Growth Hormone Used in Beef and Dairy Cattle - Research Assignment for Biology

Over the past 60 years many significant changes have taken place in the food production industry worldwide. Dairy and cattle farms have increased in size and have boosted production at an astounding rate to meet the demands of the growing population. Through scientific advances in genetics, changes in feed and the use of hormones, farmers have been able to speed up the natural growth process of beef cattle and increase the natural production of milk from dairy cows. This process has raised many eyebrows over the decades and is still quite a controversial issue of ethics today. 

In the 1950’s the average dairy cow could produce about 665 gallons of milk per year, however with new technology and the use of hormones, today the average cow can produce about 2,320 gallons, almost three and a half times more annually. The beef industry has seen the same types of changes since the fifties. A cow, raised naturally and grass fed takes about 23 to 25 months to mature to an appropriate age for slaughter depending on breed. With the implementation of new corn-based feeds and growth hormones, cows grow and gain weight faster, reducing their maturing period down to an astonishing 13-15 months, at least 10 months less than nature intended. Cows are natural herbivores, meant to eat grass and plants. However in the 1970‘s large feed lots discovered they could shorten the growth period and reduce feeding costs by feeding cows corn. The implementation of new feed and hormones together reduced the natural development and production to what we today see as ‘normal’.

Hormones are chemicals that are naturally produced in an animals’ (and humans’) body that control important body functions such as growth, development and reproduction. While hormones are already present in the living organism, additional hormones are sometimes given to speed up these natural body functions. Hormones can be separated into two categories, steroid hormones and protein hormones. In general steroid hormones can be taken orally, an example being birth control medication for women, while protein hormones have a tendency to break down in the stomach losing their ability to act within the body, thus they are usually administered via injection to have full effect. Both types of hormones can be further categorized as natural or synthetic. In Canada there are six hormonal growth promoters that have been approved for use in the beef and dairy industries. Progesterone, testosterone and the female sex hormone estradiol-17β are the naturally occurring hormones administered to cattle to promote rapid growth and increase milk production, while synthetic trenbolone acetate or TBA, zeranol, and the progestin melengestrol acetate or MGA are also used. Another growth promoter rBST or recombinant bovine somatotropin is widely used in the United States, approved solely for use in beef cattle, but has been banned in Canada, Japan, Australia, New Zealand, Israel, and all 27 countries in the European Union. In Canada it is illegal to administer synthetic growth hormones to dairy cows, while in the United States, these restrictions do not exist. 

The hormone MGA is a steroidal progestin that, while not approved for use in humans, is used as a feed additive for cattle to promote rapid weight gain and growth. Protein growth promoters, on the other hand are usually administered via subcutaneous implants, usually behind the cows’ ear in a small pellet form. The ear was chosen as the best injection site for cattle as the ears are always discarded after slaughter and there had been concerns that injection to other cutaneous sites could show higher concentrations of the growth hormones in the edible meat products. There are often incidences of irritation or infection at the injection sites causing discomfort to the cows. The determining factor the countries against the use of rBST was the ethical issues related to its use. It was found that cows given the rBST had extremely high chances of developing clinical mastitis, whereby painful inflammation of sensitive udder tissue occurs. The chronic inflammation is sometimes accompanied by even more painful mammary gland infections. Clinical mastitis in dairy cows can also lead to bacterial infections like staphylococcus aureus. When this type of infection occurs, somatic cell counts increase to try and fight the infection. These excess somatic cells then enter the milk humans drink. Hormones are used to keep dairy cows in a constant state of milk production. This can also lead to Bovine Leukemia Virus, Bovine Immunodeficiency Virus, and Johne's disease, similar to the human Crohn's disease and they often go unnoticed because they are difficult to detect and have long incubation periods. 

With the use of hormones, cows grow and gain weight at a rate that is quite hard on their body structures. It is not uncommon for cattle to have weak, brittle bones that break easily, and low tolerance immune systems.  

While the FDA and World Health Organization have explicitly denied there is any evidence that the use of these hormones can affect human dairy and beef consumers, there is also no evidence disproving the concerns. Many large animal rights’ activist groups and consumer groups such as the Organic Consumers’ Associations of Canada and United States all feel that the use of hormones is not only an issue of ethics where the animals are involved, but issues of concern exist widely for the consumers. It is hard to believe that consuming meat or dairy products pumped with extra hormones and growth promoters could have no effect on human consumers. In the late 1970‘s, a study conducted in northern Italy looked at specific rates of young boys and girls who consumed meat and dairy products that had been treated with illegal growth promoters. The study showed that a high percentage of both boys and girls were reaching puberty, and both were developing breasts at a much earlier age than normal, age 7-10. The ‘Beef Hormone Dispute’ eventually led to the ban of imported meat treated with hormones across the European Union in the 1990’s during the mad cow disease crisis. Still to this day, the FDA  maintains that since the bovine growth hormone is not active in humans, there is no connection between the early onset of puberty in humans and the use of growth promoters, though no effort has been made by the FDA to collect any data or evidence to confirm their claim.

It seems that the decision to support or refuse the use of hormones has been left to the consumer. Today, more and more consumers are opting to purchase their meat and dairy products from shops whose suppliers avoid the use of growth promoters. More consumers are also considering the negative impact on the animals’ health and the ethical treatment of animals. Movies and books such as ‘Food Inc.” and “Forks over Knives” exposing the use of hormone growth promoters have become popular in the past decade. These movies, while not explicit evidence according to health organizations, lend to the feeling of conspiracy over the issue, driving more people to support their local hormone-free butcher shops, farmers and dairy producers instead of the larger corporations that monopolize the beef and dairy industries. The questions that most educated consumers are left with are sincere enough to deserve proper investigations and consumers as a whole must demand in the future that proper data be available to prove or refute the issues at hand.