Factors Affecting the Development of Bovine Respiratory Disease: A Cross-Sectional Study in Beef Steers Shipped From France to Italy

Abstract

Bovine respiratory disease (BRD) is a complex, multifactorial syndrome and one of the major welfare and economical concerns for the cattle industry. This 1-year cross-sectional study was aimed at documenting the prevalence of BRD-related pathogens and clinical signs before and after a long journey and at identifying possible predisposition factors. Male Limousine beef steers (n = 169) traveling from France to Italy were health checked and sampled with Deep Nasopharyngeal Swabs (DNS) at loading (T0) and 4 days after arrival (T1). Real-time quantitative PCR was used to quantify the presence of bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), bovine alphaherpesvirus 1 (BoHV-1), bovine coronavirus (BCoV), bovine adenovirus (BAdV), bovine parainfluenza virus 3 (BPIV-3), Histophilus somni, Mannheimia haemolytica, Mycoplasma bovis, and Pasteurella multocida. Weather conditions at departure and arrival were recorded, and the travel conditions were taken from the travel documentation. At T0, even if no animals displayed clinical signs, some of them were already positive for one or more pathogens. At T1, the number of animals displaying clinical signs and positive for BCoV, BAdV, BRSV, H. somni, M. haemolytica, M. bovis, and P. multocida increased dramatically (p < 0.001). Transport also significantly increased co-infection passing from 16.0% at T0 to 82.8% at T1 (p < 0.001). An extra stop during the journey seemed to favor BRSV, M. haemolytica, and P. multocida (p < 0.05). Weather conditions, in particular sudden climate changes from departure to arrival and daily temperature variance, were found to be predisposing factors for many of the pathogens. The farm of arrival also played a role for BRSV, BAdV, and H. somni (p < 0.05). BCoV increased dramatically, but no associations were found confirming that it spreads easily during transport phases. Our findings increased our understanding of factors increasing the likelihood of BRD-related pathogens shedding and can be useful to minimize the incidence of BRD and to implement animal transport regulations.

Lack of Fetal Protection against Bovine Viral Diarrhea Virus in a Vaccinated Heifer

“…Transport-associated stress can alter immune functions, potentially compromising the animal's welfare by increasing the likelihood of infection and/or clinical disease. Among transport-related health problems, BVDV infections are common and can be severe [26][27][28]. A widespread route of spreading the virus is possible through the movement of PI cattle between herds [29,30], which is highly probable in herds in which the movement frequency is high [31].…”

Natural Bovine Coronavirus Infection in a Calf Persistently Infected with Bovine Viral Diarrhea Virus: Viral Shedding, Immunological Features and S Gene Variations

“…The reverse transcription using random hexamers and MuLV reverse transcriptase (GeneAmp ® RNA PCR, Applied Biosystems, Applera Italia, Monza, Italy) was performed in a total volume of 10 μL for the detection of BCoV, BVDV, BRSV and BPiV according to the manufacturer’s protocol. Then, the RT-qPCR for the detection of the above RNA viruses and of the DNA pathogens BAdV, BoHV-1, M. haemolytica , P. multocida , H. somni and M bovis was carried out using primers and TaqMan probe and the same reaction conditions and reaction mix components, as previously reported [ 7 , 8 , 10 ]. Briefly, 10 μL of cDNA or extracted DNA were added to 15 μL of the reaction master mix (IQ™ Supermix, Bio-Rad Laboratories Srl, Segrate, Italy) containing 0.6 μM of each primer and 0.4 μM probe.…”

“…Bovine coronavirus (BCoV) belongs to the Betacoronavirus genus, subgenus Embecovirus , and is responsible for different clinical diseases in ruminants affecting both respiratory and enteric tracts, such as neonatal diarrhea, the wintery disease in adults and respiratory diseases as a cofactor of the Bovine Respiratory Syndrome (BRD) [ 7 , 8 , 9 , 10 ]. Regardless of the clinical signs, BCoV, which is also commonly identified in healthy cattle [ 11 ], is shed both in the feces and in the nasal secretions.…”

Bovine respiratory microbiota of feedlot cattle and its association with disease

“…Another potential source to consider is the direct inhalation of air in different weather conditions as survivability of microorganisms in the air can be influenced by temperature, humidity, UV light, etc. [ 11 , 103 ]. These dynamic movements of microbiota are relevant for our understanding of pathogenesis in pulmonary health and disease [ 104 ].…”

“…Many studies have confirmed that the alteration of the respiratory microbiota can be observed in calves with clinical BRD. For example, the nasopharyngeal microbiota in BRD-affected feedlot calves was distinct from pen-matched healthy controls [ 22 , 103 ], a distinct longitudinal shift of microbial composition of the nasopharynx from feedlot arrival to when BRD was diagnosed was observed in another study [ 90 , 107 ], and bacterial families associated with BRD, including Mycoplasma and Pasteurellaceae , had greater abundances and frequencies in lung tissue samples from calves with BRD signs [ 52 ]. Although these reports support the hypothesis that microbial dysbiosis is associated with BRD, we still do not know the accuracy of the association between the microbiome and BRD despite the microbial changes found.…”