Dairy products made from milk that is free of recombinant bovine growth hormone are perceived to be safer to consumers, are more humane to cows used for milk production and are more environmentally friendly, according to animal-rights and environmental advocates. rBGH is a man-made analog of the naturally occurring bovine growth hormone. It is marketed to dairy farmers who inject it into their dairy cows to boost their milk production.
The foremost concern of food safety advocates is that milk produced from rBGH-treated cows pose an increased risk of cancer to consumers. This is because rBGH increases the level of another hormone in cows called insulin-like growth factor, which has been implicated in promoting the growth of tumors of the breast, prostate and lower digestive tract. The extra insulin-like growth factor finds its way into the milk, raising concerns on the safety and long-term effects of consuming milk and dairy products produced with rBGH.
Cows treated with rBGH are also prone to a condition called mastitis, which is characterized by inflamed udders infected with bacteria. There is concern that the pus from infected udders contaminates the milk. Cows on rBGH are also prone to indigestion, bloating and diarrhea, raising concerns among animal rights activists that the use of rBGH is tantamount to animal cruelty. Because of diseases, the dairy cows are treated prophylactically with antibiotics, raising concerns of antibiotic residues in milk and the development of antibiotic-resistant strains of pathogenic bacteria in the environment.
rBGH is not approved in Canada and the European Union. In the United States, its use by dairy farmers has steadily declined since its approval in 1993 as more consumers demand rBGH-free dairy products and strict labeling of products produced with rBGH, as of 2015. In light of this, many food companies label their products rBGH-free as a marketing tool.