Livestock Waste and Soil Microbes
The USDA'S Agricultural Research Service (ARS), in February 13, 2006, issue of Feedstuffs, stated "unmetabolized antibiotics' were part of livestock waste. Also, the Environmental Defense Study claimed about 50% of fed antibiotics are excreted by the consuming animals. With knowledge of these facts, it is easy to see how livestock waste could have a serious influence on soil microbiological life.
However, in recent times, certain protein companies are suggesting that antibiotics are no longer used as a part of their feeding operations. This suggestion comes into question when an April 7, 2022, article was published in www.drovers.com referring to research work done at George Washington University that was published in Science Magazine. This work found that current "raised without antibiotics" (RWA) labels lack integrity.
Their research suggests that even livestock manure from animals being "raised without antibiotics" can be a significant source of antibiotics (or ionophores) being applied to soil through that livestock waste, which is in addition to the traditional volume of antibiotics (or ionophores) that are known to be fed to livestock and end up being applied to soil. It has been known since the early 2000's that up to 50% by volume of fed antibiotics (or ionophores) end up on the livestock waste.
The suggestion that "raised without antibiotics" (RWA) labels lack integrity has forced the beef industry to give high priority to finding antimicrobial alternatives. Also, in recent years environmental groups have petitioned the US Food and Drug Administration (FDA) to ban the use of antibiotics in livestock and poultry in the absence of illness. Such a discussion appeared on January 25, 2023, on www.dtnpf.com "Groups: End Livestock Antibiotic Shield."
With the knowledge of antibiotics in livestock waste, a study was published on September 8, 2021, and appeared in www.sciencedaily.com investigating livestock antibiotic effects on soil microbes. This research was conducted at Cary Institute of Ecosystem Studies. These studies found with rising heat and antibiotic conditions, soil bacteria collapsed, allowing fungi to dominate the environment resulting in fewer total microbes and less microbial diversity overall. Antibiotics alone increased bioavailable carbon in the environment and reduced microbial efficiency. It is suggested that these changes to the soil microbes could diminish soil’s resilience to future stress.
These types of studies suggest that initial livestock manure applications which showed beneficial results may possibly create a soil microbial imbalance which causes less beneficial plant growth in the future. Any problems with future plant growth will occur at different time intervals and display different quantities of problems depending on the type of antibiotic, volume of antibiotic, and critical soil properties.
This is an excerpt from the Summer Growers Solution (2023) written by Jim Halbeisen, Director of Research.
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