The Prevalence, Coexistence, and Correlations between Seven Pathogens Detected by a PCR Method from South-Western Poland Dairy Cattle Suffering from Bovine Respiratory Disease.

Bovine respiratory disease (BRD) is a very important disease that contributes to economic losses in dairy and beef cattle breeding worldwide. The molecular testing of material from 296 calves showing BRD symptoms from 74 dairy herds located in south-western Poland was performed in 2019-2021. Molecular tests were performed using a commercial kit "VetMAXTM Ruminant Respiratory Screening Kit" (Thermo Fisher Scientific) for the simultaneous detection of genetic material of seven pathogens responsible for BRD. At least one pathogen was detected in 95.95% of herds. The overall prevalence was: Pasteurella multocida 87.84%, Mannheimia haemolytica 44.59%, bovine coronavirus (BcoV) 32.43%, Mycoplasma bovis 29.73%, Histophilus somni 28.38%, bovine parainfluenza virus type 3 (BPIV-3) 13.51%, and bovine respiratory syncytial virus (BRSV) 10.81%. Twenty-nine configurations of pathogen occurrences were found. Bacterial infections were the most frequently recorded as 56.7% of all results. Coinfections mainly consisted of two pathogens. Not a single purely viral coinfection was detected. The most frequent result was a single P. multocida infection accounting for 18.31% of all results. The statistically significant correlation (p = 0.001) with the highest strength of effect (ϕ 0.38) was between M. bovis and H. somni.

Antibody Response to a Live-Modified Virus Vaccine against Bovine Viral Diarrhoea in Dairy Cattle in a Field Trial.

(1) Background: The objective of the study was to evaluate the long-term antibody response of dairy cows to a single dose of a commercial modified-live virus (MLV) vaccine against bovine viral diarrhea (Mucosiffa® CEVA Sante Animale, Liburne, France). (2) Methods: The study was carried out in a dairy cattle herd counting 290 animals negative for bovine viral diarrhoea virus (BVDV). The vaccination was implemented following the manufacturer's instructions. Twelve dairy cows were randomly selected before the study, and blood samples were collected right before the vaccination and then 12 times at 1-month intervals. The serum samples were screened using a virus neutralization test (VNT) and ELISA. (3) Results: Both tests showed that antibody titers increased significantly in all animals within the first month post-vaccination, and continued to increase significantly until the second (VNT) and third (ELISA) month post-vaccination. Antibody titers remained high and stable until the end of the study. Moreover, cows did not show any adverse reactions or clinical symptoms of the disease. (4) Conclusion: The results of this study indicated that the administration of one dose MLV vaccine was able to stimulate long-lasting (12-months) and strong antibody response in all vaccinated cows.