The beneficial gastrointestinal tract microorganisms referred to as probiotics offer health benefits outside the realm of nutrition. The benefits of probiotics for pets are becoming well known for a variety of conditions and holistic wellness, including immunity, digestion and the treatment of digestive upset, vitamin synthesis, allergy prevention, parasite control, inhibiting harmful bacteria, and supporting good health in senior pets. Probiotics are also used for natural treatment and prevention of atopic dermatitis, chronic renal disease, pancreatitis, feline immunodeficiency virus (FIV), inflammatory bowel disease, and other pet illnesses.

Probiotics may be depleted by stress, illness, low-quality diet, or medication such as antibiotics or steroids. We’re all for adding a bit of live yogurt to the diet of dogs or other pets it’s suitable for, but the live cultures in yogurt are only the beginning. There are probiotic strains that have been isolated and identified for various animal species, which are required for balance of the species’ microflora and optimum benefits.

Virtually all experts agree that repopulating beneficial gut microflora with probiotics (bacteria and yeast) is beneficial. Opinions vary on how many probiotic strains we should supplement. Some experts say the more, the better. Others are more cautious out of concern for competing strains. Still others say we should only supplement probiotic strains that have been identified in the animal, as opposed to introducing new organisms. I tend to agree that it would be best to avoid upsetting the balance designed by nature, but specific knowledge of each species’ microflora is virtually non-existent. Therefore, many studies shoot in the dark to conclude which probiotics benefit the animal, rather than basing supplementation on species-specific population. Consequently, most of the recommendations out there are situational or largely anecdotal.

It’s important to note that scientific evidence for the effectiveness of each strain can be contradictory or incomplete. The results of these studies are also dependent on the dosage used. This is common for topics that require further research. We’ve included some references below, but you’ll find many more with some deep searching.

Following is a list of probiotics that have either been identified in the digestive system of each species, or have been shown in studies to benefit the species. Supplements and pet food containing probiotics should have the strain identified on the label. It’s crucial that there be an ample amount of each culture (in millions or even billions) to ensure a full range of benefits.

Keep in mind that heat-processed pet food may have added probiotics, but it’s unlikely they would survive processing. Some brands add a probiotic coating after the cooking and extrusion process, which would produce far superior results. Quality supplements are the most reliable way to add probiotics to any pet’s diet.

As always, we recommend consultation with a veterinarian before adding supplements to the diet of your pet.

Specific Probiotics for Dogs, Cats, Horses and Fish

Probiotics for Dogs

Canine studies are much more common, including those that identify the specific benefical bacteria present in a dog’s digestive system.

Lactobacillus reuteri
L. animalis
L. fermentum
L. acidophilus
Enterococcus faecalis EE4
E. faecium EF01
Bifidobacterium animalis

NWC Naturals Total-Biotics Powder is frequently recommended by holistic veterinarians due to the inclusion of 500 million CFU’s of 11 different live probiotic strains.

Probiotics for Cats

There has been very little study done on the specific probiotic strains required by cats. As a result, supplements for them are often lumped in with supplements for dogs. Strangely enough, even some Vet’s who recommend species-specific probiotics lump these two species together when recommending supplements.

“I can’t stress enough the importance of regular feeding of probiotics to your cat,” says Dr. Janice Huntingford, DVM. “It might help to think of probiotics as a food and in many ways. They are a part of food that cats receive little to none of, unless your cat enjoys regular servings of fermented sauerkraut. I know my cat doesn’t!”

The only two probiotics used in studies for felines that I’m aware of, concluded that cats benefit from Lactobacillus acidophilus and Enterococcus faecium SF68.

One of the few cat-specific probiotic formulas on the market is Ultimate Probiotic with Prebiotics for Cats.

Probiotics for Horses

The benefit of probiotics for horses has been studied to a limited degree.  To my knowledge, very little work has been done to identify species-specific probiotic strains.

