More assumed rather than confirmed
• Western rangelands
• Less than 0.1 mg/kg is common
• Management based on historical reports
• Treat the potential
• Professional health and nutrition consultant
  diagnosis

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Current OutlookMarginal Deficiency Worries?

• Selenium responsive disorders (Underwood and
  Suttle, 1999)
• 10 to 20 decrease in conception rates
• 15 to 30 decrease in lamb survival
• Increased embryonic and fetal mortality
• Increased lamb susceptibility to disease
• 4 to 10 decrease in lamb growth rates
• 4 to 8 decrease in wool yield

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Current Outlook Manufactured Se Sources

• Most common the Se-salts
• Sodium-selenite and -selenate
• New on the market Se enriched yeast
• Poultry 2001 swine 2002 cattle 2004
• Route of dietary inclusion
• Ration component limit fed
• Salt mix ingredient free choice
• FDA regulated
• Cattle 3.0 mg?hd-1/d
• Sheep 0.7 mg?hd-1/d

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Need for Supranutritional Se?Se Supplementing
Limitations

• Rangeland operations
• Land use restrictions
• Animal availability
• Extensive land masses and difficult terrain
• Brief periods of accessibility
• Prebreeding (flushing) - 7 to 14 days
• Parturition - 7 to 35 days
• Shipping/processing - lt 7 days
• Opportunities to supplement are short, and may
  occur only once every 120 to 330 days

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Need for Supranutritional Se?Supplementing
Practices

• Free choice high Se salt mix
• 30 to 90 mg/kg salt mixes

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Need for Supranutritional Se?Supplementing
Practices
Daily Se Intake (mg) of a 30, 60 or 90 ppm Se
Custom Mix
Selenium, mg/head/day
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Need for Supranutritional Se?Problems with
Se-salt Supplements

• Short lived in the body, especially during
  lactation
• Intake of salt mixes is herd based, not
  individual
• Often crosses over the FDA intake limit
• Individual treatment with injections is laborious
  and costly
• High Se depositing in confined areas

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Potential for Natural Se Sources? Naturally High
Se Feeds

• Allaway et al. (1967) recognized potential, but
  dismissed the importing of high Se feeds due to
  economic constraints and variation in Se content
• Levander et al. (1983) emphasized the long term
  effects on Se status in humans when high Se wheat
  and yeast are consumed
• van Ryssen et al. (1989) clearly demonstrated the
  ease of enhancing Se burden in sheep by feeding
  high Se wheat

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Feeding Supranutritional SeHigh Se Wheat Grain

• The majority of Se seems to be selenomethionine
• Currently, its use as a feed or ration component
  for ruminants is not regulated
• CAUTION Wheat grain can result in severe
  digestive upsets in ruminants when fed improperly

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Feeding Supranutritional Se High Se Wheat vs.
Se-salt
J. B. van Ryssen et al. 1989. J. Agric. Food
Chem. 371358 Comparative metabolism of organic
and inorganic selenium by sheep
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Feeding Supranutritional SeHigh Se Wheat
Forage vs. Se-salt
T. L. Lawler et al. 2004. J. Anim. Sci.
821488 Effect of supranutritional (2.8 ppm) and
organically bound selenium on performance,
carcass characteristics, and selenium
distribution in finishing beef steers
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Feeding Supranutritional SeTime vs. High Se
Wheat
J. B. Taylor. 2004. J. Anim. Sci.
Submitted. Time dependent influence of
supranutritional organically-bound selenium (2.7
ppm) on selenium load in growing wether lambs
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Feeding Supranutritional SeTime vs. High Se
Wheat
J. B. Taylor. 2004. J. Anim. Sci.
Submitted. (continued)
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Feeding Supranutritional SeSe Form vs.
Reproductive State
J. B. Taylor et al. 2004. J. Anim. Sci.
Submitted. Effect of selenomethionine and
cystine, fed supranutritionally (2 ppm), on
selenium load and selenoprotein activities in
virgin, pregnant, and lactating rats
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Feeding Supranutritional SeA Potential
Management Solution?

• There is a need for supranutritional Se
• Naturally high Se (selenomethionine) starch
  grains can meet this need
• Dietary inclusion is not regulated
• Rapidly enhances selenium load
• Starch grains are being used for dietary energy
  enhancement (range and finishing systems)
• Palatability is high

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Future of High Se Feeds in Livestock Production

• Whats in it for the Producer?
• Controlled means of enhancing Se load to offset
  long periods of inadequate Se intake
• Cost must be justifieddeficiency should be
  quantified
• Anything else?
• Higher nutritional value product?
• The producer must see this dollar increase at
  their level, not at the slaughter and retail
  levels
• Greater return on investment?
• Remember, the high Se feed, not the animal, is
  the investment

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Future of High Se Feeds in Livestock Production
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