Implants deliver small increases in the levels of certain hormones above the threshold required for growth.
Once the payout period of the implant ends, the level of available hormone drops below the threshold and
growth promotion stops. Oestrogenic compounds (e.g. oestradiol) stimulate the pituitary gland to release more
of the body's own natural growth hormones, increasing satellite cell proliferation, amino acid uptake and protein
deposition.1 By comparison, androgenic compounds (e.g. trenbolone acetate and testosterone) act directly on
muscle tissue, stimulating protein/muscle synthesis and reducing muscle breakdown.1
It is generally accepted that oestrogen-only implants are best used during the growing phases of production.
Conversely, implants containing trenbolone acetate are best used as a 'terminal' implant in finishing situations
when adequate nutrition, such as quality pastures, forage crops, supplementary feed, or complete rations, is
available.
What about Compudose?
Compudose 400, 200 and 100 contain oestradiol 17ß, a naturally occurring oestrogen. Each formulation
consists of an inert silicone rubber core covered with a coating of oestradiol-medicated silicone rubber. The
durable core helps in preventing crushing or breaking during implantation, ensuring consistent pay out and
long-term performance. The active ingredient is slowly released into the bloodstream to provide a daily dose
above the threshold for growth promotion over 400, 200 or 100 days, respectively.
But are hormones safe?
Hormones are naturally occurring and are found in all mammals, including humans, that help to regulate certain
physiological processes such as growth, metabolism and reproduction. All meat and many other food sources
contain hormones, including dairy products, eggs, potatoes, cabbage and soybeans.2,3,4 put simply, there is no
such thing as 'hormone-free' meat.
Humans are exposed to hormones throughout their life from synthesis in their own bodies, various medications
and many common foodstuffs. For example, a non-pregnant woman produces daily about 54,000 times the
amount of oestrogen found in a 500 gram steak from an implanted steer.5 Likewise, an adult man produces
daily about 13,500 times the amount of oestrogen found in a 500 gram steak from an implanted steer.5
The use of implants poses no risk to human safety when used in accordance with the label directions. The U.S.
Food & Drug Administration has determined that an incremental increase of hormones in beef muscle tissue of
less than 1% of the lowest daily human production rate is deemed to be safe for human consumption.6 The
levels of hormones supplied by all registered implants are well within these limits. This high margin of safety is
reflected by the nil meat withholding period for all registered implants.
In 2003, the APVMA commissioned the Chemical Review and International Harmonisation Section Office of
Chemical Safety, Therapeutic Goods Administration to review the use of Hormone Growth Promotants (HGPs)
in cattle.7 This report concluded there was unlikely to be any appreciable health risk to consumers from eating
meat from cattle that have been treated with HGPs according to good veterinary practice.7
These facts are worth remembering the next time you see supermarket or restaurant beef promoted as
having 'no added hormones'.
