Beef Cattle Acidosis
A Silent Challenge with Major Consequences for Health and Performance. In modern feedlot systems, diets rich in energy and rapidly fermentable starch are essential to optimize average daily gain and feed efficiency. However, these nutritional strategies also increase the risk of digestive acidosis, particularly ruminal and cecal acidosis. Although often subclinical, this condition can lead to significant metabolic, inflammatory, and tissue alterations, negatively affecting animal health, production performance, carcass quality, and economic profitability.
Rumen Acidosis, Origin of Ruminal Lesions and Functional Impairment
Ruminal acidosis occurs when the rapid fermentation of carbohydrates leads to excessive accumulation of volatile fatty acids (VFAs) and, in more severe cases, lactate, resulting in a prolonged decrease in ruminal pH.
When ruminal pH remains low (below 5.8) for extended periods, several structural and functional alterations develop, including deterioration of the ruminal epithelium, lesions of the ruminal papillae, development of mucosal hyperkeratinization, and reduced absorption capacity for nutrients and VFAs.
These changes progressively compromise the barrier function of the rumen and reduce its buffering capacity, creating a vicious cycle that aggravates acidosis. They also facilitate the translocation of toxins, bacteria, and inflammatory mediators into the bloodstream, contributing to the development of systemic metabolic and inflammatory disorders.
The main consequences observed include:
- reduced feed intake;
- decreased feed efficiency;
- chronic discomfort and inflammation;
- increased risk of ruminitis.
Hepatic Abscesses: A Systemic Consequence of Acidosis
Ruminal mucosal lesions induced by acidosis promote the translocation of opportunistic bacteria, particularly Fusobacterium necrophorum and Trueperella pyogenes, through the ruminal wall into the portal circulation. These bacteria subsequently reach the liver, where they may induce the formation of hepatic abscesses.
Hepatic abscesses represent one of the most common systemic complications of chronic ruminal acidosis in feedlot systems. Their prevalence generally increases in animals receiving highly concentrated diets with low levels of effective fiber.
Even when subclinical, hepatic abscesses may result in:
- reduced zootechnical performance;
- decreased average daily gain;
- poorer feed efficiency;
- economic losses associated with partial or total liver condemnation at slaughter;
- an increased risk of systemic inflammatory and infectious complications.
In severe cases, abscesses may also lead to thrombosis, embolism, or secondary infections affecting other organs.
Hepatic Abscesses: A Systemic Consequence of Acidosis
Ruminal mucosal lesions induced by acidosis promote the translocation of opportunistic bacteria, particularly Fusobacterium necrophorum and Trueperella pyogenes, through the ruminal wall into the portal circulation. These bacteria subsequently reach the liver, where they may induce the formation of hepatic abscesses.
Hepatic abscesses represent one of the most common systemic complications of chronic ruminal acidosis in feedlot systems. Their prevalence generally increases in animals receiving highly concentrated diets with low levels of effective fiber.
Even when subclinical, hepatic abscesses may result in:
- reduced zootechnical performance;
- decreased average daily gain;
- poorer feed efficiency;
- economic losses associated with partial or total liver condemnation at slaughter;
- an increased risk of systemic inflammatory and infectious complications.
In severe cases, abscesses may also lead to thrombosis, embolism, or secondary infections affecting other organs.
Cecal Acidosis: Intestinal Inflammation and Energy Diversion
When large amounts of starch escape ruminal digestion, they reach the cecum where excessive fermentation occurs. Because the cecum is particularly sensitive to decreases in pH, this intense fermentation rapidly promotes the development of intestinal lesions and functional disturbances.
Under these conditions:
- the intestinal mucosa rapidly deteriorates;
- intestinal permeability increases;
- bacterial endotoxins, particularly lipopolysaccharides (LPS), cross the intestinal barrier and enter the bloodstream.
This situation leads to the development of chronic subclinical inflammation.
Consequently, a substantial proportion of nutrients and energy, which would normally be directed toward muscle growth and production performance, is instead redirected toward immune mechanisms and inflammatory responses.
Acidosis observed in feedlot systems is not merely a transient digestive disorder, but rather a multifactorial condition capable of profoundly altering animal physiology and performance.
Its effects involve ruminal mucosal integrity, liver health, intestinal function, and activation of immune and inflammatory responses. Ultimately, these disturbances compromise zootechnical performance, carcass quality, and the economic profitability of production systems.
In this context, high-performance feedlot systems must balance high dietary energy density with the maintenance of digestive and metabolic stability. Preventing acidosis therefore relies on several complementary measures, including careful dietary transition management, proper grain processing, adequate physically effective fiber supply, monitoring of ruminal pH, and minimizing fluctuations in feed intake. The use of buffering or alkalinizing agents, such as magnesium oxide (MgO), may also help maintain ruminal pH stability and limit the adverse effects associated with excessive fermentation.
The ultimate objective is therefore not only to maximize growth and weight gain, but also to sustainably preserve digestive and metabolic health in order to ensure optimal long-term productivity.