This is because ruminal abomasal dysplasia is caused by CO2 holdup in the rumen. the accumulation of dissolved carbon dioxide. Please look at my literature review on the topic. You will realise that the the higher pH of the fluid in the abomasum is directly proportional to the amount of CO2 holdup in the rumen and the degree of the tympanism.

Thanks' José,

I believed that the gas imprisoned in the abomasum had for main origin the fermentation in this organ ! But my question is the presence of liquids rather than gases !

Thank you, I'll take a look at your review on the subject.

No, there is not fermentation on the abomasum. The molecules in liquid form: dissolved CO2 and methane are trapped in the rumen fluid due to the changes in physicochemical properties of the fluid elicited by the diet. The acid secreted in the abomasum releases those molecules by changing the physicochemical properties (destroying the matrix that trapped the molecules).

I already give another colleague a similar example. But seeing is believing so: Take two glasses and fill them with sparkling water and another with beer. You will see that the CO2 bubbles leave the sparkling water very fast and they are also big. The glass filled with beer has small bubbles and they leave the solution very slowly. The beer glass simulates the rumen fluid and CO2 holdup. The physicochemical properties of the beer trap the dissolved CO2.

This is what happened when diets rich in starch are fed to cattle. The changes in physicochemical properties i.e. viscosity modifies CO2 volatility and CO2 cannot easily escape the solution. The CO2 molecules will be trapped in the liquid and will be transported into the abomasum.

Now add table salt to both glasses. You will see that in the carbonated water because the gas can escape easily “fizzles”, whereas the beer glass will generate stable foam. This is the mechanism of bloat and abomasal dysplasia. The addition of acid in the abomasum destroys the matrix that trapped the CO2, with not where to go the abomasum will be displaced.

How do you prevent this to happen: you have to reduce CO2 holdup in the rumen by providing buffer that improve nucleation (formation of bubbles). But that is another story.

Hello José,

I don't have a beer to reproduce the experience! I am Muslim. But I understood the process, it is really interesting to be able to prevent the problems of displacement of the abomasum ! I really believed that the gases were from materials (digesta and bacteria) imported from the rumen but produced in the abomasum.

I have your article on the subject and I am going to read it.

thanks again.

Oh, Ok. Just use two glasses of carbonated water. Add dishwasher soap to one of them and stir gently. You will be able to simulate what happens when you feed cattle and see that by adding the soap you will create the same effect: slowdown the bubbles formation and the size of the bubbles. You will be also able to produce stable foam by the addition of salts. it is the same mechanism.

CO2 holdup also is the cause of ruminal acidosis. The accumulation of dissolved carbon dioxide in the rumen liquid leads to CO2 poisoning.