Silage holds more moisture than hay, so you must compare the two on a dry matter basis. Hay is often cheaper to feed out and easier to move. Silage often carries more feed value when you cut it at the right stage. The better choice depends on your season, your gear and your herd.

This guide sets out how each feed stacks up. It uses figures from FutureBeef and a published Australian trial. It also shows you how to read a feed test, so you pay for energy and not for water.

What is the difference between silage and hay?

Both feeds store pasture or crop growth for later. The difference is moisture.

You cut hay and let it dry in the paddock. It is baled at about 11% moisture. Low moisture keeps it stable for months in a shed.

You cut silage wetter and seal it from air. Fermentation then locks in the feed. A typical bale or pit of silage holds about 68% moisture, according to the example on the FutureBeef feed analysis page.

Why dry matter is the only fair comparison

One kilogram of hay as fed gives you 890 grams of dry matter. One kilogram of silage as fed gives you 320 grams. FutureBeef uses this pair of examples. A tonne of silage contains far less feed than a tonne of hay, so a price per tonne tells you little.

The same FutureBeef example shows the energy gap. Hay at 7.6 MJ of metabolisable energy (ME) per kilogram as fed supplies 8.5 MJ from 1.12 kg. Silage at 2.7 MJ per kilogram as fed needs 3.13 kg to supply the same 8.5 MJ.

Always ask for the price per kilogram of dry matter. Then ask for the price per megajoule of ME.

How do they compare on feed quality?

Silage is often better quality because you harvest earlier. Forage loses digestibility and crude protein as it matures. Fibre rises. FutureBeef states this plainly in its feed test guidance.

A 1994 Australian trial gives numbers. It was reported in the Australian Journal of Experimental Agriculture. Silage digested at 673 g/kg of dry matter. Hay from the same type of pasture digested at 609 g/kg. Steers fed silage ate more. They gained 1.03 kg a day against 0.61 kg a day on hay.

The authors tied the gap to a shorter ungrazed growing period before harvest. The silage was cut younger. The result was a feed with less stem and more leaf.

Cut hay late and you lose the advantage. Cut silage late and you lose it too. Timing matters more than the method.

Meat & Livestock Australia on silage in finishing diets

Meat & Livestock Australia (MLA) published a feedlot project on high ME silages. It reported live weight gains of 0.8 to 1.1 kg a day for yearling steers fed high quality silage as the sole diet. This result needs good silage. It does not apply to a poor stack.

What does a feed test tell you?

Send a sample to a lab before you buy or feed out. The report lists the numbers below. FutureBeef publishes an example silage analysis, shown here on a dry matter basis.

• Crude protein: 7.2%
• ME: 9.3 MJ/kg of dry matter
• Neutral detergent fibre (NDF): 57%
• Acid detergent fibre (ADF): 38%
• Digestible dry matter: 61.3%

Higher ME and protein are better. Lower fibre is better. Use the report to match feed to the class of cattle you run.

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A worked example for a 300 kg steer

FutureBeef runs this example. A 300 kg steer eats about 2.1% of its body weight in dry matter. This equals 6.3 kg of dry matter a day, or 19.7 kg of silage as fed.

The silage supplies 58 MJ of ME and 454 g of protein. A steer gaining 500 g a day needs about 54 MJ and 425 g of crude protein. This silage meets the need for 0.5 kg a day of gain, and little more.

Do the same sum for your own feed test. It shows you if the feed holds the weight gain you expect.

What is fermentation quality, and why does it matter?

High ME and high protein do not guarantee a good result. Poorly fermented silage tastes bad. Cattle eat less of it. Production falls.

Two lab results check fermentation. Ammonia nitrogen shows how much protein broke down. FutureBeef sets under 10% of total nitrogen as good fermentation. Above 15% is poor. Silage pH is the second check. It is most useful for silage below 35% dry matter.

Ask for these results with every silage test. Hay does not need them.

What does each feed cost to make and store?

Hay needs a mower, a rake and a baler. You also need dry weather for several days. Wet weather after cutting damages quality. Storage needs a shed or tarps. Bales left in the open lose quality.

