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Hay vs. Silage: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Updated on October 16, 2023
Hay is dried grass used for feed, while silage is fermented, moist fodder stored in a silo.

Key Differences

Hay is grass, legumes, or other herbaceous plants that have been cut, dried, and stored for use as animal feed, primarily for grazing animals like cattle and horses. Silage, on the other hand, is made by taking green fodder, often including entire plants, and allowing them to ferment, preserving the feed in a process that relies on the anaerobic bacteria present.
While hay requires dry conditions for its production to prevent the growth of mold, silage requires moisture and is stored in conditions that promote fermentation, usually in airtight conditions, which can be in a silo, wrapped in plastic, or in a covered pit.
The nutritional content of hay can vary based on the type of plants being dried and the conditions during drying, but it can lose some of its nutritive value during the drying process. Silage, due to its fermentation process, often retains more of its original nutritive value and can provide a more consistent nutrient content across batches.
A significant advantage of hay is its relatively long storage life under the right conditions. It can be stored for extended periods without significant nutrient loss as long as it remains dry and is kept from mold. Silage, however, has a shorter shelf life once opened, and its quality can degrade if exposed to air, as this can introduce harmful bacteria.
From a handling perspective, hay is often baled, making it easier to transport and store. Silage, being wetter and denser, can be more challenging to transport and requires specialized storage conditions to ensure its quality.

Comparison Chart


Dried grass or plants for feed
Fermented, moist fodder stored for feed

Moisture Content



Bales in dry places
Silos, wrapped in plastic, or covered pits

Nutritional Retention

Can lose some during drying
Retains more due to fermentation

Shelf Life (once opened)

Longer if kept dry
Shorter, degrades if exposed to air

Hay and Silage Definitions


Dried grasses and plants stored as animal feed.
The barn was filled with bales of hay for the winter.


Green fodder fermented and stored in a silo for livestock.
The cows thrived during winter due to the nutritious silage.


Herbaceous material dried to prevent mold and spoilage.
She spread the hay under the sun for drying.


Wet, compact feed often with a sour aroma due to its fermentation process.
He covered the silage pile with a tarp to keep air out.


Plants like alfalfa or clover, dried and used as fodder.
This year's hay was primarily alfalfa.


Moist feed preserved through fermentation.
The silage had a distinct sour smell.


A feed source commonly used for cattle, horses, and other livestock.
The horse munched on the hay contentedly.


Animal feed stored under conditions that promote anaerobic fermentation.
The farm used large pits to store the silage.


Harvested and stored plant material, often baled for convenience.
The farmers loaded the truck with hay bales.


Harvested plants, including entire plants, fermented to preserve nutrients.
Corn stalks and all were turned into silage for the herd.


Grass or other plants, such as clover or alfalfa, cut and dried for fodder.


Fodder prepared by compressing and fermenting green forage crops under anaerobic conditions, usually in a silo.


(Slang) A trifling amount of money
Gets $100 an hour, which isn't hay.


Fermented green forage fodder stored in an airtight silo or clamp.


To ensile.


Short for Ensilage.


Fodder harvested while green and kept succulent by partial fermentation as in a silo


Can hay get moldy?

Yes, if hay gets wet or isn't dried properly, it can develop mold.

How is hay produced?

Hay is made by cutting grasses or plants and allowing them to dry before storage.

What animals typically eat hay?

Animals such as cattle, horses, sheep, and goats commonly eat hay.

How is silage different from hay?

Silage is fermented, moist fodder, while hay is dried grass.

What are the risks of improperly stored silage?

Improperly stored silage can spoil, lose its nutritional value, and even produce harmful toxins.

Why is silage fermented?

Fermentation in silage helps preserve the feed and its nutritional content.

Which lasts longer once opened, hay or silage?

Hay generally has a longer shelf life if kept dry, while silage can degrade faster when exposed to air.

Do hay and silage have the same nutritional value?

While both are valuable feed sources, their nutritional content can vary based on preparation, plant type, and storage.

What is hay?

Hay is dried grasses or plants stored for use as animal feed.

Can hay be fermented to make silage?

Yes, fresh green hay can be ensiled and fermented to produce silage.

Can silage be made from crops other than grass?

yes, crops like maize, jowar, bajra, hybrid napier, oat are most suitable for silage making.

Can you feed livestock solely on hay or silage?

Both hay and silage can be primary feed sources, but a balanced diet often requires additional supplements or feeds.

Why does silage have a sour smell?

The sour smell of silage is due to the fermentation process it undergoes.

What's the significance of baling hay?

Baling makes hay easier to transport, store, and manage.

Why is silage often more moist than hay?

Silage requires moisture for fermentation, while hay is dried to prevent spoilage.

What plants are commonly used for hay?

Common hay plants include alfalfa, clover, and various grasses.

Is silage always stored in silos?

No, silage can also be stored in covered pits or wrapped in plastic.

Is silage suitable for all livestock?

While many livestock animals eat silage, its suitability can vary based on the animal and the silage's composition.

Is the fermentation process in silage natural?

Yes, silage fermentation relies on natural anaerobic bacteria present in the green fodder.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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