Equine colic: a review of the equine hindgut and colic

Abstract

Colic is the major cause of morbidity and mortality, premature deaths, and is the number one health concern in horses. To increase the quality of life for horses, it is vital to understand the causes, signs, diagnostics, treatment, and prevention of colic. Horses are hindgut fermenters and their cecal microbiome can easily be altered due to environmental and physiological changes. Colic can be induced from starch overloading, which can have detrimental effects on the cecum microbiome, such as decreasing hindgut pH and altering the production of volatile fatty acids. In addition, if the immune system becomes compromised, causing changes in the hindgut microbiome, this will trigger a proliferation of opportunistic and pathogenic bacteria, which can cause numerous gastrointestinal diseases, resulting in colic. However, identifying a variety of microorganisms in the cecum is extremely difficult and understudied because difficulties in sampling and not all bacteria strains can be cultured. Therefore, next generation sequencing has helped in identifying microbes found in the gastrointestinal tract. Using the application of metagenomics, allows scientists to be able to sequence thousands of microorganisms simultaneously. In addition, exploring new techniques to help identify and achieve a clearer picture of the microbiome population and how it may change during bouts of colic could revolutionize the way veterinarians diagnose colic and tailoring a treatment specific to the microoganisms that are proliferating. Therefore, understanding the mechanisms of colic and next technological advances could increase the quality of life for horses and minimize the mortality rates.