by Emma Hardy, PhD, R. Anim. Technol (Cert)
The correct management regime is crucial to the soundness and overall wellbeing of horses in training, and the Para professions are ideally placed to educate and advise. However, equestrians are likely to associate the physiotherapist, chiropractor or osteopath with identifying and treating skeletal and musculoskeletal conditions only. In reality, the scope of the paraprofessional’s work can reach far beyond, to include the effects of internal anatomy and physiology on other body systems, and on the horse’s overall health and performance.
In this light, understanding the important role of nutrition and the health of the digestive system can benefit the important work of the paraprofessional. In this article, the importance of nutrition to gastrointestinal (GI) tract health, and ultimately on overall health and performance, will be discussed. We will review why problems within the GI tract can occur, how these may manifest both locally and systemically, and how they may be identified during a consultation.
Optimum nutrition requires optimum GI tract health
Optimal nutrition and digestive tract health play an integral and synergistic role in determining the athletic potential of the horse. Advances in nutritional research have broadened the understanding of the nutrient requirements to support various equestrian disciplines. This has led to development of an extensive range of feedstuffs and to the rapid growth of the feed industry. However, despite the provision of high quality feed to the horse – often at great expense - the health of the GI tract, and its ability to fully absorb and utilise the nutritional content of the feed, are often overlooked. The structures and functioning of the gut must be working correctly for feed to be effectively utilised.
The horse functions when the GI tract functions
Typical diets associated with performance, can present their own risks to the GI tract. Feed rich in energy dense, non-structural carbohydrate, fed intermittently, with limited access to forage, represents a significant departure from how the horse’s GI tract has evolved to function. Problems such as starch overload, rapid feed transit times through the tract, and prolonged periods of reduced fibre intake can be characteristic and may result in damage to the gastric mucosal membrane and imbalance of the delicate fibre-digesting microbiota of the hindgut. When the stress of training, travelling and competing – and even long-term use of commonly used acid suppressing drugs – are also incorporated, specific biological responses can reduce integrity of the intestinal mucosa.
The ability to combat ingested pathogens and toxins can also be depressed. Further, components necessary for the maintenance and functioning of the tract, such as specific amino acids, can become depleted. When faced with these conditions, it may be advantageous to provide additional GI tract support and specific nutritional supplementation which can help to offset the negative effects posed by this type feeding and management.
Clearly, optimising GI tract health for feeding is equally beneficial in combating imbalance and disease, which is crucial to maximising overall wellbeing and performance potential.
Symptoms of hindgut and gastric conditions can be similar
Initially identifying GI tract inflammation and ulceration can be difficult. Individual horses can present with a range of signs, symptoms and severities, some of which are not always typical. Unexplained loss of appetite, weight and condition, changes to performance and attitude, development of stereotypies, and bouts of colic are considered the usual indicators of gastric ulceration.
However, many of these signs have also been observed in horses with a hindgut compromise. Areas of inflammation, ulceration or bleeding from the intestinal wall will undoubtedly prevent efficient nutrient uptake which, in turn, can lead to weight and condition loss. Imbalance within the bacterial populations of the large intestine will diminish important fibre fermentation and can lead to further complications.
When conditions result in an increased acidity within the gut, it is perpetuated by the subsequent proliferation of lactic acid-producing bacteria and exerts a negative impact on the populations of fibre-fermenting bacteria. This can result in the production and release of toxins into the vascular system, which can become responsible for more serious clinical conditions such as colic and laminitis.
As Pellegrini (2005) showed, gastric and hindgut inflammation and ulceration can often occur concurrently. Whilst a definitive diagnosis for gastric ulceration can be established via gastroscopy, a hindgut diagnosis can be more protracted.
Awareness of the signs pertinent to a hindgut disturbance can be useful during a consultation when seeking a diagnosis. This, in turn, helps to devise an effective treatment plan and achieve rapid resolution.
Symptoms more indicative of hindgut issues are becoming better recognised
Due to the expansive structure and location of the hindgut, discomfort there may give rise to various issues that one may not typically associate with a GI tract condition. Some signs and symptoms may include:
- Intermittent hind limb unsoundness, particularly affecting the right side.
- Changes in the length and quality of hind limb stride, and a reluctance to engage the hindquarters.
- Loss of flexibility through the body around the leg, with a deterioration in the quality of extension or collection.
- Girthyness resulting from discomfort in the large colon.
- Sensitivity of the flanks, perhaps towards brushing or rugging, often with a corresponding dislike or even an acute response to touching or palpation over the area of the abdominal oblique muscles.
Should a GI tract problem be suspected, further veterinary investigation and diagnostic tests may be warranted. Accurate, early diagnosis is crucial in selecting the most effective plan of treatment for complete recovery and limiting any long-term effects. Of equal importance is obtaining a differential diagnosis.
Gastric and hindgut conditions require different approaches for resolution, and so knowing the location of an abnormality is highly advantageous. These next steps will be explored in more detail in the third article of this series.
Pellegrini F (2005) Results of a large-scale necroscopic study of equine colonic ulcers.
Journal of Equine Veterinary Science. 25 (3): 113–117