Bovine Respiratory Syncytial Virus Research Articles

Bovine Parainfluenza Virus 3 and Bovine Respiratory Syncytial Virus: Dominant Viral Players in Bovine Respiratory Disease Complex among Serbian Cattle

Bovine Parainfluenza Virus 3 and Bovine Respiratory Syncytial Virus: Dominant Viral Players in Bovine Respiratory Disease Complex among Serbian Cattle

Immune response and protection of neonatal, colostrum-fed calves with modified live, intranasal, tri-valent vaccine using an experimental challenge with virulent bovine respiratory syncytial virus

Bovine respiratory syncytial virus (BRSV) is major viral con­tributor to bovine respiratory disease (BRD). BRD is a major cause of morbidity and mortality in all classes of cattle but par­ticularly young beef and dairy calves. Passive antibodies not only help protect the calf against infection, but may interfere with the immune responses following vaccination. The objective of this study was to evaluate the efficacy and immune response of an intranasal modified live virus (MLV) trivalent vaccine in the presence of well-defined maternal passive immunity.

Serological Profile for Major Respiratory Viruses in Unvaccinated Cows from High-Yielding Dairy Herds.

This study aims to determine the serological profile of high-yielding dairy cows for four main viruses (bovine alphaherpesvirus 1 (BoAHV1), bovine viral diarrhea virus (BVDV), bovine parainfluenza virus 3 (BPIV3), and bovine respiratory syncytial virus (BRSV)) related to bovine respiratory disease (BRD) in cattle herds worldwide. In this survey, 497 blood serum samples were collected from non-vaccinated dairy cows without clinical respiratory signs in 39 herds in the central-eastern mesoregion of Paraná State, South Brazil. The presence of neutralizing antibodies was determined by virus neutralization (VN) tests. VN antibodies against BoAHV1, BVDV, BPIV3, and BRSV were detected in 355 (71.4%), 280 (56.3%), 481 (96.8%), and 315 (63.4%) serum samples, respectively. The frequencies of seropositive herds for BoAHV1, BVDV, BPIV3, and BRSV were 79.5 (n = 31), 82.0 (n = 32), 100 (n = 39), and 84.6% (n = 33), respectively. The frequencies of seropositive cows varied according to the type of herd management and the number of cows in the herd. The detection of VN antibodies in unvaccinated dairy cattle herds demonstrated the endemic circulation of the four viruses in the herds evaluated. For BRD prevention, it is recommended to implement a vaccination program for cows that provides passive immunity in calves and active immunity in cows.

Maternal pre- and postpartum supplementation of a Bacillus-based DFM enhanced cow and calf performance.

This study evaluated the effects of maternal supplementation of a Bacillus-based direct-fed microbial (DFM) on the physiology and growth performance of Bos indicus-influenced cow-calf pairs. On day 0 (~139 d before expected calving date), 72 fall-calving, Brangus crossbred beef heifers (20 to 22 mo of age) pregnant with first offspring were stratified by their initial body weight (BW; 431 ± 31kg) and body condition score (BCS; 6.0 ± 0.36; scale 1 to 9), and randomly allocated into 1 of 12 bahiagrass pastures (1 ha and 6 heifers per pasture). Treatments were randomly assigned to pastures (6 pastures per treatment) and consisted of heifers supplemented with 1kg/d of soybean hulls (dry matter, DM) that was added (BAC) or not (CON) with DFM containing Bacillus subtilis and B. licheniformis (BovacillusTM; Chr. Hansen A/S, Hørsholm, Denmark). Treatments were provided from day 0 to 242 (139 ± 4 d prepartum to 104 ± 4 d postpartum). Calves were weaned on day 242 (96 ± 30 d of age) and then allocated into 1 of 16 drylot pens and fed the same concentrate at 3.25% of BW (DM) until day 319. Maternal treatment effects were not detected (P ≥ 0.29) for herbage allowance and forage chemical composition. Heifer BCS on days 39 and 63 tended (P ≤ 0.09) to be greater for BAC vs. CON heifers, whereas heifer BCS on day 91 was greater (P = 0.01) for BAC vs. CON heifers. Heifer BCS did not differ (P ≥ 0.20) between treatments on days 179 and 242. Plasma glucose concentration did not differ from day 0 to 63 (P ≥ 0.14) but were greater (P < 0.01) on day 179 and tended (P = 0.09) to be greater on day 242 for BAC vs. CON heifers. Calf BW at birth, ADG from birth to weaning, and BW at weaning did not differ (P ≥ 0.19) between treatments, but calf BW at drylot exit (day 319) was greater (P = 0.05) for BAC vs. CON calves. Maternal treatment effects were not detected (P ≥ 0.42) for calf serum concentration of IgG at birth and post-vaccination plasma concentrations of glucose, cortisol, and haptoglobin. Serum titers against bovine respiratory syncytial virus (BRSV) were greater (P = 0.04) for BAC vs. CON calves on day 287, whereas seroconversion against parainfluenza 3 virus (PI-3) was greater (P < 0.01) for BAC vs. CON calves on day 271. Thus, maternal supplementation of a Bacillus-based DFM increased prepartum BCS gain and postpartum plasma glucose concentration of heifers and led to positive carryover effects on post-weaning BW gain and humoral immune response in their offspring.

