THE USE OF  STEROID HORMONES FOR  GROWTH IN FOOD PRODUCING ANIMAL

Compiled & Edited by-DR. RAJESH KUMAR SINGH, (LIVESTOCK & POULTRY CONSULTANT), JAMSHEDPUR, JHARKHAND,INDIA
9431309542, rajeshsinghvet@gmail.com

 

Since the 1950s, the Food and Drug Administration (FDA) has approved a number of steroid hormone drugs for use in beef cattle and sheep, including natural estrogen, progesterone, testosterone, and their synthetic versions. These drugs increase the animals’ growth rate and the efficiency by which they convert the feed they eat into meat.

These steroid hormone drugs are typically formulated as pellets or “implants” that are placed under the skin on the back side of the animal’s ear. The implants dissolve slowly under the skin and do not require removal. The ears of the treated animals are discarded at slaughter and are not used for human food. Using scientific data, FDA establishes the acceptable safe limits for hormones in meat. A safe level for human consumption is a level of drug in the meat that would be expected to have no harmful effect in humans based on extensive scientific study and review.

All approved steroid implant products have a zero day withdrawal. This means that the meat from the animal is safe for humans to eat at any time after the animal is treated.

No steroid hormone implants are approved for growth purposes in dairy cows, veal calves, pigs, or poultry.

Hormone-dependent sex differences in growth rate have been known for a long time. It has also been known that growth rate and FCE (feed conversion efficiency) are higher in intact males than in castrates. It was natural, then, that the availability of hormones and other natural or synthetic substances displaying hormonal activity led to experiments aiming at their use to increase production. Beginning in the mid-1950s, DES (diethylstilboestrol) and hexoestrol were administered to cattle increasingly in the US and the UK respectively, either as feed additives or as implants, and other types of substances also gradually became available. In general, such treatment has resulted in 10–15% increases in daily gains, similar improvements in FCE and improvement of carcass quality (increased lean/fat ratio). Thus there has been a substantial reduction in the amount of energy required per unit weight of protein produced , and the economic implications of this have been great.

While the use of hormonally active substances in animal production rose, opposition to their use also increased, because of the theoretical possibility that residues in edible tissues might endanger consumers.. Several reports confirm that DES endangers the health of animals and man, when repeatedly used in large doses . However, as regards risks due to the presence of residues in meat produced according to regulations, no documented deleterious effects have ever been reported in man, either from DES or any other substance with hormonal activity.

A distinction should be made between the hormones as such, for which the metabolism in the body is relatively well known, and synthetic or other substances for whose metabolic inactivation the body may not possess the enzymes necessary. When natural hormones are used in animal production, claims of zero-tolerance residue levels are not meaningful, since these compounds occur in detectable and highly variable concentrations in body fluids as well as in the tissues of all animals, treated or not . For other substances with hormonal activity the situation is different. However, when residue levels are extremely low, it seems reasonable to weigh the potential risks against the undisputed positive effects some of these compounds have in animal protein production.

2. HORMONE PREPARATIONS USED IN ANIMAL PRODUCTION

2.1 Hormones of endogenous origin

These comprise the “classical” steroid sex hormones, oestradiol-17β, testosterone and progesterone. The two former are used either in the free form or as esters, mainly those of propionic or benzoic acid. Esterification generally causes prolongation of the half-life of the compounds in the body by 40 to 50%. The natural hormones having low bioavailability when administered orally, owing to rapid conjugation and metabolic transformation in the liver, they are therefore administered by subcutaneous implantation.

2.2 Hormones of exogenous origin

Of the oestrogens, the stilbene derivatives diethylstilboestrol (DES) and hexoestrol possess high biological activity and have been used most widely. They are active orally as well as by implantation. Other orally active oestrogens include ethynyl-oestradiol, a more slowly metabolized derivative of the true hormone, with higher activity. An oestrogen with an entirely different structure is zeranol, a derivative of a resorcylic acid lactone occurring in the fungus Giberella zeae.

The synthetic androgens comprise a large number of substances, most of which are steroids. Of these, trenbolone acetate (TBA) possesses strong anabolic properties and has received much attention during recent years, used alone or in combination with an oestrogen. Another anabolic steroid is methyl-testosterone.

Of synthetic gestagens, only one will be mentioned here: melengestrol acetate, which stimulates growth in heifers but not in steers, and which can also be used for the suppression of oestrus. Numerous other gestagens also exist, but at present few other than progesterone and melengestrol acetate are used to stimulate growth.

