Increased starch degradability in maize silage, which has been clamped for a few months or more, can lead to metabolic problems in early spring unless rations are reviewed and rebalanced.
These problems may be mitigated by including a feed ingredient, such as Diamond V XP, to promote rumen function, according to Cargill ruminant additive specialist Nick Berni.
“We can use these ingredients to promote the feed value in these home-grown forages, harness the extra energy and improve milk yields,” he explains.
“This is the ideal time to assess maize silage stocks on farm and to analyse the quality of this silage. But it’s important to understand the characteristics of maize silage.”
The fermentation rate and starch degradability of maize silage increases the longer that it is in a sealed clamp.
This can increase the production of lactic acid in the rumen, particularly if there is already a high level of fermentable energy such as rolled wheat or high sugar spring grass.
As a result, rumen pH may drop, increasing the risk of acidosis, with a negative effect on milk production and milk fat.
“It’s important to work out how this maize silage will complement the rest of the ration, including concentrates, forages and, for grazing herds, grass,” says Mr Berni.
“Starch content in maize has typically improved year on year. It’s an important nutrient for driving the production of propionate in the rumen. Propionate is transferred to the liver and is synthesized into glucose, which is the main energy source used in milk production,” he adds.
“There is the opportunity to harness this higher energy availability from maize silage and promote milk yields, even from some of the later harvested maize in 2019 that was mature and problematic.
The higher starch degradability must be balanced to maintain fibre utilisation and control the production of lactic acid in the rumen.
“Reviewing rapidly fermentable energy feeds, such as rolled cereals and molasses and fermentation feed products, in dairy diets will also help.
And including the fermentation feed material Diamond V XP in dairy diets has been shown to control starch degradability, with an improvement of 1.5 litres of milk seen in farm trials.
This feed material increases the activity of the rumen bacteria that use lactic acid as an energy source. It will also stimulate fibre digesting bacteria.”