Cell entry of bovine respiratory syncytial virus through clathrin-mediated endocytosis is regulated by PI3K-Akt and Src-JNK pathways.

Bovine respiratory syncytial virus (BRSV) is an RNA virus with envelope that causes acute, febrile, and highly infectious respiratory diseases in cattle. However, the manner and mechanism of BRSV entry into cells remain unclear. In this study, we aimed to explore the entry manner of BRSV into MDBK cells and its regulatory mechanism. Our findings, based on virus titer, virus copies, western blot and IFA analysis, indicate that BRSV enters MDBK cells through endocytosis, relying on dynamin, specifically via clathrin-mediated endocytosis rather than caveolin-mediated endocytosis and micropinocytosis. We observed that the entered BRSV initially localizes in early endosomes and subsequently localizes in late endosomes. Additionally, our results of western blot, virus titer and virus copies demonstrate that BRSV entry through clathrin-mediated endocytosis is regulated by PI3K-Akt and Src-JNK signaling pathways. Overall, our study suggests that BRSV enters MDBK cells through clathrin-mediated endocytosis, entered BRSV is trafficked to late endosome via early endosome, BRSV entry through clathrin-mediated endocytosis is regulated by PI3K-Akt and Src-JNK signaling pathways.

Molecular Characterisation and Antibody Response to Bovine Respiratory Syncytial Virus in Vaccinated and Infected Cattle in Turkey.

Bovine respiratory syncytial virus (BRSV) is one of the most important respiratory pathogens of cattle. In this study, frequency of infection, analysis of variants, and the immune status of vaccinated and non-vaccinated cattle were studied. Blood (n = 162) and nasal/oropharyngeal (n = 277) swabs were collected from 62 cattle herds in Turkey. Lung samples (n = 37) were also taken from dead animals and abattoirs. Antibodies to BRSV were detected in 76 (46%) out of 162 sera. The antibody levels in the vaccinated and non-vaccinated groups were statistically significant. Among 277 nasal/oropharyngeal swabs and 37 lungs, ten nasal/oropharyngeal and four lung samples were positive for BRSV-RNA. BRSV-G gene sequences of 5 out of 14 RT-PCR positive samples showed that all viruses clustered as Group-III in phylogenetic analysis with 88-100% homology. Similarity with previous Turkish BRSVs was 89-98%, and that with BRSVs detected in the USA and Czechia was 89.47-93.12%. BRSV continues to circulate in Turkish cattle, and vaccination seems beneficial in preventing BRSV. The diversity of the BRSVs found in this study needs be considered in vaccination strategies.

Impact of vaccination for respiratory disease on antibody titer responses, health, and performance in beef and dairy cattle (MEDLINE).

