By Jose Ferronatto
A perennial challenge in the dairy industry is reducing the spread of antibiotic-resistant bacteria while still protecting cow health and milk quality. Antibiotics are an important tool for preventing and treating mastitis, especially at dry off, when it is cost effective to treat subclinical mastitis and to help prevent udder infections during the early dry period.
These treatments have greatly improved animal health and milk quality on dairy farms. However, scientists and consumers are becoming increasingly concerned about antimicrobial resistance and the possibility that resistant bacteria may spread through manure into the farm environment.
Our team is investigating whether inflammation that naturally occurs around calving may play a role in increasing the shedding of resistant bacteria. Around the time cows give birth, their bodies go through major metabolic and immune changes, often leading to increased inflammation. In human medicine, studies have shown that inflammation can disrupt the gut microbiome and encourage the growth of antibiotic-resistant bacteria. We want to determine if the same process may also occur in dairy cows.
What will we study?
We are evaluating whether treating cows with oral anti-inflammatory therapy after calving can help reduce inflammation and decrease the shedding of resistant Gram-negative bacteria and antimicrobial resistance genes in manure.
The idea is simple. If inflammation contributes to microbial imbalance in the gut, reducing that inflammation may help maintain a healthier and more stable microbiome.
Throughout the study, we will collect blood, manure, and milk samples before dry-off, during the dry period, around calving, and after calving. These samples will help us evaluate:
- Levels of antibiotic-resistant bacteria in manure of both cows that got antibiotics at dry off and cows that were not treated
- Presence of antimicrobial resistance genes
- Changes in the gut microbiome
- Inflammatory biomarkers
- Mammary gland health and intramammary infections
Using advanced microbiome sequencing and molecular analyses, our team will characterize bacterial communities and track how resistance genes change over time.
Source : msu.edu