Probiotic ingredients are so common that chances are you’re feeding your horse at least one already. These healthy digestive “bugs” are said to aid your horse’s digestion and seem to be in nearly every supplement and commercial feed — and product labels make sure you’re aware of them.
Why are so many manufacturers jumping on the probiotic bandwagon' That’s easy: It’s an inexpensive ingredient that many horsemen seem to want, largely due to either talk around the barn or because they’ve taken probiotics themselves and believe probiotics positively affect the gut.
However, while probiotics do appear to help a number of horses, there isn’t enough research for us to make a blanket recommendation. And, since most products contain ingredient levels that are woefully low, you may be wasting your money unless you feed three, four or more times the label-recommended dose. So why are probiotics so popular'
What’s A Probiotic'
The talk around most barns is that probiotics help horses get through necessary stresses like deworming and shipping with fewer physical problems, such as diarrhea. Many horsemen also say probiotics help the horse better utilize — or digest — his feed, meaning the horse gets more out of what he consumes. Claims even include that a probiotic ingredient can help clear up diarrhea, minimize colic and prevent laminitis. Probiotics can make a difference in the right situation, but they don’t deserve the “miracle-bug” title.
A probiotic is a live microbe that benefits the host — the animal ingesting it — by improving the animal’s intestinal environment. A good probiotic should:
• Survive stomach acid and digestive enzymes in the small intestine.
• Be able to adhere to the bowel wall.
• Successfully establish itself and multiply in the host intestine.
• Inhibit the growth of disease-causing (pathogenic) bacteria.
•Improve fermentation in the gut.
Studies on the effect of live bacterial probiotics in horses are sorely lacking. However, studies with other newborn and weanling livestock show probiotics decrease the amount of harmful bacteria shed into the environment by the animal. This means the probiotics likely caused there to be fewer harmful bacteria. Theoretically, this also makes the animal better able to fend off disease. Treated animals also showed better weight gain in the studies.
While the changes in the animals were clear, it wasn’t proven whether the better weight gain in the probiotic-treated animals was related to their better utilization of the feed or because the animals didn’t get sick as much. Research with humans and dogs shows that probiotics help with inflammatory conditions of the intestines. Overall, though, we agree that probiotics sound good, at least for most species.
Frankly, you won’t hurt your horse by administering probiotics, but if you’re looking for ways to trim your feed budget, you can eliminate probiotics. Most adult horses at a healthy weight don’t need them.
We would consider using probiotics regularly for:
• Horses having trouble holding their weight.
• Older horses who need some help with digestion and absorption.
• Horses with a history of intestinal difficulties, including diarrhea, colic, gas and bloating.
• Foals and young horses up to age 1, as during this growth time their diets are constantly changing and they’re still establishing populations of organisms in their guts.
• Horses with hay bellies.
• Horses on high doses of antibiotics.
• Horses battling chronic low-grade colic.
Dose Is Important
Live probiotic organisms must overcome stomach acid, digestive “juices” and competition from the organisms already in the digestive tract in order to take a good hold.
Dr. Scott Weese at the University of Guelph points out that we don’t even know for certain if the species of bacteria currently used are of benefit to horses. However, assuming they are, he estimates than an effective dose for an adult horse would lie somewhere between 10 and 100 billion organisms/day. With Saccharomyces cerivisiae yeast, the dose necessary to show an acid-lowering effect in the horse’s cecum has been established by studies to be 45 billion organisms/day.
If you’re already feeding a probiotic and wonder if its recommended dosage is effective, use these figures to compare the active ingredient levels. Remember: one CFU = 1 live bacterium capable of multiplying (or one organism).
Reasonable estimates for effective doses are:
• Foals/weanlings: Use probiotic bacterial species and S. cerevisiae yeast, alone or in combination for bacterial diarrhea. Effective dose is estimated to be a minimum of 10 billion CFU/day in young foals, up to 45 billion CFUs. cerevisiae/day for yearlings, from 10 to 100 billion CFU/day of bacterial organisms for yearlings. We suggest using it for the first two weeks of life. It’s also reasonable to continue the probiotics for the foal’s first year, while the intestinal tract is changing to adult feed and fermentation patterns.
• Horses on antibiotics: Probiotics at 10-100 billion CFU/day for bacteria, 45 billion CFU/day for S. cerevisiae yeast may help restore bacterial populations after antibiotics have been stopped but aren’t necessary unless the horse developed diarrhea or other digestive upset while on the antibiotics. Probiotics can also be used at the same time as antibiotics to hopefully help prevent any problems, but the estimated required dose is high, 25 to 50 billion CFUs, three to four times a day.
Giving too low a dose is likely a waste. The organisms contained in the supplement are just as likely to be killed by the antibiotics as the ones the drug was meant to target. However, if the horse develops abdominal pain or diarrhea as a result of the antibiotic, using probiotics for a while after the antibiotics stop is reasonable. Research in humans taking oral antibiotics shows that probiotics at the same time can help avoid complications, however, the dosages necessary to do this properly are extremely high.
