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The Results Are In on Beef Cattle Research Projects
The Beef Cattle Research Council (BCRC) funds a variety of research projects on animal health and welfare, environmental sustainability, forage and grasslands, feed efficiency, food safety, beef quality and more. This post is part of an ongoing series highlighting recent research results. Find the BCRC’s entire catalog of research summaries under “For Producers” in the navigation.
Can we safely feed ergot-contaminated feed?
Even very low levels of ergot can impair intake, performance and carcass quality. While feed processing like pelleting does not reduce ergot toxicity, the mycotoxin binder showed promising preliminary results in an artificial rumen study in curbing the negative production factors.
Are calves already showing signs of antimicrobial resistance before entering the feedlot?
At feedlot entry, fewer than 2% of calves were carrying resistance to one or more antibiotic in any of the major Bovine Respiratory Disease (BRD) pathogens (Mannheimia haemolytica, Pasteurella multocida or Histophilus somni). BRD-associated viruses were virtually zero among calves well-vaccinated herds.
Neither live or heat-killed yeast were shown to benefit gut health, animal performance or grading data in finishing diets that already contained monensin and/or Tylosin. However, when comparing yeast types, it appears that live yeast may be better for rumen health than heat-killed yeast.
What can we learn about biofilms to prevent them in meat processing facilities?
STEC biofilms were more likely to form on food contact surfaces at 25°C compared to 10°C. Biofilms form more easily on thermoplastic polyurethane(TPU) than on stainless steel. Near-infrared spectroscopy (NIR) can help detect biofilms on TPU surfaces. Some sanitizers remove biofilms much more effectively than others, but regardless of product, scrubbing the surface beforehand improves their effectiveness.
How is antimicrobial resistance and BRD transmitted through the feedlot?
Respiratory disease and antibiotic resistance can develop within individual cattle one at a time, but the contagious spread of resistant BRD pathogens from animal to animal is primarily responsible for the widespread BRD early in the feeding period.
Can we increase calf marbling by upping vitamin A in the diets of pregnant cows?
Supplementing vitamin A above recommended levels to pregnant cows in late gestation can increase the marbling and marbling potential in calves from early life to slaughter without depositing fat elsewhere on the carcass. No differences in dam or calf performance were observed besides marbling. However, there was no significant difference in grade.
Sharing or reprinting BCRC posts is welcome and encouraged. Please credit the Beef Cattle Research Council, provide the website address, www.BeefResearch.ca, and let us know you have chosen to share the article by emailing us at info@beefresearch.ca.
The BCRC is funded by a portion of the Canadian Beef Cattle Check-Off.
Your questions, comments and suggestions are welcome. Contact us directly or spark a public discussion by posting your thoughts below.
Fast Action at the Watering Hole🎙️
This article written by Dr. Reynold Bergen, BCRC Science Director, originally appeared in the December 2023 issue ofCanadian Cattlemenmagazine and is reprinted on BeefResearch.ca with permission of the publisher.
Antibiotic resistance threatens the effective prevention and treatment of disease in both humans and animals. When microbes are exposed to an antibiotic, those that are susceptible to that antibiotic die out. Those that are resistant to it survive, thrive, reproduce, pass on their resistance genes on to their descendants and become more common. If those surviving bacteria cause disease, then it’s bad news for health, because that antibiotic won’t be as effective for treating that disease anymore. But it turns out that even “bystander” bacteria may play a role in antibiotic resistance.
Both antibiotics and antibiotic resistance are completely natural. Microbes produce antibiotics as defensive and offensive weapons to help them compete for space and resources in their environment. In fact, most modern antibiotics were derived from drugs that were originally isolated from different species of soil bacteria. So, it’s not surprising that antibiotic resistance is also found in the environment – microbes naturally evolve resistance to defend themselves against the antibiotics that other microbes produce. Researchers find antibiotic resistant bacteria in glaciers and other locations that have never seen modern humans or modern antibiotics. It’s a subterranean arms race.
