Cheaper option than grass
By Sue Rider
CEREALS harvested as wholecrop are cheaper to ensile than grass silage now the forage is eligible for area aid payments.
Economics suggest both the fermented and urea-treated products are forage options worth considering, according to Keenan TMR specialist Donald Brown, who has devised a guide to harvesting cereals as whole-crop (see table opposite).
He believes whole-crop is also a useful alternative to maize for northern producers. "It cant compete on dry matter yield a hectare, but it can compete on yield of starch DM," he says. Whole-crop has an average starch content of 25% DM.
Although more whole-crop harvested in the UK is urea-treated, Mr Brown cites Danish success feeding the fermented product (Livestock, June 16) and favours it for its superior feeding value.
"Despite the similar starch contents of the two materials, the fermented product is more digestible," he claims. "The grain is softer, so less will be flushed through the animal.
"Fermented whole-crop does not have the free nitrogen levels of the urea-treated product. This nitrogen can upset the rumen and reduce performance when fed as over 40% of the forage in the diet."
It could replace grass silage as 100% of the forage or serve as a useful forage extender.
"The main drawback is pit face deterioration, but that is down to bad clamp management," he says.
"Consolidation is vital, as is sealing the ensiled material with a heavy-gauge plastic sheet and covering it well with tyres. Be thorough at this stage and there should be no need for an additive.
"The Danes spread a 6in layer of fresh-wilted grass over the ensiled material to seal it and prevent straw stalks piercing the sheet. Use a narrow clamp and take the feed out as cleanly as possible.
"The product should be cut earlier than the urea-treated material, at between 40% and 45% dry matter at about five weeks post ear emergence," he says. "The cereal doesnt bulk up beyond this stage, so there is no yield loss by harvesting earlier for fermented wholecrop." But he advises against going too early.
"Dont make the mistake of cutting when the crop is too green at 35% dry matter. Its still high in sugar, which ferments to lactic acid. That is fine for those seeking milk yield, but for milk protein as much sugar should have turned to starch as possible, with just a small amount left for fermentation. Going too early also risks an extended fermentation," he adds.
Regular oven dry matter measurements would help estimate harvest date.
Producers should cut a sample of the standing crop, chop, crush and weigh it, and put it in the oven for two hours. The weight difference would indicate the moisture content of the crop.
Mr Brown advises using urea-treated whole-crop only as a silage supplement for buffering acidic grass silages. "It is also a useful source of fibre and protein to stimulate rumen function when used with maize silage-based diets," he says. There are also health benefits to feeding the higher pH forage, such as reduced laminitis, acidosis and improved fertility."
Whether harvesting cereals for urea-treated or fermented wholecrop, he warns non-arable producers to proceed with caution.
"The cereal should be a 4t/acre crop that is weed-free," he says.
"Those producers who have consistently made a mess of grass silage have been the first to jump into whole-crop – and have done no better," he warns.
"Master grass silage, then try whole-crop."
From sowing to harvest as for normal cereal. Aim for a clean crop and cereal yields of 9.8t/ha (4t/acre)
VarietiesShort-strawed with high grain yield. Can use any cereal but winter wheat gives highest yields.
Harvest timing40-42% DM50-60% DM
Soft-hard cheddarHard cheddar
Can split grain with thumb,Difficult to
but no milkinesssplit grain
Green going yellowYellow, hint of green
HarvestCut with a drum/disc mowerDirect cut with combine without conditioning (or rape header mounted-swather) and pick uped on forager
immediately with forager.
AdditiveNone required. Can useTreated with urea
inoculant/acid salt towhich is converted
improve aerobic stabilityto ammonia by the
urease enzyme in the crop (see product table)
Yield DM yields 8-14t/ha (up to 17t/ha possible) for both crops.
Clamping Good consolidation in theClamp consolidation
clamp vital. Use heavy guagenot necessary since
polythene sheet for sealing.preservation relies
Cover well with tyres. Narrowon diffusion of ammoniaclamp will help reducethrough clamp. Sheeting
aerobic spoilage at feed-out.and sealing important
(Can use Ag-bag or wrapped to avoid ammonia loss.
big bales)Use side sheets from floor Face Management at feed-out
Aerobic spoilageAerobic spoilage
is a risk. Use ashould not be a
shear grab to leaveproblem.
a smooth clamp face
or loader bucket with
downward scraper action
FeedingHigher rates – up to<40% of forage in diet
100% of the forage.(<8kg fresh wt/day)
Beware lowFeed supplement
protein contenthigh in fermentable energy such as molasses to mop up excess nitrogen.
Supplement with magnesium
since Mg availability reduced
due to high pH
Whole-crop low vitamin/mineral content compared with grass silage
Main products for alkali preservation
• Urea prills – added at 30kg/t dry matter (approx 15kg/t fresh wt). Can either be applied at harvest or at the clamp. Accurate application difficult.
• Liquid urea (Hydro Nu-crop) is sprayed onto the crop at harvest at 35-40 litres/t fresh wt. High application rate demands specialist equipment.
• Home & Dry (Dugdales). Pelleted product containing urea, an enzyme designed to improve digestibility plus a feed based carrier. Application 30kg/t fresh wt.
Source: Keenan TMR Centre
Forage variable costs & 1995 arable area payments (£/ha)
Fermented whole-crop cereal5171137-259
Fermented whole-crop with
Urea whole-crop cereal5171209(2)-331
Urea whole-crop with
(silaged & grazed)919156-256
(1) Assumes soil index of 1. Adjust cost for other soils.
(2) Spray figures include cost of urea.
(3) Estimate based on latest green exchange rate. Actual payments will depend on green exchange rate on July 1, 1995, and on any base area overshoot this year.
Urea-treated whole-crop wheat is a stable, high pH forage and a buffer to acidic grass silage.