J Vet Sci.  2020 Nov;21(6):e87. 10.4142/jvs.2020.21.e87.

A non-inferiority study evaluating a new extended-release preparation of tilmicosin injected subcutaneously vs.ceftiofur administered intramammary, as dry-cow therapy in Holstein Friesian cows

• Ortega E
• Alfonseca-Silva E
• Posadas E
• Tapia G
• Sumano H

• KMID: 2509149
• DOI: http://doi.org/10.4142/jvs.2020.21.e87

Abstract

Background
A new, extended long-acting tilmicosin (TLAe) preparation was tested against intramammary ceftiofur (CEF) using a non-inferiority trial model during dry-cow therapy (DCT) in a farm with high bovine population density and deficient hygiene application.
Objectives
To evaluate the possibility that TLAe administered parenterally can achieve noninferiority status compared to CEF administered intramammary for DCT.
Methods
Cows were randomly assigned to TLAe (20 mg/kg subcutaneous; n = 53) or CEF (CEF-HCl, 125 mg/quarter; n = 38 cows) treatment groups. California mastitis testing, colonyforming unit assessment (CFU/mL), and number of cases positive for Staphylococcus aureus were quantified before DCT and 7 d after calving. A complete cure was defined as no bacteria isolated; partial cure when CFU/mL ranged from 150 to 700, and cure-failure when CFU/mL was above 700.
Results
TLAe and CEF had overall cure rates of 57% and 53% (p > 0.05) and S. aureus cure rates of 77.7% and 25%, respectively (p < 0.05). The pathogens detected at DCT and 7 days after calving were S. aureus (62.71% and 35.55%), Staphylococcus spp. (22.03% and 35.55%), Streptococcus uberis (10.16% and 13.33%), and Escherichia coli (5.08% and 15.55%). Noninferiority and binary logistic regression analyses revealed a lack of difference in overall efficacies of TLAe and CEF. Apart from S. aureus, S. uberis was the predominant pathogen found in both groups.
Conclusions
This study is the first successful report of parenteral DCT showing comparable efficacy as CEF, the gold-standard. The extended long-term pharmacokinetic activity of TLAe explains these results.

Keyword

Mastitis; bovine; dry-cow therapy; long-acting tilmicosin; ceftiofur; non-inferiority