Corn silage: frequently asked questions

About the product

What exactly is corn silage?

Corn silage is the whole maize plant — stalk, leaves, cob and grain — chopped and preserved by fermentation rather than by drying.

The crop goes in wet and is sealed away from air. Lactic acid bacteria already living on the plant ferment the plant sugars into lactic acid. The acid drops the pH, the low pH stops everything else growing, and the forage holds in that state until air gets back in. It is pickling, applied to a fodder crop.

Two things have to be right. The crop must be cut at the correct moisture, and the seal must be airtight. Get either wrong and you have a spoiled bale rather than feed.

We harvest at the milk-line stage, chop, and bale into 60–70 kg bales wrapped in multi-layer UV-resistant film. Each bale is its own sealed silo.

How is corn silage different from hay, maize stover and fresh green fodder?

The numbers make the point better than the words do. Published averages for maize silage are 10.8 MJ/kg DM of metabolisable energy at 71.7% organic matter digestibility in the 30–35% dry matter band. Maize stover, the same crop after the grain has been taken off, sits at 6.9–8.4 MJ/kg DM and 49–59% organic matter digestibility, with crude protein down at 3.9% of DM in the dry material. Stover also loses roughly 1.5 percentage points of digestibility per week after harvest (Feedipedia).

So: silage keeps the grain, keeps the energy, and does not depend on a dry weather window. What it is not is a protein feed. At around 7% crude protein in dry matter it has to be balanced with something else.

What is the milk line, and why does harvest timing matter?

As a maize kernel matures, starch lays down from the crown of the kernel towards the base. The boundary between the hard starch above and the milky liquid below is the milk line. Break a cob, look at the kernels side on, and you can see it. It moves down the kernel as the crop matures.

It is a free field indicator of whole-plant dry matter. Feedipedia's harvest recommendation for maize forage is 30–35% whole-plant dry matter, and it puts the milk line one third to two thirds of the way down the kernel — roughly 50 to 55 days after silking — at a dry matter of 32–38%. Treat the milk line as the way to find the window in the field, not as the measurement itself.

Cut too early, and the crop is too wet. Effluent runs out of the bale, fermentation goes clostridial and butyric, intake drops and energy is lost.

Cut too late, and the crop is too dry. It will not compress, so air stays trapped inside. Fermentation is weak, kernels are hard enough to pass through the animal undigested, and mould risk goes up.

The number that actually matters is whole-plant dry matter. The milk line is how you find it standing in the field without a moisture meter. Confirm it with a moisture test before the chopper moves.

Why bale and wrap silage instead of building a pit or bunker?

Pits and bunkers are cheaper per tonne at large scale. They also assume you have the land, the compaction machinery, the labour and a herd big enough to work through the open face faster than it spoils.

Bales suit buyers who do not:

• No civil works, no sheeting, no tyres, no tractor packing.
• Every bale is a sealed unit. Damage to one bale is not damage to the batch.
• You open only what you feed that day, so there is no open face heating up.
• You can buy two tonnes or two hundred.
• Bales load onto a trolley, a pickup or into a container. A pit does not travel.

The trade-off is film cost per tonne, and the fact that film integrity becomes everything. One puncture spoils one bale.

What does a bale weigh, and how many bales are in a tonne?

Our bales are 60–70 kg wrapped.

One maund is 40 kg, so one tonne is 25 maunds.

Bale weight is as fed — wrapped, including moisture. When you compare prices between suppliers, compare on dry matter and not on fresh weight. A tonne of 35% DM silage carries 350 kg of actual feed. A tonne of 25% DM silage carries 250 kg of feed and 750 kg of water. Same tonne, very different value, and you paid freight on the water either way.

the bale weight tolerance you are willing to quote in writing within the 60–70 kg range, e.g. 65 kg ± 5 kg, and whether bales are weighed individually or by load

Can I feed corn silage to buffalo, and how much per head per day?

Yes. Buffalo handle it well — arguably better than cattle handle roughage generally. FAO's work on feeding riverine dairy buffalo reports that buffalo out-perform cattle in digesting dry matter and crude fibre from low-quality roughage such as rice straw, and digest good-quality roughages such as berseem hay about equally well. Corn silage is a good-quality roughage.

