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Yeast supplementation in ruminant: effects on the susceptibility to acidosis and on feeding behaviour (application to dairy goats)

Abstract : Sub-clinical acidosis is poorly detected and is not easily prevented in intensive herds because it is mainly characterized by instability of intake, production and rumen parameters. A meta-analysis performed on 110 papers showed that yeast supplementation can stabilize rumen fermentations, especially in animals with high intake levels and fed high concentrate diets. Feeding a high concentrate diet led to subclinical acidosis (pH < 6.25), and a variable number of spontaneous bouts of acidosis depending on the goat. These acidosis bouts could influence milk production during several weeks. Daily measurements of rumen pH, intake and milk production were used to model the day-to-day evolution of these parameters during bouts of acidosis. This model is a first step towards a more mechanistic model of sub-clinical acidosis. Several methodologies were developed in order to simultaneously and continuously record intake, rumen pH and chewing behaviour (time scale around one minute) during several weeks. These measurements allowed to design a new method to analyse intake kinetics by segmentation / classification and to determine some typical feeding behaviours, observed whatever the offered diet, and more or less stable depending on the goat. These types of feeding behaviours lead to different rumen pH kinetics despite a similar daily intake. Bouts of acidosis were characterized by a very low intake and a diminution in nycthemeral organisation of feeding behaviour. However, no relationship was found between feeding behaviour variability and goat susceptibility to acidosis. Taking the bouts of acidosis into account for the analyses of yeast supplementation effects allowed to avoid confounding effects. Yeast supplementation increased milk yield without influencing dry matter intake or milk fat and protein production. This might have been due to the higher sorting behaviour performed by supplemented goats which allowed them to eat a less fibrous diet than the one eaten by control goats. Yeast supplementation tended to increase ruminal biodiversity, which might explain the fact that the decrease in the percentage of fibre ingested by supplemented goats compared to control goats did not influence rumen pH. This study showed that spontaneous bouts of acidosis can lead to many drastic consequences and showed the relevance of analysing feeding behaviour in order to better understand the modifications in digestive or metabolic parameters.
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https://pastel.archives-ouvertes.fr/pastel-00004763
Contributor : Ecole Agroparistech <>
Submitted on : Thursday, February 12, 2009 - 8:00:00 AM
Last modification on : Wednesday, July 25, 2018 - 1:23:46 AM
Long-term archiving on: : Thursday, September 30, 2010 - 9:03:41 PM

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Marion Desnoyers. Yeast supplementation in ruminant: effects on the susceptibility to acidosis and on feeding behaviour (application to dairy goats). Life Sciences [q-bio]. AgroParisTech, 2008. English. ⟨NNT : 2008AGPT0042⟩. ⟨pastel-00004763⟩

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