Effects of a synthetic analog of the bovine appeasing pheromone on the overall welfare of dairy calves from birth through weaning
The main objective of a study by Garcia-Alvarez et al (2025) was to determine if the use of bovine appeasing pheromone (BAP) would improve the welfare of dairy calves. Therefore, in a randomised controlled trial, 72 Holstein Friesian dairy calves were housed in individual hutches and were randomly allocated to receive BAP or a placebo once every 2 weeks from birth through weaning. After weaning, calves were moved to group hutches according to treatment for 4 additional weeks. It was hypothesised that dairy calves treated with BAP would display fewer signs of stress compared with calves receiving the placebo during the weaning process. To assess stress, calves were fitted with triaxial accelerometers on the hind leg after birth, and activity levels were monitored throughout the experiment. Data on live weight gain (ADG) and cortisol levels in saliva and hair were also obtained. Calves were fitted with heart rate monitors every week for at least 24 h to assess heart rate variability (HRV). The use of BAP had a positive effect on ADG after weaning and during group housing and resulted in increased resting time after weaning. Moreover, BAP was associated with a reduction in the activation of the neuroendocrine system evidenced by higher HRV parameters after weaning. These results suggest a potential welfare benefit of the use of BAP during the artificial rearing of dairy calves.
Improved control of Johne's disease in dairy cattle through advancements in diagnostics, testing and management of young stock
Johne's disease control programmes have been regionally implemented across the globe, but few have successfully eradicated the pathogen (Mycobacterium avium ssp. paratuberculosis; MAP) causing this disease. This limited success may partly be attributed to excluding youngstock from testing strategies aimed at identifying MAP-infected cattle. Youngstock can shed MAP in faeces and can have detectable MAP-specific antibodies in blood, as confirmed in experimentally and naturally infected cattle. Furthermore, MAP transmission causes new infections in youngstock. Calves and heifers are often included in JD management strategies on dairy farms but excluded from conventional diagnostic tests due to a presumed lag between infection and detection of MAP shedding and MAP-specific serum antibodies. A recent international review paper by Martins et al (2025) with authors from Europe, Australia, North and South America summarises evidence of MAP shedding early in the course of infection and discusses promising diagnostics, testing and management strategies to support inclusion of youngstock in JD control programmes. Improvements in faecal PCR, interferon-gamma release assay (IGRA), and ELISA enable earlier detection of MAP and specific early immune responses. Studies on IGRA and ELISA have focused on evaluation of new antigens and optimal age of testing. New diagnostics have been developed, including phage-based tests to detect viable MAP, as well as gene expression patterns and metabolomics to detect MAP-infected youngstock. In addition, refinements in testing and management of calves and heifers may enable reductions in MAP prevalence. The authors provide recommendations for dairy farmers, researchers, veterinarians, and others that may improve JD control programmes with an objective to control and potentially eradicate JD. In summary, transmission among youngstock may cause new MAP infections, and appropriate use of new diagnostic tests, testing and management strategies for youngstock may improve the efficacy of JD control.
Bluetongue virus serotype 12 in sheep and cattle in the Netherlands in 2024 – A BTV serotype reported in Europe for the first time
Bluetongue is a viral vector borne disease primarily affecting ruminants. A recent paper by van den Brom et al (2025) describes the recent incursions of BT into the Netherlands. On 3 September 2023, the Netherlands reported the first case of bluetongue virus serotype 3 (BTV-3) after being BTV free for eleven years. Vaccination with inactivated BT vaccines for serotype 3 has been applied in the Netherlands since May 2024. Nonetheless, in late June/July 2024, BTV-3 re-emerged and spread over large parts of Europe. In October 2024, BTV-12 was identified by follow-up diagnostics after a BTV-3 vaccinated sheep with signs of BT was tested positive for BTV but negative for serotype 3. This marks a significant event, as BTV-12 had never been reported in Europe. Screening of farms near the sheep farm and retrospective analysis of samples from clinically affected animals that were panBTV PCR positive resulted in the detection of nine BTV-12 affected farms. The emergence of BTV-12 in the Netherlands raises important questions about the route of introduction of BT in the Netherlands and mechanisms of viral spread of this specific serotype. Possible adaptation of new BTV serotypes to the European climatic and husbandry conditions prompts reconsideration of prevention, surveillance, and control strategies in relation to changing ecological conditions and vector dynamics.
This is timely to consider since the UK is also dealing with BTV-3 and reported our first case of BTV-12 on 7 February 2025.