Harvesting and Storage of Quality Hay and Silage

High-quality forage is the key to reducing feed costs. This is done by harvesting and storing a high-yielding, good-quality crop of forage. When a crop such as alfalfa is cut just before flowering and harvested quickly under good weather conditions, protein and energy levels above 25 and 65 per cent are possible. Late harvesting decreases the crude protein content, dry matter digestibility and dry matter intake of the forage.

Unprotected hay can suffer from lost feed quality, mold growth and bleaching which can greatly reduce quality and price. The use of hay sheds or tarps can return $10 in higher prices in the cash market for every dollar invested. Tarps are less expensive than sheds initially, but require more labour and do not protect hay to the same extent as sheds. Hay sheds generally provide the most economical coverage, and result in the best quality end product.

Stage of Growth

One of the most important factors affecting forage quality is the state of maturity at cutting. Young, vegetative forage is higher in protein and energy than older, flowering material. Quality of first-cut alfalfa drops especially quickly. Producers aiming for a very high-quality forage (for example for dairy cows or cash hay sales) should consider cutting as early as June 10-15.

Relative Feed Value (RFV)

Relative Feed Value (RFV) is an indicator of forage quality, based on a combination of acid detergent fibre (ADF) and neutral detergent fibre (NDF). For high-quality hay to be fed to dairy cows or sold in the cash hay market, an RFV of 150 is considered ideal.

Handling and Leaf Loss

The feeding value of leaves is considerably higher than that of stems. Loss of leaves in handling decreases feed value. Leaf losses are likely to occur when legumes are cut and raked for hay, but can be minimized by harvesting with a mower conditioner.

Rapid Dry-down of Hay

Large losses in feeding value may result when hay is exposed to weather. Rapid-curing, collection and proper storage of forage reduces these losses. Table 18 summarizes the types and magnitude of losses that may be expected under good management and harvesting conditions. Much higher losses are possible with all systems under fair or poor conditions. These figures are valid only if proper care and management are provided to all harvesting and storage operations.

An Easy Method to Determine Forage Dry Matter

Knowing dry matter content is important when harvesting, or buying and selling forage. Forage dry matter content can be easily determined in a few minutes, using a microwave oven and a small fish or diet scale.

  1. Weigh an empty paper plate.
    Example weight: 100 grams
  2. Place forage sample on plate — approximately 200 grams — and record combined weight.
    Example: 300 grams
  3. place plate and subsample in microwave oven with a cup of water
  4. microwave on high for three minutes
  5. remove plate and sample, and re-weigh, recording the weight
  6. place sample back in oven, and microwave on high for one minute
  7. continue heating sample for one minute intervals (and re-weighing) until sample stops losing weight.
    Example subsample and plate final weight: 150 grams

Forage Dry Matter calculation:

(final wt of sample) - (wt of plate)
(original wt of sample and plate) - wt of plate

x 100 per cent = per cent forage
Dry matter (DM)


150-100 x 100 per cent = 25 per cent forage dry matter

Table 18: Dry matter losses of hay and silage during harvesting and storage.

Dry Matter Losses (per cent)
Silage Silage Square Bales Round Bales Loose Stacks
initial moisture 45% 65% 18% 18% 22%
Respiration and weathering 6 4 10 10 9
Harvesting 3 2 3 5 10
Storage 5a 10b 3c 6d 10d
Feeding 4 4 5 5 5
TOTAL 18% 20% 21% 26% 34%
Usual storage method: (a) Steel-tower silo, (b) Bunker silo sealed with plastic cover, (c) Hay shelter, (d) Outside storage

Round Bale Silage

Harvesting silage in round bales can be an economical means of reducing losses when faced with uncertain weather. Benefits include being able to use existing round-bale equipment, and lower field and feeding losses than with dry hay. Because stands with a high sugar content ensile well, best results are usually found with mixed alfalfa-grass stands cut at an early growth stage. Stands receiving rain in the swath should not be harvested as round-bale silage, because the bacteria needed for ensiling cannot compete with soil bacteria splashed onto the forage by rain. Before baling, ensure that bale handling equipment can handle the heavier bales, which can weigh as much as 2,800 lb for a 6-foot bale. Do not cut more in one day than you can bale and stack in a day. Bale at 40-60 per cent moisture. In most cases, this is achieved by baling the day after cutting. Baling too wet results in butyric acid (sour silage) production and increased freezing of the bales, and baling too dry results in greater quantities of air in the bale and mouldy silage. Seal bales in plastic as soon as possible, and always the same day. Storage options include using sheet plastic over a pyramid stack, single-row tube, and tube wrapping, or individual bale wrap. Monitor silage wrap for holes and tape holes shut with duct or construction tape.

