Issue |
Anim. Res.
Volume 55, Number 2, March-April 2006
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|
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Page(s) | 93 - 104 | |
DOI | https://doi.org/10.1051/animres:2006002 | |
Published online | 27 April 2006 |
DOI: 10.1051/animres:2006002
Rumen-protected choline for dairy cows: the in situ evaluation of a commercial source and literature evaluation of effects on performance and interactions between methionine and choline metabolism
Frank Brusemeister and Karl-Heinz SudekumInstitute of Animal Nutrition and Physiology, Christian-Albrechts-University, Kiel, Germany
(Received 13 May 2005 - Accepted 20 December 2005; published online 27 April 2006)
Abstract - The interactions were investigated between methionine
and choline metabolism due to interchangeable methyl groups. Feeding trials on dairy cows with choline administration were re-evaluated with a focus on methionine balance and the possible effects of supplementary choline on
methionine metabolism. In addition, in situ ruminal stability was estimated for a
commercial choline supplement. We examined six experiments that included 11 dietary treatments. The Cornell net carbohydrate and protein system was used
to estimate nutrient supply and requirements as well as methionine balance; further methionine supply was assessed according to the ideal protein
concept. The re-evaluation of feeding trials confirmed the positive effects of supplementary abomasally available choline on milk yield and health of
dairy cows. Although these effects were mainly attributed to an elevated
export of triglycerides from the liver, beneficial effects may be further
caused by an exoneration of methionine metabolism by sparing
S-adenosylmethionine. Therefore, the effects on milk yield or other response
variables of additional, abomasally available choline could serve as an
indicator of methyl group deficiency and thus methionine shortage. Since
from theoretical considerations the demand for methyl groups in dairy cows
is related to the stage of lactation, requirements for methionine and methyl
groups should be taken as separate entities and the latter should be
expressed in relation to energy balance or days in milk. Our in situ data indicate
that Reashure choline
was effectively
protected
against ruminal degradation because at least 600 g
kg-1 of
choline were in a rumen-protected form. In conclusion, (I) supplementary
choline may improve the yield of dairy cows by elevating the export of
triglycerides from the liver and by sparing methionine as a methyl donor,
and (II) the demand for methyl groups still lacks adequate consideration in
the design of diets for dairy cows.
Key words: dairy cow / requirement / methionine / choline / methyl group
Mots clés : vache laitière / besoin / méthionine / choline / groupement méthyle
© INRA, EDP Sciences 2006