In an arms race, shadowy arms dealers connect people with weapons to people who want weapons. Normally harmless bacteria found in water may be the arms dealers in the feedlot’s antibiotic resistance arms race. Tony Ruzzini and colleagues recently demonstrated this (Insight into antimicrobial resistance at a new beef cattle feedlot in western Canada).
What They Did
The research team collected water samples from a new dugout and new water bowls in eight empty pens at a brand-new feedlot that opened in the fall of 2021. Nineteen different groups of bacteria from those water samples were tested for resistance to the different antibiotics used in the feedlot. More water samples were collected and tested weekly over eight weeks, as feeder cattle filled the pens. On arrival, calves deemed to be at a higher risk for bovine respiratory disease (BRD) were given Draxxin, lower risk calves were given oxytetracycline, and the feed contained Tylan to control liver abscesses. Cattle that developed clinical signs of BRD were treated with Excede, Florkem or Forcyl according to the health protocol the feedlot and their veterinary consultant had developed. Antibiotic resistance genes from bacteria in the water samples were compared to antibiotic resistance genes in BRD bacteria collected in earlier studies (Mannheimia hemolytica, Histophilus somni, and Pasteurella multocida).
What They Learned
Water samples collected before the cattle arrived: bacteria resistant to Florkem and Draxxin were found in the dugout and some of the water bowls, even before cattle began to enter the feedlot. The environment was a natural reservoir for these antibiotic resistant bacteria, albeit at low levels.
Water samples after the cattle arrived: Resistance to each antibiotic was found in some water bowl samples as early as the first week cattle began arriving. Water bowls in all pens contained bacteria resistant to each antibiotic by the end of the eighth week, likely from contact with the cattle treated with antibiotics on arrival.
Antibiotic resistance in water bowls vs. BRD bacteria: Even though water bowls and the bovine respiratory tract are very, very different environments, there was considerable overlap between the antibiotic resistance genes (and multidrug resistance patterns) found in water bowls and BRD bacteria. That’s what makes these results important. Bacteria are not like mammals. Mammals can only spread genes by mating with others of their kind, and genetic change takes place slowly, over generations. Bacteria can leak whole sets of genes into the environment and absorb sets of genes leaked by other bacteria. This can occur even between very distantly related species of bacteria. Entirely different species of bacteria can also mate and share sets of antibiotic resistance genes. These sets of genes often have functions related to antibiotic resistance, some of which would occur naturally, even in the absence of antibiotic use. This means that bacteria from the water bowl may spread antibiotic resistance genes to BRD bacteria from the respiratory tract, and vice versa. This would be like penning a pig and a cow together overnight, only to find a pig with horns and a cow with a curly tail the next morning.
More research would be needed to determine whether cleaning water bowls regularly might help manage the spread of antibiotic resistant bacteria in the feedlot. Water bowls may also become a convenient place to monitor antibiotic resistance (especially compared to deep nasopharyngeal swabs). For example, the researchers reported an abundance of Moraxella bacteria in water bowls. Moraxella species make up most of the bacteria living in the nose of beef cattle.
So, What Does This Mean… to You?
Antibiotic resistance has been around ever since bacteria first appeared and will never go away. That’s why responsible antibiotic use is so important to ensure antibiotics remain effective. Your veterinarian (and doctor) can help.
Bottom line: BRD can spread among cattle when they congregate at the water bowl. But water bowls might also be a spot where antibiotic resistance spreads among bacteria and adjacent pens, and might present an opportunity to help manage antibiotic resistance.
The Beef Cattle Research Council is 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.
The sharing or reprinting of articles on BeefResearch.ca is typically welcome and encouraged, however this article requires permission of the original publisher.
The BCRC is funded by a portion of the Canadian Beef Cattle Check-Off.
We welcome your questions, comments and suggestions. Contact us directly or generate public discussion by posting your thoughts below.
