University of Nebraska-Lincoln Q and A: Rumen Inoculant to avoid acidosis? | TSLN.com

University of Nebraska-Lincoln Q and A: Rumen Inoculant to avoid acidosis?

Mary Drewnoski
UNL Beef Systems Specialist

I have heard of this rumen inoculant that I can give to avoid acidosis. Is this something I should use?

Q: I have a lot of downed corn ears in my field, I have heard of this rumen inoculant that I can give to avoid acidosis. Is this something I should use? (December 2017)

A:

Putting cattle that are not adapted to corn based diets out on fields with a lot of downed corn can cause acidosis, lameness, and if severe enough, can led to death. The reason why un-adapted cattle get acidotic when eating corn is that there is not a large enough presence of lactic acid using bacteria in the rumen. Lactic acid is a strong acid (10 X stronger than other acids produced in the rumen) that is produced by bacteria when digesting corn. In gain adapted animals there are bacteria in the rumen that will digest this acid (such as Megasphaera elsdenii) producing weaker acids in the process. Thereby, maintaining a higher ruminal pH. Essentially, the reason we want to slowly increase the amount of grain cattle consume is to allow the population of these lactic acid using bacteria to build up. Thus, the idea of inoculating cattle before turn out on to down corn is to boost the population of lactic acid using bacteria.

“Given the extreme risk with cows going from no corn to essentially an all corn diet, I would still suggest feeding corn and working up to 7 lb/d before dosing and turning out in to corn fields with high amounts of downed ears (10 plus bu/ac).” – Mary Drewnoski, UNL Beef Systems Specialist –

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To my knowledge no controlled research has been conducted using this product when turning cows out on to fields with downed corn. However, inculcation of un-adapted yearlings with Megasphaera elsdenii and placing them directly on a finishing diet has been reasonably successful. Thus, this method may have promise for mitigating some of the risks of acidosis associated with grazing down corn. Although it should be noted that in this trial they still had 35% of the diet that was not corn and that they used a high dose (100 ml for 900 lb yearlings).

Currently, the cost of dosing cows (100 ml) with Megasphaera elsdenii (Lactipro Advance, MS Biotec) is about $8/cow and the product has a very short shelf life (14 day) thus it must be manufactured after it is ordered, so thinking ahead and being ready to dose them and turn them out as soon as the product is delivered is important.

Given the extreme risk with cows going from no corn to essentially an all corn diet, I would still suggest feeding corn and working up to 7 lb/d before dosing and turning out in to corn fields with high amounts of downed ears (10 plus bu/ac).

It should also be mentioned, that if there is enough down corn for gestating spring calving cows to eat as much as they want for a month or more they are likely to become very fat. In this situation we would expect them to gain 2/3 of a BCS per month. Thus calves, cull cows, or fall pairs are much better options for using this high energy resource.

For more information on dealing with down corn, please read "Down Corn: Problem or Opportunity for Cattle Producers?".

Mary Drewnoski, UNL Beef Systems Specialist

University of Nebraska-Lincoln

–University of Nebraska-Lincoln Extension