Abstract This systematic review aimed to understand how the titer response to respiratory pathogen vaccination impacts the health and performance of beef and dairy cattle This study utilized five databases with each search reported separately to SearchRXIV. Criteria for study inclusion were: research conducted in the USA or Canada, between 1982 and October 10, 2022, on beef or dairy cattle, using a commercially available vaccine in the US or Canada labeled for a respiratory pathogen of interest, and evaluation of antibody titers, and performance or morbidity. Respiratory pathogens of interest were Mannheimia haemolytica, Pasteurella multocida , Histophilus somni, bovine viral diarrhea virus, bovine herpes virus type 1, parainfluenza 3, bovine respiratory syncytial virus, and bovine coronavirus.

Impact of vaccination for respiratory disease on antibody titer responses, health, and performance in beef and dairy cattle (CAB ABSTRACTS).

Abstract This systematic review aimed to understand how the titer response to respiratory pathogen vaccination impacts the health and performance of beef and dairy cattle This study utilized five databases with each search reported separately to SearchRXIV. Criteria for study inclusion were: research conducted in the USA or Canada, between 1982 and October 10, 2022, on beef or dairy cattle, using a commercially available vaccine in the US or Canada labeled for a respiratory pathogen of interest, and evaluation of antibody titers, and performance or morbidity. Respiratory pathogens of interest were Mannheimia haemolytica, Pasteurella multocida , Histophilus somni, bovine viral diarrhea virus, bovine herpes virus type 1, parainfluenza 3, bovine respiratory syncytial virus, and bovine coronavirus.

Impact of vaccination for respiratory disease on antibody titer responses, health, and performance in beef and dairy cattle (PROQUEST DISSERTATIONS &amp; THESES).

Abstract This systematic review aimed to understand how the titer response to respiratory pathogen vaccination impacts the health and performance of beef and dairy cattle This study utilized five databases with each search reported separately to SearchRXIV. Criteria for study inclusion were: research conducted in the USA or Canada, between 1982 and October 10, 2022, on beef or dairy cattle, using a commercially available vaccine in the US or Canada labeled for a respiratory pathogen of interest, and evaluation of antibody titers, and performance or morbidity. Respiratory pathogens of interest were Mannheimia haemolytica, Pasteurella multocida , Histophilus somni, bovine viral diarrhea virus, bovine herpes virus type 1, parainfluenza 3, bovine respiratory syncytial virus, and bovine coronavirus.

Impact of vaccination for respiratory disease on antibody titer responses, health, and performance in beef and dairy cattle (AGRICOLA).

Abstract This systematic review aimed to understand how the titer response to respiratory pathogen vaccination impacts the health and performance of beef and dairy cattle This study utilized five databases with each search reported separately to SearchRXIV. Criteria for study inclusion were: research conducted in the USA or Canada, between 1982 and October 10, 2022, on beef or dairy cattle, using a commercially available vaccine in the US or Canada labeled for a respiratory pathogen of interest, and evaluation of antibody titers, and performance or morbidity. Respiratory pathogens of interest were Mannheimia haemolytica, Pasteurella multocida , Histophilus somni, bovine viral diarrhea virus, bovine herpes virus type 1, parainfluenza 3, bovine respiratory syncytial virus, and bovine coronavirus.

Occurrence in sick animals and genetic heterogeneity of Siberian isolates of bovine respiratory syncytial virus (Pneumoviridae: &lt;i&gt;Orthopneumovirus&lt;/i&gt;; BRSV) identified in the territories of the Ural, Siberian Federal District and the Republic of Kazakhstan

