Dairy farmers sometimes include clay in rations when aflatoxin is present in milk. But one study suggests that they should make it a regular part of the diet.
Researchers at the University of Illinois took a look at clay in rations and found it has benefits above and beyond elimination of aflatoxin. It could improve the general health of cows.
When incorporated into the diet, clay binds to aflatoxin, preventing it from being absorbed into the cow’s bloodstream.
Instead, the bound clay-aflatoxin complex is simply excreted through the feces. Researchers looked at the effects of aflatoxin and clay on the liver, through biopsies, and at blood metabolites.
The research team — comprised of dairy professor Phil Cardoso, graduate student Russel Pate and Devan Compart of PMI Nutritional Additives — added varying levels of clay to the rations of dairy cows that were given aflatoxin. Results were encouraging. For one thing, the practice raised pH levels.
“That clay ended up promoting a better function for that cow,” Cardoso said. “It prevented oxidation stress. We were checking not only how much it was binding to the aflatoxin and avoiding going to milk or the liver so the cow wouldn’t get sick.”
The minerals capture some ions that can cause acidosis and lead to a bellyache or more serious health issues.
“If I give too much grain, she’s going to get acidosis,” Cardoso said. “The pH gets low. We thought this clay has a function as a buffer.”
The researchers experimented with concentrations of clay from 0.5% to 2%. They found that the ideal amount is from 0.5% to 1%. Higher concentrations necessarily reduced the amount of nutrition absorbed by the animals.
Cardoso noted that in its makeup, clay is similar to sand.
“The only difference is the size of the particles. Clay is extremely smaller than sand,” he said. “Those very small particles allow for better attaching to other substrates. That particle is not solid. There are layers of those mineral components that make up clay.”
Of course, like sand, it has no nutritive value. So adding too much is counter-productive. Cardoso believes it may be a good idea to consider removing other additives, such as sodium bicarbonate.
“It’s basically ash,” he said of clay. “The nutrient value is not there. It’s hard to include a lot of that because you want to add corn and soybean meal. It would be nice to take out something. We didn’t do that work yet. That would be a good next step.”
The measures provide a broader picture of overall health and immune function.
“That clay ended up promoting a better function for that cow,” Cardoso said.