In addition to these substances, numerous others exist, and some of them are used more or less frequently in clinical veterinary medicine. However, clinical applications of hormones are not considered to be of consequence to the consumer, since such treatment is much less frequent than the use of hormones to promote growth.

Hormone preparations in current use as growth stimulants are listed in Table 1, which also shows modes of application, dosages, etc. It will be noted that almost all preparations currently in use are based on implantation, the site usually being the base of the ear, or less frequently, the dewlap.

3. RANGE OF APPLICATION

In cattle the use of hormones is limited to veal calves and beef cattle.  Research has demonstrated that hormone treatment improves growth rate, nitrogen retention and FCE during the five- to six-week period before slaughter . Beef cattle, including steers as well as heifers, were treated in large numbers, especially in the USA and the UK, with DES or hexoestrol, administered orally, until the use of these compounds was restricted. During the last several years, practice has changed dramatically in the direction of increased use of implants of natural steroids, synthetic anabolic steroids and the phyto-oestrogen zeranol.

Table 1. Hormonally-active substances used in animal production

Substances	Dose levels	Form	Main use – Animals	Trade name
Oestrogens alone:
DES	10–20 mg/day	feed additive	steers, heifers
DES	30–60 mg/day	implant	steers
DES		oil solution	veal calves
Hexoestrol	12–60 mg	implant	steers, sheep, calves, poultry
Zeranol	12–36 mg	implant	steers, sheep	Ralgro
Gestagens alone:
Melengestrol acetate	0.25–0.50 mg/day	heifers
Androgens alone:
TBA	300 mg	implant	heifers, culled cows	Finaplix
Combined preparations:
DES + Testosterone	25 mg 120 mg	implant	calves	Rapigain
DES + Methyl-testosterone		feed additive	swine	Maxymin
Hexoestrol + TBA	30–45 mg 300 mg	implant	steers
Zeranol + TBA	36 mg 300 mg	implant	steers
Oestradiol-17β + TBA	20 mg 140 mg	implant	bulls, steers calves, sheep	Revalor
Oestradiol-17β benzoate + Testosterone propionate	20 mg 200 mg	implant	heifers, calves	(Synovex H (Implix BF
Oestradiol-17β benzoate + Progesterone	20 mg 200 mg	implant	steers	(Synovex S (Implix BM

In sheep, especially in wether lambs, some increase in gain has been reported , but results are somewhat ambiguous.

In swine, hormone treatment may increase growth rate, FCE and lean/fat ratio of the carcass in male castrates.

Poultry generally do not appear to respond to oestrogens by increased gain but by changes in lipid deposition. In male and female turkeys, androgens have recently been reported to increase growth rate as well as FCE .

4. MODES OF APPLICATION

When DES was used as a feed additive, a usual procedure was to start treatment of steers at a body weight of 360 kg and continue administration for 120 to 170 days. Since restrictions on its use were imposed, most preparations have been administered as implants, whose effect is usually limited to 80 to 100 days. Practice varies with management systems. Animals may be implanted at live weights from 270 to 450 kg. Depending upon the age and weight at the time of implantation, the animals are either slaughtered at the end of this first period, or fed for an additional period, either without further treatment or after a second implant to act for another 80 to 100 days. Most types of implants in use are not removable, but removable types have recently been tested and their effects described . When tested in steers, no reduction in performance was recorded when the implants were withdrawn 32 and 39 days before slaughter.

Implantation is subcutaneous, usually at the base of the ear, thus eliminating the risk that residues of the implantation site will be present in edible tissue.

5. EFFECTS OF HORMONES

5.1 Veal calves

In veal calves, hormone treatment may begin at a body weight of about 65 kg, the animals being slaughtered at about 170 kg. Implants of 20 mg oestradiol-17β + 200 mg progesterone in males and 20 mg oestradiol-17β + 200 mg testosterone in females resulted in a 20% increase in daily gain and 21% higher nitrogen retention in the period studied . In other studies, improvements of 10 to 12% in gain and 10% in FCE have been reported The effective preparations were DES, oestradiol-17β, and the combination of TBA + oestradiol-17β .

