Wikipedia on Cattle FeedingI thought I was done, but this is a bit disturbing. Cut and copy an excerpt, but the link is below for reading in it's entirety.
Use of growth stimulants
Antibiotics are routinely added to grain feed as a growth stimulant. Livestock consume 70% of the antibiotics in the United States.[6] This practice widely contributes to the rise of antibiotic-resistant bacteria, including MRSA.[7] The most common form of antibiotics are called ionophores. Ionophores were originally developed as coccidiostats for poultry and prevent coccidiosis in cattle as well. Ionophores work by improving both feed efficiency and growth rate and lower methane production as one result. Ionophores have not been shown to create antibiotic-resistant MRSA.[8]
[edit]Use of hormones
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. Using hormones in cattle 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]
American regulators permit hormone use 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.[citation needed]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]
[edit]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]
https://en.wikipedia.org/wiki/Cattle_feeding