Vaccination of beef cattle has proven effective in stimulating immune response and reducing disease burden across a range of study designs (1–8). However, other studies of vaccine use in cow-calf herds and at feedlot entry have shown more variable effectiveness (9–18). Adherence to evidence-based vaccine protocols can improve animal health and increase production efficiency through control and prevention of economically important diseases. For example, two recent meta-analyses summarized the evidence for mitigation of abortion risk and other negative reproductive consequences of Infectious Bovine Rhinotracheitis (IBR) and Bovine Viral Diarrhea Virus (BVDV) (2, 7).

Vaccinating against reproductive and clostridial diseases is commonly recommended by veterinary practitioners (19). The American Association of Bovine Practitioners (AABP) identified the following targets as core vaccines for all beef cattle: IBR, BVDV, Parainfluenza3 Virus (PI3), Bovine Respiratory Syncytial Virus (BRSV), and clostridial diseases with the label for all licensed products either requiring or recommending annual revaccination (20). The AABP recommends modified live viral (MLV) vaccines for IBR and BVDV due to the increased efficacy compared to killed or inactivated vaccines (20).

Other vaccines should be recommended by veterinarians on an individual herd basis, based on specific risk factors and geographical location (20). A number of studies have documented causes of morbidity and reasons for antimicrobial use in cow calf herds. For example, a 2015/2016 survey of Ontario cow-calf producers and a 2017 survey of western Canadian cow-calf producers found that neonatal calf scours (13–52%) and pre-weaning calf respiratory disease (15–16%) were important causes of total pre-weaning mortality (21, 22). Respiratory disease is the most reported reason for antimicrobial use in both cow-calf herds and feedlots (23, 24). Commercial vaccines labeled to aid in the control of scours and respiratory disease are available and are commonly used in cow-calf herds (25), although the results for published field trials are variable for both calf scours and respiratory disease preweaning (10, 12).

Timing of vaccine administration must be considered for optimizing effectiveness particularly for control of respiratory disease. While vaccination before weaning has been shown to reduce treatment for respiratory disease relative to vaccination at or after weaning and again at feedlot arrival (26, 27), improved performance across the entire feeding period was not observed in these studies for calves vaccinated before weaning. The evidence supporting beneficial effects of administration of respiratory vaccines at feedlot arrival is even more limited with many studies showing no or negative associations with vaccination (26, 28–31). The lack of current economic incentive for cow-calf producers to fully vaccinate calves prior to sale to prevent respiratory disease in feedlots limits participation by cow-calf producers.

Literature regarding national adoption and use of vaccines across the Canadian cow-calf industry is scarce. However, recent industry reports using cow-calf producer survey data have demonstrated regional vaccine use within Canada. Western Canadian studies have previously described vaccination protocols for the following years: 2016/2017 (21), 2010 (5) and 2001/2002 (6). Eastern Canadian cow-calf producers have been surveyed regarding vaccine use in Atlantic Provinces (2017) (32), Ontario (2015/2016) (33, 34), and northern Quebec (2015) (34).

A previous western Canadian surveys found that cow-calf producers used at least one vaccine in cows, heifers, unweaned calves, weaned calves and bulls in 97, 97, 96, 57 and 72% of herds, respectively (25). The most common vaccine targets for calves were clostridial diseases, and respiratory and reproductive vaccines were the most common vaccines for bulls, cows and replacement heifers (25). Producers from eastern Canada had previously reported vaccine use among cows, heifers, calves and bulls in Ontario of 70, 72, 88, and 59% and in northern Quebec of 72, 78, 94 and 68%, respectively (33, 34). Similar data were not reported for Atlantic herds, but 73% of producers reported vaccinating cattle, and 45% vaccinated females prior to breeding (32).

The primary objective of this study was to describe vaccine adoption in cow-calf herds across Canada and provide a better understanding of the types of vaccines used and timing of administration. Results will be used to investigate regional differences and opportunities for improvement in vaccination uptake and adherence to recommended protocols. The secondary objective of this study was to examine factors associated with vaccine use and explore potential associations between vaccine use and herd productivity outcomes.

This study was approved by the University of Saskatchewan’s Behavioral Research Ethics Board (Beh-REB#309).