 

5.2 Steers

Oestrogen implants have included DES, hexoestrol, oestradiol-17β and zeranol. DES implants have, as in previous studies, resulted in an increase of about 12% in gain and in improvement in FCE of the order of 10% . Hexoestrol implants, usually in doses of 30 to 60 mg, have been shown in numerous experiments to lead to considerable improvement in growth rate and FCE .TBA implants administered alone at a dose of 300 mg have also had positive effects on growth .

The evidence for highly significant positive effects on the growth rate and FCE of steers is thus beyond dispute, the most marked effects being provoked by implants combining an oestrogen with an androgen of high anabolic activity.

5.3 Bulls

Since the entire male animal produces its own anabolic androgen, testosterone, an effect of additional hormones similar to that for steers is not to be expected. The number of trials with bulls is also limited. Positive effects on gain have been reported using DES alone and combined oestrogen/TBA implants ; in other studies, no effect on gain has been recorded , while a certain increase in the deposition of fat in the carcass has been observed .

5.4 Heifers

Recent trials with beef-producing heifers have mostly been based on the use of an androgen, although oestrogens have been tested, alone or in combination. Thus, zeranol has been reported to increase gain , while in other trials no response has been observed . TBA administered alone (300 mg) has led to increases in weight gain and FCE of the order of 36% and 25% respectively. In general, it appears that the effect of TBA alone in heifers corresponds closely to the effect of combined oestrogen/TBA implants in steers.

5.5 Sheep

Trials have mainly concerned wether lambs, and positive effects of hormonal treatment have been reported using DES , hexoestrol  and zeranol , although other reports have indicated that zeranol yields no significant effects . Wether lambs implanted with TBA + oestradiol-17β have shown increases in gain, carcass weight and FCE . In general, however, the results obtained in sheep thus far do not warrant the same clear-cut conclusions as for steers and heifers.

5.6 Swine and poultry

There is little evidence that existing hormonal preparations influence the growth rate and FCE to an extent that would be interesting from a practical point of view. The lean/fat ratio in male castrate and female pig carcasses may be increased by the use of oestrogen/androgen combinations . In poultry, redistribution of fat in the body is a known effect of oestrogens. Recent research indicates improved growth rate and FCE using androgens in young male and female turkeys .

5.7 Undesirable side effects in treated animals

Reported side effects of hormone treatment for growth stimulation are few and generally concern the use of oestrogens in steers. The steer-buller syndrome is a special problem in feedlots.

6. MECHANISM OF ACTION OF HORMONES

No reliable explanation of how the growth-promoting hormones act has yet been furnished. Some observations indicate an indirect influence through changes in the balance of endogenous hormones. Thus there have been reports of DES and TBA increasing the levels of growth hormone and/or of insulin in plasma ; these hormones are known to stimulate amino acid transport across the cell membrane.

As regards the anabolic androgens, evidence exists indicating competition with glucocorticoids for receptor sites on the muscle cell membrane. Since glucocorticoids have a catabolic effect on tissues, their displacement from muscle cells would reduce catabolism. TBA alone, and even more when combined with oestradiol-17β, causes a marked decrease in the concentration of total thyroxin in plasma of steers .

7. LEVELS OF ENDOGENOUS HORMONES IN BODY FLUIDS AND TISSUES

Any discussion of possible health hazards connected with the use of hormones in animal production must take into account the normal occurrence of hormones and their metabolites in body fluids and tissues, and the fact that the levels of these hormones vary greatly, according to the physiological state of the animal. Thus, oestrogen levels in the blood of female farm animals may vary from a few pg up to 5–6 000 pg per ml plasma . As to males, the plasma of stallions and entire male pigs contains high levels of oestrogens, although mainly in the conjugated form. Milk also contains oestrogens in very high concentrations in the first drawings after parturition; in non-pregnant animals, levels in the range of 80–100 pg/ml have been reported .

8. METABOLISM, ROUTES AND RATES OF ELIMINATION

The general patterns of metabolism and elimination of endogenous hormones in farm animals have been outlined . In ruminants, testosterone and oestradiol-17β are rapidly converted to their epimers, biologically much less active, epitestosterone and oestradiol-17α. Progesterone is partially converted to androgens before excretion. In the pig, epimerization of testosterone and oestradiol-17β does not appear to take place to a significant degree. The faecal route of elimination dominates in ruminants, while in the pig urinary excretion is more important.

