We are going to take a short break from looking at the different types of roughage to look at gut health. Everything is linked and if our horse’s guts are not performing optimally then it will not matter what we feed or how much of it we feed we will not get the desired results. I once had a discussion with a vet about the efficacy of oral joint supplements. He said the problem with oral supplements is that one never knows how much is being absorbed and if the amount being absorbed is beneficial. He went on to say that gut health plays a big factor in absorption of nutrients and supplements and that if the horse does not have a healthy gut it is unlikely that nutrients and supplements are being absorbed correctly. What I took away from that chat was invest in gut health first before anything else.
The equine digestive tract is a large and complex system. Our horse’s health, much like our own health, depends on how well we look after our digestive system and how well we maintain the microbial population within it. Experts are only just beginning to understand how important gut health is and are starting to intricately link it to overall health as a significant percentage of the immune system is in the gut. Maintaining a healthy gut and stable gastrointestinal ecosystem is vital for not only the horse’s general health and happiness but can massively impact their mental and physical performance. Behaviours such as nervousness and aggressiveness have been linked to the make-up of a horse’s gut bacteria by researchers. The findings add further weight to the existence of a so-called ‘gut brain’ axis in horses with mental well-being and gut health being closely related.
Let’s take a brief look at a horse’s digestive system, which is made up of: the stomach, small intestine, cecum and colon. The digestive tract’s main function is breaking down food. Digestion will occur differently in every section of the horse’s gut. It is here that nutrients obtained from food and supplements get broken down into smaller particles to be absorbed by the bloodstream.
The stomach’s role is to mainly hold food and pass it slowly to the small intestine, where it will enter partially digested. The stomach does not absorb nutrients. The small intestine digests and absorbs fats, proteins, sugars and starch. Nutrients are absorbed through the small intestine, one thing that effects this is the rate at which food is released into the small intestine. If you feed your horse large meals, then the stomach loses its ability to release the food slowly into the small intestine which in turn effects the small intestine’s ability to absorb the nutrients effectively as it does not have time to do its job. The hindgut (cecum and colon) is the centre for structural carbohydrate digestion. Structural carbohydrates are digested in a process of microbial digestion. This means that the hind gut is essentially a large fermentation vat.
Probiotics are beneficial bacteria that live in the gastrointestinal tract. They exist along with pathogenic bacteria which cause infections and upset the gastrointestinal tract. In a healthy gastrointestinal tract, there are more beneficial bacteria than pathogenic bacteria. Prebiotics feed the probiotics. They will not be digested in the gastrointestinal tract but what they do is feed the good micro-organisms and probiotics in the horse’s digestive system which increases their numbers or activity. This means that there is less chance for the pathogenic bacteria to function in the gut as they cannot establish themselves. Prebiotics are most beneficial to hindgut health based on research. Extensive research has specifically focused on mannooligosaccharides (MOS), which forms part of the yeast cell wall. MOS helps clear the hindgut of pathogens and also aids in immune system health.
Yeast extracts directly support the structure and functioning of the gut, as well as facilitating better nutrient absorption and helping horses cope and thrive in modern feed and feed management routines. Yeast probiotics work predominantly in the hindgut, helping in fermentation of fibre from hay and forage. A study on the effects of supplementary yeast culture found that it improved fibre digestibility and amount of feed intake in horses. This fermentation process results in the production of volatile fatty acids which is a significant energy source and allows the horse to get more energy from their roughage. Technically this means that less concentrates will need to be fed which in itself is good for gut health.
All horses will benefit from a pre and probiotics as it helps them get more from the fibre they consume. Horses that will benefit the most are horses that suffer from diarrhoea, colic, weight loss, stressed horses, starved horses, injured or sick horses, horses with gastric ulcers, etc.
Colic is one of the most common causes of death amongst equines and it is said that more than 90% of horses have gastric ulcers. Having an imbalance in one or more of these sectors is likely to cause behavioural issues, weight loss, poor hoof quality, poor performance and poor coats.
Ulcers can develop in as little as 24 hours and recur in 24 hours respectively. They are painful which in turn causes stress and exacerbates the ulcers. Most common causes of ulcers are lack of forage and stress. Saliva is key to buffering. Horses produce gastric acid 24/7 because as we learnt in last week's blog, they are trickle grazers. Therefore, if nature’s design is followed salvia produced in preparation for constant food uptake is the perfect buffer. However, in domestic life horses often have periods of no roughage available to them. Supplementing with acid buffers can help with this.
Acid buffers are substances able to resist pH changes. They do this by absorbing both acid and alkaline ions. Buffers resist pH changes and maintain the solution’s pH but are consumed in the process meaning it will not last forever. This means that if you give your horse an acid buffer it will help maintain a less acidic environment for as long as it is not depleted.
When we feed horses, we always must keep in mind their nutritional requirements, but it is equally important to consider how we feed horses. For instance, if our horses stand for long periods of time without feed then their stomachs are empty which means the strong hydrochloric acid will start to accumulate and result in a highly acidic stomach, increasing the risk of gastric ulcers. Too much starch fed per meal, per day also increases the risks of gastric ulcers. Not enough fibre in a horse’s diet will result in the horse not being able to maintain proper microbial population in the hindgut. This can result in a vitamin deficiency, loss of appetite, weight loss, diarrhoea, poor hoof quality and changes in behaviour. Low fibre diets are also a major cause of colic in horses and can increase the risk of gastric ulcers.
Tips for feeding:
1. Feed lots of long stem fibre
2. Feed in small meals
3. Minimise starch
4. Give them constant access to roughage
5. Must always have access to clean water