Cows and Hormones
Are artificial growth hormones to increase cows' milk production allowed in Canada? No. Growth hormones, such as recombinant bovine somatotropin (rbST), have not been approved for sale in Canada.
Bovine somatotropin (bST) is a hormone that occurs naturally in bovines; it regulates growth and lactation. BST has no effect on humans.1 Recombinant bST (rbST) is a commercially produced version of the natural hormone and it can increase milk production by 10% to 15%.2 But it may also increase the risk of mastitis and infertility and cause lameness in cows,3 which is why Health Canada has not approved it.4 It is important to note that rbST has not been shown to have a negative effect on human health4 and its use is permitted in other countries (such as the United States), where it is considered safe.
- Report of the Canadian Veterinary Medical Association Expert Panel on rBST. Executive Summary. Can Vet J, 1999. 40(3): p. 160-2.
- Dohoo IR et al. A meta-analysis review of the effects of recombinant bovine somatotropin. Part 1. Methodology and effects on production. Can J Vet Res, 2003. 67(4): p. 241-51.
- Dohoo IR et al. A meta-analysis review of the effects of recombinant bovine somatotropin. Part 2. Effects on animal health, reproductive performance, and culling. Can J Vet Res, 2003. 67(4): p. 252-64.
- Report of the Royal College of Physicians and Surgeons of Canada Expert Panel on Human safety of rbST, 1999, available on Health Canada’s web site: www.hc-sc.gc.ca/dhp-mps/vet/issues-enjeux/rbst-stbr/rep_rcpsc-rap_crmcc-eng.php (Accessed on May 1st, 2012)
Keywords: bovine growth hormone