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Structural Fibre & Rumen pH Vital This Winter


Providing adequate structural fibre and managing rumen pH will be vital this winter in light of early first cut grass silage results. 

Analysis of 150 first cut silage samples taken in late April to mid-May and tested by Mole Valley Farmers, show good energy and protein levels (see table), which should mean that cows will milk well. However, results  also show low structural fibre, combined with high acid load, which could be detrimental to milk constituents, unless balanced carefully.

Mole Valley Farmers Senior Nutritionist, Dr Robin Hawkey explains:

“Although Neutral Detergent Fibre (NDF) and Acid Detergent Fibre (ADF) are similar to last year, the lignin value is lower. So although the NDF or useable fibre is consistent, the reduced structural fibre may have implications for rumen stability, depending on other ration components. This suggests that rations will need to be balanced with adequate structural fibre, such as wholecrop wheat or barley, or straw, in order to promote rumen health.”

Lactic acid levels are also up from 57g/ kgDM to 79g/kgDM, whilst acetic and butyric acid levels are down. This should promote stable fermentation in the clamp, but will add to rumen health challenges. Dr Hawkey also warns that lactic levels are only likely  to increase the longer silage remains in the clamp, which emphasises the need to regularly test silage stocks throughout the season.

He adds: “This means that - along with providing adequate fibre - it may also be worth considering including yeasts and buffers in the ration to aid rumen health.”


Anecdotally, several of the Mole Valley Feed Solutions team have also noticed that crude protein levels in fresh grass samples in later first cuts appear lower. This further highlights the need to analyse stocks, as lower protein levels may mean that cows will need to be provided with a higher protein, 18% cake. The fact early first cut grass silage is generally high quality will promote good intakes.

However, with many farmers already eating into forage stocks and supplies looking tight for the winter ahead, Dr Hawkey advises farmers to consider ways to extend forage stocks. This could include feeding moist feeds such as brewers’ grains or fodder beet or potatoes.

To discuss your herd’s feeding requirements, please contact the Mole Valley Feed Solutions Feed Line on 01278 444829 #MVFHotTopics

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 Newsletter 625

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