Q. “My silage smells like tobacco, which I’ve never had in silage before. Does this mean anything and do I need to be concerned?”
A: There are two noticeably different types of tobacco smells we commonly witness in silage - burnt tobacco and sweet tobacco. Since you didn’t specify which it is that you are experiencing, we will look at both scenarios.
A tobacco smell in silage is caused by a reaction process in which proteins bind with sugars in conjunction with excessive heating, which is also known as a Maillard reaction and is commonly referred to as “browining” or “caramelization”. This issue can be presented in corn silage and haylage ensiled at high dry matter (DM) levels – more than 45% and 50%, respectively.
The early stage of the maillard reaction process produces a molasses type of sweet tobacco smell. This smell is less of a concern than the burnt tobacco smell, which occurs later in the process. With a sweet smell, protein starts to become unavailable in the feed as it has bound to the sugars under heat. The silage should be tested to ensure that the level of acid detergent insoluble crude protein (ADICP) is not excessive - anything above 10% of the crude protein (CP) is a concern. In addition to the protein being unavailable, if the silage reaches a burnt tobacco smell it is a concern as the excessive heating can also lead to high levels of spoilage in the silage.
To help avoid both of these scenarios in the future, ensure the silage is chopped at the correct length and DM level and packed tightly. You should also consider treating it with a spoilage inhibitor inoculant such as Biotal Buchneri 40788 or Biotal Buchneri 500, which contain the FDA-reviewed high dose elite strain Lactobacillus buchneri 40788.
I hope this information helps.
The Silage Dr.