There are nearly one billion cows worldwide in which many of them receive a type of antimicrobial drug. Each year, millions of pounds of antimicrobial drugs end up seeping into the environment, causing harm to certain types of species. Cows' waste contains nitrogen and phosphorus, which can drain into nearby lakes and rivers, causing harmful algae blooms. Medications given to the livestock, such as antibiotics, anti-parasite medications, and even painkillers can also pollute the waterways and farm fields.
Sadly, many farmers and landowners do not have the resources to avoid polluting waterways with manure, which over the past few years has become an issue for wildlife. In 2017, the U.S. Food and Drug Administration reported over 22 MILLION pounds of antimicrobial medication, which included antibiotics and antiparasitic meds, were sold in the United States for livestock alone! Along with cows, drugs are given to chicken, pigs, sheep, and horses which is causing a staggering amount of medication entering both freshwater and marine. If contaminants are not completely removed from wastewater, they can be used on crops as well as can be ingested by wildlife and humans.
In southern Africa, Kerri Wolter, founder of the Vulture Conservation Program, concluded that the drug diclofenac, given to cattle, caused a massive decline in vultures in parts of Africa and Asia. It is safe for cattle, but highly toxic to the vultures. Vultures depend on carcasses of cattle for their food source. Minute traces of this drug in vultures causes kidney failure. When farmers in India switched to diclofenac in the 1990's (before they knew it was a problem to the birds), the number of vultures plummeted and one specie lost more than 99% of its population!
In Xalapa, Mexico, ecologists were getting calls from ranchers saying their manure was piling up in the pastures because the dung beetles seemed to be vanishing. (Dung beetles play a big role in cow pastures by recycling dung, eating pests, and distributing nutrients into the soil). Long story short, ranches in Mexico had been treating their cattle with a drug called ivermectin to treat roundworm and other parasites, and to prevent infection. This drug is excreted with cows' waste onto the ground, but it is very deadly to arthropod species, including the dung beetles.
Government has offered a few solutions that require new drugs given to cows to be tested on dung beetles to make sure they are not toxic. Other companies have programs to decrease the preventative use of antiparasitic medications. Reducing pharmaceutical pollution from livestock will require collective actions from humans to change their thinking and their habits.