8.1 Progesterone

After repeated injections of progesterone to cows and steers over 2 to 3 weeks followed by ¹⁴C-progesterone for 2 to 5 days, the animals were slaughtered 2 to 3 hours after the last injections. Activity levels were 2 to 7 times higher in the fat, 3 times higher in the kidneys, and 13 times higher in the liver than in the muscle. Excretion of radioactivity amounted to 50% and 12% in faeces and 2.0% and 1.2% in urine in cows and steers respectively. About 50% of the activity in muscle and milk was associated with unchanged progesterone, most of the remaining activity being associated with a mono-hydroxy compound. Cooking or frozen storage did not affect the nature or quantity of metabolites .

8.2 Oestradiol-17β

Following daily injections of 1 mg oestradiol-17β or its benzoate to heifers and steers for 11 days, followed by the ¹⁴C-compounds on days 12, 13 and 14, the animals were slaughtered 3 hours after the last injections, when residual levels were maximal. In muscle extracts, oestradiol-17β represented the major fraction of extracted activity (38 to 71%), followed by oestrone (17 to 45%). Levels in muscle were 161 to 225 pg/g and 40 to 86 pg/g for oestradiol-17β and oestrone respectively. In fat the levels were 3 to 5 times higher. The authors conclude that residual levels are extremely low when these hormones are administered as growth stimulants to growing/finishing cattle . Glucosides of the 17β- and the 17α- epimers, and the glucoronide of the 17α- epimer are the major metabolites in cattle . When oestradiol-17β was administered orally to swine, plasma concentrations were very high 7 min after administration. Oestradiol was completely conjugated during absorption and its first passage through the liver. Some conversion to oestrone took place .

8.3 DES

The metabolism of DES in food-producing animals has been reviewed recently . The substance seems to be eliminated to a large extent in unaltered form. After oral administration of ¹⁴C-DES to beef cattle, 99.5% of the radioactivity was excreted within 5 days after withdrawal. In liver extracts, radioactivity associated with DES-conjugate and free DES was found to be 75% and 25% respectively. Higher than background levels of activity were observed after withdrawal in kidney, liver, bile and urine/faeces for up to 5, 7, 9 and 11 to 12 days respectively .

8.4 Zeranol

Using a gas chromatographic method with a sensitivity limit of 20 ppb, no residues of zeranol could be detected in edible tissue from cattle slaughtered 65 days following implantation of 36 mg, or from lambs 40 days following implantation of 12 mg (101). In another study, tritiated zeranol was implanted in cattle as part of 36-mg doses. Skeletal muscle obtained 10, 30 and 50 days following implantation contained no detectable residual activity . This confirms previous results based on the use of ¹⁴C-labelled zeranol .

8.5 Trenbolone acetate (TBA)

Trenbolone is a 17β-OH steroid esterified in the 17 position with acetic acid. Upon release in the organism the ester is rapidly hydrolyzed to the free compound TB-17β-OH and acetate. In cattle the 17β-OH compound is rapidly transformed to its 17α-OH epimer, in the same manner as oestradiol-17β in this species. The 17α epimer possesses only about 5% of the biological activity of the 17β epimer. Another metabolite of TBA in cattle is the 17-keto compound, analogous to oestrone; quantitatively it appears to be of very little importance. Following intravenous injection of TBA, levels of TB-17β-OH and TB-17α-OH of 0.05 and 0.005, 0.10 and 1.0, 0 and 191 ppb have been recorded for muscle, liver and bile respectively. Other metabolites occurred in extremely small quantities in cattle .

9. RESIDUES IN EDIBLE TISSUES OF HORMONE-TREATED ANIMALS

Much work has been devoted to the development of sensitive methods of detecting hormone residues in meat from hormone-treated animals. As regards compounds given orally, it should in principle be possible to realize claims of zero-tolerance residue levels, by selecting the proper withdrawal time.

Residue levels of gestagens have been also measured, in connection with their use as growth stimulants. Residues of melengestrol acetate used as a feed additive in daily doses of 0.25 to 0.50 mg per head have consistently been below the sensitivity levels of the methods used (i.e., below 10 ppb in fat, liver, muscle and kidney), whether or not the compound was withdrawn 48 hrs before slaughter .

