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Livestock production: Hormones in meat

Question: How safe is it to eat meat from animals that have been treated with hormones?

Just as H₂O (better known as water) is essential to almost all forms of life, so hormones occur naturally in varying quantities in all living organisms, including vegetables, fruit, grains and oils extracted from sources such as soy beans and sunflower seeds.

Hormones also occur in products of animal origin, such as meat, milk and eggs. It is generally accepted that hormones or hormone-related substances (phytohormones and even compounds that can disturb endocrine function) occur in various food sources and in water. They form a large part of the food hormones ingested by people every day.

In general, beef provides a relatively small quantity of the 6 important hormones in the human diet. 3 of these are produced naturally in animals’ bodies, namely testosterone, oestradiol -17 beta and progesterone. Trenbolone acetate, seranol and melengesterol acetate xenobiotic (foreign, or not natural) are combined forms.

Commercial forms of these hormones are registered as growth-stimulanting compounds in South Africa, America and many other countries in the world, excluding the European Union (EU). Most of these substances are only available as subcutaneous implants in the ear which slowly release a small concentration of the hormone to the animal.

In South Africa, antibiotics are no longer used as growth stimulants, but non-steroidal repartitioning agents mixed into the feed are very popular. It is important to note that it does not make economic sense for a producer to overdose any hormone, because there are no advantages with regard to growth and effectiveness.


The safety of meat from hormone-treated animals is determined by the acceptable daily intake and maximum residual limit in the tissues. The results of various studies show that there are extremely low concentrations of these substances in the meat of hormone-treated animals.

There is scientific proof that 250 g steak from a steer treated with oestradiol -17 beta contained approximately 5 ng of the hormone. By contrast, 250 g steak from an ox not treated with hormones, contained about 2.5 ng of the hormone. Another revealing finding was that the hormone content of 1 beer (340 ml) is equal to approximately 10 steaks, each about the same weight.

The EU’s ban on the use of hormone implants in cattle production as a “safety principle”, in spite of the results of a number of similar scientific studies, is reason for great concern. This ban has unfavourably affected the opinion of the quality of meat produced outside the EU.

This has prompted several local producers and chain stores to market “hormone-free” meat, even if the meat is patently not hormone-free and the differences in hormone content are insignificant compared to those of the hormone-treated animals.

The most important point is, however, that the hormone levels, even of hormone-treated cattle, are only about 1% of the natural hormone levels in prepubescent male or female animals, which indicates how exceptionally low the levels are in reality.

As a result, the Codex Alimentarius Commission determined that meat from hormone-treated cattle (in accordance with good agricultural practice) is absolutely safe for human consumption. The hormone content of eggs, milk and certain oils – such as soy oil – is significantly higher than that of beef.

South African beef, produced according to acceptable procedures, is still 1 of the best, and safest, available sources of good-quality protein.


  • This article was written by Prof. E. C. Webb and first appeared in Afgriland, (2006) 50 (3), 26. It also appears in Ask the vet: What cattle farmers should know (1), compiled by Dr. Faffa Malan.

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