Responsible antimicrobial use
The global food animal industry continues to face growing concerns regarding antimicrobial resistance (AMR), primarily driven by the use of antimicrobials (AM) for the treatment, control and prevention of disease. Addressing this challenge involves promoting responsible antimicrobial use (AMU) practices. In 2019, the province of Québec, Canada, took a significant step by implementing a regulation that limits the use of AM of very high importance for human medicine (Category I AM as defined by Health Canada, including 3rd generation cephalosporins and fluoroquinolones) in the food animal industry. However, the implementation of such regulation can significantly influence behavioural shifts among producers, contributing to the wider effort against AMR. Therefore, the objective of an observational study by Millar et al (2024) (https:/doi.org/10.3168/jds.2024-24667) was to describe the perceived changes in dairy producers' knowledge and on-farm practices following the implementation of this regulation, using a cohort design. Data collection involved administering questionnaires to 87 dairy producers from three regions of the province of Québec before (2017–2018) and after (2020–2021) the implementation of the regulation. The questionnaires explored the descriptive characteristics of farms, the knowledge of producers about the categorisation of AM, the on-farm treatment practices and the perceived effects of the regulation. The results indicated an increase in the knowledge score (the number of AM correctly categorised by the producers by their importance for human medicine) after the implementation of the regulation, suggesting an improved understanding of the categorisation of AM based on their importance for human medicine. Trends in AMU practices for treating clinical mastitis and reproductive diseases suggested that category I AM were less likely to be reported as the primary treatment after the regulation was implemented. Adoption of the selective dry cow therapy method significantly increased, whereas the use of teat sealants remained unchanged. Moreover, producers had divergent perceptions regarding the effect of the regulation on the cure rates and disease frequencies. This disparity emphasises the need for comprehensive data collection to discern the risks associated with such regulatory shifts. The study acknowledges several limitations, including the potential for recall bias, confirmation bias and desirability bias. Despite these limitations, this study shows that implementing regulations to encourage responsible AMU drives positive transformations in producers' knowledge and on-farm practices. This underscores the pivotal effect of proactive interventions in combatting the escalating threat of AMR within the global food animal industry.
Milk feeding of calves
Diniz Neto et al (2024) (10.3168/jds.2024-24674) aimed to assess the effect of feeding bulk tank milk (BTM), waste milk (WM), and pasteurised waste milk (PWM) on nutrient digestibility, ruminal and caecal fermentation, gastrointestinal tract (GIT) development and antimicrobial resistance of faecal Escherichia coli from dairy calves at two periods (30 and 60 days of age). Calves were grouped according to bodyweight, serum protein levels and breed composition. Three treatments were included: BTM (n=21), WM from cows under antibiotic treatment (n=21) and PWM (WM submitted to pasteurisation; n=21). A total of 63 calves were used, of which 18 animals (n=6 per treatment) were evaluated in the period of 4–30 days, and 45 (n=15 per treatment) from 4–60 days. During the experimental period, a daily intake of 6 litres of milk was divided into 2 equal meals, with ad libitum access to water and starter feed. Milk and feed intakes were recorded daily. Apparent total-tract digestibility and nitrogen balance were conducted from 25–29 days of age (n=6) and from 53-57 days of age (n=15). Animals were slaughtered at 30±1 and 60±1 days of age for the assessment of ruminal and caecal fermentation and GIT development. Antimicrobial susceptibility testing was conducted at 1, 30 and 60 days of age (n=15/treatment). Treatments WM and PWM had lower rumen pH, higher ruminal acetate concentration, larger reticulorumen and liver, and a higher prevalence of faecal-resistant E. coli compared with BTM at both 30 and 60 days. Up to 60 days, both BTM and WM treatments exhibited higher digestibility of ether extract and gross energy compared with the PWM, whereas WM and PWM treatments showed increased nitrogen intake and retention compared with the BTM treatment. These findings suggest that pasteurisation of WM negatively affects nutrient digestibility and calf performance, while also affecting rumen development. Additionally, the use of milk containing antibiotic residue leads to the selection of resistant E. coli in the GIT over time.
Medicine hub
It may be timely to remind ourselves of the importance of our clients recording data on the Medicine Hub: https://ahdb.org.uk/medicine-hub. Take the opportunity now to remind yourself and your clients of this.