The animal feed legislation for which the Food Standards Agency is responsible applies principally to feed for farmed livestock but also covers feed for what are called 'non-food producing animals'. This typically means fur-bearing animals (the rearing of which in the UK has been prohibited for some years), animals kept in zoos, circuses and laboratories, creatures living freely in the wild, and pets. It does not include horses and rabbits, which since 1 September 2010 have been classified as food-producing animals.
The labelling requirements for pet food are less onerous than those for feed for farmed livestock. For livestock, the ingredients must be declared individually in descending order by weight, but pet food manufacturers have the option to declare them by category -- e.g. 'meat and animal derivatives', 'oils and fats', 'cereals', 'vegetable protein extracts'. Declaration by categories allows for fluctuations in the supply of the raw materials used and provides flexibility for labelling ingredients without incurring unreasonable cost.
Feed labelling legislation also permits manufacturers to draw particular attention to the presence of absence of a particular ingredient and to provide information over and above the statutory minimum with which purchasers must be provided (analytical declarations for protein, fibre, etc.; the name and address of the manufacturer). This additional information is subject to certain safeguards, e.g. that it should not mislead purchasers, not make medicinal claims, and must concern objective and quantifiable factors which can be substantiated. Thus a pet food product the label of which states that it contains "20% beef" must actually contain that ingredient in the stated proportion.
The material of animal origin used by the pet food industry comprises those parts of animals which are either deemed surplus to human consumption or are not normally consumed by people in the UK, and derived from animals inspected and passed as fit for human consumption prior to slaughter. Animal material of this nature, which is not intended for human consumption, is classified as 'animal by-products' under the EC Regulation on Animal By-Products for which Defra is responsible, and assigned the lowest risk rating. This rating requires that the material be free of any transmissible disease, which therefore excludes material from dying, diseased or disabled animals.
Pet food is subject to similar controls with respect to authorised additives and levels of undesirable substances as feed for farmed livestock. For pets, the main part of the risk assessment when setting the maximum permitted levels for undesirable substances will generally be the extent to which the animal can tolerate them.
Many of the particular nutritional purposes for which feeds may be marketed -- that this, the dietary management of certain conditions where the animal's metabolism is temporarily or permanently impaired -- concern pet food. Examples of these purposes include the support of renal function in renal insufficiency, the reduction of acute intestinal absorptive disorders, the regulation of glucose supply and support of skin function in dermatosis and excessive hair loss.
Enforcement of the legislation relating to pet food is the responsibility of local authority trading standards officers. This includes sampling and analysis.