Patience has paid off for those dairy farmers holding off harvesting maize early, according to Kite Consulting’s Tim Davies.
According to Mr Davies analyses have varied considerably depending on when the crop was harvested, with dry matters ranging from a wet 24% to 40%DM.
“Samples taken early in the season from early to mid-October are wetter than usual with dry matters averaging about 28%, although more recent samples from those harvested late October onwards have dry matters about 32-34%DM,” he says.
These figures mirror those of Frank Wright Trouw Nutrition, which were taken from 2000 samples, with dry matters at 30.5%, protein at 8.1%, ME at 11.3MJ/kg/DM and starch at 27.6%, according to the company’s technical director, John Allen.
“There is a range in maize silage samples, but there are some greener crops which will have lower starch and dry matter contents leading to potential problems with fermentation and acidosis.”
However, with energy levels on average 0.5MJ higher than last year, this could have a significant impact on milk yield, says Dr Allen.
“The increase from ME 10.8MJ/kg/DM last year to 11.3MJ/kg/DM this year, on a 50:50 grass silage: maize silage ration is worth the equivalent of an extra 0.5 litres a cow,” he says.
And P and L Agriconsulting’s Phil Clarke has seen the benefits of not rushing into harvest.
“One of our clients who harvested some maize early had 27% DM and 26% starch level. However, compared with the crop he harvested six weeks later, figures showed a dry matter of 31% and 32% starch. This equated to an extra two litres a cow from the later crop,” he says.
But, the range in maize silage quality means particular care must be taken when balancing the rations, says The Dairy Group’s Chris Savery.
“Because many farms have been without maize silage for a while they are keen to get it back into the diet and so it needs to be balanced carefully. There could be a big incentive to use a lot of cereals to balance the ration due to good prices, but feeding too much wheat and cereal with a wet crop could lead to acidosis and subclinical cases,” he says.
Vet Rob Howe of Lambert Leonard and May, Lancashire, has seen a few outbreaks of acidosis, although not all attributable to maize quality.
“We have probably seen as many cases of acidosis this year as any other, but it’s important to try and prevent it and pick up on any sub-clinical cases. Look at what the cows are telling you; how much they are eating, how loose faeces are, cleanliness of the cow and rumen fill. Those cows scouring and swishing tails making coats dirty are likely showing signs of sub-clinical acidosis,” he says.
Mr Davies says for those farmers feeding a green, wet maize silage, adding digestible fibres sources such as soya hulls and citrus pulp in to the ration could help.
“Also, wet silage, whether grass or maize, is also a constraint on intakes, so looking at feeding whole-crop or chopped straw or trying to dry the ration could help maintain intakes and thus production and cow health,” he says.