Do Transport Rest Stops Put Calf Health at Risk? 🎙️
This article written by Dr. Reynold Bergen, BCRC Science Director, originally appeared in the October 2023 issue ofCanadian Cattlemenmagazine and is reprinted on BeefResearch.ca with permission of the publisher.
The Canadian Food Inspection Agency revised the Transportation of Animals regulations a few years ago. Among other things, the revised regulations require longer and more frequent feed, water and rest stops during long-haul transport. Over the past few years, this column has summarized three research trials conducted by Karen Schwartzkopf-Genswein’s team at Agriculture and Agri-Food Canada’s Lethbridge Research Station. Those results repeatedly demonstrated that rest stops during long-haul transport do not provide measurable benefits for recently weaned beef calves.
In fact, new data suggests that those rest stops may pose a risk to calves. Nasal samples were collected and tested for respiratory bacteria during the three trials. The first results from those analyses have just been published (“Auction market placement and a rest stop during transportation affect the respiratory bacterial microbiota of beef cattle”; doi: 10.3389/fmicb.2023.1192763).
What They Did
160 freshly-weaned (not preconditioned) crossbred steer calves from a single ranch were split into two groups of 80 calves. One group went to an auction mart overnight (with feed and water) and was put through the ring the next day before being trucked to the research feedlot. A second “ranch direct” group went directly to the research feedlot. Commercial truckers loaded the calves (at the auction mart or the ranch), hauled them for 36 hours and unloaded them. At this point, half of the auction mart and half of the ranch direct calves were immediately reloaded and hauled for another four hours to the research feedlot. The other half of each subgroup were rested for eight hours, then reloaded and hauled the last four hours to the research feedlot.
Deep nasopharyngeal swabs were collected from 48 calves (12 from each of the four treatment groups) when they were unloaded at the research feedlot and one, three, six and 28 days after arrival. These samples were tested for the presence of bacteria that can have a protective effect on respiratory health (e.g., Lactobacillus), bacteria that can break down protective mucus and impair respiratory health (e.g., Streptococcus), and groups of bacteria that are directly involved in bovine respiratory disease (BRD; e.g., Histophilus, Mannheimia, Pasteurella and Mycoplasma).
What They Learned
Ranch direct vs. auction mart calves: The bacteria most often associated with BRD (e.g., Mycoplasma, Pasteurella, Histophilus and Mannheimia) were more common in the calves that had gone through the auction mart than in the calves that went directly from the ranch to the feedlot. That’s a bit surprising, given these research calves were not comingled with calves from other sources. At most, they shared a fenceline and waterbowl with other calves – sort of like a cattle rest facility.
Rested vs. unrested calves: Auction mart calves that were unloaded for an eight-hour feed, water and rest break carried fewer protective Lactobacillus than unrested auction mart calves each time they were sampled. Rested ranch direct calves carried less Lactobacillus than unrestedranch direct calves when they arrived at the feedlot and 28 days later.
Potentially adverse Streptococcus bacteria were much more common in rested auction mart calves than in unrested auction mart calves at four out of the five sampling points. Rested ranch direct calves also carried more Streptococcus than unrested ranch direct calves at every sampling time.
Rest stops often increased the abundance of the groups of bacteria associated with BRD. Rested auction mart calves carried more Mycoplasma than unrested auction mart calves at four of the five sampling time points. Rested ranch direct calves carried slightly fewer Mycoplasma than unrested ranch direct calves at all five time points.
Rested auction mart calves carried slightly fewer Pasteurella than unrested auction mart calves at all five time points, but rested ranch direct calves carried slightly more Pasteurella than unrested ranch direct calves at all five sampling times.
Rested auction mart calves carried more Histophilus than unrested auction mart calves on day 1, 3 and 6 after feedlot arrival. Rested ranch direct calves carried more Histophilus than unrested ranch direct calves on day 3 after feedlot arrival. Rested auction mart calves carried more Mannheimia than unrested auction mart calves the day after arrival, while rested ranch direct calves carried more Mannheimia than unrested ranch direct calves at all five measurement points.