Introduction. Bovine respiratory syncytial virus (Pneumoviridae: Orthornavirae, Orthopneumovirus; Bovine orthopneumovirus, Bovine respiratory syncytial virus, BRSV) is one of causative agents of respiratory diseases in animals. The study of the occurrence and genetic diversity of this pathogen is of particular importance.&#x0D; Objective. To study the frequency of virus in animals using RT-PCR and genetic heterogeneity of isolates based on determining the complete nucleotide sequence of glycoprotein G gene.&#x0D; Materials and methods. A 381-bp region of glycoprotein F gene was used for identification of virus genome, while complete nucleotide sequences of G gene were used for phylogenetic analysis. Phylogenetic trees were constructed using the maximum likelihood method in MEGA 7.0 software.&#x0D; Results. During outbreaks of respiratory diseases, BRSV RNA was detected in animals of all ages in samples of lungs, nasal secretions, pulmonary lymph nodes. Complete nucleotide sequences of glycoprotein G gene, 771 bp in length were obtained for five isolates and 789 bp in length ‒ for two isolates. Nucleotide similarity between them was 87–100%. Phylogenetic analysis assigned the isolates to subgroups II and III, each of which included two isolates. A separate clade formed by K18 isolate from animals imported from Canada and sequences from vaccines containing the attenuated «375» strain.&#x0D; Conclusion. The virus genome was identified in cows and heifers (20.0 and 14.3%), in calves up 1 month of age (3.05%), and in calves from 1 to 6 months of age (6.7%). Complete G gene nucleotide sequence analysis is a useful tool for studying the molecular epidemiology of BRSV on particular territories.

Intranasal booster vaccination of beef steers reduces clinical signs following experimental coinfection with BRSV and BHV-1 without reducing shedding of BRD-associated bacteria.

To determine the efficacy of primary or booster intranasal vaccination of beef steers on clinical protection and pathogen detection following simultaneous challenge with bovine respiratory syncytial virus and bovine herpes virus 1. 30 beef steers were randomly allocated to 3 different treatment groups starting at 2 months of age. Group A (n = 10) was administered a single dose of a parenteral modified-live vaccine and was moved to a separate pasture. Groups B (n = 10) and C (10) remained unvaccinated. At 6 months of age, all steers were weaned and transported. Subsequently, groups A and B received a single dose of an intranasal modified-live vaccine vaccine while group C remained unvaccinated. Group C was housed separately until challenge. Two days following vaccination, all steers were challenged with bovine respiratory syncytial virus and bovine herpes virus 1 and housed in a single pen. Clinical and antibody response outcomes and the presence of nasal pathogens were evaluated. The odds of clinical disease were lower in group A compared with group C on day 7 postchallenge; however, antibody responses and pathogen detection were not significantly different between groups before and following viral challenge. All calves remained negative for Histophilus somni and Mycoplasma bovis; however, significantly greater loads of Mannheimia haemolytica and Pasteurella multocida were detected on day 7 postchallenge compared with day -2 prechallenge. Intranasal booster vaccination of beef steers at 6 months of age reduced clinical disease early after viral challenge. Weaning, transport, and viral infection promoted increased detection rates of M haemolytica and P multocida regardless of vaccination status.

104 Maternal pre- and post-partum supplementation of Bacillus-based DFM enhanced cow and calf performance

Abstract This study evaluated the effects of maternal supplementation of Bacillus-based direct-fed microbials (DFM) on physiology and growth performance of Bos indicus-influenced cow-calf pairs. On d 0 (~139 d before expected calving date), 72 fall-calving, Brangus crossbred beef heifers (25 to 37.5% Bos indicus; 20 to 22 mo of age) pregnant with their first offspring were stratified by their initial body weight (BW; 431 ± 31 kg) and body condition score (BCS; 6.0 ± 0.36; scale 1 to 9), and randomly allocated into 1 of 12 bahiagrass pastures (1 ha and 6 heifers per pasture). Treatments were randomly assigned to pastures (6 pastures per treatment) and consisted of heifers supplemented with 1 kg/d of soybean hulls dry matter (DM) added (BAC) or not (CON) with a Bacillus-based DFM mixture (BovacillusTM; Chr. Hansen A/S, Hørsholm, Denmark) from d 0 to 242 (139 ± 4 d prepartum to 104 ± 4 d postpartum). Calves were weaned on d 242 (96 ± 30 d of age) and then allocated into 1 of 16 drylot pens and limit-fed the same concentrate at 3.25% of BW until d 319. Maternal treatment effects were not detected (P ≥ 0.29) for herbage allowance, forage nutritive value, and heifer activity on pasture. Heifer BCS on d 39 and 63 tended (P ≤ 0.09) to be greater, whereas heifer BCS on d 91 was greater (P = 0.01) for BAC vs. CON heifers and did not differ (P ≥ 0.20) between treatments on d 179 and 242. Plasma concentrations of glucose did not differ from d 0 to 63 (P ≥ 0.14) but were greater (P = 0.005) on d 179 and tended (P = 0.09) to be greater on d 242 for BAC vs. CON heifers. First offspring BW at birth, ADG from birth to early weaning, and BW weaning did not differ (P ≥ 0.19), but BW at drylot exit (d 319) was greater (P = 0.05) for BAC vs. CON calves. Maternal treatment effects were not detected (P ≥ 0.42) for calf serum concentrations of IgG at birth, and post-vaccination plasma concentrations of glucose, cortisol and haptoglobin. However, serum titers against bovine respiratory syncytial virus (BRSV) were greater (P = 0.04) for BAC vs. CON calves on d 287, whereas seroconversion against parainfluenza 3 virus (PI-3) was greater (P &amp;lt; 0.01) for BAC vs. CON calves on d 271. Thus, maternal supplementation of Bacillus-based DFM increased prepartum BCS gain and postpartum plasma concentrations of glucose of heifers and led to positive carryover effects on post-weaning BW gain and some indicators of humoral immune response to vaccination in their first offspring.