FAO's general position for lactating buffalo is that roughage should make up around 50% of total ration dry matter, with fattening rations running higher concentrate levels of 65–80%.

A worked example, for illustration only:

• A 500 kg lactating buffalo eating dry matter at 2.5–3% of body weight consumes roughly 12–15 kg DM per day.
• At 50% roughage, that is 6–7.5 kg DM from forage.
• If the silage tests at 32% DM and is the only forage, 6–7.5 kg DM works out to roughly 19–23 kg of fresh silage per head per day.

Those figures are arithmetic, not a recommendation. Your actual numbers depend on body weight, milk yield, stage of lactation, what else is in the ration, and the tested dry matter of the silage you actually buy. Work them out with your nutritionist or veterinary officer.

Two rules apply whatever the species:

1. Introduce it gradually, over 7 to 14 days. Rumen microbes need time to adapt to a new fermentation profile.
2. Balance the protein. Corn silage runs around 7% crude protein in dry matter. A buffalo in milk needs considerably more than that across the whole ration, so silage has to be paired with a protein source.

any feeding rates you have actually observed on customer farms, or a note that you do not publish feeding rates and refer buyers to their own nutritionist

Quality and testing

What dry matter should good corn silage have?

The industry target for whole-plant maize at ensiling is 30–35% dry matter. Published averages for maize silage (Feedipedia) look like this:

Note the starch column. Later harvest within the correct window puts more grain into the bale, which is where the energy comes from.

Below about 30% DM — Feedipedia's threshold — you get effluent loss, clostridial fermentation, butyric silage and depressed intake. Above about 38% DM the material will not pack, air stays in, fermentation is incomplete and the silage becomes unstable once opened.

Our published range: your measured dry matter % range across batches, e.g. 30–35%

How do I tell good silage from bad without a lab?

Open a bale and use your senses. Good corn silage:

• Smells clean and slightly sharp — acidic, a bit like pickle or sourdough. Not offensive.
• Looks olive-green through to light golden brown. Kernels visible and cracked.
• Feels moist but does not drip when you squeeze a fistful hard. It springs back. Nothing slimy.
• Is uniform — same colour and texture right through the bale, not just at the surface.

Bad silage announces itself:

• Rancid butter or vomit smell means butyric acid, which means clostridial fermentation, which usually means it was ensiled too wet.
• Sharp vinegar or a solvent smell means excess acetic acid or ethanol, and heavy fermentation losses.
• Dark tobacco brown with a sweet caramel smell means it heated. The protein is bound and the animal cannot use it.
• Slimy, dark and foul means throw it out.
• White, blue-green, black or pink patches are mould.

If you can test, pH is the most useful single number. Kung and Shaver's reference fermentation values put well-fermented corn silage at pH 3.7–4.2; Penn State's production guide gives a slightly wider 3.5–4.3. Indicator strips cost almost nothing. A pH above about 4.5 means fermentation did not complete, and above 5.0 the material is not safely preserved.

Do not buy wrapped silage on the strength of the outside of the bale. Ask for one to be opened.

Which lab numbers should I ask for, and what do they mean?

Composition figures above are published averages for maize silage from Feedipedia, not a guarantee for any particular consignment.

Ash is the underrated one. Maize silage is naturally low in ash, so a high ash figure usually means soil was picked up at chopping. Soil brings Clostridia and Listeria in with it. If ash is high, ask why.

which of these parameters you routinely test, which laboratory you use, and whether a certificate of analysis accompanies each consignment

What causes mould in a wrapped bale, and can I feed a mouldy bale?

Mould needs oxygen. In a properly sealed bale there is essentially none left after the first days of fermentation. So mould in wrapped silage nearly always means air got back in. The usual routes:

• Punctures from stubble, stones, wire, bale spears or careless handling.
• Birds and rodents. Crows and rats will open film given a week.
• Too few film layers, or film stretched thin over the shoulders of the bale.
• Baling too dry, so air was trapped inside from the start.
• Storing on uneven ground, where bales deform and the seal breaks.
• A long delay between baling and wrapping.
• Film degrading over an extended season outdoors.

