by Klaas van Zanten
Ag tech Products, Inc.

A large portion of today's dairy cow ration consists of fermented forages. In most cases this is haylage and corn silage. Most of the haylage and corn silage are treated with bacterial silage inoculants to help preserve valuable nutrients. The focus of the first generation of inoculants was solely to improve and speed up the fermentation. Recently the focus with some inoculant brands has shifted to improve aerobic stability (bunk life) on feedout. The primary bacterial strain in these inoculants produces high levels of acetic acid. It is the higher level of acetic acid that helps extend bunk life of the forage.

Most inoculants are based on lactic acid bacteria that are called homofermenters. This type of Lactic Acid Bacteria converts simple sugars into lactic acid only. The accumulation of organic acids lowers the pH (=measure of acidity). This low pH preserves the crop just as sauerkraut and pickles are preserved. These homofermentative bacteria are very efficient in helping to improve the fermentation process by accelerating the pH decline. As a result, more dry matter is retained, more protein remains available, and digestibility of nutrients remains high.

However, there are some limitations with this type of inoculant. Once forages are re-exposed to air, yeast spoilage organisms can start growing causing the forage to heat up. Most yeast strains utilize sugars to grow. There are some yeast strains however that can also utilize lactic acid. Therefore, some traditional inoculants don’t always improve bunk life. To counter this bunk life challenge, new inoculants consisting of heterofermentative bacteria were developed. One of the characteristics of a heterofermenter is that it converts simple sugars into lactic acid, acetic acid, ethanol and ammonia. The main benefit of this additional acetic acid production is extended bunk life. However, there are some serious draw backs with the excessive production of acetic acid in forages.

According to research from Kansas State University, high acetic acid levels are more commonly found in silages with a higher moisture level. The production of acetic acid is less efficient than the production of lactic acid. Along with the production of acetic acid, ethanol and ammonia are produced. Ethanol and ammonia are considered “waste products”, thus increasing the dry matter loss. In a recent study done by the Institute for Animal Science and Health in the Netherlands, it was found that forage treated with the heterofermentative bacteria had a higher dry matter loss than untreatedforage. The new product had a 3.4% higher dry matter loss during fermentation than the forage treated with an inoculant like Pro-Store. On a 1000 ton bunker this means that a producer will loose an additional 34 tons of forage. If corn silage for example is valued at $25.00 per ton the extra dry matter loss would amount to $850.00.

There is research that indicates that bunk life is improved. However, few research trials show a positive impact on milk production. In one study with treated barley silage, aerobic stability was similar for the treated forage versus the untreated forage. Also, no difference was found in milk production between treatments. Since this inoculant uses a different fermentation pathway that is less efficient, the ADF and NDF levels were higher in the treated barley silage compared to the untreated barley silage.

The higher price per ton treated is another obstacle for producers to use this inoculant.

To get the benefits of both heterofermenters and homofermenters ANC has included both types of bacteria in their Pro-Store products. This will result in what is referred to as a “mixed acid fermentation”. With this formulation a fast and efficient fermentation will occur resulting in reduced fermentation losses and improved bunk life. Heterofermenters have a place in inoculants only at moderate inclusion rates.

Pro-Store inoculants consist of multiple bacterial strains at high levels. It also has enzymes in it, to ensure sufficient levels of simple sugars. Along with these high levels of effective ingredients comes a comprehensive quality control plan. Add to that, the high quality packaging material which helps ensure that by the time the product is used on the farm it meets or exceeds the label guarantee.

When producers evaluate which silage inoculant to use, the main criteria they should consider are:
· Buy from people you know and trust
· Make sure high quality packaging is used
· A solid quality control program is in place to ensure product viability
· High level of effective ingredients
· Cost per treated ton
· Optimal ratio of homo and heterofermenters.

Talk to your ANC consultant to see which Pro-Store product would best fit your needs.