Crop-N-Rich® silage inoculants: Resilient bugs that can tolerate the heat

By Cody McCary, Vita Plus forage specialist

Dairy producers put a lot of resources, effort and focus into mitigating heat stress on their herds during the long, hot days of summer. But you might be overlooking some other organisms on your farm: the bacteria in your silage inoculant. Make sure your inoculant bugs are resilient enough to stand up to the dog days of summer.

Why we need live inoculant bacteria

It has long been discussed that silage programs should include the application of a well-researched silage inoculant to control the results of fermentation. Crop-N-Rich silage inoculants are recommended because of the benefits their specific bacteria create when they dominate the fermentation process.

Two specific and intentionally selected strains of bacteria are found in Crop-N-Rich silage inoculants:

• Lactobacillus plantarum MTD/1®: This is the only bacteria in Crop-N-Rich® MTD/1®. It dominates the fermentation process and improves dry matter and energy recovery.
• Lactobacillus buchneri PJB/1: This is the only bacteria in Crop-N-Rich Buchneri PJB/1, and it increases the stability of ensiled feeds.

Crop-N-Rich Nexus – the premier silage inoculant in the Crop-N-Rich lineup – contains two bacteria:  L. plantarum MTD/1 and L. buchneri PJB/1. This combination better preserves the nutritive quality of ensiled feeds, reduces the impact of spoilage microorganisms, and increases feedout stability.

Many factors influence how a given bacteria or silage inoculant may work, including the temperature of water mixed with the inoculant and the temperature of the mixed inoculant solution in the harvester applicator tank.  The bacteria contained in silage inoculants generally prefer a cooler environment. Product performance can be negatively impacted if a canister of silage inoculant is mixed with excessively hot water or if the mixed silage inoculant solution heats up in an applicator tank throughout the harvest.

Standing up to heat stress

In a recently concluded laboratory experiment, researchers mixed L. plantarum MTD/1 or L. buchneri PJB/1 with water ranging in temperature from 86 to 113 degrees F and evaluated the bacterial counts at various timepoints throughout two phases:

1. Harvesting phase: The solution temperature was maintained for six hours with continued agitation to mimic an applicator tank on a moving chopper during harvest.
2. Solution storage phase: After the initial six hours of the harvesting phase, all inoculant solutions were transferred to conditions that were 86 degrees F for 18 hours with no agitation.  This simulated leftover inoculant being stored in the tank with ice packs added to lower the solution temperature.

Most interesting to me were the results observed when mixing these bacteria with warmer water.  For both L. plantarum MTD/1 and L. buchneri PJB/1, when mixed with water that was 104 degrees F, no significant change in bacterial counts were observed throughout the 24 hours of the harvesting and solution storage phases.

In the most severe testing scenario, negative effects on the L. plantarum MTD/1 count did occur when mixed with 113-degree F water. Interestingly, the counts began to rebound once the solution was cooled to 86 degrees F for the solution storage phase of the experiment.  For L. buchneri PJB/1, when mixed with 113-degree F water, no significant changes in counts were observed throughout the 24 hours of the harvesting and solution storage phases.

Added assurance with Crop-N-Rich silage inoculants

These results affirm the resiliency of Crop-N-Rich silage inoculants in high-temperature conditions.  With a goal of maximizing performance of the product you purchase, it remains best practice to mix silage inoculants with cool water and maintain a cool temperature throughout the application process.  However, the resiliency of L. plantarum MTD/1 and L. buchneri PJB/1 can give farms the peace of mind that the Crop-N-Rich products they purchase can withstand some real-world abuse.