Silage needs less drying time in the paddock. Less drying time cuts weather risk. You need a wrapper, a bunker or a pit, and a way to seal out air. Air in the stack spoils the feed. Plastic costs money, and so does contract wrapping.

Price both options for your own property. Include machinery, labour, plastic or shed space, and the cost of feed lost in storage. The NSW Department of Primary Industries guide, Successful Silage, covers the making and storing steps. FutureBeef points producers to it for loss and cost detail.

Common mistakes with conserved feed

Producers lose money on conserved feed in the same few ways. Check your own routine against this list.

• Buying by the tonne. A tonne of wet silage holds far less dry matter than a tonne of dry hay. Convert every quote to dry matter.
• Cutting late. Fibre rises and digestibility falls as forage matures. Late cutting gives you feed with less energy and less protein.
• Skipping the feed test. Looks and smell do not tell you the ME or the protein. A lab report costs little against a failed weight gain target.
• Letting air into the stack. Air spoils silage. Check wrap and seals, and repair holes at once.
• Feeding one feed to every mob. Weaners and lactating cows need more energy and protein than dry cows. Match the feed to the class of cattle.

How to compare two quotes

Ask each seller for a feed test. Then follow four steps.

1. Find the dry matter percentage on the report.
2. Divide the price per tonne as fed by the dry matter fraction. This gives you the price per tonne of dry matter.
3. Multiply the dry matter by the ME value. This gives you the total megajoules in a tonne as fed.
4. Divide the price by the megajoules. Pick the feed with the lower cost per megajoule, once it meets the protein your cattle need.

Use the FutureBeef example as a check. Hay supplies 7.6 MJ per kilogram as fed. Silage supplies 2.7 MJ per kilogram as fed. A silage quote must be much lower per tonne to match hay on energy cost.

When should you choose hay?

• You have shed space and a reliable run of dry days.
• You feed small mobs or feed out over many months.
• You sell or move feed. Dry bales are lighter per unit of feed.
• You want a stable product with no fermentation test.

When should you choose silage?

• Spring growth comes faster than you graze it, and the weather is unsettled.
• You need high quality feed for weaners, growing steers or lactating cows.
• You have the gear to seal the stack and feed it out in a few weeks.
• You plan to finish cattle on a high energy ration.

For a full view of the topic, read the cattle nutrition and feeding guide.

How does this fit a drought plan?

Dry seasons change the sums. Conserved feed holds its value only if you store it well. Poor hay and poor silage both lose money at feed out.

Start from the herd’s needs. Work out the dry matter each class of cattle eats. Then decide how much you must conserve. Test the feed. Add minerals where the test shows a gap. Our guide to cattle mineral supplements explains where to start.

Read more on how pasture type changes growth in how different types of forage affect cattle growth. For high energy rations, see grain finishing cattle.

Frequently asked questions

Is silage better than hay for beef cattle?

Silage is better when you cut it young and ferment it well. A 1994 Australian trial found silage-fed steers gained 1.03 kg a day against 0.61 kg on hay. Late-cut silage loses the edge. Test both feeds.

How much silage does a beast eat each day?

FutureBeef’s example has a 300 kg steer eating 2.1% of its body weight in dry matter. This equals 6.3 kg of dry matter, or 19.7 kg of silage as fed at 32% dry matter. Your figure depends on your feed test.

What moisture should hay and silage have?

FutureBeef’s examples show hay at 11% moisture and silage at 68% moisture. Aim for stable, dry bales when you make hay. Use your contractor or adviser to set silage moisture for the stack type you use.

How do I know if my silage fermented well?

Ask the lab for ammonia nitrogen. FutureBeef treats under 10% of total nitrogen as good and above 15% as poor. Smell and appearance also tell you something. Spoiled silage smells sour or rotten, and cattle refuse it.

Is silage cheaper than hay?

It depends on your property. Compare the cost per kilogram of dry matter and per megajoule of ME. Include machinery, labour, plastic or sheds, and storage losses. Ask your local department of agriculture adviser to check your sums.