Postpartum uterine disease
The objective of a study by Cattaneo et al (2020) (The Veterinary Journal https://doi.org/10.1016/j.tvjl.2020.105533) was to assess how uterine disorders alter the lying behaviour and plasma biomarkers in dairy cows. Thirty-four multiparous cows were retrospectively classified into three groups according to the first uterine disorder the cows were diagnosed with: retained placenta (RP), metritis (MET), or healthy (H; cows without any clinical disease). Lying time (LT) and duration of lying bouts (LB) were monitored between 6 weeks prior to and 8 weeks after calving via the AfiAct II pedometer. Blood samples were collected routinely between 14 days before and 28 days after calving. Regardless of grouping, both LT and LB were longer (p<0.01) in the prepartum period (774 ±16.6 min/day and 89.9±2.1 min/bout) than in the first 28 days after calving (653±16.7 min/day and 63.7±2.1 min/bout). Cows with RP had longer LT than healthy cows during the last 3 weeks before calving (837±30.9 vs. 735±27.1 min/day; p<0.05). LT in cows with MET and healthy cows were not significantly different. The LB was similar among groups, averaging 76.1±3.4 min/bout in healthy cows, 73.2±3.8 min/bout in cows with RP, and 75.2±3.7 min/bout in cows with MET. Compared with healthy cows, cows with RP laid down longer and stood up for shorter times, particularly before calving. In addition, cows with RP had increased mobilisation of body stores and more pronounced in-flammatory status, as demonstrated by plasma haptoglobin and albumin concentrations. These data suggest that automatic monitoring of lying behaviour could help identify cows at increased risk of developing certain disorders, such as RP.
Mycoplasma bovis
Mycoplasma bovis is one of the leading causes of respiratory disease and antimicrobial use in cattle. The pathogen is widespread in different cattle industries worldwide, but the highest prevalence is found in the veal industry. Knowledge on M. bovis strain distribution over the dairy, beef and veal industries is crucial for the design of effective control and prevention programmes, but currently undocumented. Therefore, this study by Bokma et al (2020) (Veterinary Research https://doi.org/10.1186/s13567-020-00848-z Open Access) evaluated the molecular epidemiology and genetic relatedness of M. bovis isolates obtained from Belgian beef, dairy and veal farms, and how these relate to M. bovis strains obtained worldwide. Full genomes of one hundred Belgian M. bovis isolates collected over a 5-year period (2014–2019), obtained from 27 dairy, 38 beef and 29 veal farms, were sequenced by long-read nanopore sequencing. Consensus sequences were used to generate a phylogenetic tree to associate genetic clusters with cattle sector, geographical area and year of isolation. The phylogenetic analysis of the Belgian M. bovis isolates resulted in five major clusters and one outlier. No sectorspecific M. bovis clustering was identified. On a world scale, Belgian isolates clustered with Israeli, European and American strains. Different M. bovis clusters circulated for at least 1.5 consecutive years throughout the country, affecting all observed industry sectors. Therefore, the high prevalence in the veal industry is more likely the consequence of frequent purchase from the dairy and beef industry, than evidence that a reservoir of veal specific strains exists on these farms. These results emphasise the importance of biosecurity in M. bovis control and prevention, a finding that is likely to be as important here in the UK as it is in Belgium regardless of the fact that we do not have a similar veal industry in this country.
Respiratory disease vaccines
Bovine respiratory syncytial virus (BRSV) and bovine parainfluenza-3 virus (PI3) are major causes of bovine respiratory disease (BRD) in newborn calves worldwide. Vaccination is widely used to prevent BRD, and intranasal vaccines for BRSV and PI3 were developed to overcome interference from BRSV and PI3-specific maternally-derived antibodies. Many experimental challenge trials have demonstrated that intranasal vaccines for BRSV and PI3 are efficacious, but effectiveness under field conditions has been demonstrated less often, especially for newborn beef calves. The objective of this field trial by Masset et al (2020) (The Veterinary Journal https://doi.org/10.1016/j.tvjl.2020.105532) was to compare the effectiveness of a newly available commercial BRSV-PI3 intranasal vaccine with that of a benchmarked one in newborn beef calves reared in a cow-calf system. A total of 935 calves from 39 farms were randomised into two vaccine groups (Bovalto Respi Intranasal (vaccine A), n = 468; Rispoval RS + PI3 Intranasal (vaccine B), n = 467), and monitored during the in-house risk period up to 3 months after vaccination. Non-inferiority analysis was performed by calculating the difference in BRD prevalence between the two vaccine groups. No significant differences were observed between vaccines regarding clinical outcomes of morbidity, mortality, duration between vaccination and BRD occurrence, or treatments required. In conclusion, vaccine A was found to be at least as effective as vaccine B for the prevention of BRD in newborn beef cattle in a cow-calf system under field conditions.
Reading this paper at this time also serves as a reminder to get as many calves as possible vaccinated as we move into the winter, to protect them from disease but also to reduce the need for antimicrobial treatments.