Silage Inoculants: Are They An Investment, Insurance or Intervention?

Sometimes it is challenging to be a dairy farmer. When it comes to producing high quality dairy feed, the results can be affected by everything from weather, to timing, to handling and storage. One seemingly small misstep can turn a perfectly good crop into something you can’t or shouldn’t put in front of your cows. Which brings us to silage inoculants and how they may be used to maintain and improve feed.

To Inoculate or Not to Inoculate? That is the Question.

First off let’s remember that feed accounts for 55-60% of the cost of running a dairy operation. Providing high quality feed is crucial for success. Today your strategy must go beyond deciding “if” you should use an inoculant or whether you should only use it only on certain forages. Advisors are clear. “A quality silage inoculant should be used on all ensiled feeds.” A quality silage inoculant will quickly guide the fermentation process towards the production of lactic acid to drop the pH of the forage. A quality silage inoculant will also provide some measure of insurance against sub-optimal harvesting, chopping, filling, packing, and covering conditions. An inoculant will not make bad forage good, but it will maintain the quality of the forage better than uninoculated silage. Forage is the foundation of a dairy cow’s diet. Better quality forage will allow animals to perform better. Better quality silage will prevent loss of silage due to shrinking. Don’t throw 4% of your biggest expense away. It also will help you secure that your storage inventory will last you until the next harvest. Better quality silage means less need to purchase high energy, and high protein feeds. Thus, the short answer is “yes” to inoculants, in order to get improved performance at a lower cost.

Taking the Fear out of Fermentation

“Fear” may seem like an extreme choice of words because after all fermentation is simply the process where bacteria use sugars to form organic acids that lower pH and preserve the forage. Simple yes. But it’s a precarious balancing act that has water, time, oxygen and other variables working to upset the feed cart. Getting the crop harvested and ensiled at its highest nutrient level is step one. It’s at this point that all oxygen must be eliminated so that the bacteria can get to work. Any slip ups here and there will be nutrient and dry matter losses. The fact that the silage is out of sight means it could easily slip off your radar. Meanwhile, there are micro-organisms .. both good and bad … and what you want is to have sufficiently large quantities of the right bacteria dominating the fermentation. That’s where a silage inoculant can be a useful tool.

The Next Important Question. “Which Inoculant to choose?”

First of all you have to establish what you need? When you have decided whether you need a fermentation aid or a spoilage inhibitor, then you must make sure your choice is one that is backed by research. There are significant genetic differences between LAB (lactic acid bacteria) species and strains. It is difficult to compare products because not all products are equally effective. Your provider should be able to support claims of reduced dry matter losses or improved feed efficiency. You must pick based on the type of silage (corn silage vs. haylage). Not all inoculants are created equal. Seek out the answers to your quality control questions.

Okay, But Will It Actually Work?

All is lost if you use an inoculant that doesn’t work. You must make sure that you have the right bacteria that will grow rapidly in the pH range of the forage they are growing in and produce lactic acid. Here is the point where understanding silage inoculants becomes a science lesson. If this isn’t an area you readily understand, it might be best to seek out he assistance of a specialist, nutritionist or feed consultant. At the most basic level, you want the bacteria to be live and vigorous and the count of the bacteria (CFU) to be at least 100,000 CFU/g.

Population of Lactic Acid Bacteria Applied to the Forage

The population of LAB applied should be at least 10% greater than the natural bacteria that are on the forage. Most inoculants are applied at a rate of 100,000 cells per g (CFU/g) of silage, but applying L. buchneri at 400,000 to 600,000 CFU/g may further improve its efficacy provided it is addressing the problem in your silage. Inoculation at rates that are even just 1% less than natural populations can result in these additives having little impact on silage quality (Muck 1989). Consequently, proper application rates are critical to deriving value from inoculants.

Nature of the Forage Being Ensiled

The forage should have sufficient substrates (e.g. water soluble carbohydrates) and optimum moisture for fermentation (Muck 1989). Consequently, stage of growth of forage at the time of ensiling impacts the value of inoculants.