On whether to feed it:

• A small surface patch at a puncture point — cut it out generously, discard that portion, feed the rest, and use that bale the same day.
• Mould running through the bale — discard the bale. One bale costs very little next to an abortion or a fortnight of depressed yield.
• Never feed visibly mouldy silage to pregnant animals. Poorly fermented, high-pH, soil-contaminated silage is the classic source of Listeria monocytogenes, which causes listeriosis and abortion in ruminants.

Moulds found in silage include Penicillium species (blue-green), Aspergillus (grey-green, and the aflatoxin producer) and Fusarium species carried in from the field. Not all of them produce toxins, and you cannot tell which is which by looking. Visible mould is a reason to reject, not a reason to test and hope.

What mycotoxin limits should I be checking against?

Aflatoxin B1 matters most for dairy, because a lactating animal excretes part of what she eats into her milk as aflatoxin M1. That makes it a food safety question and not only a herd health question.

The EU limits under Directive 2002/32/EC, expressed relative to a feed with 12% moisture content, are widely used as a reference point outside Europe as well:

• Feed materials: 0.02 mg/kg (20 µg/kg) aflatoxin B1
• Compound feed for dairy cattle and calves, dairy sheep and lambs, dairy goats and kids: 0.005 mg/kg (5 µg/kg)

The dairy limit is four times stricter than the general one. That is deliberate.

Codex Alimentarius sets the international framework rather than a single silage number — CXC 54-2004, the Code of Practice on Good Animal Feeding, supported by CXG 80-2013 on risk assessment for feed and CXG 81-2013 on prioritising hazards in feed.

For Gulf shipments, the GCC Standardization Organization (GSO) maintains Gulf-wide standards, and UAE consignments are assessed against whatever is in force at the time of import. Confirm the applicable standard and its limits with your importer or clearing agent before you contract. These change.

If the season was wet or the crop was stressed, it is also worth screening for deoxynivalenol (DON), zearalenone and fumonisins. Those are Fusarium toxins that come in from the field rather than forming in storage, so no amount of good ensiling removes them.

which mycotoxins you test for, at what frequency (per batch / per consignment / per season), and which laboratory issues the report

How long does wrapped silage keep?

There are two different clocks.

Sealed and undamaged. Wrapped bale silage will hold for a season and beyond, provided the film is intact, the fermentation was sound and the bales are stored out of direct sun on a clean surface. The limiting factor is the film, not the silage. Inspect regularly and patch any puncture with silage tape the day you find it.

Once opened. Now the clock runs in days, not weeks. Air reaches the surface, yeasts begin consuming the lactic acid, pH climbs, moulds follow and the bale heats. In Punjab or Gulf summer temperatures this moves fast. Plan to feed out an opened bale within roughly 24 to 48 hours in hot weather.

Before you feed at all. Fermentation has to finish first. As a general rule, leave bales sealed for at least three to four weeks after wrapping. Starch digestibility keeps improving for several months after that, so older silage within its shelf life is often better silage.

the shelf life you are willing to state in writing, e.g. "12 months from wrapping if the film is undamaged", and whether you date-stamp bales

Buying in Pakistan

What is your minimum order, and how is silage priced?

Minimum order: your domestic minimum order quantity, in tonnes, bales or full trolley loads

Pricing basis: whether you price per bale, per tonne as-fed or per tonne of dry matter, and your current price or price range

Whichever basis a supplier quotes on, do the dry matter arithmetic before you compare. Take two offers at the same headline price of P rupees per tonne:

Supplier B is about a third more expensive per unit of real feed, and you paid freight on 750 kg of water in every tonne. Ask for tested dry matter before you compare anything.

Where do you deliver in Pakistan, and how does it arrive?

We grow on our own farms in Punjab, and chop, bale and wrap the crop ourselves.

• Delivery area and freight: the districts or provinces you deliver to, whether freight is included or charged separately, and the minimum load for delivery
• Vehicles: typical delivery vehicles — tractor trolley, Mazda, trailer — and bales carried per load
• Collection: whether buyers can collect ex-farm, and from which locations

When a load arrives, inspect it before it is unloaded:

1. Walk the load and look for tears, punctures and loose film.
2. Note any damaged bales on the delivery document before you sign it.
3. Have a clean, level, well-drained spot ready. Do not unload onto stubble, gravel or scrap.

