Introduction to Feed Additives
Feed additives are non-nutritive products added to rations to improve
the efficiency of animal production via an improvement in intake, digestion,
and/or metabolism efficiency, and/or the health of the animal. Feed additives
may also be added to feeds to improve manufacture and/or properties of
the feeds or to improve consumer acceptance of a product. Feed additives
are added to the feed in small quantities. Feed additives are utilized
extensively in commercial animal production. Feed additives have been
beneficial within modern animal production, allowing producers to provide
safe, wholesome, cost-effective animal products to consumers. In more
recent years, regulatory agencies and lawmaking bodies have started to
restrict feeding of specific additives for various stated reasons. For
a producer, determining the use of a feed additive requires consideration
for factors such as specific requirements of the animal, effects of other
components of the ration, presence of a withdrawal period, effect of a
withdrawal period, form of additive to feed, and cost-effectiveness of
the feed additive.
In the U.S., many of the feed additives fed to production animals are
classified as drugs. As defined by the FDA, a drug is "a substance,
a) intended for use in the diagnosis, cure, mitigation, treatment or prevention
of a disease in man or other animals or b) a substance other than food
intended to affect the structure or any function of the body of man or
other animals." In the U.S., the FDA regulates feed additives classified
as drugs. Initially, the FDA must approve the additives. For approval,
the FDA is required to establish the drug is safe and effective for a
specific species and safe for humans and the environment. The FDA must
also establish the specific chemical and manufacturing specifications.
FDA approval requires extensive research of the compound. Subsequent to
approval, the FDA continues to regulate the actual use of the additive;
monitoring the labeling and feeding of additives classified as drugs and
the safety of the animal products. Marketing of a drug is permitted after
approval of a new animal drug application. Click on the following link
for more information regarding drug products in animal production: http://www.fda.gov/cvm/default.html.
Animal drugs in medicated feeds are classified as Category I or Category
II drugs. Category I are the safest. Category I require no withdrawal
period. Category II require a withdrawal period at the lowest use level
of at least one specie or is regulated on a no-residue basis regardless
of the requirement of a withdrawal period. Table 9-1 on page 181 of the
text lists Category I and Category II drugs.
Medicated products are also categorized as Type A, Type B, or Type C.
Type A medicated products are concentrated premixes of the product. Type
A medicated products are added to additional feedstuff(s) prior to feeding.
Type B medicated products are also added to additional feedstuff(s) prior
to feeding. In comparison to Type A medicated products, the drug concentration
is less in Type B medicated products. Type C medicated products are prepared
for feeding. Type C medicated products may be fed as a complete feed,
top-dressed, or offered ad-libitum to animals. Type C medicated products
are consistent with specifications approved by the FDA.
Commercial feed mixers mixing Category II, Type A medicated products are
required to register with the FDA. Commercial feed mixers mixing Category
I drugs or Category II, Type B medicated products are not required to
register. Individuals preparing medicated products for personal animals
are subject to the same registration requirements as commercial mixers.
In addition to compounds classified as drugs, numerous additional additives
are utilized in animal rations. Table 9-5 on page 191-192 of the text
provides information regarding additional special-purpose additives. As
these compounds are not classified as drugs, the FDA does not regulate
the compounds on the feed mill level. However, feed manufacturers are
expected to use the additives as directed.
The next sections will discuss various feed additives in animal rations.
The sections will not provide an all-inclusive list of feed additives
in animal rations.
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