Recombinant bovine somatotropin

overview and results from a recent meta-analysis of effects on health and welfare of dairy cows

Abstract

Historically, the dairy industry has made remarkable gains in productivity and a gallon of milk can be produced today with less feed resource inputs and a markedly reduced carbon footprint. Recombinant bovine somatotropin is a production-enhancing technology and 20 years commercial use of POSILAC® (rbST-Zn) provided the backdrop for an updated meta-analysis of effects on cow health and welfare. Our meta-analysis used data from peer reviewed publications or regulatory reports in which the commercial formulation of rbST-Zn was used was according to label specifications. Twenty six studies were identified which had usable data (13,784 cows). Results indicated milk yield was increased by about 9 lb/d whereas milk fat, protein, and lactose content were unaltered. For health and welfare variables, treatment with rbST-Zn had little or no effect on udder health, reproduction, lameness, body condition or culling. Overall, these results and 20 years of US commercial experience demonstrate that management practices used by US dairy producers are adequate for the effective use of rbST-Zn to increase milk yield and productivity with no unmanageable adverse effects on cow health or welfare.