Ionophores like monensin, lasalocid and laidlomycin, have been readily used within the U.S. and a recent research study by Haley Larson, assistant professor of animal health at K-State Olathe, found rotating through different molecules could provide added gain benefits.
“They have a multitude of functions,” says Larson of ionophores, which are molecules that inhibit growth of certain bacteria. “They help control or prevent coccidiosis, and they also have some improvements on feed to gain.”
Benefits of Ionophores
While technically an antibiotic, ionophores do not fall under the veterinary feed directive as they are not used in human medicine. Thus can be used for the promotion of gain and feed efficiency of livestock.
Within the U.S., ionophores are labeled for continuous feeding, which the FDA defines as at least 14 days.
Larson says in order to have a study that could be easy for producers to replicate, they chose a 28-day feeding period per ionophore. This time frame also gave rumen time to adapt.
“We need to make sure that they have that full adaptation to one ionophore before you introduce the next one to shift that population in a different direction,” Larson says.
Ionophores work by inhibiting or killing certain types of bacteria in the rumen, which changes the rumen microbial population.
“We get a shift in the fermentation profile and the end products of fermentation that are produced that then, in turn, makes the animal more efficient,” explains Phillip Lancaster, K-State professor of cattle nutrition.
The idea behind rotating them would be to shift the microbial population and determine if there was a synergistic effect of using two different products or molecules on that efficiency of rumen fermentation, Lancaster adds.
Study background
The study was conducted in a commercial yard in southwest Kansas on heifers who were limit-fed for a targeted 3-lb. ADG on a growing ration. Monensin and laidlomycin were rotated through twice each on a 112-day growing period.
“We found that those heifers that were on the rotation had an 8.6% improvement in gain over their monensin-only counterparts,” Larson says.
She is continuing to analyze the data, also looking at methane production from rotating molecules as well.
To hear more of the conversation, listen to the BCI Cattle Chat.
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