Comparison of postweaning bovine respiratory disease treatment rates between non-vaccinated control beef calves and calves variably primed and boosted using commercially available bovine coronavirus vaccines.

Objective: Bovine respiratory disease (BRD) and overall postweaning treatment rates were compared among 3 groups of calves either differentially primed and boosted with commercially available bovine coronavirus (BCoV) vaccine or not vaccinated against BCoV. Animals: Commercial heifer and steer beef calves born in April and May 2022. Procedure: In June 2022, calves were randomly enrolled into 3 treatment groups. Those in 2 groups [V1 (n = 160) and V2 (n = 160)] were administered a mucosal priming dose of 1 of 2 commercial BCoV vaccines; those in the 3rd group [CTL (n = 151)] were unvaccinated against BCoV. The V1 and V2 groups were boosted by intramuscular injection pre-weaning with the same vaccine used for priming. Weaning occurred 3 wk after the last preweaning processing day. Ranch staff used a BRD case definition provided by their herd veterinarian to identify, treat, and record treatments for 45 d post-weaning. Results: Postweaning BRD treatment rates for V1, V2, and CTL were 7%, 9%, and 14%, respectively. The CTL calves had 2.2× greater odds of receiving treatment for BRD than V1 calves. There were no differences in odds of treatment between CTL and V2 calves or V1 and V2 calves. Conclusion: In a herd with previously diagnosed BCoV BRD cases, prime-boost vaccination of calves is associated with a difference in odds of BRD treatment post-weaning compared to not vaccinating calves against BCoV. Clinical relevance: Prime-boost vaccination with commercial BCoV vaccine may be an important management tool for herds with known BCoV BRD outbreaks.

Comparaison des taux de traitement des maladies respiratoires bovines après le sevrage entre des veaux de boucherie témoins non vaccinés et des veaux vaccinés amorce-rappel de manière variable à l'aide de vaccins contre le coronavirus bovin commercialement disponibles. Objectif: La maladie respiratoire bovine (BRD) et les taux globaux de traitement post-sevrage ont été comparés parmi 3 groupes de veaux soit vaccinés de manière différentielle et avec un rappel avec le vaccin contre le coronavirus bovin (BCoV) disponible commercialement, soit non vaccinés contre le BCoV. Animaux: Génisses et veaux de boucherie commerciaux nés en avril et mai 2022. Procédure: En juin 2022, les veaux ont été randomisés lors du recrutement dans 3 groupes de traitement. Ceux des 2 groupes [V1 (n = 160) et V2 (n = 160)] ont reçu une dose d'amorce par voie muqueuse de l'un des deux vaccins commerciaux BCoV; ceux du 3ème groupe [CTL (n = 151)] n'étaient pas vaccinés contre le BCoV. Les groupes V1 et V2 ont eu un rappel par injection intramusculaire avant le sevrage avec le même vaccin que celui utilisé pour l'amorçage. Le sevrage a eu lieu 3 semaines après le dernier jour de conditionnement pré-sevrage. Le personnel du ranch a utilisé une définition de cas de BRD fournie par le vétérinaire de leur troupeau pour identifier, traiter et enregistrer les traitements pendant 45 jours après le sevrage. Résultats: Les taux de traitement BRD post-sevrage pour V1, V2 et CTL étaient respectivement de 7 %, 9 % et 14 %. Les veaux CTL avaient 2,2 fois plus de chances de recevoir un traitement contre la BRD que les veaux V1. Il n'y avait aucune différence dans les probabilités de traitement entre les veaux CTL et V2 ou entre les veaux V1 et V2. Conclusion: Dans un troupeau avec des cas de BRD causés par le BCoV déjà diagnostiqués, la vaccination amorce-rappel des veaux est associée à une différence de probabilité de traitement par le BRD après le sevrage par rapport à la nonvaccination des veaux contre le BCoV. Pertinence clinique: La vaccination amorce-rappel avec le vaccin commercial BCoV peut être un outil de gestion important pour les troupeaux présentant des foyers connus de BCoV BRD.(Traduit par Dr Serge Messier).

Comparison of virus-neutralizing and virus-specific ELISA antibody responses among bovine neonates differentially primed and boosted against bovine coronavirus.

