EFFECT OF VITAMIN E SUPPLEMENTATION ON UDDER HEALTH: A META- ANALSYIS

摘要

This meta-analysis quantifies the effect of vitamin E supplementation on udder health. In total 14 randomised clinical trials were available, yielding 12 records for clinical mastitis (CM), 5 for somatic cell count (SCC) and 9 for intra mammary infection (IMI). The relative risk (RR) was calculated for CM and IMI incidence and the mean difference (MD) of the natural logarithm of the SCC (InSCC) for SCC. All udder health parameters improved with vitamin E supplementation; RR for CM was 0.70 (.59 - .83), MD InSCC was -0.35 (-.68 - 0) and RR for IMI was .86 (.73 - 1.02). Publication bias resulted in fewer 'negative' studies than expected. However, control vitamin E levels were relatively high and records were analysed at cow level, all leading to an underestimation of the effect. The findings thus seemed robust. With better knowledge of vitamin E metabolism, field interventions seem indicated to improve udder health.