Planning ahead is key to growing good yields of high quality wholecrop to meet the needs of the cows’ diet.
This is according to Steven Gate, agronomist with Agrovista, based in Cumbria.
Steven Gate says choosing a crop and variety which ‘the farm and farmer is able to grow well’ is of paramount importance when deciding which wholecrop will work best on the farm.
“Firstly, the grower should consider why they are growing wholecrop.
Is it just to provide an alternative forage in the diet or are there other agronomic reasons, for example, to precede a new grass ley? “It is vital to think about what the farm is capable of growing.
For example, if contractors will be needed to do the spraying, then a crop which can perform well with one pass is ideal.” Lisa Hambly, an Agrovista agronomist in the South West agrees and says she always has a conversation with farmers about their plans for the rotation in the short-, medium- and longterm when selecting which crop to grow.
“I am always looking forward to the next crop when making decisions as it is important not to sacrifice the ability to grow a catch crop or grass ley afterwards because a late-maturing maize variety has been chosen,” Ms Hambly says.
She supports the view that when choosing varieties for cereal wholecrop on livestock farms, looking at ‘untreated yields’ is important because the variety needs to be healthy as it is unlikely to receive the same level of inputs as it would in an arable situation.
Ms Hambly is an advocate of under-sowing arable silage mixture with peas, lupins or vetches for protein where the field is suitably clean.
She warns against mixed species crops where there is a weed problem in the field as the options for controlling weeds diminish dramatically where broad leaves are mixed with cereals.
Maize is a very popular crop with many of her clients but she emphasises the importance of growing an early variety.
“Do not settle for a poorer, late-maturing maize variety as in a wet harvest it can mean the soils are compromised by heavy traffic when harvesting in autumn.
It will take years of remedial work to put this right and it will impact on yields in the future,” she adds.
Fertility is rarely a problem when growing wholecrop on livestock farms due to the availability of organic manures, but Philip Cosgrave, of Yara, urges farmers to carry out a soil analysis to confirm this.
“Nutrient applications should be tailored to the results of a recent soil test.
Cereals are bulky crops which have a high nutrient requirement and it is also important to address any shortfalls in micronutrients.
“Waiting until a deficiency is evident from visual inspection of the crop is often too late, as much of the crop’s potential can be lost by this stage.
“If there is a history of a micronutrient deficiency then it’s worth being proactive and spray it on as a foliar spray, or alternatively use a crop-specific product that has been formulated to include the key micronutrients for that crops growth and development.
“Most farmers are applying sulphur containing nitrogen fertilisers, but it’s worthwhile making sure that 25-50kg/ha of SO3 is going on,” Mr Cosgrave adds.
James Duggleby, of Krone UK, says when harvesting relatively green, fresh wholecrop, it is possible to use a conventional mower and grass tedder because there is a very low risk of grain loss.
As the crop matures, more specialist equipment is necessary.
“If the content of grain is at the ‘cheesy’ stage there is a higher chance of grain loss, so a direct cut header should be used.
This will cut and load the crop when it is standing, so the grain is less likely to fall onto the ground.
“I would always recommend using a specific wholecrop header rather than a combine header, especially when the cereal is still sappy and green.
This is because the combine headers are designed to cut a dry, brittle stalk rather than a greener stem, so do not have the weight behind the blades to cut cleanly.
“When cutting for wholecrop when the cereal is almost ripe, a corn processor will be required on the harvester because the grain needs to be cracked open.
A conditioner will shear the grain open so it does not pass through the cow undigested.
“There is no hard and fast rule as to the stage of maturity which necessitates the use of a conditioner when making wholecrop.
The best advice is to regularly check the crop as it comes through and then it should be possible to gauge whether the right choice of machinery has been made and if the set-up is correct,” he says.
When harvesting maize, most growers choose to use contractors due to the cost and specialised nature of the machinery involved, Mr Duggleby adds.
Maturity The stage of maturity when the wholecrop is harvested will influence the nutritional content and dry matter and therefore how it is fed and which animals it is fed to.
Peter Smith, of Volac, suggests wholecrop can be considered as three discrete feed types depending on maturity and therefore the percentage dry matter (DM).
“Harvesting wholecrop when it is still quite green, at 30-40% DM, will give the maximum amount of fresh weight tonnage.
Where wholecrop has been undersown to establish a grass ley to follow on, harvesting early is preferable as it allows the grass to grow on in the second half of the summer.
“Most farmers will choose to harvest wholecrop at between 40-50% DM, as it gives a better starch level which encourages higher milk yields.
As the crop is quite dry, it is less aerobically stable and so using an additive such as Ecocool or Ecocorn will help to keep the ensiled crop cool.
“If growers are looking for a drier crop to provide scratch factor and more starch, they may choose to harvest at between 50-60% DM.
Wholecrop at these DM levels will be more difficult to consolidate in the clamp and is not normally fed in large quantities, Mr Smith adds.
The principles of ensiling are the same irrespective of the crop placed in the clamp, though depending on its maturity, wholecrop can be more difficult to consolidate and will ferment more readily than grass, Mr Smith explains.
“Wholecrop will tend to ferment relatively easily because it has a high starch content and does not have the protein content to buffer the pH.
Consequently the pH falls rapidly.
“The challenge with wholecrop is maintaining aerobic stability because it is fibrous and therefore it is more difficult to keep air out of the crop.
So the silage is more prone to heating and mould development.
“Consolidation is therefore key to making good wholecrop silage.
The clamp should be filled in thin layers between 10cm and 15cm (4in to 6in) to allow for thorough and equally dissipated pressure to aid compaction.
This will prevent the creation of hot pockets within the clamp.
“Also, by using an additive such as Ecocool or DA Ecocorn, the wholecrop silage is kept more stable, preventing these losses.
Both products contain Lactobacillus plantarum MTD/1 bacteria, which promotes the production of naturally-preserving lactic acid from the sugars in wholecrop.
“In addition Ecocool also contains L.buchneri PJB/1, a strain of bacteria producing acetic acid which acts as an aerobic spoilage inhibitor.
As an alternative, DA Ecocorn contains potassium sorbate along with the L.plantarum.
Potassium sorbate also prevents yeasts and moulds thus reducing spoilage.
“In summary, the preservation of wholecrop at each percentage DM level stands to benefit from one of these types of dual-acting additive – with wholecrop made at higher DM percentages in particular, where farmers are looking for improved animal performance, needing the greatest help to maintain its aerobic stability,” Mr Smith adds.
Click the links below to read the rest of the series:
Visit the series home page for more information