What farm animals eat

Animal feeding practices have developed over time, and have generally been validated by their use.

The pace of development has quickened markedly over the past 150 years - in particular, the intensification of the livestock industry in the second half of the 20th century means that a much wider variety of ingredients is used in feed than previously. This includes ingredients that might not be thought part of an animal's natural diet, such as fishmeal.

Concerns about the recycling of animal material into feed (a practice common in developed countries for many decades) have led, during the past ten to 15 years, to a number of prohibitions on what may be used in feed. The use of mammalian meat and bone meal (MBM) was banned because it was thought to have caused or spread BSE; the ban was subsequently extended to almost all forms of processed animal protein (PAP).

However, there is no positive, restricted list of what may be fed to farmed livestock. This is partly because of the likely length of such a list, which could run to hundreds of items, and partly because research into animal nutrition is continually revealing new uses for potential crops. Research also continues into the genetic modification of crops used for feed.

Farmers' choices of what to feed their livestock will be governed by many different factors - the age and species of the animals concerned, their intended products (meat, milk or eggs), the price and availability of feed materials, their nutritive value, and even the time of year and the geographical location (soil type and climate) of the farm.

The energy and nutrients that feed provides occur in different proportions in different materials, and for many animals a typical diet will consist of a combination of feeds to provide everything they need for their health, welfare and production. Ruminants (cattle, sheep and goats) are an exception to this because grass may be the only ingredient in their diet for much of the year.

Categories of feedingstuffs

Animal feed can be divided into four groups - forages (e.g. grasses); cereals and other home-grown crops; compound feedingstuffs; and products and by-products of the human food and brewing industries.

Forage crops generally have a high fibre content, and are usually used on the farms where they are grown. The exceptions are cereal straw and grass dried after cutting, which are traded and may be transported many miles. Cut grass can also be turned into silage by storing it in plastic sheeting, which excludes air and promotes fermentation of the sugars under anaerobic conditions. Silage can also be made from cereal crops such as maize and wheat, which are harvested whole and then chopped into fragments. Approximately 15 million tonnes of silage dry matter were produced in Great Britain in 2004.

Cereals and other home-grown crops
These are feeds with a high energy and/or protein content. They may be fed to livestock on the farm where they are grown or bought in from outside, and may be fed either singly or as compound feeds (manufactured, often pelleted, mixtures of single feed materials, minerals and vitamins).

For ruminants, feeds of this type are necessary to supplement fresh or conserved feeds that do not provide sufficient nutrients for the animals. Non-ruminants (such as pigs and poultry) are unable to digest forages, and so their diets consist almost entirely of these feeds, together with the products and by-products described below. Around 20 million tonnes of feed materials and feedingstuffs are used annually in Great Britain, approximately two-thirds in the form of compound feeds.

Products and by-products of the food and brewing industries
By-products of the food and brewing industries (sometimes described as 'co-products') which remain after the production of food for human consumption are widely used as feeds for livestock. These include the residues of vegetable processing, such as rape and soya meal, maize gluten feed (the residue of starch extraction from maize or corn), spent grains from brewing and malting, and by-products of the baking, bread-making, and confectionery industries.

Food products which were intended for human consumption but which are rejected at the factory as sub-standard, or are broken or misshaped, or have passed their 'best before' dates, or are surplus to market requirements, can also be fed to animals.

The quality of these products is high because their ingredients were selected for use in the human food chain, but their use on farms will be determined by their costs relative to those of other feeds. However, if these products were not recycled into feed - which is not in itself a new practice - they would have to be disposed of in some other way, such as landfill or composting.

Typical livestock diets

The diets of ruminants differ from those of pigs and poultry. In addition to the materials listed, livestock diets may be supplemented by compound (mixed or manufactured) feeds. Vitamins and minerals are usually also provided, either incorporated into the compound feed or fed separately (such as in capsule form).

Dairy cows and beef cattle are usually fed grass during the summer months and conserved forage (grass or maize silage, or hay) in the winter. These forages may be supplemented with cereals and other by-products to increase milk yield or liveweight gain. The diets of both may also include, as available, forage crops such as kale and rapeseed, root crops (turnips and fodder beet), and the pulp remaining from the processing of sugar beet or citrus fruit.

Sheep and goats
Sheep and goats spend less time indoors than cattle. Their diet is similar to that of cattle, although barley and other cereals are usually fed only to pregnant and lactating ewes and to young lambs. During winter months they may also be fed on root crops, including swedes, mangolds and fodder beet, which may also be grazed in the fields in which they are grown.

Pigs are omnivores, and in the past their diets included meat and meat products. However, this - and the feeding of catering waste as swill - is now prohibited because of the potential for spreading disease (particularly foot-and-mouth). Pig diets typically include cereal grains, oilseed meals, and other by-products of the human food industry. Pigs reared outdoors may also be fed root crops such as swedes, turnips and mangolds. There is more liquid feeding of pigs than other species of farmed livestock.

Poultry - chickens, turkeys, quails, ducks and geese - are typically fed on cereal grains, especially those reared in poultry houses. Free range poultry, geese and ducks in particular, will also graze on grass.

Fish reared in water cages receive a pelleted feed, which is likely to include fishmeal and other fish derivatives.

Controls on animal feed

The regulatory regime for animal feed is harmonised throughout the EU, based on legislation negotiated and adopted in Brussels, which is intended to safeguard animal and human health and ensure traceability throughout the feed chain. Most businesses that use, manufacture or sell animal feed must be registered or approved, and comply with specified standards in respect of their facilities, storage, personnel and record-keeping. This includes farmers feeding animals producing food for human consumption and arable farms growing crops for feed use.

A summary of all the feed-related legislation for which the Food Standards Agency is responsible, and more detailed guidance to the provisions of the Feeding Stuffs (England) Regulations 2005, is available at www.legislation.gov.uk/uksi/2005/3281

In addition, a number of codes of practice and quality assurance schemes apply to the production and delivery of feed to farms and the sourcing, storage and handling of feed materials and compound feeds. The main codes are those drawn up by the Agricultural Industries Confederation (AIC) and the Grain and Feed Trade Association (GAFTA). These and other codes - developed by the feed industry, farmers- unions, and trade bodies such as egg producers and the Soil Association - are voluntary, but help ensure that measures are in place to address identifiable hazards and trace feed materials. The ultimate aim of both legislation and self-regulation is to ensure that animal feed is safe, wholesome, and does not present any danger to animal or human health and the environment.

International trade in animal feed

Approximately 20% of the feed materials used in the UK are imported from outside the EU, as the quantity of home produced feed is insufficient to meet demand. Soya beans and soya bean meal from North and South America, and maize gluten feed from the USA, are the principal imported feed materials. Smaller quantities of other materials are imported from elsewhere in the world - for example, cotton seed meal from China and India, and palm kernels from Malaysia.

Some imported material will be genetically modified (GM) or derived from GM crops, and must be labelled as such. Further information on the use of GM material in animal feed is available at the link below.

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