This paper presents the first detailed picture of vaccine use practices in cow-calf herds from across Canada. Differences in vaccine use between eastern and western herds were limited. Identified differences in clostridial vaccination echoed previous reports where herds in Ontario were less likely to use clostridial vaccines than western herds (25, 33). While regional differences in some vaccines might be due to herd size, facilities, and labor availability, the risk of clostridial diseases is ubiquitous across the country.

Vaccination of the cow herd was higher compared to 2015/2016 reports from eastern provinces (18–20%) but was similar to reports of the same year from western provinces (25, 33). Most producers vaccinated their cows against viruses associated with respiratory and reproductive diseases; however, there are still herds in which these vaccines are not utilized. Less than one-third of producers vaccinated against Campylobacter and 35% of herds vaccinated against Leptospira. Producers that used community pastures were more likely to vaccinate cows against Campylobacter than those that did not. Annual Campylobacter and Leptospira revaccination are not considered core vaccines by the American Association of Bovine Practitioners, but are recommended for herds considered to be at high risk for either of these infections due to biosecurity challenges, comingling on community pastures or geographic location (19, 20). Waldner et al. reported similar vaccination trends for BVDV in cows, but higher levels of bacterial respiratory vaccines in cows (39).

Vaccination of bulls was less common than for cows and replacement heifers and continues to present an opportunity for improvement. Commonly, bulls were vaccinated against BVDV, IBR, BRSV, PI3, clostridial pathogens, footrot (Fusobacterium) and Leptospira spp. Most producers followed recommended practices, and vaccinated bulls prior to breeding. According to a survey of US and Canadian beef cattle veterinarians, 79% recommended vaccinating bulls at the same time as the cow herd (19). The proportion of western producers that vaccinated bulls for at least one target was at a similar level to a 2016 study (25); however, the proportion that vaccinated against BVDV, IBR, PI3, BRSV, bovine genital campylobacteriosis, and clostridial diseases seemed to be moderately higher. Compared to eastern Canadian herds in 2015/2016, overall vaccination of bulls was higher by 15–24% (33). It was more common for Canadian herds to administer one or more vaccines to bulls (83%) than US cow-calf herds surveyed in 2016 (44%) (40).

While clostridial vaccines are considered a core vaccine for bulls, only 47% of producers vaccinated their bulls during 2020 (20). Some producers are potentially boosting clostridial vaccines every 2 or more years rather than vaccinating annually. Thus, this survey might have overlooked herds where 2020 was an “off” year for clostridial vaccinations. Clostridial vaccine use was only modestly higher in cows. Although most replacement heifer vaccination practices were similar to that reported for cows, the proportion of herds reporting clostridial vaccine use was higher for heifers than for cows. This might reflect more consistent annual vaccination protocols for heifers. While not all herds report annual use of clostridial vaccines, all clostridial vaccines approved for use in Canada recommend annual revaccination in adult beef cattle. Biannual vaccination with these products is an off-label recommendation.

Replacement heifers were more commonly vaccinated than cows and bulls for all other core vaccines, and these were given almost exclusively as MLV vaccines, prior to breeding. No heifers in this cohort of herds were administered a MLV BVDV/IBR/BRSV/PI3 vaccine at pregnancy testing without at least one prior vaccination of the same kind. More than 9 out of 10 producers using MLV at pregnancy testing provided two prior doses to their heifers as recommended by at least one commonly used commercial vaccine (38). This is a good indication that many producers are aware of the potential risks of MLV vaccines and label recommendations for proper use (20). However, while more replacement heifers than cows were vaccinated for scours or calf diarrhea pathogens, less than half received the second dose recommended by product labels.

Vaccination of both suckling and weaned calves against at least one pathogen has increased since previous reports of herds from western Canada, and northern Ontario and Quebec (25, 34). The potential benefits of vaccinating suckling calves against BRD pathogens particularly for herds with a history of BRD likely influenced vaccine choices (30). Many producers identified the “importance of the disease in the herd” as an influential factor when determining vaccine protocols. The most common vaccines administered to calves were the core vaccines recommended by the AABP (BVDV, IBR, BRSV, PI3 and clostridial vaccines) (20).

