Effects of selenium yeast on rumen fermentation, lactation performance and feed digestibilities in lactating dairy cows

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Effects of selenium yeast on rumen fermentation,
lactation performance andfeed digestibilities
in lactating dairy cows

• C. Wang A, Q. Liu A,?, W.Z. Yang A,B, Q. Dong A,
  X.M. Yang C, D.C. He C, P. Zhang D, (July 2009)
• Presented by AbouBaker Elhajee

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Introduction

• Selenium is recognized as an essential trace
  element.
• It is a powerful catalytic element constituting
• the active centre of about 20 selenoproteins
• Selenium displays metabolic function related to
  maintenance of integrity and defenses of the
  organism.

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Supplementation

• Se content within plants can be extremely
  variable. Consequently, selenium in diets can be
  deficient.
• Se supplementation may be required to improve the
  performance and health of dairy , enhance the
  nutritional quality of the milk product

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Forms

• Inorganic Se (i.e., sodium selenite or selenate)
  and organic Se (i.e., selenium-yeast SY).
• Most studies reported that organic Se is less
  toxic than inorganic Se, Bioavailability of SY
  higher than inorganic Se sources , leads to
  higher Se content in milk.

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• Results of SY on milk yields and milk components
  from literature are inconclusive.
• These contrasting results could be due to
  differences in the composition of the diet and/or
  to the dose of SY and lactation period of dairy
  cow (Juniper et al., 2006)..

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Objectives

• The aim of this work was to evaluate the effects
  of SY supplemented dose on rumen fermentation,
  lactation performance, milk selenium content and
  feed digestion in mid-lactation dairy cows.

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Materials and methods

• Animals and experimental design.
• - Twenty-eight Holstein dairy cows were
  assigned to a replicated 44 Latin square.
• - Treatments were control, LSY, MSY and HSY
  with 0,150, 300, and 450 mg SY per kg of (DM)
  respectively.
• - Experimental periods were 45 days with 30
  days of adaptation and 15 days of sampling.

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• Dry matter intake, milk yield, milk components
  and milk selenium.
• - Feed offered and refused were measured daily
  for each cow (DM intake).
• - Milk yields were recorded daily.
• - Milk Samples for analysis of
  milkcomposition and measure milk Se
  concentration.

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• Rumen pH and fermentation characteristics.
• - were measured on two consecutive days at the
  beginning (days 1 and 2) and end (days 44 and 45)
  of each period. At 0, 3, 6, and 9 h after the
  morning feeding, samples (about 100 mL) of rumen
  fluid were obtained anaerobically via the
  esophagus using a stomach tube
• - Ruminal pH was immediately measured using an
  electric pH meter

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• Rumen pH and fermentation characteristics.
• -Samples were then strained through four layers
  of cheesecloth. Five milliliters of filtrate was
  preserved by adding 1 mL of 250 g/L (w/v)
  meta-phosphoric acid to determine acetate,
  propionate and butyrate, and 5 mL of filtrate was
  preserved by adding 1 mL of 20 g/L (w/v) H2SO4 to
  determine NH3.

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• Apparent digestibility in the total tract
• -Cows were dosed via the esophagus with 5 g of
  chromic oxide per day per cow in two equal
  proportions at 0700 and 1900 h from days 23 to
  43 of each period as a digestion marker..
• -fecal samples were collected from the rectum of
  each cow during days 31 to 43 of each period .

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Results

• Ruminal pH and fermentation.
• -There was no significant difference in ruminal
  pH .
• -Ratio of acetate to propionate was lower for
  LSY, MSY and HSY than for control

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• Dry matter intake, milk yield, milk components
  and milk selenium
• -Dry matter intake was not affected.
• -Milk yields were higher for LSY and MSY than
  for HSY and control
• -Milk selenium content was linearly and
  quadratically increased as increasing SY
  supplementation.

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• Digestibility in the total tract.
• Were higher for LSY and MSY than for control
  and HSY.

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Conclusion

• Increasing supplementation of cow diet with
  selenium yeast from 150 to 300 mg/kg dietary DM
  compared with control increased milk yield and 4
  FCM.
• Improved milk production was likely due to the
  increased total digestibilities of feeds since
  DMI was not affected.
• The further increase of SY dose from 300 to 450
  mg/kg dietary DM was not beneficial

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Recommendation

• Selenium yeast modulates the digestive
  microorganisms or enzymes in a dose-dependent
  manner and the optimum SY supplemented dose was
  about 300 mg/kg in the present experimental
  conditions.
• SY supplementation in the diets of lactating
  dairy cows could be an efficient way to increase
  milk Se content.

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