Balage is used by farmers to provide feed for ruminant livestock (e.g. cows, sheep and goats) when pasture or crop growth is inadequate to meet animals needs or for feeding housed ruminants.The fermentation process used to make balage is the same as when grass, maize or other green crops are ensiled in a pit or bunker. Balage is also sometimes called haylage but it is not hay.
Making Balage
The steps involved in making balage form pasture or grass are:
- Cutting
- Wilting
- Baling
- Wrapping
Cutting and Wilting
Pasture is cut with a mower and left to wilt until the moisture content is between 30% and 60%, with the most stable balage usually made between 45% and 60%. Moisture content greater than 60% can cause spoilage from clostridial organisms. Wilting should take a day or less.
Sugar content also needs to be high because it is important to have enough sugar in the bale to drive fermentation and drop the pH to below 5.0 which ensures stability of the preserved feed. Generally, the longer the sun is on the grass, the higher its sugar content so baling should ideally be carried out in the afternoon rather than the morning. Also, young grass tends to have higher sugar levels than more mature plants with coarse stems, seed heads or flowers so pasture-based balage is best made in spring.
Baling
When the desired moisture and sugar levels are reached the wilted pasture is baled as compactly as possible to ensure as little air as possible in the bale. Bales can be large rounds or medium to large cubes. To speed up the ensiling process machinery may chop the grass as it is fed into the baling chamber. Inoculants, containing helpful bacteria and enzymes, or an acid-based preservative can also be sprayed on the cut grass before baling. These treatments are more important to ensure the successful ensiling of pasture that has been rained on during the wilting phase or is drier than desirable.
Wrapping
After baling, each bale is individually wrapped by specialised machinery in plastic wrap. Alternatively, the bales are wrapped in a continuous tube of plastic, typically containing about 50 bales set end-to-end in a long row. Ideally bales should be wrapped where they are to be stored as it is easy to rip holes in the plastic when moving them. For this reason stacking of balage is also not recommended.
The Ensiling Process
The ensiling process begins shortly after the bale is wrapped. Natural plant respiration and the action of aerobic bacteria begin to heat the bale. However aerobic bacteria need oxygen and, on a warm day, all the oxygen in a wrapped bale may be used up in half an hour. If conditions are cooler, or there is too much air in the bale, this process can take hours or sometimes even days.
A well-compacted bale may heat as little as three degrees Celsius before it runs out of oxygen. Loose bales, often resulting from forage being too dry, have more air trapped in them and the heating process can continue too long resulting in heat damage and significant reductions in protein content of the balage. Generally, the quicker the aerobic phase is over, the better, because bacteria are turning useful water-soluble sugars into carbon dioxide and water, with heat released as a by-product.
When the aerobic heating phase ends, the anaerobic bacteria, which function without the need for oxygen, then take over. They multiply quickly and begin to ferment the forage, turning the plant sugars into organic acids - mainly lactic and acetic acid. As fermentation continues, the bale becomes increasingly acidic.
When the bale reaches a pH of about 3.8 to 5.0, the anaerobic bacteria find it difficult to survive and the fermentation process ceases. The bale should now be stable and remain preserved in this state until it is fed out. The speed at which it takes to get the pH down is also critical. The longer the bale stays outside the desired pH range, the more likely that undesirable bacteria such as clostridial organisms, can take hold. Ideally wrapped bales should drop below pH 5.0 in a few days or, at most, a week.
Clostridial spoilage arises from the production of butyric acid. Signs of this type of spoilage are sour and ammonia-like, foul smelling balage. Slime moulds are also likely to be present. Never feed spoiled balage to livestock. In fact, any mouldy balage, even if it still smells okay, should not be fed to livestock.
Advantages of Balage
The advantages of balage over traditional silage pits include:
- ease and speed of harvest - compaction of the bale occurs in the field as the grass is harvested rather than transporting the grass to a pit then spending hours driving back and forth over the pit with a tractor to compact it
- ease of storage – can be stored in the field where it is to be used or other convenient locations on the farm
- ease of feeding out – machinery to lift and carry balage is readily available and it is usually less messy than cutting silage from the face of a pit or bunker
- ease of calculating silage requirements to be fed to livestock – balage weight and volume is generally easier to accurately calculate compared to silage in pits, hence, in conjunction with balage energy levels, it is easier to calculate the quantity of balage to be fed out
- possibly less risk of spoilage by clostridial organisms or moulds because pits generally have a higher moisture content than balage
Balage gives farmers an alternative to pit or bunker silage that can give more flexibility to their farming operations.
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