Modified-live vaccines were used almost exclusively in calves for all viral targets. Most (90–93%) surveyed North American beef cattle veterinarians recommended the use of MLV vaccines in calves prior to and after weaning (19). According to previous reports of western herds, modified-live BVDV vaccines were used exclusively in both suckling calves and weaned calves (25). Vaccine use differentiated by type (MLV or inactivated/killed) has not been reported for eastern provinces.

Compared to western cow-calf herd vaccination benchmarks reported in 1997 and 1998, the current vaccination landscape is unrecognizable (41). The focus of calf vaccination has shifted to respiratory disease. Compared to 1997/98, vaccination of calves in 2020 was at a higher proportion for all reported targets except for P. multocida. This includes BVDV (↑ 53%), IBR (↑49%), PI3 (↑54%), BRSV (↑62%), and H. somni (↑7%) (41). Compared to western Canadian herds in 2016, the proportion of herds administered one dose to suckling calves was at a similar proportion; IBR, BRSV and PI3 vaccination was higher (7%), while BVDV vaccination was slightly lower (4%), but the proportion of producers who boosted calves prior to weaning was higher for all viral respiratory targets (4–13%) (25). This is likely attributed to the increased use of intranasal respiratory vaccines, which do not contain BVDV. Use of intranasal viral respiratory vaccines at birth (21%) was higher compared to previous reports for western Canada (9%), Ontario (12%) and Atlantic Canada (14%) (25, 32, 33). Compared to parenteral vaccines, intranasal respiratory vaccines administered in young calves has been shown to produce a better immune priming response in the face of maternal antibodies (13, 14, 42, 43). Protection provided by intranasal respiratory vaccines may be unpredictable and short term (44).

Before weaning, 47% of herds boosted IBR/BRSV/PI3 vaccines, but less than 20% boosted clostridial vaccines. Most commercially available IBR/BRSV/PI3 and clostridial vaccines approved for use in Canadian calves require a second dose after initial vaccination. Calves from herds given an initial IBR/BRSV/PI3 vaccines before 3 months of age were more likely to receive a second vaccine prior to weaning.

Producers identified “convenience (calves were being handled for another reason)” as the top factor influencing their decision to vaccinate nursing calves. Lack of labor, time, access to facilities, weather, or the desire to minimize handling stress might have contributed to limited vaccine boosting in nursing calves. Further, due to a lack of preconditioning incentives for Canadian producers, the largest economic return from optimizing protection due to vaccination is not seen by the cow-calf producer, but rather the in feedlot. Vaccination prior to weaning as part of a preconditioning program has shown to reduce the incidence of respiratory disease and increase average daily gain in the feedlot (26, 27).

Bacterial respiratory vaccines including M. haemolytica and P. multocida were less common than viral respiratory vaccines which is expected as these vaccines are considered “risk based,” and recommended on an individual herd basis (20). Most herds administered this vaccine after 2 weeks of age and before weaning. Surveyed North American bovine veterinarian’s recommendations for best timing of initial M. haemolytica vaccination were inconsistent; recommended times were at branding (45%), before weaning (77%), and after weaning (49%) (19).

The apparent association between vaccination of suckling calves against BVDV or M. haemolytica and an increased risk of pneumonia in suckling calves is consistent with previous western Canadian herd surveys that reported beef calves vaccinated for BRD near birth were more likely to be treated for BRD (39). As was noted earlier, producers reported using vaccines in response to the importance of disease in their herds. This association is likely explained by this factor, whereby herds with a historical or ongoing respiratory disease problem were more likely to use these vaccines. Further, in 20% of herds from the current study these vaccines were first administered after 3 months of age after and following the first peak risk for respiratory disease (39).

Conversely, while the reduced risk of calf mortality in suckling calves that were vaccinated against clostridial disease could reflect vaccine success, vaccine use could also potentially reflect overall herd management. One earlier study from western Canada reported the potential benefits of vaccinating cows for clostridial diseases and subsequent protection of the calf crop, and while clostridial vaccines are generally recognized as being highly effective this is the first specific report from Canadian beef herds documenting a beneficial association with use (5).