10. ECONOMIC IMPLICATIONS OF THE USE OF HORMONES IN ANIMAL PRODUCTION

In the production of meat for human consumption, a hormonally-induced increase in growth rate of the order of 10% evidently has major economic implications. The improvement in FCE which usually accompanies the increase in gain adds to the economic benefits, and at the same time makes possible greater production of edible protein per unit energy used, and this in itself is of importance in a world lacking in protein supplies. Some of the hormones that have become available recently appear on average to increase gain as well as FCE considerably beyond the 10% level, and in examining whether they should be approved for use in animal production, the

11. ALTERNATIVES TO THE USE OF HORMONES

Growth rates are influenced by many factors, especially genetic constitution and feeding. Over time, selection as well as improvements in management systems, feed composition and feeding programmes have contributed much to increasing productivity in meat as well as milk. Although it is difficult to evaluate the exact relative contributions of these factors, the overall improvements have been dramatic. In addition to the use of hormones, many avenues are still open for increasing productivity in meat and milk production , including breeding programmes, regulation of rumen fermentation, optimalization of the balance between the indirect and direct feeding of the ruminant organism proper, and disease control.

11.1 Breeding programmes

Systematic selection of high-quality sires, combined with an increase in the number of offspring from high-yielding females through embryo transfer, may bring about further improvements in beef and milk production. In many countries, development along these lines has hardly begun. However, the establishment of effective breeding associations and the strict organization of programme planning and execution are prerequisites for realizing the potentials in this sector.

11.2 Regulation of rumen fermentation

The microbial systems in the rumen are extremely complex, and the balance between the various strains of bacteria is susceptible to changes brought about by many factors. The recent introduction of substances such as monensin offers great promise in altering the fermentation pattern to the benefit of productivity by increasing FCE. Since the very extensive breakdown of carbohydrates and protein represents loss of much energy, research is currently being conducted in many laboratories in order to find new methods of increasing FCE.

11.3 Optimalization of the balance between the indirect and the direct feeding of the ruminant organism proper

To a large extent, feeding a ruminant means feeding the rumen microbes which then themselves serve as feed for the organism proper. This is indirect feeding, expensive in energy. On the other hand, the ruminant possesses, in the postruminal part of its digestive tract, all the enzymes necessary for utilizing all types of nutrients except cellulose. The rumen microbes are necessary for the utilization of cellulose, which globally represents an enormous source of energy. However, it is possible to sustain an adequate microbial population in the rumen even when ruminal breakdown of part of the easily digestible nutrients is prevented. Enabling nutrients to bypass the rumen will increase the utilization of feed for production, and also create a more adequate supply of amino acids. Increased rumen bypass of nutrients can currently be brought about by several means, including formaldehyde and heat treatment of protein-rich feeds. In the future, new methods of increasing rumen bypass will undoubtedly contribute significantly to increased productivity of ruminants.

11.4 Disease control

Whatever management system is adopted, effective disease control is essential for productivity. In many areas of the world, infectious and parasitic diseases inflict heavy losses on animal production. A recent study has disclosed nearly a one-to-one relationship between investment in agricultural research and annual productivity of edible protein in ruminants. An increase of about 45% in scientist/man years and a corresponding increase in funding for research and development is considered sufficient to raise productivity in this sector by 50% .

FAQ ON THE USE OF HORMONES IN ANIMAL PRODUCTION

 

 

What are hormones?

 

Hormones are chemical messenger substances which convey specific signals for the regulation of endogenous processes within the body (Greek hormon = impetus). To guarantee that only cells of the target tissue react specifically to the signal, these cells are equipped with the corresponding receptors which specifically bind the hormone. Cells without this receptor cannot bind any hormones and ‘ignore’ the signal.

Can hormones be contained naturally in meat?

 

As hormones are chemical messenger substances formed by the body for the regulation of endogenous processes, meat such as muscle meat, liver and kidneys contains natural hormones.

Under what circumstances can the natural hormone level fluctuate in meat?

 

Higher hormone levels can occur in uncastrated as opposed to castrated animals. With uncastrated boars, for example, nandrolone has been detected in some high concentrations as a natural metabolite of the testosterone metabolism in the liver, kidneys and testicles. In the muscle meat, on the other hand, the nandrolene levels are roughly the same in castrated and uncastrated animals.

If marketed at all, the meat of pregnant animals contains naturally higher levels of certain hormones than the meat of animals that are not pregnant. Another source of hormonally effective substances which can occur in muscle meat or edible organs is to be found in mycotoxins with an oestrogenic effect (e.g. zearalenone) which are formed by certain fungi and can infest cereal crops such as maize, wheat and barley. The meat of livestock which has ingested feed contaminated with zearalenone can then possibly contain additional low levels of these hormonally effective substances. Meat is understood to be all of the edible parts of the animal carcass, such as muscle meat or liver.

