Corn Silage

What corn silage is

Maize is cut as a whole plant while it is still green and still carrying moisture. It is chopped into short lengths, packed tightly to exclude air, and sealed. Bacteria already present on the crop convert plant sugars into lactic acid. The acid drops the pH low enough that nothing else can grow. The forage is then stable for as long as the seal holds.

Maize is one of the easiest crops in the world to ensile. It carries a high load of water-soluble carbohydrate and has low buffering capacity, so the pH falls fast and stays down. Grasses and legumes fight back; maize does not. This is why corn silage is the base forage in intensive dairy systems from Wisconsin to the Punjab.

For a buffalo or crossbred herd in Pakistan, the practical argument is simpler. Green fodder supply is seasonal. Silage lets you carry summer maize into the winter gap, or the other way round, without losing the energy. For an importer in the Gulf with no arable land behind them, silage is the only way to buy forage that still has starch in it.

How the fermentation works

Ensiling runs in four phases. The published description below follows the FAO review of silage fermentation processes.

Phase 1 — aerobic. Oxygen trapped between the chopped particles is consumed by plant respiration and aerobic microbes. It normally takes only a few hours. Every hour of it burns sugar you wanted to keep, which is why speed from chopper to seal matters more than almost anything else.

Phase 2 — fermentation. Once oxygen is gone, lactic acid bacteria dominate. This continues for several days to several weeks and drives pH down into the 3.8-5.0 range. Homofermentative bacteria produce more than 85% lactic acid from glucose and give the fastest, most efficient pH drop. Heterofermentative species produce lactic acid plus acetic acid, ethanol and carbon dioxide — less efficient in dry matter terms, but the acetic acid they produce suppresses yeasts and improves stability once the bale is opened.

Phase 3 — stable storage. Microbial populations fall away. Provided the seal holds, very little happens. This is the phase your silage should spend most of its life in.

Phase 4 — feed-out. Air re-enters. Yeasts that survived the acid conditions begin degrading lactic acid to carbon dioxide and water, the pH rises, and moulds follow wherever oxygen has reached. FAO's wording is precise and worth keeping precise: spoilage losses of 1.5-4.5% of dry matter per day can be observed in the affected areas — that is, in the zones air has actually reached, not uniformly across the whole exposed face. It is still the number that should govern how fast you feed out.

Two failures are worth naming. Clostridium tyrobutyricum converts two molecules of lactic acid into one of butyric acid plus hydrogen and carbon dioxide — it undoes the fermentation. Clostridial silage shows pH above 5, high ammonia and butyric acid above 5 g/kg DM. Separately, enterobacteria and clostridia break protein down to ammonia, which raises the buffering capacity of the crop and works against the very pH drop you need. Both problems are driven by wet material and slow sealing.

Milk-line harvest timing

The milk line is a visible boundary on the maize kernel. Cut a cob in half, or snap it and look at the kernel face. Starch deposits from the crown of the kernel downwards, and the line between the hard, opaque starch above and the soft, milky material below is the milk line. It starts at the top of the kernel and moves down as the grain fills. When it reaches the base, the kernel has a black layer and the plant is physiologically mature.

The milk line matters because it tracks two things at once: how much starch has been laid down in the grain, and how much moisture is left in the whole plant.

• Too early (milk line barely started). The plant is wet, the grain is not filled, starch content is low and fibre content is proportionally high. Feedipedia's maturity data shows maize silage cut below 25% DM at around 14.6% starch and 49.3% NDF, against roughly 29-32% starch and 44% NDF for the same crop cut at 30-40% DM. You also lose sugar and nutrients in effluent.
• Too late (past black layer). The plant is dry, the stover has lignified, the kernels are hard and the crop will not compact. Hard kernels pass through the animal undigested unless they are cracked at chopping.

