Why great gut health in foals is key to a healthier life

Why great gut health in foals is key to a healthier life

Why great gut health in foals is key to a healthier life

DR ERIN RODDY, DVM - Proprietor and Head Veterinarian


All horses are designed to eat a high fibre diet and use microbiota in their gut (especially the hind gut) to extract energy and other nutrients from this fibre. The ‘microbiota’ - bacteria, fungi and protozoa - in the horse's gut help break down the food the horse eats to provide it with energy and nutrients. Healthy microbiota (supporting a healthy gut) are crucial to the overall health of your thoroughbreds.

Foals are born without any fibre-digesting bacteria in their gastrointestinal tracts, so they will eat their dam's manure to get it. If the broodmare’s gut is healthy and populated by mostly ‘good’ (fibre fermenting) bacteria, her manure will provide plenty of useful bacteria for her foal too, which will populate the foal’s gut and set it up for a lifetime of efficient fibre digesting and good gut health. Make sure your broodmare fields are not cleaned too quickly for their foals to get their special dose!

A foal's first two weeks matter the most for gut bacteria

Research from Kentucky, USA suggests that the bacteria colonisation of the foal’s gut occurs in its first 2 weeks of life. By weeks 4 - 6 the foal’s microbiota does not change significantly week to week. So, the first two weeks are crucial for setting a foal up with ‘good’ bacteria for a healthy gut for life.

Foals populate their microbiome based on microbiota they ingest mainly from their mother’s manure but also, from what’s present in the environment. 

The mare's milk also supports healthy gut microbiota in the foal. Mare’s colostrum contains milk oligosaccharides, a special type of carbohydrate that help to feed the foal’s new population of gut bacteria, and support the foal against immune challenges. 

A healthy gut microbiome allows the foal to digest fibre efficiently but also aids vitamin production, supports a healthy appetite, strong hooves and a resilient immune system.  

Supporting your broodmare's gut microbiome 

You want your mare to have the healthiest gut possible, so she provides your foal with the ideal gut bacteria; and so she is healthy and well nourished and can produce a strong healthy foal and provide it with high quality milk.

Feed broodmares a high fibre diet

Broodmares require a fibre-based diet with a variety of good quality fibre sources including low NSC pastures such as rhodes grass or native grasses, lucerne hay, lucerne chaff and teff hay.

Choose low starch & sugar feeds

Studies have shown that horses tend to have unhealthy gut microbiota if fed diets high in starch and sugars – especially if fed in large meals and where the diet doesn’t also contain a lot of fibre. Starch and sugars are found in grains, grain by-products, molasses and high NSC pastures (such as ryegrass).

Changes in diet can disrupt the hindgut as soon as 4 hours after the dietary modification and can last for up to 30 days. Shifts in gut microbiota populations are especially high in the right ventral colon, which is where the majority of impaction colics occur.

The problem with feeding too much starch and sugar, is that ‘bad’ bacteria proliferate and can make the hindgut acidic, which in turn kills off the beneficial fibre-fermenting bacteria. If possible, avoid feeding your broodmares high starch and sugar feeds.

High fibre, low starch feeds like lupins, beet pulp, copra meal and lupin hulls can be used to top up calorie requirements and provide additional fibre diversity for the hindgut. The more of these ingredients you can use in combination, the better! Properly extruded grains can also be used safely if needed, as these are better digested by the horse in its small intestine, so are less likely to negatively impact its ‘good’ hindgut bacteria.

Quality protein, vitamins and minerals

It's especially important during pregnancy and lactation that a broodmare’s diet is balanced to contain enough energy and good quality protein, vitamins and minerals. You would normally top up the mare's fibre intake with a good quality protein source, and a vitamin and mineral supplement like Digestive VM. Digestive VM is a high spec vitamin, mineral and amino acid supplement which can be used to help balance the mare’s diet.

Digestive VM is ideal for foals and weanlings also as it is designed to fill the nutrient gaps of forage (pasture or hay) based diets, unfortified grain diets, or horses with diets where they get less than the recommended daily feeding rate of a commercial feed that is formulated with all the required vitamins and minerals.

Support your broodmares gut bacteria health

    In addition to feeding a high fibre, low starch diet, sometimes your mare may also benefit from having her gut health supported by a good quality gut health supplement. Digestive RP is also safe for lactating mares and their foals who will often nibble at their dam's feed from an early age.

    Gut support for high-stress times in the foal's early life

    Stress Paste is a concentrated gut support supplement designed to nutritionally support horses experiencing physical or mental stress. As well as being ideal for broodmares who need extra gut support during travel or if they are moved to a different stud farm, it can be fed to foals and weanlings during travel or weaning, as well as adult horses. 

    Stress Paste will do a great job of helping foals and weanlings under stress. For foals, feed a quarter of the recommended dose for their dam, and for weanlings use a half dose.

    A note about antibiotics

    Antibiotics can alter or damage the developing microbiome, so they should be used extremely judiciously, especially in the first two-six weeks of a foal’s life, in order to avoid long lasting damage to the microbiota.

    Doing everything you can to support good gut health in your broodmares will go a long way to setting your new foals up for a lifetime of robust health.


    Always check with your vet if you have concerns about potential underlying health issues or if your horse is on medication.