Effects of selenium yeast on rumen fermentation,
lactation performance and
feed 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
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.
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
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.
• 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)..
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 midlactation dairy cows.
Materials and methods
• Animals and experimental design.
- Twenty-eight Holstein dairy cows were
assigned to a replicated 4×4 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.
• 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.
• 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
• 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.
• 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 07:00 and 19:00 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 .
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
• 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.
• Digestibility in the total tract.
Were higher for LSY and MSY than for control
and HSY.
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
Recommendation
• Selenium yeast modulates the digestive
microorganisms or enzymes in a dosedependent 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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