Published targets differ slightly by source, which tells you something useful — this is a window, not a point. Feedipedia gives the optimum as milk line between one-third and two-thirds down the kernel, corresponding to 32-38% whole-plant dry matter, typically 50-55 days after silking, while recommending harvest at 30-35% DM. University of Wisconsin-Madison Extension advises targeting 33-37% dry matter between two-thirds and three-quarters milk line. In practice most commercial operations aim between half and two-thirds milk line.

One caveat you should hold onto, because it is the single most useful thing an agronomist will tell you about harvest: milk line is an indicator, not a measurement. Penn State Extension is explicit that moisture content cannot be determined accurately from kernel milk line because it varies with hybrid and weather. The milk line tells you when to start testing. A dry matter test tells you when to cut. Anyone selling silage should be measuring dry matter directly, on their own crop, on the day.

We harvest at the milk-line stage. state the milk line fraction you target, e.g. 1/2 to 2/3, and whether whole-plant dry matter is measured before cutting

The dry matter window

Corn silage is made between about 30% and 38% dry matter, and the harvest target used throughout this site is 30-35% DM. That is what Feedipedia recommends, and it matches Penn State's storage-specific guidance of 65-70% moisture (30-35% DM) for horizontal silos; Penn State puts bags slightly drier at around 65% moisture (35% DM), and Wisconsin targets 33-37%. Feedipedia notes that below 30% DM the risk of bacterial and fungal spoilage rises. An FAO field report from tropical Australia puts it bluntly: ensiling material below 30% DM will almost certainly produce poor silage with high wastage.

Below about 30% DM you get:

• Effluent. Sugars and soluble nutrients run out of the bottom of the stack or bale. It is a direct loss of the most digestible fraction.
• Clostridial fermentation. Wet, low-sugar conditions favour clostridia, giving butyric acid, high ammonia-N and a pH that will not come down.
• Rancid smell and depressed intake. Cattle and buffalo will eat less of it.

Above about 38% DM you get:

• Poor compaction. Dry material springs back and traps air. Trapped air means a long Phase 1, more sugar burnt, and pockets where mould can establish.
• Hard kernels. Starch that the animal cannot reach. Kernel processing becomes critical, and chop length has to come down.
• Poor aerobic stability. Silage made too dry heats faster once it is opened.

Dry matter is the first number on any spec sheet for a reason. Everything else is conditional on it.

Chopping, processing and packing

Chop length balances two things: short material packs densely and ferments cleanly, long material provides effective fibre for rumen function. Feedipedia gives conventional chop lengths for maize silage in the 8-10 mm to 11-15 mm range, with shredlage-type processing at 26-30 mm; kernel-processed practice in the United States commonly runs a theoretical length of cut of around 19-26 mm. Whatever the machine is set to, the setting is adjusted for crop dry matter and for how much effective fibre the ration needs — drier crop, shorter chop, so it still packs.

Kernel processing is not optional at milk-line maturity. Rolls running at differential speed crack the grain so the starch is available. Wisconsin Extension's guidance is to keep the processor tight and to tighten it further as the crop dries; if you are harvesting on the early side, open the processor slightly and lengthen the chop. Uncracked kernels in the manure are the cheapest quality audit there is — do it on your own farm after a week of feeding.

Our settings: chop length your chop length setting in mm, kernel processing your kernel processor spec, roll gap and speed differential. Inoculant: state whether you apply a bacterial inoculant, and which — or state that you do not.

Reading a spec sheet

Here is what each figure tells you, and the general industry range for well-made corn silage. Ask for all of them. A seller who can only give you dry matter and a price is guessing.

Dry matter (DM). Everything else on the sheet is expressed as a percentage of DM, so DM is the conversion factor between the sheet and the lorry. At 33% DM, a tonne of silage carries 330 kg of actual feed and 670 kg of water. Always compare prices on a dry matter basis, not a fresh weight basis. At 26.8 maunds to the tonne (37.32 kg to the maund), you are paying for roughly 8.8 maunds of feed and 18 maunds of water.

