Farm Ireland

Wednesday 21 March 2018

Make silage at 72pc DM or more

Michael Gottstein

Experience on most moderately stocked sheep farms is that grass supply is tight and growth rates are still behind normal for this time of year. Hopefully, milder weather will soon arrive and grass growth will take off. Given the very long winter, coupled with poor spring growth, many farmers have completely exhausted their winter feed supplies. Therefore, it is now time to start planning to replenish winter feed reserves.

Last week I said that where grass supply is tight, it is a good idea to delay closing up silage ground until growth rates pick up. This still holds true. Ewes rearing lambs take precedence over winter fodder at this time of year. But it is not uncommon to see grass growth rates in late May hitting 100kg DM/ day/ha. At these growth rates, a famine can quickly turn into a feast in a few days. Therefore, it is important to be ready to close up for silage or take out a few paddocks when the need arises.

Grazed grass is the cheapest feed available to every sheep farmer. The challenge is to be able to manage that grass to keep it leafy and digestible. Conserving winter forage not only plays an important role in terms of providing feed for stock, but it is also an important tool in controlling grass surpluses and maintaining sward quality over the grazing season.

As a general rule, sheep do not need lots of silage. A 70kg ewe will eat around 1kg of forage DM/day. That's the equivalent of 4-5kg/hd/day of silage (fresh weight) or 150kg a month.

When compared to cattle, sheep only need a relatively small amount of silage. For this reason it should be possible to cut the crop relatively early rather than having to wait for it to bulk up. The quality of silage offered to ewes influences a ewe's intake characteristics and the amount of concentrate supplementation that is required.

The aim should be to make silage that is 72pc DM or better. So the crop should not be growing for longer than six weeks.

Make enough winter fodder so ewes can be confined or housed when grass runs out.

Every year I meet sheep farmers who don't have enough grass at turnout in the spring because ewes were not housed in time. Often this happens because there isn't enough hay or silage made. To have enough grass at turnout, pastures need a minimum 120-day rest period. For this to happen, sufficient winter feed needs to be available to allow sheep to be housed when the time is appropriate.

Also Read

Traditionally, the winter period for sheep on intensively stocked lowland farms is three months. This means that each ewe will require 90 ewe-feeding days or 0.45t of 20pc DM grass silage. The table outlines the quantities in terms of ewe feedings days that the commonly used forms of winter fodder storage contain. This should help you to plan the amount of winter forage that you need to have going into the winter.

Making good quality silage does not happen by accident. It needs to be planned:

  • Limit nitrogen to 90 kg/ha (72 units/ac). Take account of any nitrogen in slurry that has been spread or any residual nitrogen from previous grazing.
  • Graze silage ground bare (ideally 4cm) prior to closing off.
  • Allow the crop to grow for a maximum of six weeks -- but harvest before it starts heading.
  • Roll silage ground to stop soil contamination at harvest.
  • Wilt pit silage for 24 hours.
  • Treat with additive (if needed).
  • Manage pit/bales to avoid spoilage from air or vermin.

More and more sheep farmers are making haylage or dry silage in bale form to reduce the level of bedding and foot problems in straw-bedded houses. Where high DM silage is being made, it is more important to make sure the pit or bales are airtight at all stages in storage right up until they are fed.

Teagasc research has shown that sheep will eat more silage when they are offered short chop length (ie, precision chop vs baled silage) and require less concentrate supplementation. However, this benefit needs to be looked at in terms of the additional bedding costs in straw-bedded houses which may outweigh the benefit.

Irish Independent