ONA REPORT

published in

THE FLORIDA CATTLEMAN AND LIVESTOCK JOURNAL


April 2010

Haylage of Perennial Warm-Season Grasses in Florida

Joe Vendramini
University of Florida/IFAS

Joao

For questions or comments regarding this publication contact: Joe Vendramini


Hay is the most widely used method of forage conservation in the southeastern United States; however, there are significant obstacles to making high-quality hay from warm-season grasses in Florida. The relatively high proportion of stems vs. leaves of some warm-season grass species extends the time required for field drying and increases the chances of weather-related dry matter losses. In addition, poor forage drying conditions (high humidity and rainfall) are common during the periods when growth rates of warm-season grasses are greatest in Florida.

Haylage, baleage, and round-bale silage are all different names for the same method of preserving forage with intermediate moisture in plastic wrapped bales. The forage is baled with dry matter concentrations between hay (80-85%) and silage (30-35%) and wrapped in plastic for preservation. This preservation method has provided a feasible alternative for conserving warm-season grasses in Florida in the absence of favorable hay cutting conditions; however, the chemical composition and morphology of these grasses make them more difficult to obtain an acceptable fermentation profile, and consequently, satisfactory preservation as haylage. Despite the high yields produced by perennial warm-season grasses, high moisture and low water-soluble carbohydrate concentrations limit the success and subsequent adoption of this practice. Further, the nutritive value of these grasses decreases rapidly with increasing maturity, increasing the challenge of preserving high yields and high quality forage. It is a commonly believed that the fermentation process observed in haylage improves the nutritive value of the grass; however, this is FALSE. In reality, a slight decrease in nutritive value is expected after ensiling. Research conducted at the Range Cattle Research and Education Center tested the nutritive value of 10 warm-season grasses before and after ensiling and all species decreased nutritive value after ensiling.

Wilting is required to improve the fermentation characteristics and preservation of warm-season grasses. Increasing dry matter concentrations decreases the development of undesirable microorganisms, such as Clostridia. The target dry matter concentration to achieve acceptable preservation is approximately 50%. Research has shown that dry matter concentrations below 40% increase the appearance of undesirable bacteria while dry matter concentrations above 65% limit the desirable fermentation process. Wilting time is highly variable and depends upon the forage species and climatic conditions. Research conducted at the Range Cattle Research and Education Center found that after 4 hours of wilting, limpograss increased dry matter concentration from 20 to 40% in the summer, but only from 20 to 32% in the fall because of lower average temperatures. Limpograss also had lower dry matter concentrations after 4 hours of wilting when compared to stargrass and Jiggs bermudagrass.

After wilting, the forage should be baled and wrapped as soon as possible to decrease further losses in the field. Wrapping the forage excludes oxygen, providing the necessary environment for anaerobic fermentation. A sufficient number of layers of plastic must be used to ensure that the integrity of the plastic wrap will not be compromised, which could allow oxygen to enter the wrap. In general, 4 to 8 layers of plastic are recommended.

Microbial inoculants can be added to silages to increase the acidification rate by shifting fermentation towards lactic acid production rather than production of VFA, ethanol, and CO2. This improves fermentation efficiency, dry matter recovery, and nutrient preservation. The positive responses of microbial inoculants in warm-season grass haylage has not been consistent. Fermentation enhancers, called additives, such as molasses and citrus pulp have been successfully used to enhance the preservation and quality of warm-season grass haylage in research projects. The technology to spread additives uniformly for use under field conditions is still being developed.

Haylage bales should be fed immediately after removing plastic to avoid spoilage losses that occur in the presence of oxygen. Well-preserved haylage is more resistant to aerobic deterioration; however, losses are unavoidable after extensive periods of exposure.

Summary
  • Haylage, baleage, and round-bale silage are different names for the same method of preserving forage with greater moisture than hay.
  • The ensiling process does not improve nutritive value.
  • Warm-season grasses should be wilted to approximately 50% dry matter for better fermentation and preservation.
  • Microbial inoculants may improve the fermentation process, but results are inconsistent.
  • Bale and wrap the forage as soon as possible after wilting
  • Feed haylage bales immediately after the bale is unwrapped

    For more information about haylage in Florida, contact Joe Vendramini, jv@ufl.edu.


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