Crude protein (CP). Corn silage is not a protein feed. Published values sit between about 5% and 10% of DM and fall as the crop matures — Feedipedia records 8.0% at under 25% DM against 6.8% at 35-40% DM. You will be balancing with oilseed cake or another protein source regardless. Do not pay a premium for CP in corn silage; pay for starch.

Starch. This is what you are actually buying. Feedipedia gives corn silage starch as highly variable, 18-37% of DM, rising sharply with maturity. Starch is the energy that drives milk yield. A silage with high starch and correctly cracked kernels does work that grain would otherwise have to do.

NDF (neutral detergent fibre). Total cell wall. It drives gut fill and therefore how much the animal can eat. Higher NDF means lower intake potential.

ADF (acid detergent fibre). Cellulose and lignin. It correlates inversely with digestibility. Rising ADF with no rise in starch means the crop was cut late in the stover but the grain did not fill.

pH. The verdict on the fermentation. Penn State gives 3.5-4.3 for quality corn silage. Above about 4.5 on a normal-DM corn silage, ask what went wrong. Note that pH must be read alongside DM — drier silages stabilise at a slightly higher pH because there is less water for the acid to work in.

Lactic, acetic and butyric acid. Penn State's targets: lactic acid 4-6%, acetic acid 2% or less, butyric acid less than 0.1%. Lactic acid should dominate. Meaningful butyric acid means clostridia got in and the crop was too wet.

Ammonia-N. Expressed as a percentage of total nitrogen. Penn State's target is below 5%. It measures how much protein was broken down during storage. High ammonia-N means slow sealing, wet crop, or a fermentation that never properly took hold.

Ash. Feedipedia records 3.6-4.8% of DM across maturity stages. Ash above that range usually means soil contamination — cutting height too low, or material dragged through mud. Soil brings clostridia with it.

Aflatoxin B1. Non-negotiable for a dairy buyer. Aspergillus flavus produces aflatoxin in the field under heat and drought stress and in storage wherever oxygen reaches the forage. Cows convert aflatoxin B1 in feed into aflatoxin M1 in milk. Codex Alimentarius sets a maximum level of 0.5 µg/kg for aflatoxin M1 in milk (CXS 193-1995). On the feed side, EU Directive 2002/32/EC sets aflatoxin B1 at a maximum of 0.02 mg/kg (20 ppb) in feed materials, 0.01 mg/kg (10 ppb) in complementary and complete feed generally, and 0.005 mg/kg (5 ppb) in compound feed for dairy cattle and calves, all expressed relative to a feed with 12% moisture content. That last clause matters: a lab result on silage at 33% DM has to be converted to the same 12%-moisture basis before you compare it to the limit. Buyers in the GCC should also check the current mycotoxin limits in the applicable GSO standard and their own national feed import requirements, which are not always identical to EU figures.

Specification table

Publication gate: this table does not go live until the right-hand column is filled. An empty branded spec sheet is worse than no spec sheet — it is the document a buyer asks for and quotes back at you, and it must not leave the building with blanks in it.

Sources for the left-hand column are listed at the foot of this page. confirm whether forage analysis is carried out, by which laboratory, and at what frequency — or state that analysis is available on request Certifications held: list any certifications, or delete this line.

Wrapped bales versus bunker and pit silage

Bunker and pit silage is the standard for a farm making its own feed. Chopped forage goes into a walled clamp or a trench, gets rolled by a tractor, and is sheeted over. It is cheap per tonne at scale and it works.

It does not travel. A bunker is a single sealed mass, and once you open the face, the clock from Phase 4 above starts running on the entire exposed surface. FAO's 1.5-4.5% DM loss per day applies in the affected areas of that face — and on a face that is opened faster than it is eaten, the affected area keeps growing. A bunker sized for a 300-cow herd, opened by a 20-buffalo farm, will spoil faster than it is eaten. And no one is loading a bunker into a container.