Objective: This study addressed the current gap in knowledge of neonatal prime-boost immune responses for the control of bovine coronavirus (BCoV) respiratory disease in weaning-age beef cattle. Animals: Study 1 and Study 2 had 33 and 22 commercial cross neonatal beef calves, respectively. Procedures: Study 1 compared BCoV-neutralizing antibody concentrations of control calves with 3 groups of calves differentially vaccinated with mucosal and/or systemic BCoV modified live virus (MLV) vaccines. Study 2 compared specific and neutralizing antibody concentrations among mucosally BCoV primed groups of calves that were differentially systemically boosted. Results: In Study 1, calves that were mucosally primed and systemically boosted had higher BCoV-neutralizing antibody concentrations than the control group at weaning. In Study 2, boosting mucosally primed calves by injecting inactivated or MLV vaccine resulted in anamnestic BCoV-specific antibody responses at weaning. Conclusion: Neonatal mucosal priming and systemic boosting resulted in anamnestic BCoV antibody responses at weaning. Clinical relevance: Prime-boost vaccination should be considered for control of BCoV respiratory disease.

Comparaison des réponses en anticorps ELISA neutralisant le virus et spécifiques du virus chez des nouveau-nés bovins vaccinés par amorces-rappels différenciés contre le coronavirus bovin. Objectif: Cette étude a abordé le manque actuel de connaissances sur les réponses immunitaires néonatales de stimulation pour maitriser la maladie respiratoire à coronavirus bovin (BCoV) chez les bovins de boucherie en âge de sevrage. Animaux: Les études 1 et 2 portaient respectivement sur 33 et 22 veaux de boucherie néonatals croisés commerciaux. Procédures: L'étude 1 a comparé les concentrations d'anticorps neutralisant le BCoV de veaux témoins avec 3 groupes de veaux vaccinés de manière différentielle avec des vaccins à virus vivant modifié (MLV) contre le BCoV pour administration par voie mucosale et/ou systémique. L'étude 2 a comparé les concentrations d'anticorps spécifiques et neutralisants parmi des groupes de veaux sensibilisés au BCoV par voie mucosale et qui ont eu un rappel par voie systémique différentielle. Résultats: Dans l'étude 1, les veaux qui avaient reçu une amorce au niveau des muqueuses et un rappel systémique présentaient des concentrations d'anticorps neutralisant le BCoV plus élevées que le groupe témoin au sevrage. Dans l'étude 2, le rappel des veaux amorcés par voie mucosale par l'injection d'un vaccin inactivé ou MLV a entraîné une réponse anamnestique en anticorps spécifiques du BCoV au sevrage. Conclusion: En période néonatale, l'amorce par voie mucosale et le renforcement systémique ont entraîné des réponses anamnestiques en anticorps BCoV au sevrage. Pertinence clinique: La vaccination de rappel doit être envisagée pour maitriser la maladie respiratoire causée par le BCoV.(Traduit par Dr Serge Messier).

Vaccine use in Canadian cow-calf herds and opportunities for improvement.

Vaccinations are one of the most impactful tools available to cow-calf producers to control within herd disease and later, in feedlots. While vaccine use has been studied across Canada, inconsistent and variable regional data makes analysis and interpretation difficult. The objective of this study was to describe vaccination protocols and factors associated with vaccine use in Canadian cow-calf herds and define associations between vaccine use and productivity outcomes. Surveys describing vaccine use in 2020 were collected from 131 cow-calf herds (40 eastern, 91 western), recruited through a national beef cattle surveillance program. Ninety-two percent of cows and replacement heifers, and 72% of bulls were vaccinated with Infectious Bovine Rhinotracheitis (IBR), Bovine Viral Diarrhea Virus (BVDV), Parainfluenza3 Virus (PI3), and Bovine Respiratory Syncytial Virus (BRSV). At least half of cows and bulls were vaccinated for clostridial pathogens and cows and heifers for viral calf scours. Clostridial vaccines were significantly more likely to be used in western Canada compared to eastern Canada. While 92% of producers vaccinated suckling calves against IBR/BRSV/PI3, only 47% provided a second vaccine prior to weaning; 78% of calves were also vaccinated at least once for BVDV before weaning. Producers who vaccinated calves against IBR/BRSV/PI3 before 3 months of age provided a second dose prior to weaning more often than producers who administer the first IBR/BRSV/PI3 vaccine later. Vaccine use has increased across Canada, particularly in calves, prior to weaning. Relative to label recommendations for annual vaccination, clostridial vaccines were generally underutilized in cows and bulls, and by producers in eastern Canada as compared to western Canada. Opportunities also exist to improve adherence to label recommendations for the booster dose of scours vaccine when used in bred replacement heifers. Protocols including product choices, the timing and boosting of respiratory vaccines in nursing calves vary widely across herds. Use of intranasal vaccines in neonatal calves less than 2 weeks old has increased in western Canada compared to previous reports. There is a need to better understand how timing of vaccination in nursing calves contributes to effectiveness, for respiratory disease in nursing and weaned calves.

