7.04 - Hormonal growth promotants
Hormonal growth promotants (HGPs) are supplements of the hormones that naturally occur in all animals.
HGPs are contained in silicone or compressed powder and implanted under the skin on the back of the animals ear, releasing a low dose of hormone to the animal over the life of the implant. They are used to improve growth rates and feed efficiency.
HGPs cause no harm to the animal being implanted and research has shown meat treated with HGPs is safe for human consumption.
HGPs have been used in Australia since 1979 and are used in most major beef producing countries around the world including the United States.
The use of HGPs is strictly regulated and all HGP products must go through a rigorous accreditation process which is administered by the Australian Pesticides and Veterinary Medicines Authority (APVMA).
Research trials have shown that animals treated with an HGP have increased weight gain of 10–30% over untreated animals depending on the HGP used and the quality of feed available to the animal. Although feed intake also increases, treated animals gain weight more efficiently. Being able to produce more beef from less feed means that producers can increase productivity and minimise environmental impacts.
HGPs are available to all beef producers at many rural retail outlets. Producers who use them must identify treated animals with an ear mark and maintain purchase and use records in the event of a producer audit.
It is important to have an accurate record system that traces all HGP use. Losses and damaged HGP implants must be recorded. Grazing cattle treated with a trenbolone acetate (TBA) or androgen compound implant should receive minimal handling for two months after treatment. These compounds are known as ‘aggressive’ implants.
Current over the hooks selling pays on a carcase weight/P8 fatness grid. Subsequent adjustments are for pH or meat colour. Of these, HGPs impact on fatness and tenderness. It is now known that HGP application has a negative effect on meat eating quality. However, few meat markets adjust prices for specific meat quality attributes.
The MSA grading model now includes an HGP treatment effect. It will have the one penalty for all HGP products. Research has shown that HGPs will reduce marbling (intramuscular fat) so this impacts on the MSA score. The same research also found that the HGP effect varied across different cuts (muscles). The main grilling cuts (higher priced) show the greatest effect.
Processors can use tenderstretch hanging and/or extended ageing (eg cryovac) to offset the negative eating effects.
The European Union has banned the use of HGPs and also the import of products from treated cattle since 1998. Some other domestic markets have also banned their use (eg Coles supermarkets) and producers are cautioned to determine their market requirements for HGPs.
- The Beef CRC publication: HGPs - Good for profit, not so good for meat quality is available for download online: www.beefcrc.com.au/beefcrcfactsheets.
- The NSW Department of Primary Industries Primefacts No 790: Understanding hormonal growth promotants is available online: www.dpi.nsw.gov.au/
- The MLA Tip & Tool: The effect of growth promotants on beef eating quality can be downloaded from the MLA publications database: www.mla.com.au/publications
- The SAFEMEAT publication Cattle and HGPs, available for download from: www.safemeat.com.au