In 2018, over-the-counter sales ended for the few antibiotics (such as tetracycline) still available in Canadian farm supply stores. The new requirement for a veterinary-client-patient relationship before all antibiotics could be prescribed or sold was designed to ensure that the right antibiotics are used in the right animals, at the right dose, at the right time.
Dr. Cheryl Waldner and colleagues from the Western College of Veterinary Medicine have studied the early impacts of these changes (Antimicrobial use in western Canadian cow-calf herds; doi.org/10.3390/vetsci10050366, and Producer attitudes regarding antimicrobial use and resistance in Canadian cow-calf herds; PMC10581348).
What they did: They surveyed 168 Canadian producers in the Canadian Cow-Calf Surveillance Network in 2020, a year after the regulatory change came into full effect. Participants were asked about what antibiotics they used to treat different classes of cattle, and how the regulatory changes had affected their operations. Responses were received from 146 producers, 67 per cent from Western Canada and 33 per cent from Eastern Canada. Since some western producers had also participated in the earlier Western Canadian Cow-Calf Surveillance Network, antibiotic use could be compared over time.
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What they learned: Nearly all cow-calf producers use antibiotics, but they don’t use them often. Nationally, 95 per cent of producers used antibiotics in cows and calves. But only nine per cent of producers treated more than five per cent of cows and only 12 per cent of producers treated more than five per cent of their calves.
Antibiotics were mainly used to treat lameness in cows (83 per cent of producers), diarrhea in newborn calves (67 per cent of producers), and bovine respiratory disease (BRD) in pre-weaned calves (78 per cent of producers). But remember, very few producers treated more than five per cent of animals for any condition. Overall treatment rates for all three diseases in Western Canada were the same in 2020 as in 2014, though fewer producers treated more than five per cent of their calves for BRD in 2020 (17 per cent) than in 2014 (29 per cent).
Most producers (77 per cent) reported no change in their access to antibiotics, 21 per cent said antibiotics were less accessible and two per cent said they had become more accessible. Most (63 per cent) reported no change in antibiotic cost; a few (two per cent) said antibiotic costs had gone down, and 35 per cent said prices had increased. Those who felt that antibiotics had become more expensive included the producers who treated more than five per cent of their calves before weaning.
Most producers (95 per cent) reported that their antibiotic use practices had not changed since the regulations changed. A few (four per cent) said they were using less, and only one per cent indicated they were using more. Nearly everyone (99 per cent) said the veterinarian was their main source of information regarding antibiotics and appropriate antibiotic use (88 per cent).
What has changed is macrolide use. Injectable macrolide antibiotics used by cow-calf producers include Micotil (and its generic counterparts Hymatil and Tilcomed), Draxxin (and its generic counterparts Increxxa, Lydaxx, Macrosyn, Rexxolide, Tulaven, Tulinovet, Tulissin), Zactran and Zuprevo. These antibiotics are also widely used to prevent and treat BRD in the feedlot. These antibiotics have always been prescription-only; they were never available over the counter. In 2020, 55 per cent of Canadian cow-calf producers surveyed reported using macrolides. In the West, the proportion of producers using macrolides increased from 44 per cent (2014) to 61 per cent (2020), mostly to treat lameness in cows and BRD in calves before weaning.
Although more Canadian cow-calf producers used macrolides in 2020, tetracyclines were still used by more producers (58 per cent) than macrolides (21 per cent) to treat lame cows. Sixty per cent of producers used florfenicol (Fenicyl, Florkem, Nuflor, Resflor, Zeleris) to treat BRD in calves before weaning compared to 33 per cent using macrolides.
Macrolides have become more popular for a few reasons. The requirement to obtain antibiotics from a veterinarian means that producers receive solid advice about which product is most appropriate in any given situation. The recent proliferation of generic macrolide antibiotics has made them much more affordable and cost-effective. Finally, macrolides generally require a smaller dose and are a better fit for dart guns, crossbows and pole syringes. For more, see this page on Remote Drug Delivery at the Beef Cattle Research Council website.
If the initial antibiotic treatment failed, producers were more likely to consult with their veterinarian than to try a different antibiotic for diarrhea (74 per cent versus 71 per cent) and BRD (68 per cent versus 46 per cent). But they were more likely to try a different antibiotic (53 per cent) than call the veterinarian (49 per cent) when an initial lameness treatment failed.
Bottom line: An ounce of prevention is still worth more than a pound of cure. Good nutrition and an appropriate vaccination program won’t completely prevent all disease, but they will reduce the number of animals that need antibiotics.
So what does this mean to you? Review your herd vaccination program with your veterinarian. New oral and intranasal vaccines can be given at birth to help protect against scours and BRD (BRD still needs a booster at spring processing). There is no effective vaccine available for any form of lameness, but foot rot responds well to antibiotic treatment. If the first lameness treatment doesn’t work, don’t just switch antibiotics. That throws good money after bad, and the cause is not always infectious. Take advantage of your veterinary-client-patient relationship. Ask your veterinarian what you’re dealing with and how to treat it effectively.
The Beef Cattle Research Council is a not-for-profit industry organization funded by the Canadian Beef Cattle Check-Off. The BCRC partners with Agriculture and Agri-Food Canada, provincial beef industry groups and governments to advance research and technology transfer supporting the Canadian beef industry’s vision to be recognized as a preferred supplier of healthy, high-quality beef, cattle, and genetics. Learn more about the BCRC at beefresearch.ca.
