Antibiotic growth promoters are still being widely used on farms in the USA, a local vet has found. As part of his Nuffield Scholarship, Dr Mark Little visited a feedlot business in Texas where 1.2m cattle are finished every year.

“They told me that the vast majority of beef feedlots in the USA use feed additives in large quantities,” Little said during a CAFRE webinar on Tuesday evening.

He gave the example of Tylan, an antibiotic which is used to reduce the incidence and severity of liver abscesses in cattle on the feedlot in Texas.

Little suggested that the cattle’s diet could be adjusted to have a lower starch content so that liver abscesses would be less common and blanket treatments of Tylan could be stopped.

He also found that in a farm supply shop in Texas, all antibiotics were available to purchase without a prescription from a vet

“They told me very quickly that they had already conducted a study into this, and they found that cattle grow faster on the diet with antibiotics,” Little said.

“Using Tylan makes them an extra $28/head and when you kill 1.2m cattle that equates to $34m per year,” he added.

With antimicrobial resistance posing a threat to both human and animal health, Little described the practice of blanket treating cattle with antibiotics as “extremely, extremely unsustainable”.

He also found that in a farm supply shop in Texas, all antibiotics were available to purchase without a prescription from a vet, including those products which are classified as critically important.

“A critically important one that we all know is, for example, Marbocyl. These are the most important to preserve for human diseases and resistance developing for these antibiotics would be disastrous,” Little said.

The progression over the past while has been to continue reducing the use of antibiotics

He captured a photo of a “50% clearance sale” for antibiotics which are passed their expiry date. “[These] products have a reduced activity, so if they are used, they deliver a sub-optimal dose to cattle which is one of the major drivers of antibiotic resistance,” Little said.

His advice to local farmers in NI is to take a preventative approach to animal health by drawing up an effective herd health plan and properly diagnosing health problems before administering treatments.

“The progression over the past while has been to continue reducing the use of antibiotics, and I don’t see that changing,” Little said.