So What Does This Mean…To You?
Although animal numbers and BRD treatment rates were too low (less than 6%) to detect significant differences between the auction and ranch-direct groups, the microbiology results suggest that a rest stop during long-distance transport may increase the risk of BRD in newly weaned beef calves. An eight-hour rest stop reduced the numbers of good (protective) bacteria and increased the numbers of bacteria that can compromise respiratory health and/or can cause BRD.
Bottom line: Canadian research had already shown that rest stops during long haul transport don’t benefit newly weaned beef calves. This new research suggests that rest stops may increase the risk of BRD and potentially the need for preventative or therapeutic antimicrobial use (increased treatment not seen in this study). We’ll bring you the results from the other two trials as they become available.
The Beef Cattle Research Council is 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.
The sharing or reprinting of articles on BeefResearch.ca is typically welcome and encouraged, however this article requires permission of the original publisher.
The BCRC is funded by a portion of the Canadian Beef Cattle Check-Off.
We welcome your questions, comments and suggestions. Contact us directly or generate public discussion by posting your thoughts below.
Getting the Dirt on Cleaning Versus Disinfecting 🎙️
We all know raising animals is a dirty job. The piles of mucky boots at the door and the stacks of laundry that seem to grow out of thin air are all evidence of the constant battle for cleanliness in the day-to-day operations of a cattle farm. Although we do our best to keep the dirt where it belongs, are we being mindful of the germs that could be lurking within?
“Germs” or pathogens come in all shapes and sizes, and all can pose risk to the health and wellbeing of both the cattle and the people handling them. These tiny invaders can be transferred around your property in dozens of different ways. This can lead to devastating losses, such as abortion in the cow herd, scouring of calves and even decreased performance of herd sires. It is important to know how to implement best practices to both prevent infections from occurring and eliminate the spread once they are already present.
The first step in developing any best practice protocol is always to ask the question: “What are we trying to accomplish?” When tackling the job of cleaning and/or disinfecting a particular part of a farm, we need to ask a few basic questions.
Are we cleaning or disinfecting, or both?
What types of pathogens are we trying to eliminate?
What products should we use?
What is the contact time needed for disinfection?
The difference between cleaning and disinfecting
Disinfection products (such as Prevail, Dettol, or Virkon) are chemical compounds designed to destroy specific pathogens. In order for these products to work, the area to be disinfected must be free from organic compounds (such as manure, dirt, feed and bedding) to ensure the chemicals can come into contact with the pathogens themselves and are not inactivated by any organic materials. We accomplish this by cleaning. Without this step, the time and effort spent disinfecting is money down the drain.
Cleaning can further be broken down into three steps:
Dry cleaning: Physically removing as much of the organic matter as possible prior to applying any detergents or water (e.g., shoveling out the trailer before washing it, or scraping boots before heading to the boot dip).
Wet cleaning: The process of applying detergent and water. The detergent can chemically break down the biofilm (a thin, slimy film of bacteria that adheres to a surface) and the mechanical action of scrubbing and water spray will whisk away the organic material that remains in the way of proper disinfection. Rinse all cleaner residues from surfaces using clean water at the end of this step.
Drying: All surfaces should be allowed to dry completely before proceeding to disinfection.
Once your surface is clean and dry, you can proceed to disinfection.
Disinfection can only occur once the surface is clean. There are three main considerations when choosing a disinfection product:
What pathogens are you dealing with? Are you trying to prevent as many pathogens as possible when you clean out a neighbour’s trailer for use on your farm? Or, have you had an outbreak in your calving barn and you know specifically what pathogen you are targeting? Be careful to choose a product that covers the types of pathogens that may be threatening your herd.
