| | Hay is the most common source of stored feed used on livestock operations. It is also one of the most versatile stored feeds because:
- it can be stored for long periods of time with minimal nutrient loss
- there are a wide range of plant species that can be harvested as hay
- it can be produced and fed in large or small amounts
- it can supply the majority of the nutrients required by many different classes of livestock
"Understanding the factors that affect hay quality is vital to ensure quality hay in the quantity desired is produced," says Stephanie Kosinski with Alberta Agriculture and Rural Development, Stettler. "High quality hay can be thought of as hay that is palatable, highly digestible, with sufficient nutrients to meet the dietary needs of the livestock it is being fed to. Factors that determine hay quality include: stage of maturity when harvested, plant species, harvest management, weather, moisture content, and storage conditions. Of these, stage of maturity at harvest is one of the most important factors affecting hay quality."
As forage crops mature, their quality decreases. Fibre levels increase as grasses head out and as legumes flower, while crude protein, digestibility and palatability decline. Harvesting mature forages will result in lower quality hay that may not meet the needs of livestock during the winter. However, cutting to optimize quality can come at the expense of yield. For example, the quality of an alfalfa hay crop is highest just before flowering. At this stage, though, yield hasn't been maximized. For many grasses, maximum quality is reached before flowering begins, but maximum yield occurs at, or just after, the bloom stage. Producers need to find the balance between quality and yield when cutting forage crops for hay.
"Forage species also has a large impact on hay quality," says Kosinski. "In general, legumes are higher in quality than grasses. Legumes tend to have lower fibre levels, higher crude protein levels, and increased digestibility. However, properly managed legume-grass mixtures and grass crops can produce high quality hay. The key factors are to cut at the optimal plant stage and minimize losses during harvesting and storage."
Forage quality can be maintained during harvest by promoting rapid dry-down, maintaining a high leaf content and baling at the correct moisture. Plant cells continue to respire and use energy even when cut. Respiration stops once the material has reached a moisture content of 40 per cent. To avoid excess quality losses, manage hay to reach that 40 per cent moisture content as soon as possible.
"Even though it is difficult to predict the weather, harvesting forage for hay is best done under warm, dry conditions," says Kosinski. "This helps speed up the drying process and reduces the risk of losing quality. Rain on cut forages causes nutrients to leach out of the plant cells and increase dry matter losses. The longer the forage is wet and the more rain that washes through the cut hay, the higher the nutrient losses will be."
When hay is baled, it should not be more than 12 to 18 per cent moisture (depending on shape and size of the bale, and humidity). If the bale is at a higher moisture level, large dry matter losses can occur due to heating and mould growth. Moulds consume nutrients and produce heat. Heating causes a browning reaction to occur that ties up amino acids and sugars into insoluble nitrogen compounds that are unavailable to animals. This increase in insoluble fibre leads to lower digestibility and reduced hay quality.
"The amount of storage losses in hay is related to both the moisture content during baling and the environmental conditions the hay is subjected to," says Kosinski. "As stated earlier, hay baled at higher than the recommended moisture content will heat and experience mould growth, leading to losses in both dry matter and nutrient content. Bales stored inside will be protected from weathering due to precipitation."
If a producer has to store bales outside, large quality and dry matter losses can be avoided by avoiding stacking bales, and by storing bales:
- on a well-drained area
- with space between bales for air circulation to facilitate drying
- away from tree line, fences, and buildings
"When managing for high quality hay, numerous factors need to be considered," says Kosinski. "It never hurts to come up with a plan of action on how to achieve the hay quality and yield needed for an operation. The overall goal is to produce enough hay to meet the nutritional needs of your livestock over the winter."
The Alberta Forage Manual, produced by Alberta Agriculture and Rural Development, offers producers comprehensive information on a range of forage topics: adaptation, legumes and grasses, annuals, mixtures, establishment, fertility, pasture management, harvesting and rejuvenation. In addition, sections on forage pest insects and diseases present detailed discussion of these problems in forage crops, helping producers diagnose damage. The extensive descriptions of forage species and their growth habits will help in planning forage management programs. Fully illustrated with colour images, line drawings, tables, charts and graphs, this forage reference work provides a wealth of information. The manual is available for purchase for $30 plus GST and shipping and handling. It can be ordered online by visiting www.agriculture.alberta.ca/publications, or by calling the Alberta Agriculture Publications Office toll-free at 1-800-292-5697.
Contact:
Stephanie Kosinski
310-FARM (3276) |
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