Association of clinical respiratory disease signs and lower respiratory tract bacterial pathogens with systemic inflammatory response in pre-weaned dairy calves

This study investigated the potential associations between 3 acute phase proteins (APPs) haptoglobin, serum amyloid A, and fibrinogen, clinical signs of respiratory disease, and the presence of bacterial pathogens in the lower respiratory tract (LRT) of pre-weaned dairy calves. This cross-sectional study included 150 pre-weaned calves (2-86 d old) from 15 large dairy herds in Estonia. Tracheobronchial lavage, blood, and fecal samples were collected from 5 calves showing clinical signs indicative of LRT disease, and samples from 5 calves without clinical signs of LRT disease per herd. All samples collected from these calves were analyzed for concentrations of systemic APPs, LRT bacteria, and intestinal pathogens. Heifer blood and bulk tank milk samples were collected for the detection of disease-specific antibodies against bovine herpesvirus 1, bovine viral diarrhea virus, bovine respiratory syncytial virus, and Mycoplasma bovis. Mixed-effects linear regression models were used to analyze the associations of clinical respiratory disease signs and LRT bacteria with APPs. Increased plasma fibrinogen concentrations in calves were associated with higher rectal temperature (>39.5°C), increased respiratory rate (>50 breaths/min), and coughing. Increased serum amyloid A concentrations were associated with higher rectal temperature (>39.5°C) and respiratory rate between 40 and 50 breaths/min. Calves with the presence of fecal Cryptosporidium spp. and rectal temperature of 39°C and above had increased serum haptoglobin concentrations. Increased fibrinogen concentrations were associated with the presence of Pasteurella multocida in the calf LRT, whereas increased concentrations of fibrinogen and serum amyloid A were associated with the presence of Trueperella pyogenes. In conclusion, APPs showed variable associations with clinical signs of respiratory disease and LRT bacteria. Plasma fibrinogen concentration could be used as a complementary calf-side test to assess systemic inflammation caused by LRT bacteria such as P. multocida and T. pyogenes in pre-weaned dairy calves.

Investigation into the safety, and serological responses elicited by delivery of live intranasal vaccines for bovine herpes virus type 1, bovine respiratory syncytial virus, and parainfluenza type 3 in pre-weaned calves.

