MSE Dry Microbial Concentrate (Natur’s Way, Inc.) v. Impact + (Liquid + Feeds):

A comparison


Lark L. Burnham, Ph.D.

Ruminant nutrition




Probiotics/DFM effectiveness is dependent on several factors:


·        Numbers of LIVE microorganisms or colony forming units (CFU) - One cell can grow into one colony, but only if it is live. Generally speaking, the higher, the better, with a recommended minimum of 100,000,000 or 1 x 108 CFU (100,000,000).

·        Choice of species/varieties – Several probiotic/DFM species/varieties have been identified as good competitors. This is important because beneficial gut microflora are killed when an animal is stressed. The depleted species will recover, but only if pathogenic species are held in check until they regain control. Although many probiotic/DFM species are present in the digestive tract, their numbers are too low to successfully compete with opportunistic pathogens. Feeding high levels of probiotic/DFM during periods of stress will allow normal beneficial microbes to recover. Many probiotic/DFM “heavy hitters” (strong competitors) belong to the Lactic Acid Bacteria (LAB) and include Lactobacillus sp. and E. faecium.

·        The “Broad spectrum” approach – No one microorganism can thrive in all segments of the digestive tract, whether probiotic/DFM or pathogenic. Acidity, turbulence, and nutrient availability are just a few of the factors that affect preferred location. A combination of species/varieties of beneficial microbes is recommended for greater protection during stress. This approach can only be effective if the CFU of the “heavy hitters” mentions above are not diluted by less competitive microbes. Guaranteed analysis for individual good competitors, especially if the CFU is at or above 108, is more impressive than a long list of microorganisms with questionable impact.

·        Form of inclusion – Probiotics/DFM can be included either as pure cultures (MSE), or as “fermentation products (Impact+). Fermentation products are the dried remains of whatever was in the fermentation tank, this can include both live and dead cells (and parts of cells), growth media, and by-products of the growth process. Pure cultures are more expensive, but the CFU are easier to guarantee. The vast majority of probiotics/DFM available to the beef industry contain fermentation products.

·        Enzymes – All bacteria produce enzymes. They, like higher animals, require them to digest feed. The pancreas of mammals and other higher animals secretes enzymes into the small intestine. Microorganisms secrete them into the environment, and then absorb the resulting nutrients. In addition, enzymes are not ‘used up’ during the process of digestion and are re-used many times. The addition of enzymes (which have been derived from microorganisms) to a probiotic/DFM that contains live microbes is redundant and increases product cost.  Live bacteria do much more than secrete enzymes, they compete for nutrients and living space.


Guaranteed analysis



MSE, CFU/g/d


Impact+, CFU/g

Lactobacillus acidophilu

515 million

125 million

Lactobacillus casei

113.4 million


Streptococcus faecium

113.4 million

125 million

Saccharomyces cerevisiae

584 million

560 million

Bifidobacterium thermophilus


125 million

Bifidobacterium longus


125 million


924.2 million

1060 million




At first glance, one would think that Impact + is superior because it reports a higher CFU total. History of the company, the manufacturing process, and pre-sale storage should all be considered before drawing any conclusions.


Natur’s Way has been perfecting and producing MSE for 50 years. Liquid * Feeds appeared in 2015. Microorganisms may be mighty warriors in animals, but vulnerable beyond the body. They are easily killed by heat above 80 F, sunlight (radiation), and desiccation. Natur’s Way only makes small batches that are stored in a cool place and sold within a few weeks. Large orders are often made one day and shipped the next, no storage necessary. In addition, Natur’s Way is based on science, with two ruminant nutritionists on staff, including the author.


Every batch of MSE is sampled out of the mixer, and then that sample is sent to an independent lab for testing. We do everything possible to maintain guaranteed CFU before shipment. Conditions during transport, incorrect storage after receipt, and exposure to heat and sunlight before administration can all reduce CFU once MSE is on the farm. Try to order when it is cooler (below 80 F), store in a cool place away from direct sunlight, and mix with feed or mineral in small batches that are consumed quickly. Use good bunk management to minimize waste and exposure to sunlight and weather.


Natur’s Way has funded research at several universities. Experiments conducted involved comparisons of MSE and Rumensin in diets with various feedstuffs, MSE v. antibiotics, and the effect of MSE on the shedding of E. coli O157:H7. Summaries of all these experiments are posted on our website ( and are available by mail. MSE significantly improves rate of gain and feed efficiency, and has been shown to be as or more effective than Rumensin.


Only pure cultures of guaranteed species are used in MSE, which also contains Bacillus subtilis and Aspergillus oryzae. These species can easily raise the total CFU to over that claimed by Liquids +, which only uses fermentation products.


Natural cattle


Beef producers who market their cattle to natural beef packers such as Meyers meats (now owned by Tyson), are required to feed an approved probiotic/DFM to receive a premium. There are only four products, including MSE, that have been approved and Impact + is NOT one of them. Producers who have been told otherwise need to contact their Meyers rep for confirmation. Approved probiotics/DFM have been shown through very expensive university research to significantly reduce the shedding of E. coli O157:H7.


For questions and comments, please contact Lark Burnham at 785-486-9557, or