Is silage available all year, or only at harvest?

Silage is made at harvest and fed all year. That is the entire point of making it.

Pakistan's fodder calendar has two lean windows — broadly the hot gap between the rabi and kharif fodder crops, and again in mid-winter. Green fodder is short and dear in both, which is exactly when herds are under heat or cold stress and least able to absorb a feed gap. Silage made at the peak of the season carries known, tested feed across those windows.

In practice that makes buying a stocking decision rather than a weekly one. Work out how many days of feeding you need to cover, multiply by head count and daily feeding rate, add a margin for waste, and buy that quantity while it is available.

Availability: your harvest windows, whether you hold year-round stock, and lead time from order to dispatch

Can I see it or get a sample before I commit?

You should. Nobody should buy wrapped silage on the strength of the outside of a bale.

Our head office is at 52 A3 Johar Town, Lahore. Our research farm is Highlight Research Farm, Bahawalnagar Road, Arifwala 57450. We breed our own hybrid corn genetics and inbred lines.

• Visits: whether buyers can visit, which locations, and whether an appointment is required
• Samples: whether you provide sample bales, at what cost, and whether that cost is credited against a first order
• Analysis: whether you supply a laboratory analysis before purchase, and for which parameters

When you inspect, ask for a bale to be opened in front of you. Smell it. Squeeze a handful. Look for cracked kernels. Put a pH strip on it if you have one.

How should I store bales on my own farm?

Keeping the film intact is the whole job.

Site. Flat, well-drained, hard or compacted ground. Not on stubble, stones, gravel or scrap metal. Away from tree lines where birds perch and branches drop.

Stacking. Stack conservatively, and only as high as the bales hold their shape. Over-stacking deforms the bales at the bottom, and a deformed bale has lost its seal. the stacking height you recommend for your bale size

Pests. Rats and crows will open film within days if nothing is done. Bait, net or fence, and check after every storm and after any machinery has moved nearby.

Repairs. Keep a roll of silage repair tape where the bales are, not in an office. Patch every puncture the day you find it.

Heat and sun. The film is UV-resistant, but shade still helps through a Punjab or Gulf summer. Do not throw dark tarpaulins over bales — they trap heat rather than releasing it.

Handling. Use grabs or handlers designed for wrapped bales. Do not spear them and do not roll them across rough ground.

Feed-out. Open only what will be eaten within a day or two.

Export and shipping

Do you export, and from which port?

We sell silage domestically across Pakistan, and we are set up to serve export buyers.

your actual export status — whether you are currently shipping abroad, to which countries, since when, and whether you can provide trade references

How the lane works, as general trade knowledge rather than as a description of our own shipments: silage exported from Pakistan moves by road to Karachi, which handles the bulk of the country's general cargo, and sails from there. Gulf-bound cargo is normally discharged at Jebel Ali, the main import and transhipment gateway for the UAE. The requirements on that lane are the same for any exporter — an import permit obtained by the buyer before shipment, a phytosanitary certificate issued by the exporting country's NPPO, and whatever analysis or fumigation the permit specifies. Those are covered in the answers below.

• Order size: your typical and minimum export order size

How many tonnes fit into a 40ft container?

Start with the container, not the cargo.

Some newer equipment is plated higher. The authoritative figure is the CSC plate on the actual container, not a table.

Wrapped silage is dense relative to its volume, so a container of it is normally weight-limited rather than volume-limited — you reach the payload ceiling well before you run out of cubic metres. Two things routinely cut the usable payload below the nominal figure:

• Road weight limits at origin and at destination, which are often lower than what the container itself can legally carry.
• Carrier, terminal and route restrictions, which vary.

Bale count per container depends on bale dimensions and stacking pattern, so it is a figure to ask for rather than calculate.

the tonnage and bale count you actually load into a 40ft container, and whether bales are loose-stacked or palletised

What is a phytosanitary certificate, and who issues it in Pakistan?

