Relationships between pig farm management and facilities and lung lesions' scores and between lung lesions scores and carcass characteristics.

BACKGROUND: The objective of this study was to examine the inter-relationships between pig farm management and facilities (as assessed by questionnaire) and post-mortem lung lesion (lung score assesment), which are the result of respiratory infections. The relationships between carcass characteristics and post-mortem lung lesion scores were also investigated. RESULTS: Questionnaire responses were collected from 22 self-selecting pig farmers about their farm facilities/management and health condition of the respiratory system of pigs, including the occurrence of clinical respiratory signs, results of laboratory testing for respiratory pathogens, and the use of respiratory vaccines. When fatteners were sent to the abattoir, their carcasses (n = 1,976) were examined for evidence of respiratory disease by lung lesion (pleuritis pneumonia-like (PP-like) and enzootic pneumonia-like (EP-like) lesions) scoring and the Actinobacillus pleuropneumoniae Index (APPI) was calculated. Carcass characteristics were recorded and, retrospectively, the prevalence of cachectic pigs was calculated. Using these variables, the relationships between farm facilities/management and lung lesions scores and the relationships between the latter and carcass characteristics and cachexia were explored. The key findings relating farm facilities and management to lung lesions were: slatted floors were associated with significantly higher EP-like lesions scores than litter bedding in weaners, single-stage fattening in the same building was associated with significantly higher EP-like lesions scores than two-stage fattening, but herd size, stocking density, use of all-in/all-out (AIAO) rule, technological break duration and variation in daily temperature did not affect lung lesions scores. The key findings relating lung lesion scores to carcass characteristics were: a significant, negative correlation between EP-like scores and carcass weight but not with other carcass characteristics, a significant positive correlation between PP-like scores and carcass meat content and prevalence of cachectic carcasses and a significant positive correlation between lung APPI and prevalence of cachectic carcasses. CONCLUSIONS: It can be concluded that both farm facilities and management affect lung lesions scores and that the latter affect carcass characteristics. Lung lesion scoring is an inexpensive technique suitable for rapid monitoring of large numbers of carcasses that can be performed after animal slaughter. It provides useful information to inform producers about possible deficits in farm facilities or management and is a predictor of economic loss due to poorer quality carcasses.

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.

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

The aim of the report was to present the circulation of BVDV (bovine viral diarrhea virus) in the cattle population and determine the cause of the failure of vaccination failure leading to the birth of the PI (persistently infected) calf. The case study was carried out at the BVDV-free animal breeding center and cattle farm, where the vaccination program against BVDV was implemented in 2012, and each newly introduced animal was serologically and virologically tested for BVDV. In this case, a blood sample was taken from a 9-month-old breeding bull. Positive RT-PCR and negative ELISA serology results were obtained. The tests were repeated at 2-week intervals, and the results confirmed the presence of the virus and the absence of specific antibodies, i.e., persistent infection. Additionally, sequencing and phylogenetic analysis were performed, and the BVDV-1d subgenotype was detected. The results of this study showed that pregnant heifers and cows that are vaccinated multiple times with the killed vaccine containing BVDV-1a may not be fully protected against infection with other subgenotypes of BVDV, including their fetuses, which can become PI calves.

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.

Occurrence of BVDV Infection and the Presence of Potential Risk Factors in Dairy Cattle Herds in Poland.

The aim of the study was to analyze the risk factors of BVDV infection, in different regions of Poland, with respect to certain parameters of animal health, including productivity, herd management practices, the presence of BVDV, and the effect of non-vaccination. A total of 354 cattle herds were estimated and linked to the analysis of the different factors that might be correlated with productive results. The presence of antibodies against BVDV was found in 33.3% of examined herds, and the heterogenous distribution of BVDV-positive herds in all regions of Poland (p = 0.001) was confirmed. We found statistical correlations between BVDV infection and pasture (p = 0.004) and the number of grazing animals (p < 0.001), and also the purchase of animals for replacement (p = 0.004) was observed. Production or clear clinical outcomes potentially linked to BVDV infection in the herd have not been observed. The results of this study indicate that the rate of BVDV infection was most strongly correlated with the geographical location of the examined cattle populations in Poland. The second most significant factors were the grazing of animals and the purchasing of new animals to be introduced to herds. The strengthened procedures of management, as well as the implementation of eradication programs, should be considered in the examined herds.