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).

Prevalence, Risk Factors, and Antimicrobial Resistance Profile of Respiratory Pathogens Isolated From Suckling Beef Calves to Reprocessing at the Feedlot: A Longitudinal Study.

Here, we investigated the prevalence and risk factors for the presence of Histophilus somni, Mannheimia haemolytica, Mycoplasma bovis, and Pasteurella multocida in the respiratory tract of calves from the spring processing to the reprocessing at feedlots. Additionally, we characterized, phenotypically and genotypically, the antimicrobial resistance (AMR) profile of the four species. Calves from 22 cow-calf operations were enrolled in the study (n = 30 calves per operation) and sampled by deep nasopharyngeal swabs at three time points: spring processing, weaning, or induction into feedlots, and at reprocessing at the feedlot. Isolates were tested for susceptibility using the minimum inhibitory concentration (MIC) test against commonly administered antimicrobials. Additionally, a subset of isolates underwent whole-genome sequencing to infer presence of AMR genes and resistance determinants. Among studied pathogens, P. multocida was the most prevalent species, regardless of time point, followed by M. haemolytica, M. bovis, and H. somni. For M. bovis, a sharp increase in prevalence was detected at the reprocessing sampling, whereas for P. multocida, an increase in prevalence was observed at the weaning/induction sampling. Comingling and co-location of feedlots were not associated with prevalence of any respiratory pathogen. In terms of AMR, resistance against macrolides was prevalent in M. bovis, with most isolates resistant against tildipirosin, tilmicosin, and tylosin. In general, there was limited evidence to support an increase in resistance rates of respiratory bacteria from the spring processing to reprocessing at feedlots, with the exception of florfenicol resistance in M. bovis, which increased at reprocessing. Metaphylactic administration of tetracyclines at feedlot induction was not associated with the MIC of tetracyclines in any respiratory bacteria. Conversely, there were clear associations between the parenteral use of macrolides as metaphylaxis at the feedlot induction, and increased MIC against macrolides in P. multocida, M. haemolytica, and H. somni. Overall, the AMR phenotypes were corroborated by presence of AMR genes. We hypothesize that the administration of macrolides such as tulathromycin at feedlot induction contributes to historical changes in macrolides MIC data of respiratory bacteria of beef cattle.

Impact of meloxicam on respiratory virus titers and health outcomes when administered concurrently with a modified live respiratory vaccine in abruptly weaned beef steers.

Abruptly weaned crossbred steer calves (N = 271) were used in a randomized, blinded 2-arm clinical trial to assess the impact of a long-acting non-steroidal anti-inflammatory drug on bovine herpesvirus type 1, bovine respiratory syncytial virus, parainfluenza virus type 3, and coronavirus titers and health outcomes when administered concurrently with a modified live respiratory vaccine upon arrival at a feedlot. Treatment groups included a control (saline; n = 135) and an experimental group (injectable meloxicam; n = 136). Viral antibody titers and body weight were measured on arrival, day 7, and day 21, along with a final weight on day 45. Body weight and antibody titers for all viruses increased over time (P < 0.001); however, there were no differences by treatment group or a significant group × time interaction when evaluated using repeated measures analysis of variance. Interestingly, the use of meloxicam was associated with increased treatment risk (P < 0.05). In conclusion, the administration of meloxicam may adversely affect health; however, a decreased vaccine response is likely not a contributing factor.

Des bouvillons croisés sevrés rapidement (N = 271) ont été utilisés dans un essai clinique randomisé en aveugle à deux bras pour évaluer l'impact d'un anti-inflammatoire non stéroïdien à action prolongée sur les titres du virus de la rhinotrachéite infectieuse bovine, du virus respiratoire syncytial bovin, du virus parainfluenza 3 et du coronavirus, et les résultats pour la santé lorsqu'administré en même temps qu'un vaccin vivant modifié respiratoire à l'arrivée dans un parc d'engraissement. Les groupes de traitement comprenaient un témoin (solution saline; n = 135) et un groupe expérimental (méloxicam injectable; n = 136). Les titres d'anticorps viraux et le poids corporel ont été mesurés à l'arrivée, au jour 7 et au jour 21, ainsi qu'un poids final au jour 45. Le poids corporel et les titres d'anticorps pour tous les virus ont augmenté avec le temps (P < 0,001); cependant, il n'y avait aucune différence selon le groupe de traitement ou une interaction groupe × temps significative lors de l'évaluation à l'aide de mesures répétées d'analyse de la variance. Fait intéressant, l'utilisation du méloxicam était associée à un risque de traitement accru (P < 0,05). En conclusion, l'administration de méloxicam peut nuire à la santé; cependant, une réponse vaccinale réduite n'est probablement pas un facteur contributif.(Traduit par Docteur Serge Messier).

An outbreak of congenital goiter and chondrodystrophy among calves born to spring-calving beef cows.

An outbreak of congenital diffuse hyperplastic goiter and chondrodystrophy occurred among springborn calves at an Angus-based cow-calf operation in southern Alberta. Although these diseases are observed globally in multiple species, reports of their occurrence concurrently are exceptionally rare. A nutritional cause is highly suspected as previous matings between the same sires and dams resulted in apparently normal calves. However, it is unclear if multiple mineral deficiencies manifested as goiter and chondrodystrophy independently or if a primary hypothyroidism inhibited normal fetal growth and skeletal development. This is apparently the first large-scale outbreak of concurrent congenital goiter and chondrodystrophy reported in calves.

