Pay Close Attention to Rumen Conditions to Get the Most out of Forage this Winter16 September 2016
UK - With many of the year’s grass silages higher in fibre and lower in energy than in 2015, maintaining ration energy levels and maximising milk from forage could be a challenge this winter, warns Dr Derek McIlmoyle, AB Vista’s Technical Director for GB and Ireland.
“The rumen will need to be working at its very best if cows are to fully utilise the fibre in forages once housed on full winter rations,” he explains. “The milk production potential of these forages is already lower, so it’ll be important to avoid overloading the rumen with too much starch trying to make up the energy deficit.
“Unless done carefully, you might solve the energy problem but it will be at the expense of causing another – sub-acute ruminal acidosis (SARA).”
According to Dr McIlmoyle, managing feed to minimise the risk of SARA – and low rumen pH in general – is essential if the breakdown of forage fibre in the rumen is to be optimised. Although pH 5.5 is considered to be the threshold for SARA, fibre digestion and fermentation efficiency are both compromised any time rumen pH drops below 5.8.
“Only by ensuring the rumen spends as much time as possible close to its optimum pH 6.0 can the maximum potential be extracted from the forage in the diet and bought-in feed costs be kept to a minimum.
“Where starch levels are high, at least consider using a slow-release rumen conditioner such as Acid Buf to counter the high risk of SARA,” he adds. “The same applies where silages are at the other end of the spectrum, being high in feed value but wet and acidic.
“It’s also sometimes necessary to add a metabolically active yeast like Vistacell to help ‘mop up’ excess oxygen in the rumen which fibre-digesting microbes are sensitive to. In fact, research has shown that when the rumen acid load is high, using a yeast and rumen conditioner together, rather than just yeast on its own, can produce a significant improvement in rumen function and feed efficiency.”
For more information, contact AB Vista on +44(0)1672 517 650 or firstname.lastname@example.org.
TheCattleSite News Desk