Probiotics for Dogs By Manuel Bralic


Probiotics for dogs (v.2)

by Manuel Bralic, based on my limited ability to search the net for information, 28-Aug-2012


For a short version, please scroll down to the last page, for some additional info please continue reading.

After a somewhat lengthy online research and compiling very different sources for the matter of probiotics and their possible beneficial effect on dogs, in this document I will try and describe my findings.

I apologize in advance for all the possible misspelling and repetition, as my last assignment was some twenty years ago. I would also advise that the information in this document is in no way complete, as it can never be. Research is done as we speak, and the results we may or may not find at some stage later down the track. This is what I found and what I will be using as my own reference, in case that I need to get a probiotic for my dog.

First of all we need to understand what probiotics are and how they “work”.

Probiotics are simply said bacteria that live in the hosts intestines.

There are trillions of bacteria living in each and every gut of all mammals. Most of them are good bacteria, but there are also bad bacteria and those which are considered “neutral”. All of them together is what is called intestinal flora. It is just logical that good bacteria must prevail in the host’s gut, for the host to be healthy. Good/beneficial bacteria introduced to and maintained in host’s intestines is what we call probiotics.

Most research on probiotics has been done for the benefit of humans, but increasingly there are studies on animals for animals, of course including dogs and cats. All of the studies concentrate on the possible beneficial effects of probiotics on host’s organism.



Why LAB (Lactic Acid Bacteria, also known as Lactobacilli)?


Simply because they are the most common non-harmful bacteria which are also able to survive low pH levels (high acidity) of the intestinal tract. The only one another probiotic I was able to find (commercially available) which is not LAB is Streptococcus thermophilus. It is a yeast, but although it can be found in some products, I was not able to find one study on dogs where this specific probiotic was tested.


Lactobacilli are mostly mentioned in some relation to yogurt, which would potentially put them away for our purpose of feeding a carnivore his carnivorous diet, and deprive them of this bacterium/probiotic.

Even though those bacteria are used (among others) for producing yogurt and cheese, they do live in dogs’ colon (as we will see later) and also in most other mucous membranes (and there is no yogurt in there, right?). This is also valid for Bifidobacteria.


It is interesting to notice that Bifidobacteria is found in much smaller numbers in dogs than most other animals, and in cats actually only sporadically. My guess would be somewhat less resistance against high stomach acidity of those animals.


I hope this will help to understand why Lactobacilli and Bifidobacteria are so interesting for research and why are they “chosen” to be probiotics (“chosen” in terms of being produced commercially and sold as beneficial supplements).


It has nothing to do with milk. It has to do with their ability to survive in their hosts’ acidic intestine, do no harm to the host, but rather help it.


Why not any other bacteria?


Well, there are many other beneficial bacteria, but my findings indicate that many of them can’t be efficiently produced on commercial level, thus being virtually unavailable. There are exceptions, as we’ll see later.



Probiotics work in different ways, the most obvious ones are, in my opinion:

* producing substances which will kill bad bacteria;

* competing for food and thus “starving” bad bacteria;

* taking over the receptors in the gut, thus making it impossible for the bad guys to stick to the gut.


There are more things that they do, but since we are discussing dogs here, let’s keep it simple.


For the probiotics to do their job, they must survive the time until they reach their “intended” home – large intestine. As we all know, dogs’ guts are highly acidic, around pH1-3 (with the exception of the large intestine/colon which has somewhat lower acidity), whereas human guts have lower acidity level/concentration of acid. That means that some probiotics produced for humans might not have the same ability to survive their journey from the mouth to the large intestine in dogs.


Anyway, I was on a mission to try and find out what bacteria is found naturally in dogs’ intestines, so that in the case that I have to supplement my dog’s diet with a probiotic, I will be able to look for a specific/appropriate one. And this is what I found:



One healthy GSD dog tested One healthy LABRADOR tested

Clostridia Enterococci Bifidobacteria

Bifidobacteria Lactobacilli


Streptococci Clostridia

Fusobacteria Bacteroides

Lactobacilli Eubacteria




The chart is to be read as follows:

Bacteria to the left of is considered bad, those in the middle are considered to be neutral and those to the right are considered beneficial to the hosts’ (in this case dogs’) health. Differencies found between the two candidates might be due to different enumeration methods, but it could also be that different dogs (not breeds, each single dog) have different intestinal flora.

