Cutting Silage this Spring

October24

Cutting Silage this Spring

Lisa Castleman, Agronomist Riverina Local Land Services  (0427 201 963)

 

With a milder winter behind us and now a cooler, extended spring there are opportunities in some paddocks.

 

This season is posing some unusual challenges, particularly with trafficability and animal husbandry jobs mounting, while some pastures are under pretty severe stress from soaks and general waterlogging.

 

Pastures without waterlogging stress or high grazing pressure are showing high amounts of feed-on-offer with plenty of bulk and height as grasses bolt into reproductive mode and aim to set seed. It has been an exceptional year for legumes. The autumn break resulted in an excellent first strike and then the prolonged wet weather has seen a lot of hard seed break down and germinate, giving us the best clover in years (requiring bloat management in many herds).

 

A silage system can typically show higher forage quality than the same pasture, cut 3 weeks later in the season for hay. The Dry Matter digestibility, the Metabolisable Energy (ME) content and the Crude Protein (%) content will all be higher in silage cut, compared to a hay cut, for the same pasture, due to the growth stage of the pasture progressing in this period.

 

If targeting ryegrass and clover pastures for fodder conservation then these pastures will shortly be around the right stage, probably  about 7-10 days behind where they were last year.

 

Once the first heads are out in the grass pastures, including the annuals: ryegrass, brome grass and barleygrass, followed by the perennials: fescue, cocksfoot and phalaris, then the quality of the pasture starts declining.

 

In a more clover dominant pasture e.g. 80% Sub clover and 20% ryegrass, quality decline is a little slower than in the grass dominant pastures.

 

The risk of injury from Barley grass to livestock is still an issue in silage as the fermentation process doesn’t break down the problematic awns, and cattle can get them caught in their mouths. For baled silage, treat the risk the same as you would for hay. With chopped silage, assume the risk of Barley grass issues is higher for cattle because they can’t sort through and select out the barley grass like sheep can.

 

While cutting silage can assist in reducing the broadleaf weed species from setting seed in a paddock, the broadleaf weeds in a pasture can reduce the quality of silage made. Broadleaf weeds can have a lower feed value (digestibility) than the pasture they are present in, and a lower Dry Matter content than other species. Because broadleaf weeds are often more moist (juicy, fleshy leaves with thick juicy stems) to other plants in the pasture, they take longer to dry out. This normally means a longer wilt is required, resulting in lower silage quality. By incorporating wet broadleaved weeds into the silage there is a greater risk of poor quality fermentation.

 

At this point of the discussion about cutting pastures for silage I phoned John Piltz, Livestock Researcher (Ruminant Nutrition) from NSW DPI and sought his advice for some TOPFODDER silage tips. John and I discussed the technical points of why the broadleaf weeds can be an issue.

 

In particular, Paterson’s Curse and Capeweed are difficult to ensile because they have a high buffering capacity i.e. they need more acid to be produced to preserve the silage. If these weeds are a significant portion of your pasture, it will increase the risk of poor fermentation. If there is only a smattering of these weeds, then silage is still an option and chopped silage will better distribute the weeds throughout the silage.

 

If there are patches of broadleaf weeds throughout your paddock chosen for silage-making, then avoid these dense patches and spray them out after cutting. If the patches of broadleaf weeds are too dense for making a good quality silage, then graze or spray-graze instead.

 

Wilting your cut silage will be more problematic this spring with the wet conditions underfoot.

 

John also suggested that you “can maximise the chances of a successful wilt by conditioning the pasture and tedding straight after mowing if you can. Tedding increases wilting rate by allowing more sun into the swath and allowing the moisture to move out more freely.” (J. Piltz, pers.comm.)

 

Plants have pores (stomates) through which moisture escapes. John explained that “these pores close as the plant wilts, usually within ½ to 2 hours after mowing. Tedding straight away is more effective because it maximises moisture loss while the stomata’s are still open.”

 

If you don’t have a tedder, then leave the windrow as wide as possible to increase surface area and exposure to the sun.

 

“Rake as needed this season, it will be suck it and see” says John. “Don’t rake over 35% dry matter to reduce losses, target dry matter is 35% for chopped and 45-50% for baled silage.”

 

Refer to the TOPFODDER SILAGE note for more information at

http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0007/229291/Silage-Note-7—Measuring-the-Dry-Matter-Content-of-Forages.pdf

 

If  dirt or mud gets in your silage, then it can lead to a poor fermentation.  This may limit how much silage you will make this year. To avoid mud, pick a silage paddock with better trafficability this season.

“Try to achieve the required dry matter within 48 hour after mowing. Wrap bales quickly after baling and compact and cover chopped silage as soon as possible to minimise losses” advised John.

 

Be logical, if rain is coming, then wait a little longer. You do need to be confident that rain is not coming for at least 3 days before you start making silage from pasture.

 

Note that cereal crops have thicker stems so it is harder for the moisture to get out and crop stems hold moisture in the nodes. These crops will take longer before they are ready to ensile. In lieu of

 

In conclusion, high quality silage is an excellent resource for filling feed gaps and making better utilisation of pastures. With a cool, wet spring the shorter window of silage-making may be more attractive than making hay. Choose your paddock wisely without a high proportion of Barley grass or broadleaf weeds. Use a mower/conditioner and a tedder where possible. Keep your fingers crossed for 3 days of sunlight!

 

If the Quantity is there, then Quality in=Quality out.

 

References:

http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0005/294053/successful-silage-topfodder-complete.pdf

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