Mixing instructions: Ensure that you are following the product label and mixing instructions. Not mixing strong enough could lead to incomplete disinfection. Mixing too strong could potentially cause health effects from concentrated chemical exposure. Either mistake is a waste of disinfectant and money.
What is the contact time to accomplish disinfection? Many disinfectants need upwards of 30 minutes of “contact time” (the amount of time that a chemical must be in contact with a pathogen in order to destroy it). Be sure to double check the recommended contact time on the product label. During this time the surface must be kept wet with the disinfectant, which can be challenging to accomplish, especially with vertical smooth surfaces such as stall walls or trailer walls. Many products or product combinations have taken this obstacle into consideration and will include a foaming action to help the product adhere to surfaces for a longer period of time. Once contact time has been accomplished, most disinfectants will need to be rinsed off and the surface air dried.
The key to good disinfection is certainly cleaning. One can clean without disinfecting, but you cannot disinfect without cleaning. When choosing cleaning and disinfecting products for your farm, make sure you make yourself familiar with the label. Although labels can be daunting it is important to familiarize yourself with the pathogens that the product is effective against, mixing instructions, and the contact time. Just as you would not use an antibiotic without knowing the dose, it is crucial to use these products as directed. When used properly, disinfecting agents can be your first defense against pathogens entering and spreading through your animals, saving you precious time and money.
Sharing or reprinting BCRC posts is welcome and encouraged. Please credit the Beef Cattle Research Council, provide the website address, www.BeefResearch.ca, and let us know you have chosen to share the article by emailing us at info@beefresearch.ca.
The BCRC is funded by a portion of the Canadian Beef Cattle Check-Off.
Your questions, comments and suggestions are welcome. Contact us directly or spark a public discussion by posting your thoughts below.
Vaccines Are Cheap Insurance – Don’t Let Your Premiums Lapse
This article written by Dr. Reynold Bergen, BCRC Science Director, originally appeared in the May 2022 issue ofCanadian Cattlemenmagazine and is reprinted on the BCRC Blog with permission of the publisher.
After last summer’s pasture conditions and last winter’s feed costs, it’s safe to say that many cow-calf producers are facing the upcoming grazing season with some anxiety. Some are looking for new grazing arrangements, opportunities to trim input costs, or both. No single solution can solve every challenge for every operation, but nearly all decisions have trade-offs. Using a community pasture or other shared grazing arrangement may reduce pasture costs but mixing different herds can spread reproductive (and other) diseases. This risk is magnified if you’re tempted to save costs this year by skimping on your vaccination program.
The February and March editions of this column drew from a large beef cow productivity study that happened to coincide with the 2001-02 drought in Western Canada. That study also revealed how important vaccination programs are to maintaining reproductive performance. These results were published in Livestock Science 163:126-139 and Theriogenology 79:1083-1094; 81:840-848.
What They Did:
To recap, Dr. Cheryl Waldner and her colleagues from the Western College of Veterinary Medicine studied the productivity of over 30,000 beef cows in over 200 well-managed herds in Alberta, Saskatchewan and B.C. Participating producers individually identified each cow and calf, recorded all calf births (including abortions), maintained an active veterinary-client-patient relationship, had good animal handling facilities, pregnancy tested all breeding females, had a veterinarian evaluate all herd bulls, had an established spring or summer breeding season (i.e., didn’t calve year-round), and worked with the researchers to collect the needed samples and data.
As part of the study, they compared the pregnancy and abortion rates in these herds, based on whether they used community pastures and whether they vaccinated their cows against BVD and IBR before the breeding season. These two diseases don’t just affect calves; they can also reduce reproductive success in cows.
What They Learned:
Overall, 83% of herds vaccinated their cows for BVD and IBR using either live or inactivated vaccines before the breeding season began, while the other 17% did not.
Herds that were commingled during the breeding season had poorer reproductive performance, especially when cows weren’t vaccinated pre-breeding. Cows from herds that used community pastures were less likely to be pregnant in fall and were more likely to abort the next spring than cows from herds that didn’t use community pastures.