Despite the fact that pneumonia remains a leading cause of mortality and morbidity in pre-weaned calves, relatively little is known regarding the effects of the concurrent administration of intranasal pneumonia virus vaccines, particularly in calves with high levels of maternally derived antibodies. The objective of this study was to use a cohort of 40 dairy and dairy-beef female and male calves (27 females and 13 males) to determine serological responses to concurrent administration at 3 weeks of age (22 ± 4.85 days) of two commercially available intranasal (IN) vaccines for the viruses: bovine respiratory syncytial virus (BRSV), bovine herpes virus 1 (BoHV-1), and parainfluenza-3-virus (PI3-V). The study groups were as follows: (i) Bovilis IBR Marker Live only® (IO), (ii) Bovilis INtranasal RSP Live® only (RPO), (iii) Concurrent vaccination with Bovilis IBR Marker Live® & Bovilis Intranasal RSP Live® (CV), and (iv) a control group of non-vaccinated calves (CONT). The calves' serological response post-IN vaccination, clinical health scores, rectal temperatures, and weights were measured. Data were analyzed in SAS using mixed models and logistic regression. The CV calves had an average daily weight gain (ADG) of 0.74 (±0.02) kg, which was similar to CONT (0.77 ± 0.02 kg). Despite no significant differences in the antibody levels between study groups 3 weeks post-IN vaccination, following the administration of subsequent parenteral injections in the form of Bovilis Bovipast RSP®(antigens; inactivated BRSV, inactivated PI3-V, inactivated Mannheimia haemolytica) and Bovilis IBR Marker Live®, the antibody levels of the BRSV and PI3-V increased in both the CV and RPO study groups. Concurrent vaccination resulted in no increase in fever and no difference in health scores when compared to CONT.

Imunoestimulação da resposta broncoalveolar de bezerros vacinados contra complexo respiratório bovino

ABSTRACT: Although intranasal bovine respiratory disease (BRD) vaccines containing live attenuated virus elicit greater stimulation of local humoral immunity response, they can mimic a viral infection, responsible for reducing innate defense during the establishment of vaccine-induced immunity. Probiotics containing Saccharomyces cerevisiae or Enterococcus faecium reduced the occurrence of BRD in neonatal calves challenged with the bovine respiratory syncytial virus (BRSV). Furthermore, the probiotics potentiated the humoral immune response after vaccination in murine models, raising the question of whether they could have the same effect in calves. This study aimed to verify if the probiotic containing E. faecium and S. cerevisiae attenuates the inflammation caused by the vaccine against BRD in the respiratory tract region in calves. Twenty-four healthy Jersey calves, aged 6 to 7 months old, were divided into the groups: control (C), supplemented (S), vaccinated (V), and supplemented and vaccinated (SV), with six animals in each of them. Supplemented groups (S and SV) received S. cerevisiae and E. faecium once a day on D-15 for 51 days (Probios precise®, Ouro Fino®, 2g/day/animal). Vaccinated groups (V and SV) received a single dose of an intranasal BRD vaccine on day 0 (Inforce®, Zoetis®, 1ml/ nostril). The control group was not supplemented or vaccined. Irritation of the respiratory tract and bronchoalveolar (BA) evaluations: cytology, phagocyte function, and IgA were measured on D-15, D3, D7, and D21. The vaccinated groups showed greater irritation of the nasopharynx and trachea. However, only Group V showed a reduction in BA phagocyte function and an increase in cellularity by a neutrophil influx in the BA region. Regarding IgA BA, SV showed the greatest increase, followed by S and V, concerning C. We conclude that isolated supplementation with E. faecium and S. cerevisiae promoted increased production of BA IgA. In association with the vaccine, the supplementation attenuated the inflammation of the respiratory tract produced by the vaccine itself, avoiding the reduction of phagocyte function BA, besides potentiating the humoral immune response of the vaccine containing live attenuated virus against BRD.

A study on co-infection of bovine parainfluenza 3 virus (BPI3V) and bovine respiratory syncytial virus (BRSV) in cattle

A study on co-infection of bovine parainfluenza 3 virus (BPI3V) and bovine respiratory syncytial virus (BRSV) in cattle

Comparative Evaluation between Nested RT-PCR andMono-Screen Antigen ELISA for Diagnosis of Bovine Respiratory Syncytial Virus in cattle

Comparative Evaluation between Nested RT-PCR andMono-Screen Antigen ELISA for Diagnosis of Bovine Respiratory Syncytial Virus in cattle

A Serological Survey and Risk Factors of Respiratory Syncytial Virus in Goats in Different Locations in Al-Najaf, Iraq