Wrapped bale silage solves a different problem. Each bale is its own silo. The film is the seal, the bale is the mass, and the fermentation happens inside that unit and nowhere else. That gives you three things a pit cannot:

1. Portability. A sealed bale can be moved by lorry, stacked, and loaded into a container. This is what makes long-distance trade in silage possible at all: silage exported from Pakistan ships out of Karachi, and Gulf-bound cargo typically routes to Jebel Ali. You cannot do that with a clamp.
2. Feed-out control. You open only what you feed. A small herd faces the same daily spoilage rate as a large one, but across a far smaller exposed surface, because only today's bale is open.
3. No capital works. No concrete, no walls, no drainage, no roller tractor. A buyer needs flat, clean, well-drained ground and something to move the bale with.

The cost is real and we will not pretend otherwise. Baling and wrapping is more expensive per tonne than rolling a bunker, and the film is a consumable you pay for on every tonne. You are buying convenience, portability and low feed-out loss, and you are paying for it in film and handling.

Film: layers, microns and UV

The film is not packaging. It is the silo wall. Everything the fermentation needs depends on it.

Layers. Stretch film is applied in overlapping passes; at 50% overlap, each pass lays down two layers. Standard commercial practice for wrapped bale silage is a minimum of four layers, with six or more used for long storage, for handling-intensive supply chains, and in hot climates. More layers means lower oxygen transmission and more tolerance of a single puncture — with four layers a thorn can reach the forage; with six it usually cannot. We apply 6-8 layers of UV-resistant film.

Thickness and stretch. Silage stretch film is commonly supplied at around 25 microns and is stretched during application, so the finished thickness per layer on the bale is lower than the film off the roll. Thickness and tack together determine whether the layers cling into a genuinely airtight skin. Our film specification is film thickness in microns, brand or grade.

UV resistance — and why it matters more here. Polyethylene degrades under ultraviolet light. The chains break, the film loses elasticity, goes brittle and chalky, and eventually splits — often along the shoulder of the bale where tension is highest. Silage films carry UV stabiliser packages rated for a stated period of outdoor exposure at a stated level of cumulative solar radiation. In northern Europe, a film rated for 12 months of exposure lasts 12 months. In Bahawalnagar in June, or on a yard in Sharjah, the same film sees far higher UV dose and far higher surface temperature, and the rated period is consumed faster. This is why a film specification written for a temperate market is not automatically fit for Punjab or the Gulf.

Two practical consequences. First, film colour: white film reflects more solar radiation and runs cooler than black or dark green, which reduces both film stress and the internal temperature of the bale. Second, storage: bales held in direct sun for extended periods should be checked more often, and a light-coloured cover over a stack costs very little.

Our film is rated at UV rating of your film, e.g. 12 months at X kLy, colour film colour. Stated shelf life for unopened, undamaged bales stored correctly: your stated shelf life.

The 60-70 kg bale, and its honest trade-off

Our bales are 60-70 kg — roughly 1.6 to 1.9 maunds each, at 37.32 kg to the maund. That is a deliberate choice, and it has a cost attached.

Why small bales.

• Two people can move them. No loader, no bale spike, no tractor. On a farm with 15 buffalo and a brick shed, that is the difference between silage being usable and not.
• They match a day's feeding. A herd of 20-30 animals opens a bale, feeds it, and finishes it. Nothing sits open overnight going warm.
• They stack and load by hand. For container work this matters — bales can be hand-stacked into the container to fill the cube rather than leaving the void spaces a large round bale forces.
• They spread risk. One punctured bale in a consignment is one spoiled bale, not a quarter of a tonne.

The trade-off: film cost per tonne is higher. This is geometry, not opinion. Film use scales with the surface area of the bale; the forage you are selling scales with its volume. As bale diameter falls, the ratio of surface area to mass rises, so a small bale needs more film per tonne of silage than a 500 kg round bale wrapped to the same number of layers. There is more handling per tonne too — more units to stack, count, load and inspect.

