FAQ: Conserved Feed

Is there a difference in N levels in good meadow hay with high clover content compared with lucerne hay?

Not really – however, some meadow hay can cause problems because endophyte levels in the grass can be high which can cause animal health issues. This will depend on the type of grass and when it was cut. There should not be any issues if the hay was taken from non-endophyte based grass pasture, for example timothy based pasture.

What crude protein levels should we expect from baled lucerne hay to supplement cattle grazing?

The crude protein level in lucerne hay is dependent on the DM yield at cutting.

The protein level of lucerne leaf is consistently around 28% compared with stem which consistently has around 11% – so then it is a straight dilution. If the lucerne stand was cut at a yield of 5 t DM/ha, when it had 50% leaf and 50% stem, the average protein would be 20.5%.

In any lucerne stand about 2.5 t DM/ha is high quality leaf. The result is lower quality stem material. So if you have a 5 t DM/ha yield then the 50:50 rule would apply and the protein would be about 20.5%. If it was a 7 t/ha crop when harvested then about 35% was leaf and about 65% was stem so the crude protein would be about 18%. So a greater quantity of feed was conserved but the quality is lower.

But – that is purely on a yield harvested basis. What the cows eat will depend on how well you feed it out. If the hay is too dry and all the leaf falls off you are feeding them lower quality stem. Given the chance they will eat the leaf. To make things work you could make silage at about 5.0 t DM/ha using an inoculant. With the wetter silage the leaf tends to stay attached more than with hay. But if you do chose to make lucerne hay – ensure you keep as much leaf as possible.

Does lucerne hay, when used as horse feed, contain high levels of nitrogen when fed out?

No – lucerne hay is the preferred source of feed for horses all over the world since Genghis Khan took it with him to conquer Asia. In the horse racing industry it may be used in the form of pellets, hay or baleage.

Is the nitrogen concentration the same or different in lucerne baleage compared with lucerne hay?

The difference relates to at what growth stage the lucerne was at when harvested. If it was young fresh and leafy with no flowers it will contain a higher nitrogen percentage than mature lucerne which was conserved at flowering.

Is it correct standard tests can underestimate ME in lucerne baleage?

At Lincoln we have not come across this issue. In theory it could possibly occur if the machine being used to analyse quality of the baleage sample has not been calibrated specifically to lucerne and is working off a grass based calibration. However, a well calibrated lab service should be able to give accurate measurements of lucerne ME. Ask if their machine is calibrated for lucerne.

Silage and baleage both require high levels of sugar to grow Lactobacilli bacteria that cause the ensilage process to happen. Because lucerne has high protein levels it can have low water soluble carbohydrate levels (sugars) which is why an additional source of sugar or inoculant is recommended when making silage.

Is there a risk to feeding lucerne baleage to cycling breeding cows when the bull is out?

Baleage is fine for supplementary feed unless:

It was in full flower when cut

It was attacked by aphids &/or had leaf diseases when cut.

Both factors can result in increased levels of a phyto-oestrogen compound called coumestrol. Previous research indicates these compounds remain in the feed when made into baleage or silage (i.e. they don’t degrade after the lucerne is conserved). Levels stay elevated so don’t use for flushing feed (but it’s ok for non-breeding stock). However, fresh vegetative lucerne (without pest or disease) eaten in situ or made into baleage is fine. Check out our blog post.

How can I use lucerne to produce high quality silage?

The main issue for lucerne silage is that it has high protein content, but the ensilage process requires high sugar levels. There are two ways to overcome this:

Use a commercially available silage inoculant, or

Add a source of sugar (e.g. Italian ryegrass) layered throughout the lucerne.

If you try to make lucerne silage without adding an inoculant or alternative source of sugar, the ensilage process can be slow and non-desirable bacteria (clostridium) can multiply. These bacteria are less effective for making silage because they produce a weaker acid. When you have high water soluble carbohydrates (like sugar that dissolves in your tea), then the bacteria responsible for making silage (Lactobacilli) thrive. This is why young leafy grass is good for silage. But you can help the lucerne by adding sugar by including a leafy grass, perennial, or preferably a tetraploid or Italian ryegrass, etc.

By layering the ryegrass and lucerne you evenly distribute the sugar source (ryegrass) throughout the silage.

The addition of other high protein species (e.g. red clover) to lucerne will not help the ensilage process because it has the same issue – high protein content. Herbs, such as chicory or plantain, will also not be as effective in increasing silage quality compared to an Italian ryegrass because they have a lower amount of water soluble carbohydrates.

Is lucerne quality affected by the date of shutting up for silage?

No – the quality of conserved is based on the ratio of stem to leaf and that is pretty consistent throughout the year.

Cutting a 5 t/ha crop for silage in October will have the same quality as a 5 t/ha crop cut for silage in December (unless the December one is dryland and may be shorter and flower earlier so then the quality could be a bit lower). This is because your lucerne crop will never have more than ~2.5 t/ha of leaf. So for these crops you have 2.5 t/ha of leaf and 2.5 t/ha of stem so the silage ends up similar quality. If you cut at 4 t DM/ha you’ll have 2.5 t/ha of high quality leaf and 1.5 t/ha of stem – so higher quality overall.

If you close your lucerne stand early but keep the same harvest date you end up with more silage of lower quality. For example if you produce 7 t DM/ha again only 2.5 t/ha is leaf the other 4.5 t/ha is lower quality stem material which dilutes the high quality leaf material. This is not recommended as you need to balance quality and quantity of your conserved feed. On average the 2.5 t/ha has an ME of 12 MJ/kg DM and a crude protein of around 28%. The poorer quality residual has an ME of 8.0 MJ/kg DM and crude protein of 11%. So a weighted average will give you an idea of the quality of your silage.