Frothy Bloat In Ruminants

Learning Objectives

• Describe normal ruminant digestion
• Explain what frothy bloat is and what causes it
• Understand how to treat frothy bloat

Ruminant Digestion

Ruminants, including cows, have 3 more stomachs than we humans do. This is how they are able to eat almost exclusively grasses and hay and are able to draw out so many nutrients. If we humans with only one stomach were to rely solely on grass it would not bode well.  Ruminants have 4 compartments of their stomach which include the rumen, reticulum, omasum, and abomasum.

The Rumen:

This is the largest component of the stomach and acts as a fermentation compartment. Within the rumen, there is large microbial diversity that is responsible for the breakdown of complex molecules into more simple ones that host animals can use as energy sources. These microbes produce volatile fatty acids and proteins that are vital for the animal.

The Reticulum:

This compartment is smaller than the rumen but works closely with it. The reticulum is responsible for the mixing of the food. It is also responsible for stimulating regurgitation in which the animal will rechew the food, now called cud. This process is called rumination and helps further break down food improving digestion and absorption.

The Omasum:

This section of the stomach is responsible for the further breakdown of food and water absorption. The omasum acts similarly as a filter, removing water and minerals from the food before moving onto the final stomach.

The Abomasum:

This section of the stomach is the most similar to our stomach. the abomasum is referred to as the “true stomach” because of its secretory ability. This compartment has the ability to secrete gastric juices to further break down food increasing digestibility and absorptivity within the small intestine.

Frothy Bloat

What is Frothy Bloat?

This is a digestive disorder that affects ruminants. This disorder occurs when gas is produced by microbes in the rumen during normal fermentation but the gas becomes trapped in a stable foam. This prevents the normal release of gasses through burping leading to acessive gas accumulation within the rumen.

Symptoms of Frothy Bloat:

• Distended left side of the abdomen: the rumen will become visibly enlarged on the left side of the abdomen
  

  

• Labored breathing: due to pressure on the diaphragm from the distended rumen
• Increased salivation
• Restlessness and general discomfort: Animals may show signs of
  kicking their abdomen

What Causes Frothy Bloat?

Frothy bloat is due to the ingestion of certain forages and feeds that cause the formation of stable froth in the rumen. Some examples of the feed factors include:

• Legume-rich feeds: pastures with legumes such as alfalfa and clover that can contain compounds that lead to the production of stable foam in the rumen
• Highly fermentation diets: excess carbohydrate fermentation can lead to the stable foam in the rumen
• Certain plant species: plant species that are lush and consumed in large quantities can increase the risk of developing frothy bloat

How Do You Treat Frothy Bloat?

Antifoaming agents are commonly used to treat frothy bloat. These agents may include dimethicone or polaxolene which disrupt the foam releasing gas freely into the stomach and allowing the animal to burp it out. In severe cases, a stomach tube may be used to release the gas from the rumen.

The video below further explains frothy bloat in comparison to free-gas bloat in cattle.

Knowledge Check

Resources

• https://open.lib.umn.edu/vetphysioapplied/chapter/bloat/
• https://www.merckvetmanual.com/digestive-system/diseases-of-the-ruminant-forestomach/bloat-in-ruminants
• https://extensionpublications.unl.edu/assets/html/g2018/build/g2018.htm#:~:text=Pasture%20(frothy)%20bloat%20can%20occur,may%20not%20contain%20legume%20forage.
• https://youtu.be/F7x20UMO2U4