The whole study can be found here:



From the above mentioned study, which I invite you to read through and make your own conclusions, I conclude that (at least for the short term benefit) probiotics MIGHT WORK BEST if given together with prebiotics. (Notice: prebiotics are non-digestible carbs fed selectively for the benefit of probiotic bacteria.)

(Nice chart of some possibly exceptional combos is also to be found in this study).


Another very interesting (promising) study I found on Enterococcus faecium (SF68), to be found here:

But there is no benefit without risk (for humans in this case):



It is interesting to mention that some dogs’ probiotic products on the market apparently contain Propionibacteria, but here again I couldn’t find a study to confirm it’s presence in normal dogs’ intestine flora, or any potential benefit.


It is my belief that probiotics can help dogs, especially after a course of antibiotics, in that they can outnumber bad bacteria and together with good raw diet help gain and maintain a healthy gut flora and therefore an overall dogs’ health.

Since probiotics made for human consumption usually don’t have “animal-specific” probiotics (which would be silly, since some of them could be potentially harmful for humans), ie. Enterococcus Faecium, it is my belief that probiotics made for dogs are in greater chance to help dogs, rather then those made for humans. Unfortunately, most products have added another ingredients (ie. vitamins, minerals, trace elements), but they would most likely do no harm .


Another very important fact to be mentioned is that some probiotics are resident in the body, while some are transient, which means they do not live in the gut forever, actually they disappear 2-4 weeks after supplementation has stopped. Some (easy understandable info on the topic, obviously human related, but it’s easy to think of it the same way with other species, IMO)



More info to be found here, in no specific order. Some are just about probiotics generally, some about probiotics for animals, and some are interesting studies done:




* Probiotics made for dogs are potentially better then those made for humans, due to the differencies in the normal gut flora of each species (but there are similarities as well).

* It is possible that some normal/neutral bacteria of dogs’ gut are potentially harmful for humans.

* Probiotics might be best given together with prebiotics (prebiotic = food for probiotic).

* Probiotics should not be given constantly “just in case”, but rather as a helpful supplement after a course of antibiotics, or in case of severe diarrhea (and not just loose stool)

* Probiotics should be given over the course of 2-4 weeks, as per manufacturer’s or veterinarian’s instruction.

* Always read the labels and make sure that you are buying living bacteria, not fermented products.

* Try to get many different strains in one product and make sure there are bazillions of CFU (stands for colony forming units) per serving.

* I would suggest same for cats, although I didn’t take my time to search for anything specific about cats at this point.

* Realize that there are many different strains of even the same probiotic species, so they all might work in a different way.



Beneficial probiotics for dogs IMO:


L. acidophilus,

L. murinus,

L. reuteri,

L. mucosae,

L. rhamnosus

Bifidobacteria (different strains)

Enterococcus faecium


* All information collected from the almighty internet and interpreted by me. I used a lot of Google and Wikipedia, which both lead me often to the website of the Journal of Nutrition (

** Always talk to a veterinarian of your trust before giving any drugs or supplements to your pet.

*** This document can be printed and/or otherwise distributed as long as it is in it’s original, non altered form. **** Say thanks on Crispy’s blog ( if you think this document is helpful.


I breed Naturally Reared UKC Carolina Dogs, I consult/coach natural rearing to carnivore pet owners, with a focus on Naturopathy and the Raw Diet. I live on a mini farm with my husband, dogs and goats and various fowl and in my spare time, I make all natural lotions and enjoy Barn Hunt trials with my dogs.

Posted in Carnivore Nutrition, Natural Rearing, Raw Feeding
One comment on “Probiotics for Dogs By Manuel Bralic

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