Digestive System

Obviously as with humans the digestive system is there to take nutrients from the food that is put through it.

It starts with the teeth which cut and grind the food.  The horses jaw moves from side to side and the molars grind the food, a horses teeth are slowly worn down but they continue to grow.  Something to watch out for is sharp edges to the molars, as the lower jaw is narrower than the upper.  This means the teeth wear unevenly and the sharp edges can cause sores to the inside of the mouth or the tongue.  If they have sore mouths then they may not eat properly and can be difficult to ride.  Getting teeth checked regularly by a vet or trained horse dentist is a must to keep your horse healthy.  Whilst the teeth are doing their thing saliva wets and lubricates the food so that it is more easily swallowed. 

From the mouth food passes down the oesophagus and on into the stomach.  Between the oesophagus and the stomach is a ring of muscle called the ‘cardiac sphincter’ this ring does not allow food or gas to be regurgitated.  Therefore a horse cannot be sick and this makes them more susceptible to colic.  

A horses’ stomach is relatively small as they have evolved to be ‘trickle feeders’ which means they need to eat little and often.  If you look at their natural environment they eat almost constantly and so we need to try and imitate this with our management.  Their stomach when full can put pressure on the diaphragm which will affect their ability to fill their lungs.  So don’t give them a big meal and then take them for a gallop!  In the stomach some types of food begin to be broken down by enzymes. 

From the stomach the food moves into the small intestine and this is where a horses concentrate rations are broken down by more enzymes.  However, the most significant digestion of the horses feed occurs in the large intestine (small and large colon).  This is where grass, hay and similar parts of the diet are digested.  These plants are made of complex insoluble carbohydrates which the horses’ enzymes are not able to break down.  The key is that a horses’ large intestine contains a huge number of micro-organisms.  These micro-organisms breakdown the carbohydrates by a process of fermentation.  Specific micro-organisms breakdown specific types of carbohydrates. This is why you should make gradual changes to a horses diet as they need to build up the numbers of bacteria to be able to get the nutrition from the food.

Water is extracted with the nutrients the food then passes into the rectum where more water is removed and the waste material is formed into balls of dung.  This then passes out through the anus at intervals.

There is a lot more detail to the system so in the future i will blog about each organ and what it does.