• Thin/debilitated/older horses having difficulty holding weight: Poor fermentation of fiber to byproducts the horse can use as a calorie source may be contributing to poor weight gain in these situations. Ration Plus has documented effectiveness in this regard. If using live organisms, it is estimated you will need to feed 10 to 100 billion CFU/day of bacterial species or 45 billion CFU/day yeast.
• Chronic colic: Recurrent episodes of colic, especially “gas colic,” may also be related to poor fiber digestion, but you need to be sure the horse is thoroughly checked out for other problems as well. Use the same doses as above for thin horses.
• Hay belly: A prominent abdomen disproportionate in size to the rest of the body can signal poor fiber digestion. If intensive deworming doesn’t correct the problem, try probiotics as above for thin horses/chronic colic.
Pro- and prebiotics are relatively inexpensive ingredients. Many manufacturers include them in low amounts so they can add words like “digestive enhancer” to the product&rsqu o;s list of claims. Don’t be taken in.
If you’re thinking the presence of probiotics on a label influences your choice of products, first check carefully to make sure the label specifies the species included and guarantees potency in terms of CFU or colony-forming units.
Organisms identified as a probiotic for other animals and people won’t necessarily benefit horses, especially at the same amounts. However, both bacteria-based probiotics and yeast-based probiotics have potential benefits for horses.
Fermentation products qualify as prebiotics as they likely contain factors that promote bacterial growth. Aspergillus is a prebiotic, as is the Ration Plus formula. An intake of soluble fiber like psyllium, pectins or complex carbohydrates that can’t be digested in the small intestine are known to increase the numbers of beneficial bacteria in the large intestines of people, dogs and other experimental species. However, a horse’s diet is already rich in these nutrients from common feed ingredients.
Ration Plus is a liquid concentrate of fermentation products and contains no live organisms. Fermentation products refer to the material siphoned off vats containing actively multiplying bacteria. Studies of fecal bacteria before and after treatment, in healthy adult horses, show little change in bacterial counts but some increase in the diversity of species (see www.rationplus.com).
The most impressive research with Ration Plus was a study done on captured mustangs being held for adoption. Over a 51-day period, horses were divided into two groups. One was given Ration Plus, the other was not. The horses were fed, handled and generally managed in an identical fashion otherwise. The horses, which were thin to begin with, showed weight gains of 86.3 pounds in the Ration Plus. Without it, they gained only 41.4 pounds, a difference of 108%.
Dried fermentation products containing variable counts of live bacteria are commonly used as sources of probiotic organisms in many different products, but we found no studies to show the dried fermentation products without live organisms have beneficial effects.
Saccharomyces yeast species fed to other species have the same beneficial effects in terms of inhibiting growth of pathogenic organisms as probiotic bacteria.
The interest in them for adult animals is on their potential to improve utilization of feeds. A study in horses noted the most-obvious effect when feeding Saccharomyces yeast was a reduction in acidity and lactate in horses being fed grain, more than likely because the yeast were themselves utilizing some of the lactate being produced.
Although yeast probiotic products are widely claimed to improve fiber digestion, it hasn’t been scientifically proven to have a significant effect on horses, except for those consuming large amounts of grain.
Aspergillus oryza is another yeast often listed as a probiotic. This organism produces lactic acid, so it has the opposite effect of Saccharomyces. However, dried Aspergillus cultures are used as food by many beneficial bacterial organisms and may be included in products in small amounts for that purpose.
Probiotics may help adult horses having trouble utilizing their fiber sources, with diseases that disrupt bowel activity or when oral antibiotics are administered to the horse.
Probiotics also can help protect young foals from bacterial diarrhea, and in other species they appear to help prevent antibiotic-associated diarrhea when given at the proper time and at appropriately high dosages. However, except for Ration Plus, most of the products we evaluated in this trial have dosage recommendations that are likely too low to do the intended job.
For an overall choice of a prebiotic for your horse, we think your best choice is Ration Plus. This bacteria-based probiotic impresses us with its documented effectiveness and has been used in our test barns for years. We’ve found it especially helpful in reducing hay bellies, for low-grade colic and to combat diarrhea.
If liquid isn’t a feasible option or you simply prefer a powdered live probiotic, our choice for potency and price is Horses Prefer DFM-EQ powder. At only one ounce per day, less even that the manufacturer’s recommendations, you will meet the current minimum estimated effective dosage for horses.
For yeast-based products, we like the products containing Saccharomyces cerivisiae best. This makes our pick Uckele’s Yeast 100X due to its low cost and high concentration of organisms. You should get a therapeutic effect topdressing grain with ?? to 1 teaspoon per day.
For a product that combines yeast and probitoic bacteria, we suggest Foal Bac. A 3.5 oz. dose per day provides minimum estimated effective doses of bacteria and three times the minimum documented effective dose of S. cerevisiae.
For rapid establishment of beneficial strains in new foals, we like both Equi-Bac at a 15 cc dose and DFM-EQ paste at 10 cc/day.