A Comparison of Dry Period Outcomes after Selective Dry Cow Therapy Carried Out by Farm Staff versus Veterinary Students in a Low-Cell-Count Dairy Herd

SIMPLE SUMMARY: Selective dry cow therapy involves giving local antibiotic treatment into the udder only to those cows which are likely to be infected with a mastitis-causing organism, while uninfected cows receive an internal teat sealant only, a physical barrier inserted into the teat to prevent infections entering the udder via the teat canal.

The application of teat sealant only without antibiotics can induce infections into the udder if not done hygienically, and veterinarians should be training farmers in hygienic application.

Therefore, veterinary students have to be trained in the technique themselves, and farmers may be concerned about allowing students to practice on their cows.

This study follows up cows dried off by farm staff and students on a single dairy farm and compares several parameters indicative of mastitis and also looks into the survival of cows in the herd.

There is no indication that cows perform worse when dried off by students under close supervision, and the risk of culling within twelve months was lower in cows dried off by students.

ABSTRACT: (1) Background: Selective dry cow therapy is widely promoted in many countries worldwide, however, concerns have been raised about the consequences of the unhygienic application of preparations by untrained operators, especially if no antimicrobials are being used, risking deteriorating mastitis outcomes.

(2) Method: This study follows up on cows being dried off by farm staff and those dried off by final-year veterinary students and first-year graduate interns in a supervised training session.

Subsequent mastitis parameters and culling data in a single herd with a low somatic cell count were evaluated.

(3) Results: A total of 316 dry periods were enrolled in the study.

There was no significant difference in the percentage of cows showing at least one high SCC reading within 90 days of the following lactation or cows with at least one case of clinical mastitis within the same period, neither in the total nor in the subset of cows dried off without an antimicrobial.

Dry period cure rates and dry period new infection rates were similar too, as was the percentage of cows surviving in the herd after six months.

The risk of culling within twelve months post-drying off was lower in cows dried off by students, the difference in survival manifesting itself from 150 days post-drying off, which is an unexplained finding.

(4) Conclusion: Well-supervised practical training sessions on drying off routine can be responsibly implemented on well-managed commercial dairy herds.