Follow-up on A Symptomatic Look at Your Silages
(March 2006 Dairy Newsletter)
Dr. Duarte Diaz
USU Extension Dairy Specialist
I received several calls following my article on silage quality (A symptomatic look at our silages, in the March 2006 Dairy Newsletter) concerning the utilization of damaged silages. The objective of the guidelines presented in the article were to help identify the reasons for improper fermentation and to take the appropriate actions to avoid those pitfalls in the future. When we are confronted with problem silages, we must also determine the best feeding strategy. Each case must be treated individually. Different approaches may be needed depending on the farm situation and the nature and severity of the silage problem.
Ideally, damaged (or improperly fermented) silages should not be fed to dairy cattle. At the least, spoiled portions should be separated and discarded since they may not only affect milk production (lower nutritional quality), but may also affect DM intake, rumen health, and digestibility. Remaining silage to be fed should be analyzed prior to feeding, because these silages usually have undergone significant changes in DM, protein and energy. Protein and energy losses must be replaced in the ration, or milk production will suffer. Using protein loss as an example, let�s look at the impact of feeding silage that had a loss in protein equal to one percentage point. If the cows are consuming 20 lbs of DM from the silage, the 1% protein loss will create a 0.20 lb protein shortage for the cow, equivalent to a loss in milk of about 2.4 lb per cow daily. In some cases, spoiled silage can be a source of bacterial infection (listeria, etc.) or toxicities (mycosis or mycotoxicosis), both of which can have severe effects on production and health. These problems are difficult to predict, but risks can be greatly reduced by discarding spoiled silage.
Because feed cost is a major expense in dairying and because silages represent a significant portion of the feed, care must be taken to make and feed the best quality silage possible.