As starch degradability of maize in the clamp increases, dairy producers are being warned to watch for the effects of rumen pH drop.

Bronwen Pihlwret, QLF nutritional adviser said: "With a turbulent outlook for milk prices, it’s essential not to underestimate the importance of re-balancing rations to maintain milk quality and diet cost-effectiveness as the season progresses.

“As farmers begin to move through maize clamps, they’ll notice that the starch degradability of the forage will improve. Therefore, it’s likely farmers will need to re-balance their rations to counteract this increase in degradability, to maximise rumen function by ensuring rumen protein and energy requirements are being met and rumen pH isn’t being disrupted."

The starch element of maize breaks down into propionic acid in the rumen which can lead to increased acidity. This in turn can depress rumen pH, so care must be taken to avoid sub clinical acidosis, particularly when fed with other cereals.

To prevent the rumen environment becoming unstable, Ms Pihlwret advises feeding molasses in the ration, to not only buffer the rumen against the possible pH drop, but also to provide a vital source of energy for rumen microbes.

She said: “Feeding molasses alongside maize with this year’s generally high protein grass silages, will provide the microbes with a source of rumen fermentable energy, to maximise forage breakdown and microbial protein production. This produces the amino acids essential for milk production."