Ionophores are feed additives routinely included in cattle rations to enhance performance efficiency. These additives, such as Rumensin or Bovatec (chemical name Monensin, Lasalocid, respectively) prevent certain bacteria and protozoa within the digestive system that provide no benefits while allowing increases of symbiotic organisms that do profit the animal. Specifically, these products select against “gram-positive” bacteria that generally produce methane (CH4) and carbon dioxide (CO2) while promoting “gram-negative” bacteria that produce compounds the animal can use for energy sources.
Some of these affected bacteria produce substantial levels of lactic acid which can significantly reduce pH, promoting decreased feed intake. Since the ionophore reduces these specific bacteria, the potential severity of ruminal acidosis and bloat is lowered. Also, ionophores will somewhat reduce ruminal protein degradation, allowing for lower tract digestibility and less urinary nitrogen (N) loss and possibly reducing the nitrogen footprint. Further, ionophores are considered coccidiostat, which prevents the occurrences of coccidiosis outbreaks. All these factors together result in potential increases in efficiency since performance can be maintained with less dry matter intake or performance can be increased when animals consume similar dry matter.
Ionophores are a different type of antibiotic in that they are not necessarily bactericidal but inhibit all functions causing a significant shift in ruminal fermentation design and shape. Because these types of antibiotics target only specific bacteria and are not used in any pertinent or important human disease prevention, they are not subject to regulations under the Veterinary Feed Directive (VFD) of January 2017. Since ionophores are gut-acting products and do not work systemically, there is no withdrawal period.
Mature cows along with growing calves gain from consuming diets containing an ionophore. Research from the 1970s and 80s (including my research conducted at the University of Tennessee) revealed an increased rate of weight gain and efficiency compared to unsupplemented cattle. Since feed price represents a significant portion of production cost, the addition of ionophores is an excellent investment, with many studies suggesting a 4:1 return.
Additionally, all phases of the cattle industry continue to face scrutiny regarding its contribution to ecological concerns. Since CH4 and nitrous excretions have always been considered prime sources of greenhouse gases, research is beginning to quantify the benefits of ionophores in decreasing suspected gas and ammonia (NH3) emissions to the atmosphere. Even from an environmental perspective, ionophore usage can provide an advantage to sustainable production systems.
Both the potential health benefits and economic gains promote the use of additives that control digestive fermentation. Your feed and animal health specialist can help with the implementation specific feeding practices to capture optimal economic value.