How to feed a probiotic: introduction, timing, storage and records

Once you have decided a probiotic is worth trying, how you feed it matters. Live organisms are sensitive to heat and moisture, the timing around a change in routine affects how useful the product can be, and without some form of record it is very hard to tell whether it has made any difference. This guide covers the practical side, from the first scoop to deciding whether to continue. If you are still deciding whether to use one, start with our guide to equine probiotics.

Before you start

Read the label carefully. Note the feeding rate for your horse's bodyweight, whether there is a loading rate and a maintenance rate, and any instructions about mixing or storage. BETA's guide to labels stresses that feeding less than advised may mean a product is not effective, while feeding more may be wasteful. Weigh the scoop once so you know what a level scoop actually delivers.

Then record a baseline. Before the first dose, note your horse's droppings, appetite, weight tape measurement, body condition and behaviour. Without that starting point, any later judgement relies on memory, which is easily coloured by the hope that a product is working.

Introducing a probiotic gradually

There is little published research on how quickly a probiotic should be introduced. In practice, a gradual start makes sense for a simple reason: anything new in the feed bowl is a change, and starting gently makes it easier to spot refusal or an unexpected reaction.

• Use a small, damp feed. Mixing a powder into a handful of dampened chaff or fibre helps it stick and reduces sorting. Use cool or lukewarm water rather than hot, because live organisms are sensitive to heat.
• Build up over a few days. Many owners start with part of a dose and reach the full rate within the first week, unless the label says otherwise.
• Mind the carrier. If you are adding a new chaff or feed just to carry the probiotic, that is a diet change in its own right and should also be introduced gradually.
• Feed it fresh. Add the probiotic when you make up the feed, rather than leaving pre-mixed feeds standing for hours or overnight.

Fussy feeders may accept pellets more readily than powders, and pastes can be given directly by mouth. Our comparison of probiotic powder, pellets and paste explains the trade-offs.

Timing around travel and diet changes

A 2014 review by Schoster, Weese and Guardabassi found that probiotic strains were generally shed for only days after dosing, so any effect depends on regular feeding during the period you want to support. There is little trial evidence on the ideal timing, but most owners and manufacturers follow a similar pattern.

Planned diet changes

The British Horse Society advises changing diet and routine gradually over at least 10 to 14 days, including new forage, rested pasture and changes to turnout. A common approach is to start the probiotic several days before the change, feed it throughout the transition and continue for a while once the new routine has settled. The probiotic supports the process; it does not replace the gradual change itself. Our section on diet changes and turnout covers spring grass, yard moves and box rest.

Travel and competition

Transport can unsettle the gut. A 2022 review by Chaucheyras-Durand and colleagues cites evidence that a two-hour road journey can shift faecal bacteria towards a less balanced state. For regular travellers, a daily probiotic may be simpler than trying to time doses around each trip, while a paste can cover a single journey or a short stay away. Water matters more than any supplement on the road: the BHS recommends rest stops every three to four hours on long journeys to offer water, and notes that many horses drink less in unfamiliar places. Our page on travel and competition has more on planning trips.

How long to feed it

Some owners feed a probiotic only around specific events; others feed one all year to horses that have repeatedly struggled with change. Either approach can be reasonable. What matters is that the decision is reviewed, rather than a product being fed indefinitely out of habit.

Storage and heat

Live organisms lose viability over time, and heat and moisture speed this up. Research from Washington State University, reported by EquiManagement, found that none of 11 commercial equine probiotics fully met their label claims, and the authors suggested that manufacturing, transport and storage may all reduce viability. You cannot control the first two, but you can control storage.

• Keep the lid tightly closed and use a dry scoop, so moisture does not get in.
• Store tubs in a cool, dry, shaded place, not on a sunny windowsill or next to a heater.
• Do not leave products in a horsebox, lorry or car boot in warm weather.
• Buy pack sizes you will use within the period the manufacturer recommends after opening.
• Check the best before date and note the batch number, which BETA says should appear on all packaging.

Prebiotics and postbiotics, which do not rely on living cells, are less vulnerable to storage conditions, as our guide to prebiotics and postbiotics explains.

Judging the results

Judging a probiotic fairly is difficult. Changes in the gut are gradual, many other factors such as grass growth, workload and weather affect droppings and condition, and a 2022 review by Perricone and colleagues noted that the individual horse often has more influence on gut microbes than the yeast supplement does. Some horses may show no visible change even when a product is doing what it is designed to do, and others may improve for reasons unrelated to the probiotic.

• Set a defined trial period. Decide in advance how long you will feed the product before reviewing it, and stick to it.
• Change one thing at a time. If you change forage, workload and supplements together, you cannot tell which made the difference.
• Compare against your baseline. Look at your records rather than your impression.
• Be honest about cost per day. If you see no meaningful change after a fair trial, it is reasonable to stop.

Our article on signs of poor gut health in horses describes what owners commonly monitor.

Record keeping

A simple weekly record makes judging results far easier and is useful if you later need to talk to your vet or a nutritionist. It also helps competition riders show what has been fed.

For comparisons between products, our desk reviews set out published ingredients and feeding rates.