09/02/2026
Intestinal hyperpermeability aka ‘Leaky Gut’ occurs when the gastrointestinal barrier has been compromised, consequently leaking digestive contents through the epithelium & into the bloodstream. With 70-80% of all immunologic cells within the gut, intestinal integrity is the foundation of health for all animals whether monogastric, hindgut fermenters or ruminants.
There are numerous causes of leaky gut:
❗Dietary changes,
❗Subacute ruminal acidosis (SARA),
❗Dysbiosis (microbial imbalance),
❗Heat stress,
❗Physical stress,
❗Environmental stress,
❗Pathogenic infection.
All of the above leads to circulating lipopolysaccharides (endotoxin) that in ‘normal’ circumstances would remain within the intestinal lumen. When LPS crosses the intestinal barrier & enters circulation it becomes a potent immune system activator, triggering an energy-expensive systemic inflammatory response reducing feed intake, feed conversion, production, reproduction & increasing incidence of liver dysfunction, infection & lameness.
Specific causes of leaky gut in pasture-based systems:
🍀DIETARY CHANGES are frequent with variations in seasonal growth, use of monocrops or ‘rocket fuel’ crops with little consideration to the requirement of the rumen for fibre & it’s limited capacity to metabolise protein.
We don’t provide enough effective fibre (long stranded, essentially the lignified/indigestible portion) directly reducing cud chewing & saliva production. The consequential increased rate of passage further increases intestinal epithelium damage.
🤢SARA often incorrectly assumed to only be an issue with high grain/starch diets but just as much of a concern in low fibre & excessive degradable protein diets. In these instances, it’s not the ammonia that causes acidosis but the increase in rumen bacterial growth beyond the rumen capacity. This causes excessive VFA production in effect mimicking the same mechanism as would be expected with high grain diets. Soluble protein digestion indirectly increases rate of glycolysis through increased lactate but the increased lactate itself can further increase the glycolytic flux, a vicious cycle.
Lack of effective fibre, & high rates of degradable protein are both independent causes of acidosis but when combined, an even higher risk for acidosis & inevitable reduced performance. Stock grazing lush pastures or crops, high in phosphorus, potassium, low dry matter, low effective fibre will all be to some degree in a state of acidosis with rumen & gastrointestinal dysfunction reducing feed conversion efficiency, preventing full potential being achieved.
🦠DYSBIOSIS, goes without saying when we have the issues above.
❌STRESS another underrated cause for reduced production so minimise wherever possible. Shade, shelter, good water access, handling, space, herd dynamics etc. are just the basics but I’d add fibre to this list – if a ruminant can’t ruminate, animal welfare is brought into question.
Image sourced from Kermin.com