The survey response rate was slightly lower than the 2016 western Canadian cow-calf survey (88% vs. 81%) and might have been impacted by the severe drought related pressures placed particularly on western producers in 2021 during survey collection (25). Due to the criteria to be enrolled in the study, this group of producers likely represents a progressive subset of producers and might not be reflective of all Canadian cow-calf producers. This cohort of producers represents the early adopters of innovative practices, and are therefore potentially an overrepresentation of vaccine use in the average Canadian cow-calf herd. It is unknown whether responses to the survey or overall vaccination rates were affected by the COVID-19 pandemic or if management decisions were negatively impacted by vaccine hesitancy surrounding viral respiratory vaccines. While surveys suffer from recall bias, producers were provided with color photos and a book to help them find the name of the products used if they did not have access to receipts or records. Misclassification was also managed by asking the producers to report the actual trade name of the product used from their receipts and records rather than asking them what diseases they vaccinated for. The trade names were then re-coded to capture the vaccine components by the study team.

Vaccine use across Canada has shown significant improvement over the past few decades. Cow-calf producers generally followed recommended vaccination protocols for all core vaccines. The number of herds that vaccinated animals increased for nearly all cattle groups since previous reports. One notable change is the increased use of intranasal respiratory vaccines, specifically in neonatal calves. While many positive changes have been made in the industry, there are still some areas where improvement is needed. Producers should be encouraged to vaccinate calves against respiratory disease before 3 months of age, in consultation with their veterinarian, to allow more time for the vaccine to have an effect before high-risk periods for the disease and to allow time to administer a second dose prior to weaning. The literature is scant as to the relative benefits of mucosal vaccination of calves near the time of birth, as well as for the optimal type of follow up vaccination. Recently several projects observing mucosal prime systemic boost have found a benefit for mucosal priming of neonates that is variable depending on the pathogen and form of booster vaccine used; a benefit for mucosal prime and systemic boost has been found for BRSV, bovine coronavirus and BVDV (14–16, 18). Mucosal prime and systemic boost, of neonatal calves, has been shown to improve virus specific and neutralizing antibody concentrations and their booster responses for BRSV, BCoV and BVDV. Improved protection against disease has also been observed when primed and boosted calves were challenged with BRSV or BVDV type 2 (16, 18). More research is needed on the relative benefits of vaccinating calves near time of birth and optimal timing of a booster to minimize risks of respiratory disease associated with stress and increased animal density during activities such as artificial insemination (24, 39, 42).

While all classes of cattle were examined, this study contributes unique information on the types, timing and number of vaccine doses used in nursing calves from a cohort of privately owned herds. While participants likely represent a relatively progressive subset of producers, more producers reported vaccinating nursing calves for BRD as compared to previous work in similar cohorts. The results show that high adoption rates for preweaning vaccination is a reasonable goal for commercial cow-calf herds. However, there was very little consistency in vaccine protocols for nursing beef calves, highlighting opportunities to optimize vaccination timing for challenges specific to each operation such as the timing of calving season and resource limitations. In addition, protocols might vary depending on whether the primary goal of calf vaccination is to reduce disease following weaning, or in nursing calves either before or after summer pasture turnout.

To improve vaccine efficacy, producers must properly follow product labels instructions, specifically regarding administration of booster doses within the specified period. This issue was most apparent for clostridial vaccines in cows and bulls, and scours vaccines in bred heifers. Economic incentives for producers to vaccinate calves prior to feedlot entry should be a top priority for industry to ensure the long-term sustainability of Canadian beef production. There are still a small percentage of cow-calf producers that are not using the core viral vaccines for whom targeted technology transfer activities might be necessary. Finally, clostridial vaccines are underused in cows and bulls, particularly in eastern herds. These vaccines should be administered yearly to ensure cattle are fully protected and optimal clostridial transfer of antibodies.

The datasets presented in this article are not readily available because the information was provided by the study participants under the restriction that only summary data would be shared. That is included in the detailed tables and figures provided in this paper. Requests to access the datasets should be directed to cheryl.waldner@usask.ca.

The studies involving humans were approved by University of Saskatchewan’s Behavioral Research Ethics Board. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

CW designed the study and survey tool. CW and ML recoded the data and completed the statistical analyses. ML wrote the manuscript. CW, NE, JC, and SG edited, revised, and provided feedback on the manuscript. All authors contributed to the article and approved the submitted version.

Funding provided by Beef Cattle Research Council.

The authors wish to acknowledge the assistance of Sharlene April in managing the survey distribution and data entry for this project. The authors also with to thank the cow-calf producers who participated in the Canadian Cow-Calf Surveillance Network.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.