Ergonomic assessment of veterinarians during performance of bovine reproductive examinations.

OBJECTIVE: To identify and quantify potential ergonomic hazards associated with routine reproductive examinations of cattle. SAMPLE: 7 bovine veterinarians. PROCEDURES: Each veterinarian was observed and videotaped during 2 bovine reproductive examination appointments. During each appointment, a force-matching protocol was used to estimate the entry force used by the veterinarian to insert an arm into a cow's rectum. Veterinarian posture and repetitive movements and the work environment were assessed and quantified during review of the video recordings. Descriptive data were generated. RESULTS: Of the 14 appointments observed, 9 and 5 involved examination of beef and dairy cows, respectively. For all veterinarians, an arm inclination ≥ 60° was observed during most reproductive examinations. The number of examinations performed per hour ranged from 19.1 to 116.8. The estimated entry force ranged from 121 to 349 N. During all 9 appointments involving beef cows, the veterinarian participated in other tasks (eg, operating overhead levers, opening gates, or assisting with cattle handling) that represented ergonomic hazards. CONCLUSIONS AND CLINICAL RELEVANCE: Results confirmed that reproductive examination of cattle exposes veterinarians to various ergonomic hazards involving awkward positions and repetitive and forceful exertions that can contribute to musculoskeletal discomfort and injury, particularly of the upper extremities (neck, shoulders, upper back, arms, elbows, wrists, and hands). Veterinarians frequently participated in other tasks during reproductive examination appointments that exposed them to additional ergonomic hazards. Risk mitigation strategies should prioritize minimizing exposure of veterinarians to tasks not directly associated with the reproductive examination procedure to decrease their overall ergonomic hazard burden.

Evaluation of bovine respiratory syncytial virus (BRSV) and bovine herpesvirus (BHV) specific antibody responses between heterologous and homologous prime-boost vaccinated western Canadian beef calves.

Bovine respiratory disease (BRD) is an economically important cause of morbidity and mortality in beef calves. Control of BRD is most often addressed through "homologous" vaccination utilizing the same injectable modified-live viral (MLV) vaccine for both priming and boosting. Heterologous prime-boosting uses different routes and antigenic forms for priming and boosting. Three vaccine protocols were compared: an injectable (IJ) MLV (IJ-MLV) group (IJ-MLV priming at ~48 days and boosted with IJ-MLV at weaning), intranasal (IN) MLV (IN-MLV) group (intranasal priming with MLV at ~24 hours, boosted twice with an IJ-MLV), and intranasal killed viral (IN-KV) group (primed with an IN-MLV at ~24 hours, boosted twice with an IJ-KV). Serum antibody concentrations determined by enzyme-linked immunosorbent assays (ELISAs) were compared and the IN-KV group had significantly higher BRSV-specific antibody concentrations after boosting compared with the 2 homologous groups. No differences in BHV-specific antibody concentrations were observed between any of the groups.

Évaluation des réponses spécifiques en anticorps contre le virus respiratoire syncitial bovin (BRSV) et l'herpèsvirus bovin (BHV) chez des bovins d'embouche de l'Ouest canadien vaccinés en primo-vaccination et en rappel de manière homologue ou hétérologue. Les maladies respiratoires bovines (BRD) sont une cause économiquement importante de morbidité et de mortalité chez les veaux d'embouche. La maitrise des BRD fait appel le plus souvent à une vaccination « homologue ¼ utilisant le même vaccin injectable de virus vivant modifié (MLV) pour la primo-vaccination et le rappel. La primo-vaccination et le rappel hétérologue utilisent différentes voies et formes antigéniques pour l'amorçage et le rappel. Trois protocoles de vaccination furent comparés : un groupe MLV injectable (IJ) (IJ-MLV) (amorçage avec IJ-MLV à environ 48 jours et rappel avec IJ-MLV au sevrage). Un groupe MLV intranasal (IN) (IN-MLV) (amorçage intranasal avec MLV à environ 24 heures, deux rappels avec IJ-MLV), et un groupe avec un vaccin intranasal de virus tué (IN-KV) (amorçage avec IN-MLV à environ 24 heures, deux rappels avec IJ-KV). Les concentrations d'anticorps sériques déterminées par épreuves immuno-enzymatiques (ELISAs) furent comparées et le groupe IN-KV avait des concentrations d'anticorps spécifiques contre BRSV significativement plus élevées après le rappel comparativement aux deux groups homologues. Aucune différence dans les concentrations d'anticorps spécifiques contre le BHV ne furent observées entre les groupes.(Traduit par Dr Serge Messier).

