Comparative efficacy of teat sealants given prepartum for prevention of intramammary infections and clinical mastitis: a systematic review and network meta-analysis.

C B Winder,J M Sargeant,J Glanville,H Wood,M D Bergevin,C Moody,A M O'Connor,K J Churchill,B Deb,K Dawkins,J Dunn,S Meadows,D Hu,S J Leblanc,T F Duffield,C Wang,D F Kelton,M Reist

doi:10.1017/s1466252319000276

Abstract

A systematic review and network meta-analysis were conducted to assess the relative efficacy of internal or external teat sealants given at dry-off in dairy cattle. Controlled trials were eligible if they assessed the use of internal or external teat sealants, with or without concurrent antimicrobial therapy, compared to no treatment or an alternative treatment, and measured one or more of the following outcomes: incidence of intramammary infection (IMI) at calving, IMI during the first 30 days in milk (DIM), or clinical mastitis during the first 30 DIM. Risk of bias was based on the Cochrane Risk of Bias 2.0 tool with modified signaling questions. From 2280 initially identified records, 32 trials had data extracted for one or more outcomes. Network meta-analysis was conducted for IMI at calving. Use of an internal teat sealant (bismuth subnitrate) significantly reduced the risk of new IMI at calving compared to non-treated controls (RR = 0.36, 95% CI 0.25-0.72). For comparisons between antimicrobial and teat sealant groups, concerns regarding precision were seen. Synthesis of the primary research identified important challenges related to the comparability of outcomes, replication and connection of interventions, and quality of reporting of study conduct.

Highlights

A large proportion of total antimicrobial use is for the prevention and treatment of intramammary infections (IMI), with a large portion of the total mass used aimed at controlling IMI during the dry period (Lam et al, 2012)
A network meta-analysis was conducted for trials examining the incidence of IMI at calving; no trials were identified examining the incidence of IMI in the first 30 days in milk (DIM), and too few trials examining clinical mastitis in the first 30 DIM were found to inform a treatment network
As multiple intervention options exist for cows at dry-off to prevent IMI and clinical mastitis and comparative efficacy is an important part of choosing a preventative strategy, network meta-analysis is an appropriate instrument to provide veterinarians and other decision makers with information regarding relative efficacy

Summary

Introduction

A large proportion of total antimicrobial use is for the prevention and treatment of intramammary infections (IMI), with a large portion of the total mass used aimed at controlling IMI during the dry period (Lam et al, 2012). Prepartum IMI is an important risk factor for the development of clinical mastitis in early lactation (Piepers et al, 2009). As a consequence of this mastitis risk, teat sealants can be employed to close the teat canal in a more consistent and timely manner. Teat sealants applied internally or externally to close the teat canal provide a nonantimicrobial means to prevent new IMI in the pre-calving period, which is of increasing importance due to concern over antimicrobial use and its relationship with the development of antimicrobial resistance (World Health Organisation, 2015). Understanding the efficacy of teat sealants is essential for optimizing their use in order to decrease reliance on antimicrobials for both treatment and prevention of disease

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