This is from the FEI.org site
Annex III Equine Prohibited List
SUBSTANCES AND METHODS PROHIBITED IN-COMPETITION
PROHIBITED SUBSTANCES (DOPING)
Agents, cocktails or mixtures of substances that may affect the performance of a horse;
masking agents; substances with no generally accepted medical use in competition
horses; substances which are usually products prescribed for use in humans or other
species; agents used to hypersensitise or desensitise the limbs or body parts, including
but not limited to:
• two or more anti-inflammatory drugs (steroidal and/or non-steroidal) or other
combinations of anti-inflammatory substances with similar or distinct
pharmacological actions;
• antipsychotic, anti-epileptic and antihypertensive substances including reserpine,
gabapentin, fluphenazine, and guanabenz;
• antidepressants such as selective serotonin reuptake inhibitors (SSRIs),
monoamine oxidase inhibitors (MAOIs), and tricyclic antidepressants (TCAs);
• tranquilizers, sedatives (including sedating antihistaminics) commonly used in
humans and/or non-equine species, including benzodiazepines, barbiturates and
azaperone ;
• narcotics and opioid analgesics; endorphins;
• amphetamines and other central nervous system (CNS) stimulants including
cocaine and related psychotic drugs;
• beta-blockers including propranolol, atenolol, and timolol;
• diuretics and other masking agents;
• anabolic steroids (including testosterone in mares and geldings) and growth
promoters;
• peptides and genetically recombinant substances such as erythropoietin, insulin
growth factor and growth hormone;
• hormonal products (natural or synthesized) including adrenocorticotropic hormone
(ACTH) and cortisol (above the threshold);
• substances designed and marketed primarily for human use or use in other species
and for which alternative and generally accepted products are available for use in
horses;
• hypersensitizing or sensitizing agents (organic or inorganic or other substances
likely to have been applied to body parts or to tack to influence performance);
• oxygen carriers;
and other substances with a similar chemical structure or similar biological
effect(s).
2
PROHIBITED SUBSTANCES (MEDICATION CLASS A)
Agents which could influence performance by relieving pain, sedating, stimulating or
producing/modifying other physiological or behavioural effects, including:
• local anaesthetics;
• sympathomimetic cardiac stimulants;
• central and respiratory stimulants;
• clenbuterol and other bronchodilators and products used for the treatment of
recurrent airway disease (RAD);
• a single non-steroidal anti-inflammatory drug ± metabolite(s);
• a single corticosteroid;
• sedatives or tranquillisers indicated for equine use including antihistamines;
thiamine; valerian and other herbal products other than those listed as Prohibited
Substances (Doping);
• muscle relaxants including methocarbamol and propantheline;
• anti-coagulants including heparin or warfarin;
and other substances with a similar chemical structure or similar biological
effect(s).
Doesn’t the FEI cover themselves by stating:
“agents used to hypersensitise or desensitise the limbs or body parts, including
but not limited to:”
and
"and other substances with a similar chemical structure or similar biological
effect(s). "
As far as feed goes I had a major problem with my broodmares a while back and had everything at my barn tested. The problem was in the feed and the manufacturer was a major feed company. Very scary.
All of the barns I have visited in Europe have mixed their own feed on site. They could still have a problem with the ingredients they purchase to mix but would be less likely to incur any problems.