Ammoniating Forage

Ammoniation can be used when storing damp hay or to improve the feeding value of low-quality forages. Ammonia (NH3), which contains nitrogen, increases the protein content of low-quality feed. It further increases the feeding value by assisting in the breakdown of the poorly digested lignin fraction of mature forages.

In addition, ammonia acts as a preservative, allowing forages to be safely harvested at higher moisture levels. Bacteria and moulds are destroyed during the ammoniation process, preventing overheating. This results in a safer and more palatable end-product, with less destruction of plant nutrients during storage. It also reduces field harvesting losses and is less weather dependent.

For a description of the ammoniation process and the safety precautions required, refer to Manitoba Agriculture and Resource Development fact sheet Ammoniation of Forages.

Storage Tips

  •  Keep different fields or lots of hay separate so that they are accessible for viewing, inspection and shipping.
  • Locate outside stacks so that they can be built from both ends allowing two different lots to be accessible in one stack.
  • Consider hay sheds which are the most satisfactory and economical type of hay storage. A basic pole shed with truss rafters and sheeting on 2-3 sides will have a low maintenance lifespan of 40 years. Total cost is $3-$4 per tonne. Returns with a hay shed are estimated at $10-$50 per tonne. Bottom bales can be saved with a hay shed if plastic is laid down on the ground first. Hay sheds are excellent dual purpose buildings that can be used for machinery, grain or livestock.
  • Hay being exported overseas in containers must be less than 12% moisture. In certain situations, producers in the industry will start baling small square bales at as high as 14% moisture. They have been successful in having this hay "sweat down" in the stack. To accomplish this, bale weights should not exceed 60 lbs and bales should be properly stacked to capitalize on stack dry down.  There is some risk to this situation in that the weather has to co-operate and a producer has to accurately know moisture levels. Be aware that under rapid drying conditions hay may test dryer than it really is as moisture contained inside the stems is not detected to the same extent as outer moisture. As a result, hay which is considere dry but has cured for a shor period of time may spoil. 
Tips on Tarping
  • Storage site location should have good truck access, good drainage, and lots of room for snow removal.
  • Have stacks running north and south or angled northwest to southeast.
  • Space stacks at least 40 feet from other stacks, buildings or trees to allow for good ventilation, sun exposure and accessibility.
  • Use a ridge bale or peak the top of the stack for rain, snow run-off and also ventilation.
  • The ends of the stack should be left open to allow air to circulate through the top of the stack. This will allow the condensation caused from sweating to escape.
  • Overlap tarps 3-5 feet to avoid water from running in.
  • When tying down tarps, tie close to the edge of the tarp.
  • Retie and tighten tarps every month or as needed. Do not allow your tarps to flap in the wind, as this will decrease the life span of the tarp.
  • Tarps should cover at least 3 feet down the side of the stack. the wider the tarp the less wind problem and also the less wastage. Tie-tier bales should be covered.
  • The bottom layer of bales will be damaged by ground moisture, and should not be marketed with the rest of the stack. Find another use for these bales.
  • Buy a quality tarp with reinforced grommets. Tarps should last 3-5 years with only minor repairs required periodically.
  • A number of local businesses sell tarps. They are also available from Inland Plastics in Saskatoon (306-931-1122) and Northwest Tent and Awning in Edmonton (403-451-6828). A 7 mill tarp with sewn in pockets is available from Northwest Tent. This has become popular in that producers will run 1" or 1 1/2" plastic pipe through the pockets and tie down the tarp with the pipe.