So the small-bale format costs more per tonne to produce than large bales would. What you get back is that you can actually handle it without machinery, and that your daily feed-out losses are lower because you are never leaving a large face open. For a farm with a loader and 200 animals, large bales may genuinely be the better economics. For most of the herds we sell to, they are not. Our film cost per tonne is state your film cost per tonne if you want to publish it, or delete.

Bale specification: dimensions bale dimensions, density bale density kg/m³, weight tolerance your stated weight tolerance, e.g. ±5%.

Aerobic stability and spoilage

A sealed bale is stable. An unsealed bale is a compost heap with a head start.

Yeasts survive the acid conditions of storage. Give them oxygen and they degrade lactic acid to carbon dioxide and water. The acid disappears, the pH rises, and once the pH is up, moulds and bacteria that the acid had been suppressing move in. Moulds develop wherever oxygen is present and some of them produce mycotoxins. The visible sequence — warm, then grey-white patches, then blue-green or black — is the end of a process that started the moment air got in.

Practical rules:

• Feed the bale out the day you open it, or as close to it as you can manage. FAO's figure of 1.5-4.5% DM loss per day in the affected areas is what you are racing.
• Repair punctures immediately with proper silage repair tape. A pinhole is a slow leak and a slow leak spoils a whole bale.
• Keep birds and rodents off the stack. They are the most common cause of punctures in stored bales. The FAO record of the Little Bag Silage work — developed in Pakistan and Nepal in the late 1980s — found undamaged bags kept well for six months with little fungal spoilage, while mice damage on maize fodder caused aerobic spoilage. Seal integrity, not sophistication, decided the outcome.
• Do not stack too high. Weight on the lower bales distorts them and stresses the film at the corners. Maximum recommended stack height for our bales is max stack height in bales.
• Store off wet ground, on a clean, level, drained surface.

How to inspect a bale on arrival

Do this on the lorry or the yard, before the vehicle leaves. Photograph anything you are unhappy with.

Before opening — check every bale visually:

1. Film intact. No tears, no punctures, no scuffs worn through to the forage. Pay attention to the shoulders and the corners where handling damage concentrates.
2. Film tight against the bale. Slack or ballooning film means gas movement — either a leak, or a fermentation still running that should have finished.
3. No mould visible through or under the film. White, grey or blue-green patches are visible from outside on a light-coloured film.
4. No liquid seeping from the base. That is effluent, and it means the crop went in too wet.
5. Weigh a sample. Take three or four bales at random and check them against the declared weight range.

On opening one bale for inspection:

6. Smell first. Good corn silage smells clean, faintly sweet and slightly acidic — lactic. Rancid butter is butyric acid and means clostridia. Sharp ammonia means protein breakdown. Strong vinegar means an acetic-dominant fermentation. Alcohol or a fruity, solventy note means yeast activity.
7. Colour. Olive green through to golden yellow-green or light tan. Dark brown or black means heat damage — the material has caramelised, and heat-damaged protein is not available to the animal.
8. Texture. Firm, with the chopped stalk, leaf and kernel still individually recognisable. Slimy or mushy material is a wet, failed fermentation.
9. Temperature. Push your hand into the middle. It should be at ambient temperature or cooler. Warm silage is already spoiling.
10. Kernels. Look for cracked grain. Whole, intact kernels mean the processor was not doing its job and the starch will pass through the animal.
11. Take a sample for analysis. A 500 g sample, sealed in a plastic bag with the air pressed out, sent to a feed laboratory. Compare the result to the spec sheet you were sold on. Every serious buyer should be doing this at least on first delivery from a new supplier.

If a consignment fails inspection, our policy is your policy on rejected or damaged bales — replacement, credit, or otherwise.

