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.