Risk factors associated with work-preventing musculoskeletal discomfort in the upper extremities of bovine practitioners.

OBJECTIVE: To identify risk factors associated with work-preventing musculoskeletal discomfort (MSKD) in the upper extremities (defined as neck, shoulders, upper back, arms, elbows, wrists, and hands) of bovine practitioners. SAMPLE: 116 members of the Western Canadian Association of Bovine Practitioners. PROCEDURES: Data from a previously described cross-sectional survey of western Canadian bovine practitioners underwent further analysis. The survey, developed to glean information about MSKD in bovine practitioners, was a modified standardized Nordic questionnaire that included questions regarding personal and work characteristics and incidence and location of MSKD during the preceding 12 months along with perceptions about most physically demanding tasks. Logistic regression was used to identify factors associated with work-preventing upper extremity MSKD. RESULTS: 18 of 116 (15.5%) respondents indicated they had experienced work-preventing upper extremity MSKD during the preceding 12 months. The final multivariable regression model indicated that practice type (mixed animal vs primarily [> 50%] bovine; OR, 3.20; 95% CI, 0.96 to 10.67), practitioner height (OR, 0.93; 95% CI, 0.87 to 0.99), and number of veterinarians in the practice (OR, 1.32; 95% CI, 1.05 to 1.66) were significantly associated with the odds of work-preventing upper extremity MSKD. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that reproductive examination of cattle was not a significant risk factor for upper extremity MSKD in bovine practitioners. Further research into the effects of biomechanical, organizational, and psychosocial workplace factors on the development of MSKD in bovine practitioners is necessary to help inform prevention strategies to foster career longevity in this increasingly diverse practitioner group.

Evaluation of long-acting oxytetracycline and a commercial monovalent vaccine for the control of Campylobacter fetus subsp. venerealis infection in beef bulls.

A blinded randomized controlled trial was used to evaluate a multi-modal therapeutic regime for treatment of beef bulls infected with Campylobacter fetus subsp. venerealis (Cfv). Treatment included 2 doses of a commercially available monovalent vaccine and long-acting oxytetracycline applied twice at a 2-week interval with treatment completed 2 weeks before post-treatment observation. Fifteen confirmed Cfv infected bulls were randomly allocated to control (n = 8) or treatment groups (n = 7). Preputial scrapings were collected each week from before infection to 11 weeks following the last treatment. When the polymerase chain reaction (PCR) results for both culture and preputial scrapings were interpreted in parallel, there were no significant differences between treated and untreated bulls. Regardless of the type of diagnostic testing considered, treatment with 2 label doses of this regime did not stop shedding of Cfv in all treated bulls and is, therefore, not recommended as an effective management strategy.

Évaluation de l'oxytétracycline d'action prolongée et d'un vaccin monovalent commercial pour maîtriser l'infection parCampylobacter fetusssp.venerealischez les taureaux de boucherie. Un essai clinique randomisé à l'insu a été utilisé pour évaluer un régime thérapeutique multimodal pour le traitement des taureaux de boucherie infectés par Campylobacter fetus ssp. venerealis (Cfv). Le traitement a inclus deux doses d'un vaccin monovalent disponible dans le commerce et de l'oxytétracycline d'action prolongée appliquée deux fois à un intervalle de 2 semaines et le traitement a été complété deux semaines avant l'observation post-traitement. Quinze taureaux présentant une infection confirmée par Cfv ont été assignés au hasard au groupe témoin (n = 8) ou au groupe de traitement (n = 7). Des grattages de la surface du prépuce ont été prélevés à chaque semaine à partir du moment avant l'infection jusqu'à 11 semaines suite au dernier traitement. Lorsque les résultats de l'amplification en chaîne par polymérase (ACP) pour les cultures et les biopsies de surface du prépuce ont été interprétés en parallèle, il n'y avait aucune différence significative entre les taureaux traités et les taureaux non traités. Sans égard au type de test diagnostique considéré, le traitement à l'aide de deux doses recommandées sur l'étiquette n'a pas freiné l'excrétion de Cfv chez tous les taureaux traités et n'est donc pas recommandé comme une stratégie de gestion efficace.(Traduit par Isabelle Vallières).