Antibiotic use in poultry, beef may need rethink

RED DEER — Raising animals without the use of antibiotics is a growing trend, but it is not always the best approach for livestock health, says a poultry veterinarian.

“The truth is, sometimes we need to treat flocks. Raising birds without antibiotics is not a sustainable industry position,” said Tom Inglis at the recent western poultry research conference in Red Deer.

Companies like Wendy’s and McDonald’s have promised to offer chicken raised without the use of antibiotics medically important to humans by 2017. A&W restaurant already advertises that its beef, chicken and pork are raised without antibiotics.

Last year, the Canadian chicken industry voluntarily banned the use of category one antibiotics — those most important in human medical treatments.

The message is that indiscriminate use of antibiotics in the livestock world could ultimately affect human health and contribute to antimicrobial resistance to commonly used treatments.

The beef industry is also evaluating its use of antimicrobials and recognizes some products are also prescribed in human medicine. The drugs need to work while providing assurance to consumers that beef is safe to eat, said Reynold Bergen, science director with the Beef Cattle Research Council.

“We need animal health products to be effective when our animals get sick and we need those human drugs to be effective when we get sick,” he said during a March 2 webinar.

Some bacteria have always carried resistance to antimicrobials but overuse in some quarters may exacerbate the problem.

“There is no evidence that antimicrobial use in Canadian beef cattle production is causing the antibiotics used in human medicine to become less effective and that is in spite of the fact that people are really looking to see if the link exists,” Bergen said.

A cross disciplinary study involving 2.5 million head in 25 to 35 commercial feedlots across Western Canada is examining the potential link. Researchers are collecting feedlot samples, manure, soil and downstream water samples as well as municipal water supplies to detect antibiotic resistant bacteria.

Genomic technology will look at the specific DNA mutations that confer antibiotic resistance in the feedlot samples and see if those mutations are responsible for illness in humans. If the mutations are not the same, then beef cattle are not responsible for what is happening in human medicine.

The study should be done in 2018.

In the meantime, government is clamping down.

Health Canada announced a plan last year to phase out all livestock growth promotion use on medically important drugs by December 2016. The government also wants more veterinary supervision over access to growth promoting drugs and how they are added to feed or water. This measure will require amendments to the food and drug regulations and the feeds regulations.

The next change could be ending the practice of metaphylaxis or mass medication to eliminate or minimize an expected outbreak of disease.

Also, off-label use of medications is coming under scrutiny. The label provides information on the therapeutic treatment of a diagnosed disease or disorder for a particular species.

However, extra uses are sometimes needed. For example, ducks are not included on drug labels so veterinarians must determine what the best course of action is when prescribing a treatment, said Inglis.

Antimicrobials have been used extensively for years in beef cattle production, particularly in feedlots. A common practice is meta-phylaxis where all cattle are treated upon arrival.

“We found antimicrobials were one of the tools we could use. Preventing disease was far more rewarding and more productive than trying to treat animals that were already sick.

“Can we defend the use of this long term and is society going to allow us antibiotic products on animals that might get sick but aren’t currently sick,” Inglis said.

Producers also found that certain antimicrobial helped improve animals’ growth. A product like Tylesin controls liver abscesses. Animals with healthy livers grow faster and fewer livers are condemned at the packing plant.

Rumensin is an antibiotic that makes rumen microbes more efficient and ferment feed better. This offers improved feed conversion and higher average daily gain.

There are new products coming so the supply of antimicrobials for beef cattle is not an issue. The question is how they are used.

“Society is going to review how we do this and they are going to have expectations of us and so we need to have a mind shift on how we approach our use of these products and defend the fact we are using them prudently and also in a sustainable manner,” said Dr. Craig Dorin of Veterinary Agri-Health Services in Airdrie, Alta.

The cow-calf sector is the best area to make management changes and reduce the use of antimicrobials. In the last few years with the increased value of cattle, people are using antibiotics to prevent illness on the farm, said Dorin

He offered the following suggestions:

  • Do not use antimicrobials for diseases that do not require antimicrobials. It is common for calves to get pus-filled abscesses. If there is no fever, no antimicrobials are needed. It is a localized infection that needs to be drained and flushed.
  • Understand the classes of antimicrobials. Pick products that are further away from those used in human medicine.
  • Use the appropriate product. Understand what the antibiotic is best suited for.
  • Use products for the proper duration. A foot rot may need three days worth of treatment, whereas a calf with a joint infection due to naval infection needs a longer treatment. Some infections are deep rooted and require a longer duration of therapy to be effective.
  • Ensure all cattle are getting the right amount of energy, protein, vitamins and minerals. Inadequate vitamin and mineral supplementation often leads to health problems.
  • Vaccination protocols can reduce persistent conditions like bovine viral disease. Producers in natural programs do not use antibiotics so good tools like preweaning vaccination are effective. This can be done two weeks prior to weaning.
  • Develop biosecurity plan. Other livestock groups have closed herds but steps can be taken on beef operations to implement biosecurity, like monitoring visitors and trucks entering the property or health history of new animals. For example, do not bring dairy cows onto a beef operation for colostrum because there is a risk of introducing Johne’s disease through the milk.
  • Calving management. More producers are calving later from April to June. Calves are born on dry, clean ground or green grass and are much healthier.
  • Direct farm to feedlot sales reduce travel stress and commingling at public auction so there is less disease.
  • Up-to-date animal records allow feedlots to handle cattle better.
  • Get accurate disease diagnosis to make sure the right treatment is being used.
  • A wider antimicrobial resistance surveillance program is needed.

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