Comparative efficacy of antimicrobial treatments in dairy cows at dry-off to prevent new intramammary infections during the dry period or clinical mastitis during early lactation: a systematic review and network meta-analysis

Abstract

A systematic review and network meta-analysis were conducted to assess the relative efficacy of antimicrobial therapy given to dairy cows at dry-off. Eligible studies were controlled trials assessing the use of antimicrobials compared to no treatment or an alternative treatment, and assessed one or more of the following outcomes: incidence of intramammary infection (IMI) at calving, incidence of IMI during the first 30 days in milk (DIM), or incidence of clinical mastitis during the first 30 DIM. Databases and conference proceedings were searched for relevant articles. The potential for bias was assessed using the Cochrane Risk of Bias 2.0 algorithm. From 3480 initially identified records, 45 trials had data extracted for one or more outcomes. Network meta-analysis was conducted for IMI at calving. The use of cephalosporins, cloxacillin, or penicillin with aminoglycoside significantly reduced the risk of new IMI at calving compared to non-treated controls (cephalosporins, RR = 0.37, 95% CI 0.23–0.65; cloxacillin, RR = 0.55, 95% CI 0.38–0.79; penicillin with aminoglycoside, RR = 0.42, 95% CI 0.26–0.72). Synthesis revealed challenges with a comparability of outcomes, replication of interventions, definitions of outcomes, and quality of reporting. The use of reporting guidelines, replication among interventions, and standardization of outcome definitions would increase the utility of primary research in this area.

Relative Efficacy of Dry-Off Antimicrobial Treatments in Dairy Cattle to Cure Existing Intramammary Infections: A Systematic Review and Network Meta-Analysis

“…Risk of bias was assessed at the outcome level for the cure of existing IMI in dairy cattle at dry-off using the Cochrane Risk of Bias 2.0 instrument (Cochrane, Denmark) (Higgins et al, 2016), with the assessment questions modified as described in Winder et al (2019b). The risk of bias was assessed independently two times, with disagreement resolved by consensus and mediation by a third reviewer where needed.…”

“…An a priori plan to merge the treatment groups was not considered in the protocol; however, a great deal of heterogeneity exists in the antimicrobial compounds and dosing in the literature. A previous network meta-analysis indicated creating a unique treatment regimen for each product and dose would have led to a sparse network (Winder et al, 2019b). Therefore, a post-hoc decision was made to merge several treatments based on biological and clinical relevancy.…”

“…Pairwise meta-analyses have compared the efficacy of antimicrobials for the prevention of new IMI (Robert et al, 2006;Halasa et al, 2009b) and cure of existing IMI (Halasa et al, 2009a), examined blanket vs. selective dry cow therapy (Winder et al, 2019e), examined non-antimicrobial products for cure and prevention of IMI (Rabiee and Lean, 2013;Dufour et al, 2019), and prevention of IMI in heifers (Naqvi et al, 2018). Network meta-analyses have been used to investigate antimicrobials to prevent new IMI and CM in the early lactation period (Winder et al, 2019b), the treatment of CM in lactating cattle (Winder et al, 2019c;Nobrega et al, 2020), and the use of teat sealants to prevent IMI and CM (Winder et al, 2019d). The objective of this systematic review and network meta-analysis was to investigate the comparative efficacy of dry cow antimicrobial therapy, registered in Canada and/or the United States, to cure existing IMI in dairy cattle, which till today has not been Abbreviations: IMI, intramammary infections; CM, clinical mastitis; DIM, days in milk; SCC, somatic cell count; OR, odds ratio; RR, relative risk; JAGS, Just Another Gibbs Sampler; CINeMA, Confidence in Network Meta-Analysis.…”

Modifiable management practices to improve udder health in dairy cattle during the dry period and early lactation: A scoping review

“…However, other management strategies have been evaluated for their effects on udder health, including method of milk cessation (Dingwell et al, 2003a;Vilar and Rajala-Schultz, 2020) and bedding and housing of dry cows (Dufour et al, 2011). Systematic reviews and meta-analyses have assessed the impact of adjusting dry period length on the risk of CM (van Knegsel et al, 2013) as well as the effects of antimicrobials (Winder et al, 2019a) and teat sealants (Dufour et al, 2019;Winder et al, 2019b) given at DO to prevent IMI and Modifiable management practices to improve udder health in dairy cattle during the dry period and early lactation: A scoping review mastitis postcalving, and a meta-analysis assessing the effect of DO antimicrobials, teat sealants, and vaccines in nulliparous heifers has been published (Naqvi et al, 2018). Other aspects of dry cow management have also been evaluated for their effects on udder health in multiparous cows, including strategies for cessation of lactation, bedding materials, hygiene of the environment, standing behavior following dry cow therapy, vaccinations, fly control, and nutrition (Green et al, 2007).…”

Editorial: Systematic reviews reveal a need for more, better data to inform antimicrobial stewardship practices in animal agriculture

“…Articles in this special issue include scoping reviews of systematic reviews in animal health (Vriezen et al, 2019a) and of non-antibiotic approaches to reduce the need for antibiotic treatments in beef and veal production (Wisener et al, 2019). The systematic reviews with meta-analyses or network meta-analyses include an assessment of the efficacy of vaccines and injectable antibiotics administered on arrival to control respiratory disease in feedlot cattle (O'Connor et al, 2019a(O'Connor et al, , 2019b; the efficacy of teat sealants, antibiotics at dry off, selective dry cow treatment to reduce the incidence of mastitis and intra-mammary infection in early lactation, and the efficacy of antibiotics to treat clinical mastitis in dairy cattle (Winder et al, 2019a(Winder et al, , 2019b(Winder et al, , 2019c(Winder et al, , 2019d; the comparative efficacy of litter type for preventing illness in broiler chickens (Sargeant et al, 2019a); the efficacy of antibiotics to prevent colibacillosis in broiler chickens (Sargeant et al, 2019b); and the efficacy of bacterial vaccines and of preventive antibiotics to prevent respiratory disease in swine (Sargeant et al, 2019c(Sargeant et al, , 2019d. Finally, an evaluation of the methodological quality of systematic reviews and meta-analyses evaluating preventive antibiotics or management to reduce disease in livestock species is included (Vriezen et al, 2019b).…”