Some of the silage research done the past few years is creative as well as informative. Here are a couple presented at recent meetings:
Seeing Isn't Believing. Nutritionists tested their own abilities to evaluate the quality of corn silage, using their visual and tactual senses, during Penn State University dairy nutrition workshops in 2006 and 2007. The first year, 34 nutritionists evaluated 12 samples; the second year, 21 nutritionists rated eight samples. Each was allowed 2.5 minutes to evaluate each sample for moisture content – describing it as “too wet” or “just right” or “too dry."” They were also asked to judge particle size for impact on fermentation and rumen health – using descriptions of “too fine” or “just right” or “too coarse.”
The results: Participants were better able to assess “too wet” corn silage vs. that that was “too dry.” Analyzing particle size was more difficult. “The results indicated that nutritionists who routinely evaluate forage quality can not adequately assess the value of corn silage without actual analysis.”
Paper Or Plastic? Miner Institute researchers tested the use of plastic bags vs. paper bags for shipping silage samples for analysis. Some commercial forage labs were recommending that forage samples intended for mold and yeast analysis be sent in paper bags and coolant packs to prevent additional mold and yeast growth. Forage samples are usually sent tightly packed, with most of the air removed, in plastic bags kept cool.
The scientists found that shipping samples in either type of bag did not significantly improve mold and yeast assessments, although plastic bags produced lower increases in counts. Samples shipped by paper bag showed an increase in forage dry matter, indicating that the paper absorbed moisture from the samples. Freezing or refrigerating samples significantly reduced mold and yeast, while counts increased dramatically with samples stored in warmer conditions. Samples stored at greater than room temperature showed significantly higher dry matter and pH after 48 hours.
Forage samples shipped via FedEx were delivered within 16 hours and kept relatively cool. U.S. Postal Service-shipped samples were delivered within three days. Those shipped with coolant packs were kept cooler for about 24 hours.
The scientists’ recommendation: Use plastic bags to ship forage samples to be tested for mold and yeast, using a coolant bag to reduce forage heating. “However, the dramatic differences realized even under the most optimum conditions used in this study question the accuracy and therefore usefulness of yeast and mold counts obtained after shipping silage samples to commercial labs.” Corn silage and haylage samples were used.