DAIRY 101 SILAGE
The good stuff – a silage stack opened for winter feeding.
The lowdown on good silage Story and photos by: Karen Trebilcock
S
o it’s spring (almost) and the grass is growing and one morning soon you’ll wake up and there will be so much grass on the farm the cows won’t be able to eat it all. It’s time to make silage. The energy (metabolisable energy ME) in the grass will be high so if you have dry paddocks which the machinery won’t destroy and a genuine surplus then go for it. Any paddocks which will have more than 3000kg DM/ha before they are due to be eaten are likely candidates. If left to be grazed, the energy in the grass will be falling and the fibre content will go up which is not what calving cows with limited rumen space need. Make sure paddocks are free of stumps, tomos and anything that shouldn’t be 84
there. If there are hazards tell the tractor drivers so they know to stay clear. Walk the paddock to check there are no forgotten standards or waratahs. One of those in a mower is not pretty. Hopefully the weather will behave and you can cut after a couple of days of sunshine so energy in the grass will be extra high. Cutting the grass at the right height is essential – you are trying to make the best silage possible, not deck the paddock so leave the dead matter behind and any dirt. Aim to wilt it in less than 24 hours aiming for a dry matter (DM) content of between 25% and 30%. You can tell by squeezing the wilted grass – if it’s right your hand will be wet but there won’t be liquid running out. And it stays in a compacted damp ball afterwards. If it’s less than 25% DM, your chop
length should be about 8cm to 10cm. If higher than 30% it should be a lot shorter – 2.5cm. If it’s in between, where it should be, go for about 5cm. This makes sure you get it can get it compacted correctly in the stack. Once the grass is harvested, it’s all about making sure fermentation happens and your high quality grass turns into high quality silage and not something else. The bacteria in the grass gets busy converting the plant energy (sugars) into acid. Silage is pickled grass – the acid drops the pH of the grass and preserves the silage. The quicker this happens the higher the quality of the silage and the lower the losses. Your cows will also love it and you more. It’s best to give the process a helping hand, instead of leaving it up to nature, by using an inoculant.
Dairy Exporter | www.nzfarmlife.co.nz | August 2020
