The development of the export hay market over the past 15 years has seen a vast improvement in quality required for both export and domestic markets.
When to cut hay:
Export markets currently demand bright green, dry hay. Selecting the appropriate cutting time is critical in achieving this standard whilst maintaining hay yield and quality. When planning for hay cutting it is important to consider rain events.
Rain over 12mm on cut hay may drastically downgrade it compared to hay left standing for an extra two weeks.
Research has shown that the optimum time for cutting oaten hay is at the watery ripe stage (Z71), the earliest stage of milk development. Cutting at this stage will deliver the best compromise between yield and quality.
Many processors recommend cutting at this stage as quality declines significantly after the watery ripe stage. Some processors however may prefer hay cut at a different development stage, so check with your exporter before cutting. Figure 1 shows the impact on hay digestibility (in vitro) when hay cutting is delayed.
When monitoring hay crops to determine when to cut:
- Walk into the crop and check a number of areas of the paddock;
- Take the top floret and squeeze between the tops of your fingers;
- A watery green substance will come out when it is at the watery ripe stage (Z71);
- Check the crop every two days and then daily as development gets closer; and
- Organise contractors to cut hay as soon as possible after watery ripe, keeping in mind rainfall events.
New hay varieties such as Wintaroo maintain a green plant colour throughout the milky dough stage. This has seen many growers cut too late and deliver poor quality hay over the last couple of years.
You need to monitor Wintaroo regularly and check the stems to ensure it is cut at the right time to obtain good quality hay. DAFWA hay trials in 2004 investigated the impact on quality of cutting at watery ripe and 7 days after watery ripe for several oat varieties such as Carrolup, Winjardie, Wandering, Wintaroo, Brusher, Kangaroo, Swan and Vasse.
We found that all varieties cut at watery ripe (when sown in late May) met the premium grade. When cut seven days after watery ripe, quality declined for most varieties. Always keep in mind that relying solely on contractors can result in a delay in cutting. It is therefore advisable to establish early contacts with potential contractors for probable cutting dates and (also) arrange some other alternatives in advance.
Cutting at watery ripe will achieve optimum quality in all varieties, however there is a window of five to seven days before quality will fall below premium quality which will allow time to arrange contractors. Rain periods need to be taken into account as rainfall events can drastically reduce quality.
Storing hay:
It is important to have hay in storage as soon as possible after bailing to prevent any further damage from weather. Many hay exporters will require growers to store hay for long periods of time (which will actually attract a premium on top of the graded price) as they can only handle so much hay at a time.
It is therefore important to have adequate storage to prevent weather damage (sun, rain and wind). Sheds should have at least three walls (with the opening facing away from prevailing weather) and if floors are not concrete, black plastic should be used to prevent moisture from the bare ground rising into the bales. Moisture affected bales will be rejected for export.
Shed lay outs should also provide adequate air flow throughout the stack to provide for the dissipation of any heated hay which can eventually lead to spontaneous combustion.
Preventing shed fires (source: AFIA)
Spontaneous combustion is a common cause of hay fires. In the rush of hay making, with impending rain, farmers and contractors are under great pressure to complete hay baling and have hay ‘safely’ in the shed. In this haste, problems can occur and high moisture hay can lead to spontaneous combustion and loss of valuable hay and sheds.
Time line: Spontaneous fires in stacked hay do not usually occur in less than 10 to 14 days after stacking, and generally require 5 to 10 weeks. Under ideal conditions of moisture and high ambient temperatures ignition has been observed in 6-7 days.
Monitoring (a simple test): The temperature of a stack may be checked by the use of a “temperature probe”, a crow bar or other piece of steel. The bars should be left in place and checked regularly. A pipe or tubing should not be used as this may entrain air into the stack and cause ignition to occur.
The feel of the bar and corresponding temperatures are:
- Comfortable 27 - 38C
- Tolerable 38 - 55C
- Tolerable for a short time 55 - 60C
- Tolerable to touch only 60 - 66C
- Too hot to touch and above the danger point 71C +
Any stack that is known to be heating should be checked even more regularly to determine if temps are rising or falling. If the stack continues to rise the only solution is to pull it apart. Water and fire fighting equipment should always be on hand to extinguish a possible fire. Bales that have reached a high enough temperature may ignite as they are introduced to a more available oxygen supply.
Hay exports to some eastern states are restricted due to issues with Green Snail, Lupin Anthracnose and others. View an print information outlining known restriction issues for SA, NSW & VIC and a declaration for exporting hay, straw and chaff to each state.
Silage:
Successful Silage (TopFodder silage manual) is available for sale from the Department of Agriculture, NSW. This book is a reference manual detailing the practicalities and basic principles in producing silage in Australia, from growing and harvesting the parent forage to storing and feeding the silage to ruminants.
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