Breakthrough research, published in the Journal of Dairy Science in 2018, details the effects of the calving transition on the rumen epithelium. This study has been supplemented with metagenomics data, confirming the association between changes in the rumen microbiota and feed efficiency improvements around calving, as well as the protective role of Saccharomyces cerevisiae CNCM I-1077 to help the cows face this challenging period.
The transition period in dairy cows spans 3 weeks pre-calving to 3 or 4 weeks following calving. It represents a critical time for the cow with major dietary, metabolic and physiological changes.
In particular, the transition from a high-fibre diet to a diet high in rapidly fermentable carbohydrates represents important challenges for rumen health. It can also have a negative impact on the cow’s inflammatory status. A trial was conducted in partnership with Professor Alex Bach’s team (IRTA, Spain) at the Blanca Experimental Farm (Spain), on the impact of transition challenges on rumen health and microbiota profiles as well as the effect of live yeast.
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The trial was conducted on 21 Holstein dairy cows from 21 days before calving until 21 days after calving. The diet changed from 28% concentrate before calving (51.2% neutral detergent fibre, NDF, 13.2% crude protein, CP) to 64% concentrate after calving (34.8% NDF, 15.2% CP).
Metagenomics is the genetic identification of the whole microbiota of a host and their relative abundance. These technologies generate millions of genetic sequences. Thanks to biostatistics analysis, this data could be pooled together according to bacteria genus — which shows more than a hundred of different bacteria types. Such analysis can help microbiologists have a better understanding of the complex composition of the microbiota, like that found in the rumen.
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In the case of transition cows, the goal was to focus on the relative abundance of functionally relevant bacteria. Results from 2 main categories of microbes were combined: bacteria that degrade complex carbohydrates, such as fibre; and bacteria that degrade rapidly fermentable carbohydrates, like starch (Figure 1).
The first part of the study published in 2018 showed that feeding S. cerevisiae CNCM I-1077 from 3 weeks pre-calving positively improved the rumen dynamics by:
Dr Bach explains: “Because LEVUCELL SC cows consumed more feed, a lower rumen pH and greater relative abundance of Prevotella (rapidly fermentable carbohydrate degrader) would have been expected, unless LEVUCELL SC had exerted a positive effect on rumen pH.”
In conclusion, the live yeast — by stabilising the rumen pH despite a higher non-fibre intake — limits the burst of rapidly fermentable carbohydrates degraders.
Source and for more info: www.lallemandanimalnutrition.com.