They are widely used with approximately 40% of Australia’s cattle herd receiving an implant during some part of their lives (Hunter R., 2009).
There is no food safety concern with eating HGP treated cattle. In fact the FEDESA - European Federation of Health study found there are more hormones in 100g of cabbage than in 100g of treated beef (1).
Cattle in feedlots are generally implanted with a pellet containing Oestradiol Benzoate and Progesterone for males, Testosterone Propionate for females, or Trenbolone Acetate (TBA) for the use in both sexes.
Alternatively, silicone based core coated by Oestradiol-17ß HGPs are used for grass fed cattle. These are designed to release the active hormone gradually and extend the time in which the active constituents are released into the bloodstream. This is generally between 60 and 120 days, although, can be up to 400 days.
The silicon rubber hormone delivery method is slower in comparison to the compressed tablet. However, the amount of Oestradiol released is higher in the compressed tablet delivery method.
Benefits of using HGPs in Australia (Hunter R. , 2010)
- In 2010 4-5% of nations beef production attributed to HGPs
- $210 million added benefits to the industry
- $130 million associated to pasture fed cattle
- $80 million attributed to the feedlot sector
- National herd size increase by approximately 29.75 million head (HGP-free beef) to produce the same amount of beef tonnage
HGP’s are used to increase production by improving feed conversion efficiencies in beef cattle.
They are more widely used in northern extensive beef herds to even out variation in nutrition between seasons and feedlots than southern pasture raised cattle.
Studies have shown that combination HGPs can increase feed efficiency by 15% and liveweight gain by 46% compared with unimplanted animals (McCrabb, et. al, 1997). As well as showing that Oestrogen only implants can increase average daily gain by 0.15kg/d liveweight and feed intake by 0.40kg/d liveweight improving feed conversion efficiency by -0.48kg feed/kg liveweight gain (2).
Detriments of Using HGPs in Australia (Davies, 2008)
- In 2007, 551,831 HGP treated animals were presented for MSA grading
- Average additional cost of $10.30/head to industry
- Added $5.7 million cost to the industry
- Cost to producers is $1.5 million
- Cost to processor is $4.2 million
Impact On Meat Quality
Studies have shown that HGPs impact meat eating quality. For example, the striploin and to a lesser extent the outside flat muscles from both steers and heifers with a HGP implant have lower sensory scores and greater shear force values, therefore are less tender, than meat from a control group (Watson, 2008).
The greatest factor involved with reduced meat tenderness as a result of HGP use in beef cattle is the decreased rate of post-mortem proteolysis through the alteration of the Calpain/Calpastatin system in the muscle.
Calpastatin inhibits the μ-calpain Enzyme which during the aging period breaks down muscle fibers, thus making the meat more tender (Dransfield, 1994). With less μ-Calpain activity, there is reduced protein degradation which results in lower aging rates and less tender meat post-slaughter (Spooncer, 2015).
HGP implanted cattle are graded lower for MSA due to the effect of alteration of the Calpain/Calpastatin system.
The European Union (EU) banned the use of HGPs in 1988 after teenage girls in an Italian town experienced an increase in breast size at a younger age then normal.
The hormone used was immediately banned in Europe and Australia. The ban remains regardless and many emerging markets in Asia for example China and Vietnam, who have adopted the EUs position on HGPs.
While there is no doubt HGPs are very safe and significantly increase the efficiency of producing beef, the tension between consumer demands and production efficiency is yet to be resolved.
Elizabeth McClymont was the 2016 Winner of the Gus McGown Memorial Bursary.
1 Ref: http://safemeat.com.au/FAQRetrieve.aspx?ID=44591 RL Preston (1997) Rational for the Safety of Implants.
2 Duckett, et al., 1996