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  • Lancaster / Wi
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 The Cause & The Solution

There appears to be much confusion concerning the causes of bloat. Here, we will direct discussion towards the causes and solutions for favorable outcomes. There are two major types of bloat which we at FCE categorize as acidosis (acid bloat) and alkalosis (alkaline bloat). Acid bloat is a result of high carbohydrate rations that produce excess lactic acid, which results in the formation of excess methane gas. Alkaline bloat, typical of grass and legume rations, is more complicated and difficult to control. If the pH of the animal's urine is acidic, it has acidosis. If the pH of the urine is alkaline, it has alkalosis. Since the majority of customer and researcher interest centers around grass and legumes, we’ll focus our discussion on alkalosis.

Grasses and legumes (predominately legumes) produce a substance called saponins. Saponins are any numerous glycosides (abundant in plants; can be resolved by hydrolysis into sugars and aglycones), which appear in many plants. They are characterized by properties that form colloidal solutions and produce soapy lathers, especially when mixed with water. Gas entrapment caused by surface tension of saponins results in frothy bloat. Evidence indicates that the primary gas responsible for bloat is ammonium gas (NH4+). NH4+ is produced by deamination of excess protein by rumen microflora (i.e., bacteria). As a plant matures, protein content decreases and energy content increases, which explains why alkaline bloat is more prevalent in cattle fed immaturely harvested or grazed forages. The presence of nitrates in forages intensifies these effects.

Alkalosis, like most problems, has no single solution. As we are in the “sunshine harvesting” business, bloat will always be a consideration where immature forages are present. Besides not feeding lush fast growing pasture, there are alternate solutions to the problem. First, it is necessary to address the problem of saponins. This oily layer may be chemically dissolved by using a surfactant such as paloxalene (a detergent), mineral oil, or an acid. Any of these will dissolve the saponin layer, although consideration of cost and administration method must be taken into account.

Secondly, it is necessary to address the problem of NH4+ gas. One method to decrease the accumulation of excess NH4+ is using bentonite, a monmorillanite clay. Its ability to uptake and attract positively charged ions like NH4+ decreases excess NH4+ in the rumen. According to the New Zealand Journal of Agricultural Research, bentonite "reduced the incidence, but not the severity of bloat and may be even less effective under severe bloat conditions." Another more effective way to neutralize alkaline NH4+ gas is by using an acid. Acids readily combine with NH4+ to form a neutral compound; thus, neutralizing the pH of the rumen. The amount of NH4+ neutralized is dependent upon the strength and how much of the acid is added. However, too much acid is not desirable. Our mineral programs offer a strong acid product free choice (Formula D-), which allows the animal to help buffer their rumen pH back to normal. This neutralizes NH4+ gas in the rumen, dissolves the saponin layer, and removes the risk of administering too much acid.

Although addition of an acid decreases the incidence and severity of bloat, it does not eliminate the undesirable effects of excess protein in the ration. Therefore, the ultimate course of action is to eliminate the production of NH4+ gas so it cannot accumulate. Raising the energy of the ration will decrease deamination of protein by rumen microflora, thereby reducing NH4+ production and improving animal health. If increased production is not a primary goal, animal health can be improved by simply diluting the protein excess with a low protein feedstuff such as corn stalks, straw, cottonseed hulls, grass hay, or very mature grass. Both dilution of the protein excess and raising the energy are very acceptable solutions.