Feeding notes

Corn silage is an energy and fibre base, not a complete ration. It is low in protein and will need balancing with a protein source. Introduce it gradually over 7-14 days rather than switching a herd overnight; rumen microbial populations need time to adapt to a starch-rich forage. Buffalo, which dominate Pakistani dairy herds, adapt well to corn silage as an energy base, though intake and ration formulation should follow your own nutritionist's advice for the herd and the stage of lactation.

Store unopened bales in shade where you can. Feed out from open bales the same day.

Ordering

We sell silage domestically across Pakistan, and the product is built to travel — small, individually sealed, hand-stackable bales. your current export status — which markets you already ship to, if any, and what you can commit to now

• Minimum order, domestic: your domestic MOQ
• Delivery regions covered in Pakistan: list delivery regions
• Bales per 40 ft container: bales per 40ft container. Note the general constraint: a 40 ft dry container is commonly plated at a maximum gross mass of 30,480 kg, and with a tare of roughly 3.7-3.9 tonnes that puts the payload ceiling at about 26.6-26.8 tonnes. Some units are plated higher — DSV lists a 40 ft dry container at 3,750 kg tare and 27,600 kg maximum payload — so read the CSC plate on the container in front of you rather than assuming a figure. Road weight limits at either end of the journey often bind before the container does.
• Export route and documentation, in general terms: silage exported from Pakistan ships out of Karachi, and Gulf-bound cargo typically routes to Jebel Ali. An importer should require a phytosanitary certificate issued by the exporting country's national plant protection organisation, alongside the commercial invoice, packing list and whatever analysis certificate the contract calls for. Requirements vary by destination and they change, so check the current rules of the importing country before you fix a shipping date. list the export documents you are able to supply as standard
• Lead time: your lead time
• Price basis: your price basis — per tonne ex-farm, delivered, FOB Karachi, etc.

Send a WhatsApp message to +92 310 4603311 with your herd size, location and the volume you need, and we will come back with a current specification sheet and price. Or email [email protected].

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

Sources

• Feedipedia (INRAE, CIRAD, AFZ, FAO), Maize silage — composition by maturity stage, milk-line target, DM window, chop length: https://www.feedipedia.org/node/13883
• Penn State Extension, Corn Silage Production and Management — moisture by storage type, fermentation targets (pH, lactic, acetic, butyric, ammonia-N), milk-line limitations: https://extension.psu.edu/corn-silage-production-and-management
• University of Wisconsin-Madison Division of Extension, Practices to Optimize the Nutritive Value of Corn Silage — 33-37% DM at 2/3 to 3/4 milk line, kernel processing: https://cropsandsoils.extension.wisc.edu/articles/practices-to-optimize-the-nutritive-value-of-corn-silage/
• FAO, Silage fermentation processes and their manipulation (Pahlow et al.), in Silage Making in the Tropics with Particular Emphasis on Smallholders — four phases of ensiling, LAB types, clostridial fermentation, 1.5-4.5% DM/day spoilage loss in affected areas: https://www.fao.org/4/x8486e/x8486e09.htm
• FAO, Wet season silage production (Regan), same proceedings — consequences of ensiling below 30% DM: https://www.fao.org/4/x8486e/x8486e0f.htm
• FAO, Little Bag Silage (Lane), same proceedings — seal integrity and storage life, work conducted in Pakistan and Nepal: https://www.fao.org/4/x8486e/x8486e0k.htm
• Directive 2002/32/EC on undesirable substances in animal feed, consolidated text, Annex I — aflatoxin B1 limits: https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:02002L0032-20191128
• Codex Alimentarius, General Standard for Contaminants and Toxins in Food and Feed (CXS 193-1995) — aflatoxin M1 maximum level in milk: https://www.fao.org/fileadmin/user_upload/livestockgov/documents/1_CXS_193e.pdf
• DSV, Shipping container dimensions — 40 ft dry container tare and maximum payload: https://www.dsv.com/en/our-solutions/modes-of-transport/sea-freight/shipping-container-dimensions/dry-container