Bovine respiratory syncytial virus (BRSV) is one of the most common causes of respiratory illness in goats globally, resulting in major financial losses. The goal of this Survey was to determine the incidence of Bovine Respiratory Syncytial virus in Al-Najaf goats and the risk factors for this disease. Between December 2021 and November 2022 For this study, 200 goats of various ages and breeds from Al Kufa, Qadisiyia, Hayderia, and Abbasyia in Al-Najaf, Iraq, were tested. The animals’ epidemiological information was recorded. An indirect Elisa test kit was used to establish the disease’s incidence. The incidence of BRSV in goats was 44.5%, and it was substantially higher in Goats aged more than one-year (50.4%). The incidence of BRSV in male and female goats did not vary significantly. Compared to samples taken during the other seasons, those collected in the winter had a significantly higher BRSV incidence. There was a significantly difference in disease infection rate (P≤0.05) among mixed goats compared with others that were not mixed with other specious. The results revealed that the imported animals had a significantly higher prevalence than the native goats. In Conclusion: Bovine Respiratory Syncytial Virus is predominant in goats from the Al-Najaf province and risk factors such as animal age, herd size, origin, and the herd’s geographical location are related to an increased occurrence of the disease in this region. Routine vaccination plans must be assumed to decrease the incidence of BRSV in goats.

Associations of serostatus upon arrival with clinical respiratory disease, lung consolidation and growth in veal calves

Respiratory tract infections remain a major problem during calf rearing, especially among milk (formula) fed veal. Preconditioning of calves through appropriate colostrum management and vaccination could be helpful to address this issue. The objective of this study was to investigate whether the presence of serum antibodies against major respiratory tract pathogens (Bovine Respiratory Syncytial virus, Parainfluenza 3 virus, Bovine coronavirus, Mycoplasmopsis bovis, Histophilus somni, Pasteurella multocida and Mannheimia haemolytica) and total serum immunoglobulin G (IgG) concentration in calves upon arrival at the veal facility were associated with the occurrence of clinical bovine respiratory disease (BRD) or lung consolidation in the first 3 weeks, as assessed by both the Wisconsin BRD scorecard (based on 5 clinical signs: cough, rectal temperature, ear position, nasal-and ocular discharge) and by quick thoracic ultrasound scanning (qTUS). Additionally, the association between calves' serostatus production parameters were explored. A prospective cohort study was conducted among 442 male dairy calves on a large veal calf facility in Belgium. Both clinical scoring and qTUS were performed on all calves at 4 key moments in the production cycle: arrival at the facility, initiation of first metaphylactic antimicrobial treatment at peak incidence of BRD (wk 1), end of the first metaphylactic treatment (short-term evaluation) and at wk 10 (long-term evaluation). Mixed effects logit regression models were fitted to quantify relationships. The outcomes of interest were clinical respiratory disease (Wisconsin BRD scorecard positive), lung consolidation (≥1cm or ≥ 3cm), average daily weight gain and cold carcass weight. In the first week of production, incidence of lung consolidation (≥1cm) quickly increased from 14.9% upon arrival to 43.0% at the peak of the BRD incidence, while clinical BRD increased from 3.6% to 16.1%. The main finding of this study was that calves who were seropositive for bovine respiratory syncytial virus (BRSV) and bovine coronavirus (BCoV) at arrival had reduced odds of developing lung consolidation at the peak of the outbreak, 0.58 OR (95% CI: 0.38 - 0.89) and 0.37 OR (95% CI: 0.20 - 0.69), respectively. No relationships between serum IgG concentration at arrival and the development of lung consolidations or clinical respiratory disease were found. Nevertheless, on average, throughout the first 10 weeks of the fattening cycle, calves with failed transfer of passive immunity (FPT, serum IgG < 7.5 g/L) gained 40 g/day (95% CI: 10-70g/day) less weight (ADG). Hence, ensuring that calves have a positive serostatus for these respiratory tract pathogens before entering the facility may help lower the incidence of lung consolidations, subsequently reducing treatment incidence and the adverse effects on primary economic outcomes.