Unfortunately, the same amount of grass doesn’t grow in your paddocks every day of the year. It would make farming a breeze if it did.

Some days you will grow grass, some days you will lose grass due to frost, flood or drought. And some days it won’t grow at all because it’s too cold, too dry or the sun hasn’t shone for weeks.

If you think you’re farming cows, think again. You’re really farming grass.

If you’ve got it in your paddock it’s your cheapest feed. If you’ve got too much of it, it is your cheapest supplement when you make it into silage, balage or hay.

But feeding it out as a supplement is not the same as feeding grass.

For starters, it will always be lower in energy than the grass it was made from as there are energy losses in the ensiling process making it into silage or balage, or the drying process making it into hay.

While spring grass can be about 12MJME/kg DM and 18% to 35% crude protein, the best grass silage and balage is 10MJME/kg DM with 16% crude protein.

Hay is usually about 9MJME/kg DM with 15% crude protein or less.

They also differ from grass by being higher in roughage, known as neutral detergent fibre (NDF).

The NDF of spring grass is about 40% of drymatter while silage and balage is about 50% and hay about 60%.

This roughage takes up more space in the rumen and takes a longer time for the cow to digest – it has to ruminate for longer.

You really want your cows to eat it last, when they have eaten all of the grass available and ruminated that.

But they don’t. If you feed cows silage, balage or hay when you shift them onto a fresh break of grass, they will always go for the lower energy, lower protein, high fibre feed instead.

It’s because silage, balage and hay are all higher in starch than fresh grass. Silage and balage is about double and hay can have 10 times the amount. Your cows all have a sweet tooth.

They’re eating pudding before their meat and potatoes.

If you think you’re farming cows, think again. You’re really farming grass.

But that sugary starch doesn’t make milk. For that your cows need energy and protein, so when you feed silage, balage and hay, don’t be surprised if milk production drops.

Make sure you use it strategically – feed cows the grass you have so they eat it all and then give out the sweet stuff, maybe on a pad.

If they are eating the silage, balage or hay and leaving the grass, it’s not good. Production will drop, paddocks will grow rank, and worst of all, it costs more for you to make that lower quality feed than to grow the grass your cows are leaving behind.

Feed out silage, balage and hay only when the amount of pasture eaten needs to be restricted, such as early spring when you are on a slow round before grass growth picks up, or in autumn when you are trying to push the round out longer and maintain production and condition.

It will keep your cows full and happy and not walking around wet pastures on soft ground searching for feed.

And when you are in the midst of a summer drought, the protein content of well-made silage and balage from spring pasture will be above the protein content of your dried out grasses.

You can also feed as much of it as you want. It is just preserved grass so it’s a safe and natural feed for cows, unlike grain and other concentrates.

But silage, balage and hay don’t just have to be made from grass.

Lucerne, which is a legume, can cause cows to bloat when fed fresh, but made into hay or balage/silage, it becomes a high protein feed that is easily digested.

It grows fast too in the right conditions, so multiple cuts can be made.

Fed in summer, when the protein in grass is lower, it can keep milk production up where you want it with its 11 MJME/kg DM and 23% protein.

However, maize silage is only 10.5 MJME/kg DM and 7% protein, so it is more of a filler when there is not enough grass in your paddocks.

It’s a low energy, low protein, high fibre supplement, so feed it only when pasture is limiting, especially in early spring when pastures are high in protein but your cows still need fibre.

Maize silage can vary in quality depending on the amount of air introduced and the poorer the chop. It’s wise to get it tested before you buy.

Whole crop silage (WCS), also known as small grain cereals, is made from cereals such as barley, oats, wheat and triticale and is harvested when the grain has reached full size but is still soft (38% DM).

It is usually planted in the spring, but autumn-sown cereal crops are also made into WCS in New Zealand.

It is the grain component that is the most important contributor to the feed quality, especially the digestibility and the energy.

But not only do the different crops give different feed values, the time of harvest can also make WCS vary greatly.

Made too late and it is a combination of straw and pips – with hard pips that are poorly digested and often pass through the cow altogether.

At about 9-10 MJME/kg DM and 10% protein, it is a great pasture replacer and filler when pasture is in short supply, but not a production booster if pasture is available.

And then there is straw. Usually the remains of a cereal crop after the mature grain and chaff have been removed, straw has a ME about half that of grass.

Maybe best used for bedding.