Vaccinated cows were more likely to get pregnant, especially in commingling situations. On community pastures, cows that had been vaccinated before the breeding season with either a live or inactivated vaccine against BVD and IBR were 6 times more likely to be pregnant in fall than cows that had not been vaccinated. In fact, reproductive performance in commingled herds that had been vaccinated against BVD and IBR was the same as in herds that hadn’t been commingled at all.
Vaccinated cows were less likely to abort, especially in commingling situations. On community pastures, cows that had been vaccinated before the breeding season with either a live or inactivated vaccine against BVD and IBR were nearly four times less likely to abort than cows that had not been vaccinated.
Calves born to vaccinated cows were less likely to be treated before weaning. An upcoming paper from Dr. Waldner’s research team (Improving beef calf health: frequency of disease syndromes, uptake of management practices following calving, and potential for antimicrobial usage reduction in western Canadian herds) drew on information from 89 cow-calf producers participating in the Western Cow-Calf Surveillance Network. Although nearly all the herds vaccinated cows against BVD and IBR, only 29% of the herds vaccinated their cows against BRD bacteria (Mannheimia, Histophilus and Pasteurella). In this study, herds that had not been vaccinated against BRD bacteria were more than eight times more likely to treat their calves for BRD between four months of age and weaning.
So What Does This Mean… to Me?
Your vaccination program will be particularly valuable insurance this year, especially if you end up sharing a breeding pasture with others. Annual booster vaccinations are the insurance premium. A 2019 report entitled “Adoption Rates of Recommended Practices by Cow-Calf Operators in Canada“ indicated that over 25% of Canadian cow-calf operations don’t vaccinate their cows for IBR and BVD before the breeding season. The most common reason for not vaccinating against these reproductive diseases was “I have a closed herd.”
That’s pretty unlikely. Closed herds are exceedingly rare. Commingling doesn’t just happen on community pastures, forestry reserves and other grazing lease arrangements where different herds mix. Commingling also happens when new breeding stock (purchased or leased females, bulls or calves) enter the herd and when fences break or get jumped. Disease can also spread through nose-to-nose contact across fences.
Vaccination is far less costly than even a few more open cows or a few more abortions, and much less costly than a reproductive disaster, an abortion storm or a BRD wreck in next year’s calves. Talk to your veterinarian to make sure that your vaccination plans are still appropriate for this summer’s possible grazing scenarios. The BCRC also has calculators to help you assess the cost-benefit of vaccinating against several different diseases:
The Beef Cattle Research Council is 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.
The sharing or reprinting of articles on BeefResearch.ca is typically welcome and encouraged, however this article requires permission of the original publisher.
The BCRC is funded by a portion of the Canadian Beef Cattle Check-Off.
We welcome your questions, comments and suggestions. Contact us directly or generate public discussion by posting your thoughts below.
Is This a Good Investment?
This article written by Dr. Reynold Bergen, BCRC Science Director, originally appeared in a September 2021 issue ofCanadian Cattlemenmagazine and is reprinted on the BCRC Blog with permission of the publisher.
The Beef Cattle Research Council (BCRC) projects featured in this column are funded by the Canadian Beef Cattle Check-Off. When the checkoff increased a few years ago, the BCRC’s budget rose from around 15 cents to 67 cents per head marketed. This allowed us to start some new research programs. Now that we’re a few years in I can update you on how they’re going.
One is our “Proof of Concept” program. Research is complicated and costly, so we have independent scientists review each research proposal to make sure it is scientifically sound and likely to achieve its goal before investing your dollars into it. Sometimes the reviewers say, “This is an interesting project, but it’s really costly, and it all hinges on an untested idea. It’d be better if they had some preliminary evidence that this new idea is worth pursuing, before funding a costly, full-scale project.”