Are Enzymes Value Added?

In an effort to make more plant sugars available to the bacteria, enzymes can be added to a quality inoculant and is particularly helpful if the plant sugar content of the silage is low. Adding enzymes that work is more costly but can increase dry matter recovery and dry matter digestibility. This is a case where you have to trust that “you get what you pay for.”

Doing your homework and getting advice from knowledgeable feed consultants will certainly help with informed decision making in this area.

Good Inoculants Have Good Data or “Buyer Beware.”

Another key is to make sure the inoculant you are going to use has good research documenting its’ efficacy. Multiple university research trails over different years and growing conditions on the forage type you are inoculating is highly desirable. Research should support the efficacy of the product at the application rate it is being sold at and should validate any and all claims made for the product. Be very cautious VOUR using only “testimonials.”

Don’t buy an inoculant only on price. Often, you get what you pay for. Quality bacteria and enzymes cost more money to manufacture than cheap bacterial. You are better off not spending any money on an inoculant than spending a small amount of money on an unproven or low-quality inoculant. Find the inoculants that all have the technology and research you want and then look at the price.

The Economics of Silage Inoculants from Feed Bunk to the Bank

You are ready to accept that silage inoculants are insurance but are they an investment that either saves the silage of increases profit or both. Results of many research studies show that inoculants improve DM intake and milk production by 4 to 5% for grass, corn and alfalfa silages. Assuming that inoculants improved DM recovery by 1.25 to 2.5% and milk production by 0.1 L per cow per day, net returns were estimated at $5.76 and $14.40 per tonne of corn and alfalfa silage, respectively. (Bolsen et al.)

Worth the Money or Not?

Will you get your money back from using inoculants? It is hard to see subtle changes in animal performance. Measuring reduced dry matter losses or silage shrink. If the bottom line shows improved production is it due to the inoculants or should some other management factor get the credit. Fortunately, university research is providing data showing the successes of inoculant products.

The cost of silage additives can range from 25 cents a treated ton to almost $2 per treated ton. Paying 30 cents a ton on a product that does nothing to improve fermentation is a bigger waste of money than spending 30 cents too much on a product that does improve the value of your feed. Evaluate additives to be sure the product can lower pH and preserve the silage.

Where Does that Leave Your Inoculant Knowledge?

To make good quality silage, one must have an appreciation of the plant and microbial and environmental factors that influence silage fermentation, all of which ultimately dictate the nutrient value and quality of silage.

Advancements in inoculant science have produced inoculants that can improve the aerobic stability of silage and in the case of 3rd-generation inoculants, even the digestibility of fibre. Fourth-generation inoculants are presently under development with a focus on delivering silage with probiotic properties that could deliver health benefits to the animal.

All of the preceding factors must be considered as an integrated package. Neglect of any one component can lead to a breakdown in the forage preservation process. Silage inoculants can facilitate the ensiling process, but they are not a replacement for paying attention to the fundamental factors that are the keys to making good quality silage.

Proper Application Is Key

Make sure that you have the ability and knowledge to properly apply silage inoculants according to manufacturer’s recommendations combined with sound ensiling best practices. Remember the application of a silage inoculant will not overcome the effects of poor silage management or poor weather conditions. Three important keys to good silage fermentation are harvesting at the correct moisture and chop length, quick and adequate packing, and sealing immediately after filling. If all of these are well handled, commercial inoculants can be a valuable tool in silage systems.

The Bullvine Bottom Line

The ecology of ensiling is exceedingly complicated, however, since forages represent a large proportion of the feed costs of dairy production, the generation of high-quality silage is especially important in achieving profitability. At the end of the day, properly selected, applied and managed silage inoculants can make three significant contributions: insurance for obtaining quality forage, an intervention to prevent negative organisms in harvested forage and an investment to increase DM intake and milk production.