Monday, February 15, 2010

Probiotics - Do We Need Them?

I want to know what everyone is using for probiotics - and didnt you tell me once you could just add some yogurt to their feed? Wouldnt this be a different kind of bacteria than a horse would normally get?

The following quote is from Dr. Kellon's Nutrition as Therapy course. There's an entire chapter on probiotics/prebiotics which I can't reproduce here.

"The bacteria you see in equine probiotic products are all “borrowed” from human data with no studies whatsoever to support their use in horses. Then there's the issue of dose. Dr. Scott Weese in Canada is the closest thing to an expert on veterinary probiotics there is. He has estimated it would take a minimum dose of 10 to 20 billion live organisms to have any effect in a horse. Humans taking probiotics to ward off antibiotic associated diarrhea often take a higher dose than that 4 times a day! If you read the label on probiotic products, forgetting for the moment that the bacteria they contain may well be useless, very few measure up to this potency. For a horse that might benefit from pre/probiotic support, I usually recommend:

  • High potency prebiotic like Forco or Ration Plus for support of upper intestinal Lactobacilli (contains growth factors for these organisms)
  • Easily fermentable prebiotic foods for the hindgut organisms, like beet pulp or psyllium.
  • If populations may be low (older horses, horses with diarrhea,horses with a chronic history of bloating/hay belly) and use a high potency probiotic like Equine Generator from, or start with a human high potency acidophilus only product (acidophilus is one species of Lactobacillus.)"

Scott Weese, DVM, is an expert in diseases of the equine GI tract. His paper on probiotics can be accessed on IVIS at

(If you're not already a member at IVIS, go ahead and join - it is free and a valuable source of international veterinary information).

Because of the paucity of actual research about probiotics, when I first read Dr. Weese's paper I checked out yogurt (yoghurt) as a possible source of microbes for our horses. The "requirement" for a manufacturer to use the "live and active cultures" logo is 100 million per gram at time of manufacture; Mountain High yoghurt, for example, promotes "An 8-ounce serving of Mountain High Yoghurt contains more than 22 billion cultures at the time of manufacture." The recommended minimum dose for horses is 10 billion CFU (cultures or "colony forming units")/day.

So, IMO, it would probably be sufficient to use yogurt (a quality brand like Mountain High, Dannon or a good organic or home made) for the occasional need to boost gut microbes, such as after worming or a normal course of antibiotics.

Probiotics usually shouldn't be needed on a daily basis. Once an ill horse is recovered, or a stressed horse is back to their regular routine, a few days or a week's dosing should get their gut flora going. The main exceptions would be a horse with high carbs in their diet – usually from grain or pre-mixed feeds - which spill over into their hind gut, or a horse with chronic diarrhea (and cultures should be done here to help determine the cause). Some older horses with chronic digestive problems may also benefit. Then it makes sense to use a quality probiotic for simplicity, along with a pre-biotic, which provides "food" for the gut flora. But for most healthy horses, daily probiotics are probably an unnecessary expense (which could be better spent on testing hay).

Pre-biotics: Ration Plus, Forco, beet pulp, flax, psyllium fed daily (will lose some of it's purported sand clearing ability if fed daily), yeast (Yea-Sac)

Pro-biotics: Equine Generator, also available at, DFM EQ from Horses Prefer

Check labels to make sure the product is supplying at least 10 billion CFU per SERVING. Ex: the DFM EQ provides 200 billion CFU per ounce, but the serving size is 1 scoop, which is 5 grams or 1/5th ounce; this still provides 35 billion CFU per serving which is fine.

The DFM ProLactic from HorseTech is on the low side (2 billion CFU), as are most levels added to feeds or supplements. There’s a complete listing of probiotic products in Dr. Kellon’s Horse Journal Guide to Equine Supplements and Nutraceuticals.