The use of growth hormones is highly controversial. The benefits of using growth hormones includes improved feed efficiency, carcase quality, and rate of muscle development. It is argued that with the use of growth hormones, more plentiful quality meats can be sold for affordable prices. Growth hormones are often not well looked upon due to the use of synthetic hormones and also fears about the consumption of these hormones from the meat products. Due to the fact that synthetic hormones are unnatural, there are concerns about how it could affect the bodily functions of consumers. The long term effects of the consumption of synthetic hormones have not been thoroughly examined.

American regulators permit hormone implants on the grounds that no risk to human health has been proven, even though measurable hormone residues do turn up in the meat we eat. These contribute to the buildup of estrogenic compounds in the environment, which some scientists believe may explain falling sperm counts and premature maturation in girls. Recent studies have also found elevated levels of synthetic growth hormones in feedlot wastes; these persistent chemicals eventually wind up in the waterways downstream of feedlots, where scientists have found fish exhibiting abnormal sex characteristics.^[9]

The F.D.A. is opening an inquiry into the problem, but for now, implanting hormones in beef cattle is legal and financially irresistible: an implant costs $1.50 and adds between 40 and 50 pounds to the weight of a steer at slaughter, for a return of at least $25.^[9]

Safety Level of Hormone Use in Cattle

In Canada, all veterinary drugs used in food production processes are required to pass stringent tests and regulations set by the Veterinary Drugs Directorate (VDD) and are enforced by the Food and Drug Act of Health Canada. The CFIA monitors all food products in Canada by sampling and testing by veterinarians and inspectors working on behalf of the provincial and federal governments. They monitor the food supply to condemn and destroy any product that is unacceptable. In the rare case where the CFIA have found a residue, it has been substantially below the Maximum Residue Limit (MRL) to make acceptable for safe consumption. The MRL is the maximum amount of a drug residue that may remain in a food product at the time of human consumption. MRLs are safety measures based on Accepted Daily Intakes (ADIs).^[10] The ADI level is determined from toxicology studies to be the highest amount of a substance that can be consumed daily throughout a lifespan without causing adverse effects.^[11] Beef hormone residues are MRLs that have been established by the Joint Expert Committee on Food Additives of the United Nations.^[10] Although there is growing concern that hormone residues in meat and milk might be harmful to human and animal health, the quantities of hormones found in a serving of meat are far below the level considered to be a risk to the development of cancer. Besides, the World Health Organization stated that the hormone levels are indistinguishable between the implanted and nonimplanted animals.^[11]

There are three natural hormones (estradiol or estrogen, progesterone, and testosterone) and their synthetic alternatives (zeranol, melengestrol acetate, and trenbolone acetate) have been approved by the VDD for use in Canadian beef production.^[10]

Estrogen, progesterone, and testosterone are naturally present in beef cattle regardless of whether or not they have been treated with hormones. Despite the fact these hormones are also present in human, the contribution of estrogen, progesterone and testosterone from beef is minuscule compared to the quantities produced naturally in the body. By comparison, an adult male will produce 136,000 ng of estrogen on a given day; whereas the estrogen levels present in a 6-ounce serving of beef from a treated animal is only approximately 3.8 ng.^[10] In another word, a human being will produce almost 36,000 times the amount of estrogen in one day that would be present in a piece of beef produced with the growth hormones treated.^[10] Thus, the quantities of hormones found in a serving of meat are far below the level considered to be a risk to the development of cancer. Current scientific evidence does not support that pubescent maturation is caused by the hormonal substance use in animals.^[11]

Artificial Hormone Use in Cattle

Bovine somatotropin or bovine growth hormone is a naturally produced protein in cattle. Recombinant bovine somatotropin (rBST) or recombinant bovine growth hormone (rBGH) is an artificial growth hormone produced using recombinant DNA technology (biotechnology). When injected into cows, rBGH increases milk production 10-15 percent and even up to 40 percent in some cases. It is approved in the United States since 1993; however, its use has been controversial since farmers have started using it. Recent studies have shown that rBGH use in animal production cause problems including an alarming rise in the number of deformed calves and dramatic increases in mastitis, a painful bacterial infection of the udder which causes inflammation, swelling, and pus and blood secretions into milk.^[12] Studies have also shown that the presence of rBGH in the cow's blood stimulates production of Insulin-Like Growth Factor-1 (IGF-1) in the cow, however, neither IGF-1 or rBST concentrations in milk are increased by rBST treatment.^[13] An increase level of IGF-1 in human has been linked to colon and breast cancer. The European Union, Japan, Australia and Canada have all outlawed the use of rBST in animal production due to the animal and human health concerns