Types of Growth Hormones Used in Animals

The world's dependence on beef products has created a problem that could grow to cripple the beef industry. With the demand growing, cattle ranchers must produce more product. That means breeding more stock. That might not seem like a problem until you take into account that fact that those additional cattle must be fed, and the price for grain feeds goes up every year. So what does a cattleman do to reduce the cost but increase his herd? He implants hormones in his stock.

  1. History

    • The use of growth hormones in animals began in the 1950s with the introduction of DES (diethylstilbestrol) as a feed additive. The less feed a rancher had to buy, the more money they could save. Later, DES was produced as a pellet that was implanted between the cow's jaw and the ear, where it would slowly release the hormone over a maximum of 120 days. Once the 120 days had elapsed, a new pellet would be implanted. These pellets were seen as a great advancement in beef industry. Unfortunately, by the 1970s, it was discovered that continued use of DES could cause cancer in fetuses. The use of DES and growth hormone implants was quickly banned.

      Eventually, a new type of implant was developed; one that caused the animal to increase its own hormone levels. These new implants weren't given approval until they were proven to not cause birth defects, or any other detrimental effect.

    Natural Growth Hormones

    • One of the most popular growth implants are the ones that are naturally occurring in the cow. These implants naturally trigger the animal to increase its own hormone levels without any negative side effects. Since these hormones are already naturally occurring in the animal, many advocates encourage the use of natural growth hormones only.

    Exogenous Growth Hormones

    • Another growth hormone used widely is the estrogen growth hormone. These implants are not made from the naturally occurring estrogen in the animal, but rather are manufactured from mold found on corn. These implants increase the estrogen levels in cows by 25 percent which encourages faster maturity.

    Combination of Growth Hormones

    • Combination growth hormones are a mixture of naturally occurring hormones and exogenous hormones. In 1994, a new product was created when estradiol (the naturally occurring female hormone that produces estrogen) was combined with manufactured androgenic hormones which mimicked the effects of testosterone.

    Warnings

    • Growth hormones are used to speed up the physical maturity of cattle. Because these hormones stimulate the natural hormones present in the cattle, reproductive cycles can be tampered with resulting shorter ovulation cycles or missing cycles. Because of this, growth hormones are recommended for use in heifers intended for breeding stock. Also, many organic food advocates rally against the use of growth hormones in dairy cows due to the fact that the hormones transfer to the milk, and the milk is consumed in large quantities by the public.