A phytosanitary certificate is an official document issued by the National Plant Protection Organization (NPPO) of the exporting country. It certifies that a consignment of plants or plant products has been inspected and, where required, tested according to appropriate procedures; that it is considered free from the quarantine pests specified by the importing country; and that it otherwise conforms to that country's phytosanitary import requirements.

The format and wording are standardised internationally under the International Plant Protection Convention, in ISPM 12, Phytosanitary certificates. That is why the document looks the same whichever country issues it.

In Pakistan the NPPO is the Department of Plant Protection, under the Ministry of National Food Security and Research. Inspection and certification are arranged through DPP before the consignment sails.

One point importers get caught by: the certificate is issued against the importing country's requirements. Send your import permit and its stated conditions to the exporter before shipment so that the correct additional declarations appear on the certificate. A certificate that is missing a required declaration will hold a consignment at the destination port even though nothing is wrong with the cargo.

confirm you obtain phytosanitary certification for every export consignment, and whether fumigation is carried out as standard or on request

What documents are needed to import corn silage into the UAE?

The usual document set for an agricultural consignment arriving at Jebel Ali.

Provided by the exporter:

• Commercial invoice
• Packing list
• Bill of lading
• Certificate of origin
• Phytosanitary certificate from the exporting country's NPPO
• Fumigation certificate, if the import permit calls for one
• Laboratory certificate of analysis, if the importer or the permit requires it

Arranged by the importer:

• Import permit from the UAE Ministry of Climate Change and Environment (MOCCAE) for agricultural and feed consignments, obtained before shipment
• Customs declaration filed through the relevant customs authority — Dubai Customs for Jebel Ali
• A valid trade licence covering the activity
• Any product registration or conformity requirement in force at the time

Two practical warnings.

Get the permit first. Permit conditions determine what the exporter must declare on the phytosanitary certificate. Shipping first and permitting afterwards is how containers end up sitting on the quay accruing demurrage.

Requirements change. Confirm the current list with your clearing agent or with MOCCAE directly before you contract. Nothing on this page substitutes for that check.

On classification: the HS code you declare for baled maize silage on export documentation. Tariff classification is decided by the importing country's customs authority, so have your broker confirm it rather than assuming a code carries across from another market.

which of these documents you issue as standard, and whether you help importers with permit applications

Will the bales survive the sea leg and Gulf summer heat?

Fermentation is complete before the bale is loaded, and inside a sealed bale there is no oxygen. Heat on its own does not spoil sealed silage the way it spoils fresh fodder. What spoils silage is air.

So the risks on an export leg are mechanical and procedural rather than thermal:

• Handling damage. Punctures during loading, stuffing, unstuffing and yard movement.
• Stacking pressure. Bales at the bottom of a tall stack deform, and a deformed bale has broken its seal.
• Time standing. A container waiting in the sun with one damaged bale inside will show it on arrival.
• Delay after unstuffing. Once bales are opened at destination, the 24–48 hour feed-out rule applies, and applies harder in Gulf summer conditions.

What reduces the risk is adequate film layers, careful stuffing with proper dunnage, and documented inspection at both ends. Photograph the load before the doors close and again when they open. It settles claims in an afternoon instead of a month.

your number of film layers, loading and dunnage method, and whether you photograph or independently inspect each container before sealing

Payment and terms

Which Incoterms do you quote?

Incoterms 2020, published by the International Chamber of Commerce, define who arranges and pays for carriage, who carries the risk at each stage, and who handles export and import clearance. There are eleven rules.

• Any mode of transport: EXW, FCA, CPT, CIP, DAP, DPU, DDP
• Sea and inland waterway only: FAS, FOB, CFR, CIF

For containerised cargo the ICC recommends the "any mode" rules — FCA, CPT, CIP, DAP — rather than FOB, CFR or CIF. Container cargo is handed over at a terminal, not lifted over a ship's rail, so the sea-only rules put the risk transfer point somewhere that does not match what physically happens. FOB and CIF are still used constantly for containers out of habit. Use them if your bank or your buyer insists, but know where the mismatch sits.

Terms we quote: which Incoterms you sell on, e.g. EXW Arifwala, FOB Karachi, CFR Jebel Ali, DAP customer site

Whatever term you agree, name the place. "FCA" on its own means very little. "FCA Karachi Port, Incoterms 2020" is a term you can enforce.

