Growth Hormones (used in livestock)
Growth hormones are used in the US and Canada in both beef and milk cows to increase productivity. In milk cows growth hormones such as RBST are used to prolong the duration of the milk cycle, thus getting the cow to produce more milk after giving birth to a calf.
It's estimated that using the growth hormone RBST increases US milk production by 12%. In beef cows growth hormones are used to increase feed productivity and muscle mass, and to decrease fat. Growth hormones have been linked to cancer and infertility (low sperm counts) as well as the early onset of puberty in girls which has been linked to higher cancer rates.
