Ruminal Acidosis in Feedlot: From Aetiology to Prevention

Abstract

Acute ruminal acidosis is a metabolic status defined by decreased blood pH and bicarbonate, caused by overproduction of ruminal D-lactate. It will appear when animals ingest excessive amount of nonstructural carbohydrates with low neutral detergent fiber. Animals will show ruminal hypotony/atony with hydrorumen and a typical parakeratosis-rumenitis liver abscess complex, associated with a plethora of systemic manifestations such as diarrhea and dehydration, liver abscesses, infections of the lung, the heart, and/or the kidney, and laminitis, as well as neurologic symptoms due to both cerebrocortical necrosis and the direct effect of D-lactate on neurons. In feedlots, warning signs include decrease in chewing activity, weight, and dry matter intake and increase in laminitis and diarrhea prevalence. The prognosis is quite variable. Treatment will be based on the control of systemic acidosis and dehydration. Prevention is the most important tool and will require normalization of ruminal pH and microbiota. Appropriate feeding strategies are essential and involve changing the dietary composition to increase neutral detergent fiber content and greater particle size and length. Appropriate grain processing can control the fermentation rate while additives such as prebiotics or probiotics can help to stabilize the ruminal environment. Immunization against producers of D-lactate is being explored.

Effects of maternal protein supplementation and inclusion of rumen‐protected fat in the finishing diet on nutrient digestibility and expression of intestinal genes in Nellore steers

“…Gressley, Hall, and Armentano (2011) reported that the quantity of starch flowing to the large intestine might potentially lead to hindgut acidosis. As a result, fecal pH follows the patterns of the lower GIT and rumen, which had a pH decreased by the production of volatile fatty acids (VFA) and potentially high lactic acid levels when high-concentrate diets were fed (Hernández, Benedito, Abuelo, & Castillo, 2014).…”

Aspects of Acidosis in Ruminants with a Focus on Nutrition: A Review

“…Thus, that leads ton additional in ruminal pH eventually drops to 3.8, which is the isoelectric point of this acid. At this pH, at which the acid remains un-dissociated that results in the movement of the acid via the ruminal wall into the bloodstream leading to metabolic acidosis (Hernández et al, 2014).…”

“…In fact, some researchers believe that one of the main functions of saliva is to increase the rate of passage of the liquid phase of the rumen and not necessarily to neutralize the acids produced by ruminal fermentation. When ruminants are fed on the diets that are rich in fiber, the rate of rumination and saliva production is increased (Hernández et al, 2014;Pan et al, 2016). This increases the rate of passage of the liquid phase by up to 20% per hour.…”

“…This results in the elevated VFA production in the absence of a compensatory increase in the saliva buffering. Therefore, in such cases, an increase in the VFA absorption rate by ruminal epithelium and the increase in the rate of passage of the liquid and solid phases of the rumen mechanisms are critical to evaluate a possible accumulation of acids in the rumen (Hernández et al, 2014).…”

Probiotic yeasts in livestock sector

“…Under stressful conditions, rumen microflora gets disturbed resulting in rumen dysfunctions which reduce feed intake, digestion, health and performance and increase the contribution towards environmental pollution and can also lead to death. One of the major problems in ruminants is ruminal acidosis (Hernández et al, 2014). Ruminal acidosis is a pathological condition in high producing dairy or beef cattle that results from consumption of large amounts of feeds rich in ruminally fermentable carbohydrates (Crichlow and Chaplin, 1985;Nocek, 1997).…”