Épidémie de goitre congénital et de chondrodystrophie chez des veaux nés de vaches de boucherie mettant bas au printemps. Une épidémie de cas de goitre hyperplastique diffus et de chondrodystrophie est survenue chez des veaux de l'année dans un établissement de vaches-veaux Angus dans le sud de l'Alberta. Bien que ces conditions soient observées globalement chez une multitude d'espèces, la description de leur présence de manière concomitante est exceptionnellement rare. Une cause nutritionnelle est hautement soupçonnée étant donné que des accouplements antérieurs entre les mêmes taureaux et vaches ont produit des veaux apparemment normaux. Toutefois, il n'est pas clair si des déficiences minérales multiples se sont manifestées par du goitre et de la chondrodystrophie de manière indépendante ou si un hypothyroïdisme primaire a inhibé la croissance foetale normale et le développement squelettique. Le cas présent serait apparemment la première épidémie d'envergure concomitante de goitre congénital et de chondrodystrophie rapportée chez des veaux.(Traduit par Dr Serge Messier).

Quantifying subclinical trauma associated with calving difficulty, vigour, and passive immunity in newborn beef calves.

This cross-sectional study quantifies subclinical trauma associated with calving difficulty, calf vigour, and passive immunity (PI) in newborn beef calves. The degree of calving difficulty was categorised as: unassisted, easy assist (one or two people manually pulling to deliver the calf) and difficult assist (more than two people pulling, a fetal extractor (ie, calf jack), or caesarean section). Vigour assessment occurred at 10 minutes and blood sampling at 24 hours after birth in 77 beef calves. The measured blood parameters associated with trauma were creatine kinase (CK), aspartate aminotransferase (AST), and haptoglobin. Serum IgG concentration was measured, and an IgG concentration at least 24 g/l was considered as adequate PI. Calving difficulty was associated with elevated levels of CK (P=0.002) and AST (P=0.01), weak suckle reflex (P=0.001), abnormal mucous membrane colour (P<0.0001), and decreased odds of adequate PI (P=0.004). Elevated levels of CK and AST were associated with abnormal mucous membrane colour, incomplete tongue withdrawal and weak suckle reflex at birth (P<0.001). An incomplete tongue withdrawal (P=0.005) and weak suckle reflex (P=0.02) were associated with decreased IgG concentrations. Abnormal mucous membrane colour, incomplete tongue withdrawal, and a weak suckle reflex were associated with decreased odds of having adequate PI (P<0.05). Haptoglobin was not associated with any of the parameters measured. Subclinical trauma was associated with calving difficulty, decreased vigour and decreased odds of having adequate PI. Understanding the impacts of a traumatic birth may aid the development of management strategies for compromised newborn beef calves.

Application of transmission infrared spectroscopy and partial least squares regression to predict immunoglobulin G concentration in dairy and beef cow colostrum.

The objective of this study was to explore the potential of transmission infrared (TIR) spectroscopy in combination with partial least squares regression (PLSR) for quantification of dairy and beef cow colostral immunoglobulin G (IgG) concentration and assessment of colostrum quality. A total of 430 colostrum samples were collected from dairy (n = 235) and beef (n = 195) cows and tested by a radial immunodiffusion (RID) assay and TIR spectroscopy. Colostral IgG concentrations obtained by the RID assay were linked to the preprocessed spectra and divided into combined and prediction data sets. Three PLSR calibration models were built: one for the dairy cow colostrum only, the second for beef cow colostrum only, and the third for the merged dairy and beef cow colostrum. The predictive performance of each model was evaluated separately using the independent prediction data set. The Pearson correlation coefficients between IgG concentrations as determined by the TIR-based assay and the RID assay were 0.84 for dairy cow colostrum, 0.88 for beef cow colostrum, and 0.92 for the merged set of dairy and beef cow colostrum. The average of the differences between colostral IgG concentrations obtained by the RID- and TIR-based assays were -3.5, 2.7, and 1.4 g/L for dairy, beef, and merged colostrum samples, respectively. Further, the average relative error of the colostral IgG predicted by the TIR spectroscopy from the RID assay was 5% for dairy cow, 1.2% for beef cow, and 0.8% for the merged data set. The average intra-assay CV% of the IgG concentration predicted by the TIR-based method were 3.2%, 2.5%, and 6.9% for dairy cow, beef cow, and merged data set, respectively.The utility of TIR method for assessment of colostrum quality was evaluated using the entire data set and showed that TIR spectroscopy accurately identified the quality status of 91% of dairy cow colostrum, 95% of beef cow colostrum, and 89% and 93% of the merged dairy and beef cow colostrum samples, respectively. The results showed that TIR spectroscopy demonstrates potential as a simple, rapid, and cost-efficient method for use as an estimate of IgG concentration in dairy and beef cow colostrum samples and assessment of colostrum quality. The results also showed that merging the dairy and beef cow colostrum sample data sets improved the predictive ability of the TIR spectroscopy.