Probiotics commonly used for horses include:

Lactobacillus pentosus
L. rhamnosus (particularly in foals)
L. acidophilus
L. lactis
L. plantarum
L. casei
S. boulardii
S. cerevisiae
S. faecium
Bacillus subtillis
B. thermephilum
B. lichentiformis
Enterococcus faecium
P. acidilactici

Probiotics for Fish

Research suggests fish benefit from probiotics too. Not only do they enjoy the typical benefits noted above, but they also have a demonstrated requirement for repopulation due to routine exposure to antibiotics used on some fish farms.

Strain and species-specific information is lacking, as the gastrointestinal microbiota of fish has been poorly characterized to date.  I suspect they’ll find inconsistencies when they do study it, as very little information regarding the digestive system is universally applicable to all species of fish.

Note that probiotics will only survive in heat-processed fish food if they’re added after cooking/extrusion and they must be stabilized.

Probiotic genus commonly used in aquaculture include:


For aquarium fish, there are fish foods available that contain probiotics, such as NutriDiet Chlorella Flakes.

The general consensus is pets do benefit from probiotics, but further research is required to pinpoint the full range of species-specific strains.

??? Do you give probiotic supplements to your pets? Have you noticed an improvement in their health? Please share your experience with us in the comments below.

Pascher, M. et al. Effects of a Probiotic Lactobacillus acidophilus Strain on Feed Tolerance in Dogs with Non-specific Dietary Sensitivity. 2008.
Weese, J. Scott et al. Preliminary evaluation of Lactobacillus rhamnosus strain GG, a potential probiotic in dogs. 2002.
Kelly, R. L. et al. Clinical Benefits of Probiotic Canine-Derived Bifidobacterium animalis Strain AHC7 in Dogs with Acute Idiopathic Diarrhea. 2009.
Wynn, S. G. Probiotics in Veterinary Practice. 2009.
Strompfova, V. et al. Selection of Enterococci for Potential Canine Probiotic Additives. 2004.
Marsella, R. Evaluation of Lactobacillus rhamnosus Strain GG for the Prevention of Atopic Dermatitis in dogs. 2009.
Banfield Applied Research and Knowledge (BARK). Literature Review – Probiotics. 2011.
Marshall-Jones, Z. V. et al. Effects of Lactobacillus acidophilus DSM13241 as a probiotic in healthy adult cats.
Travers, Marie-Agnès. Probiotics for the Control of Parasites: An Overview. 2011.
Stoekera, Laura et al. Infection with feline immunodeficiency virus alters intestinal epithelial transport and mucosal immune responses to probiotics. 2013.
Weese, J. S. et al. Screening of the equine intestinal microflora for potential probiotic organisms. 2010.
Weese, J. S. et al. Preliminary investigation of the probiotic potential of Lactobacillus rhamnosus strain GG in horses.2003.
Kellon, Eleanor M. V.M.D. Horse Journal Guide to Equine Supplements and Nutraceuticals. 2008.
Nayak, S. K. Probiotics and immunity: A fish perspective. 2010.
Irianto, A. et al Probiotics in aquaculture. 2002
BalcAzar, Luis et al. Health and nutritional properties of probiotics in fish and shellfish. 2006.


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7 thoughts on “Specific Probiotics for Dogs, Cats, Horses and Fish ©

  1. I have not come across Probiotics prior to reading it here on your site. I think I need to read this in depth as I have dogs and it sounds almost like a miracle cure.

    DO they actually make this for dogs or do I just use Probiotics for people?

  2. With all the meds given to pets these days I can see how theyd need probiotics. It’s nice to know which kind dogs have too. Good one.

  3. FISH? Really? That’s a new one for me but it makes sense. I can’t wait to order more Bottombites now!

  4. I’ve been meaning to try probiotics for all of my pets but its confusing. It doesn’t make senese for every animal and human to need the the same bugs but yet yogurt helps them all. They’re expensive too. At least now I can go in knowing more about what kind they need.

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