New test analyzes silage quality A cow is still the best tester for silage palatability. But if you want to evaluate silage before it hits the bunk, you can try the fermentation analysis offered by Cumberland Valley Analytical Services (CVAS), Hagerstown, MD.
Testing silage for fermentation qualities has several benefits, according to Bob Corbett, Dairy Health Consultation, Spring City, UT. Corbett, a veterinarian specializing in production medicine, currently formulates rations for more than 50,000 dairy cows in seven states.
"Fermentation analysis helps you evaluate the palatability of the forage," he says. "That information helps you determine how much of the silage to use in a ration without reducing dry matter intake.
"Normally, we recommend 45-50 lbs of corn silage in the ration. But we'll drop that down to 20 lbs if there's a problem with palatability," he says. "I've had several cases where herds averaged 80 lbs of milk and then dropped 5-8 lbs overnight because the palatability reduced intake. I'm to the point that I won't formulate rations without a fermentation analysis of the silage."
Traditionally, fermentation analysis has been used primarily by research labs due to cost and availability. CVAS now offers the analysis for $21.50/sample. The analysis report includes dry matter, pH, titratable acidity, ammonia, lactic acid, acetic acid, propionic acid, butyric acid and isobutyric acid.
"The service we offer is primarily for consultants like veterinarians and feed company nutritionists," says Ralph Ward of CVAS.
"Fermentation analysis provides a comparative report card on silage management practices and may be used as a troubleshooting tool," Ward says. "It's meant to provide a comparative evaluation that allows the user to better characterize the silage and to lend insight into possible problems.
"It's valuable as a tool to evaluate forage management. It provides black-and-white evidence when silage material doesn't ensile properly. Then you need to decide what you need to do differently," he says. "As a troubleshooting tool it helps detect problems with dry matter intake and animal performance."
"The goal for a good fermentation is to have at least 70% of the fermentation acids be lactic acid," says Corbett. "It's important for the pH of the silage to drop as fast as possible during the fermentation process."
"The type and degree of fermentation will significantly affect the amount of dry matter recovery from the silage-making process," adds Ward. "Silages that have high levels of acetic, propionic, butyric or isobutyric acid imply conditions of improper fermentation resulting in inferior silage."
The critical criteria for producing silage with higher levels of lactic acid are a sufficient amount of plant sugars, large numbers of lactic acid-producing bacteria, anaerobic conditions and a proper dry matter content. The ideal dry matter is 30-35% for corn silage; 35-40% for alfalfa silage, according to Corbett.
Corbett and Ward agree that moisture content is the most important criteria in putting up silage that ferments correctly. Corbett also recommends that producers use inoculants to ensure that a large number of lactic acid-producing bacteria are present.
"Utilizing a good inoculant takes the risk out of whether or not the right strains are present to complete the fermentation process as rapidly as possible," he says.
It only takes about a quart of silage for CVAS to do the fermentation analysis.
"Ideally, the fermentation process should be complete, which normally takes about three weeks," says Ward. "Representative samples should be sealed in a plastic bag with air removed and sent to the lab within two days."
Any type of silage can be tested. For more information, contact the company at 18501 Maugans Ave., Hagerstown, MD. 21742. Telephone: 301-790-1980.