Which foods are the main sources of hormones?

 

Levels of progesterone, testosterone and oestrogen are higher in milk than they are in muscle meat or the edible organs of slaughtered animals or in fish, eggs and vegetable foods. A considerable proportion of the daily adult total intake of oestrogens (approximately 60 per cent) and progesterones (approximately 80 per cent) via these foods comes from cow’s milk.

Do naturally occurring hormones have a different effect than synthetically produced
hormones?

 

Naturally occurring and synthetically produced hormones do not normally differ with regard to their effect mechanism at the receptor. Under certain circumstances, however, synthetically produced hormones can have a different potency or can differ from hormones produced in the body in the intake, distribution or metabolism. This means that some synthetic hormones take longer to metabolise in the body, which means that their retention time within the body can be longer. The metabolic products of synthetic hormones can also have a different potency from the basic substance, or they can interact with other receptors to unfold a different activity spectrum.

Is the use of hormones in animal feed allowed?

 

The use of hormones in animal feed is not generally permitted within the European Union (EU).

In the past, substances with a hormonal effect were used for fattening purposes (so-called ‘feeding hormones’) because they improve the animals’ feed conversion ratio, a term used to describe how many kilograms of feed an animal has to ingest to gain one kilogram of body mass. Due to the possible health risks for humans and the change in ethical and environmental consciousness, the use of feeding hormones of this kind in livestock production was banned throughout the EU in 1988.

Is the use of hormones with livestock fundamentally prohibited?

 

Hormones may be used in livestock farming for breeding and therapeutic purposes. The hormones authorised for use in livestock farming are listed in Table 1 of the appendix to Regulation (EU) No. 37/2010. They may only be used in accordance with specific regulations.

After treatment, the waiting times specified in the authorisation procedure must be complied with until the animal is slaughtered or its products are allowed to be traded again. With livestock, the possible areas of application for hormones include cycle synchronisation, the treatment of fertility disorders and the termination of undesired pregnancies.

Are hormones being detected in food?

 

In Germany, control of the use of pharmacologically effective substances in animals and evidence of their use in foods of animal origin are the responsibility of the regional authorities in each federal state. Accordingly, regular checks are made for residues of banned or unauthorised hormones by the monitoring authorities within the scope of the National Residue Control Plan.

An overview of the results of the tests of food of animal origin by the national monitoring authorities in Germany is provided every year by the Federal Office of Consumer Protection and Food Safety (BVL). In the years 2008-2012, there was only one positive finding in horse urine, even though the hormone detected in that instance can also occur naturally.

The European Food Safety Authority (EFSA) reports on the monitoring for residues of medicinal products and other substances in animals and foods of animal origin. In 2010, 0.19 per cent (90 of 47,337 samples) tested positively for hormones. In 2011, 0.11 per cent (53 of 46,378 samples) tested positive in the same class.

Are there any health risks connected with the consumption of meat due to the administering of hormones to livestock as veterinary drugs?

 

A health assessment of the substances is made within the scope of the authorisation process of veterinary drugs during which an ‘acceptable daily intake’ (ADI value) is determined. The ADI stipulates the quantity of a substance which can be ingested every day over an entire life span without endangering consumer health. On the basis of the ADI value, so-called maximum residue quantities which may not be exceeded are determined for certain foods.

If the waiting times laid down in the authorisation process between the administering of hormones and the slaughter of the animals are complied with, it has to be assumed that the determined maximum residue levels of the hormones used in foods of animal origin will not be exceeded, so that a risk to consumer health can be practically excluded. This also applies to veterinary drugs intended for cycle synchronisation.

Are there any health risks for consumers posed by the consumption of meat acquired from animals treated with hormones to enhance their performance?

 

In the European Union, there is a general ban on the use of hormones to enhance animal performance and/or promote growth in livestock production, but there is no ban of this kind in all third-countries.

At the request of the European Commission, the European Food Safety Authority (EFSA) published a report in 2007 on examinations of the effects of hormones used legally in third-countries for the production of animal foods in those countries. It focused, among other things, on hormones used to promote animal growth in third-countries. In this report, EFSA comes to the conclusion that not enough toxicological data are available to make a final assessment of the health risks which could result from the consumption of the meat.

Reference-On Request