What payment methods and terms do you accept?

Domestic: domestic payment methods accepted — bank transfer/IBFT, pay order, cheque, cash — and whether advance, part-advance or credit terms apply

Export: your export payment terms, e.g. advance TT percentage with balance against documents, or irrevocable LC at sight

For reference, the instruments normally used in this trade:

• Advance telegraphic transfer (TT). Simplest and cheapest. All of the risk sits with the buyer.
• Irrevocable documentary letter of credit, at sight or usance. The buyer's bank undertakes to pay against compliant documents. Governed by UCP 600. Costs more and protects both sides.
• Documentary collection — documents against payment (D/P) or documents against acceptance (D/A), handled bank to bank under URC 522. Cheaper than a letter of credit, with less protection.
• Open account. Goods first, payment later. Only sensible once a relationship has a history.

First export orders between parties with no track record are usually done on advance TT or a confirmed letter of credit. That is not a negotiating position, it is just where two strangers start.

What happens if the delivered quality does not match the agreed spec?

Agree the mechanism before the goods move, not after they arrive.

A workable structure has five parts:

1. Specification in writing. State the parameters you are actually contracting on — dry matter and pH at minimum, plus whichever of crude protein, starch, NDF and mycotoxin limits matter to you — each with a tolerance. A specification without tolerances is not a specification.
2. Sampling method agreed. How many bales are sampled, by whom, at which point (loading or discharge), and how samples are split and sealed so both parties hold an identical retained sample.
3. Nominated laboratory. Name it in the contract, and name a referee laboratory for the case where the two parties' results disagree.
4. Remedy defined. Price adjustment, replacement or rejection, with the threshold that triggers each one.
5. Time limits. How many days after discharge a claim can be raised, and what evidence has to accompany it.

For export shipments, an independent surveyor at loading, at discharge, or both, removes most disputes before they start. The fee is small next to a container in limbo.

Our policy: your written quality guarantee, tolerances, claims window, sampling method and remedy process

Talk to us

WhatsApp +92 310 4603311 or email [email protected]. Tell us head count, species, what you are feeding now, and where you are. That is enough for a straight answer on quantity, availability and price.

Head office: 52 A3 Johar Town, Lahore. Highlight Research Farm: Bahawalnagar Road, Arifwala 57450.

Sources

• Feedipedia, Maize silage — composition, energy values and harvest stage guidance: https://www.feedipedia.org/node/13883
• Feedipedia, Maize stover — composition and digestibility decline: https://www.feedipedia.org/node/16072
• FAO, Feeding riverline buffaloes for milk/dual purpose production, in Feeding Dairy Cows in the Tropics (FAO Animal Production and Health Paper): https://www.fao.org/4/t0413e/T0413E09.htm
• Penn State Extension, Corn silage production and management — fermentation targets, ammonia nitrogen below 5% of total N, pH range: https://extension.psu.edu/corn-silage-production-and-management
• Kung and Shaver, Interpretation and use of silage fermentation analysis reports (University of Wisconsin Extension) — reference fermentation values for corn silage: https://fyi.extension.wisc.edu/forage/files/2014/01/Fermentation.pdf
• FAO, Silage making in the tropics with particular emphasis on smallholders (Plant Production and Protection Paper 161, 2000): https://www.fao.org/4/x8486e/x8486e00.htm
• European Union, Directive 2002/32/EC on undesirable substances in animal feed, consolidated text — aflatoxin B1 limits: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02002L0032-20191128
• Codex Alimentarius, animal feed thematic area — CXC 54-2004, CXG 80-2013, CXG 81-2013: https://www.fao.org/fao-who-codexalimentarius/thematic-areas/animal-feed/en/
• International Plant Protection Convention, International Standards for Phytosanitary Measures, including ISPM 12 Phytosanitary certificates: https://www.ippc.int/en/core-activities/standards-setting/ispms/
• International Chamber of Commerce, Incoterms 2020: https://www.iccwbo.org/business-solutions/incoterms-rules/incoterms-2020/

General composition figures on this page are published industry averages for maize silage, not measured values for any particular consignment. Ask for a laboratory analysis of the batch you are actually buying.