In 2018 the BCRC started funding Proof of Concept projects to gather these preliminary results and help decide whether these new ideas are worth scaling up into full-scale research trials. Here’s what two of the first Proof of Concept projects told us.
Drs. Emma McGeough and Yvonne Lawley ran a small plot study to compare the yields, nutritional value and economics of corn grown on its own or intercropped with high protein forages (either Italian ryegrass, hairy vetch, forage radish, or red clover or a mixture of all four species) at two sites in Manitoba in 2019. Forage was sampled and analyzed in October and December.
All treatments were established successfully at both locations despite drought challenges. The intercropping treatments increased production costs but did not significantly improve yields or energy and protein content compared to corn alone. Regardless of cropping strategy, feed analyses indicated that energy levels were adequate for cows and replacement heifers at the start of the second trimester but too low for growing steers. Crude protein levels were borderline for cows but still too low for both replacement heifers and growing steers.
Corn and high protein forage crops can be intercropped successfully, but more work is needed to make intercropping an economically reliable strategy to meet the nutritional needs of younger, growing cattle in winter. This team is refining intercrop seeding and fertilization recommendations for different locations across western Canada, as well as grazing trials to refine nutritional recommendations for wintering replacement heifers and growing steers on these mixtures.
Rapid disease diagnostics for Bovine Respiratory Disease (BRD): BRD remains one of the most common and costly feedlot diseases. Many different pathogenic bacteria can cause BRD, including Mannheimia, Pasteurella, Histophilus, Mycoplasma, and possibly others that haven’t been identified yet. Different bacteria respond to different antibiotics. In a perfect world, we’d have a point-of-care test that could instantly diagnose which bacteria are primarily responsible for each BRD case so that we could use the most appropriate antibiotic for each animal. Current tests to diagnose which specific bacteria are causing BRD in a particular animal can take up to a week. Even if the animal survived that long, the disease would have progressed. A completely different BRD bacteria (responding to a different antimicrobial) may have taken over, so we’d be back to square one. To avoid these unacceptable health, welfare and economic consequences, veterinarians and feedlot staff pull and treat cattle as soon as possible, using a broad-spectrum antibiotic that combats many different bacteria. Over time, this increases the risk of antibiotic resistance. We need to be able to treat BRD more strategically to maintain the effectiveness of these antibiotics.
Dr. Cheryl Waldner’s team conducted a proof-of-concept study to refine, simplify, speed up and automate an existing test for BRD pathogens. Samples were obtained veterinarians and from chronic feedlot cattle. The researchers evaluated a metagenomic sequencing methodology that identifies all the bacteria in the sample; most other approaches look for specific bacteria, running the risk of missing others. The results of the new test were compared to the gold standard lab culture.
The new test almost always detected the same (or more) bacteria than culture. They also detected antibiotic resistance genes, but more work is needed to identify which bacteria the genes came from. The new technique performed best in samples from very sick cattle that contain a lot of bacteria. More work is needed to make the tool effective for detecting BRD before symptoms appear.
Most of the steps involved in the new test could be reliably performed at a veterinary clinic with limited equipment. However, some steps (e.g., isolating DNA from the sample and separating calf DNA from bacterial DNA) are currently challenging to do outside the laboratory. The new test takes less than 6 hours. That is 97% faster than the week needed for traditional lab culture-based diagnostics, but still too slow to use in a commercial setting. This team is continuing to refine the test and improve its speed, informativeness and portability.
These two Proof of Concept projects showed enough promise to be pursued as larger research projects. Others showed less promise and allowed us to cut our losses. The BCRC started a few other programs when the National Check-Off increased, and I’ll explain those from time to time over the coming months.
The Beef Cattle Research Council is 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.
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The sharing or reprinting of BCRC Blog articles is typically welcome and encouraged, however this article requires permission of the original publisher.
We welcome your questions, comments and suggestions. Contact us directly or generate public discussion by posting your thoughts below.
