Page 147 - Microsoft Word -Cow Book 10-06-09 final update.doc

K. Polymyxins

Polymyxins have been used for the treatment of enteritis in young calves and
pigs and of bovine mastitis as well as preputial irrigation of bulls. This class of
polypeptide antibiotic is somewhat toxic and is rarely employed systemically
injected.

L. Novobiocin

Novobiocin is a narrow-spectrum antibiotic with a bacteriostatic action against
gram-negative organisms. Its principal use in food animal medicine is for the
intramammary treatment of bovine mastitis.

M. Bacitracin

Bacitracin is a narrow-spectrum antibiotic against a range of bacteria similar to
those affected by penicillin G.

N. Rifamycins

Rifamycins are extended-spectrum antibiotics. Two types of which (rifampin
and rifanide) have enjoyed some clinical use in veterinary medicine.

O. Fluoroquinolines

Fluoroquinolines are derivatives of the class of quinolone acids. They
have broad spectrum anti-bacterial activity. FDA issued an order on May 22,
1997 in the Federal Register prohibiting the extra-label use of these drugs and
glycopeptides in food producing animals. Glycopeptides have only been
approved for use in humans. On July 24, 1998, the FDA approved a new
animal drug application for the use of enrofloxacin, which is a flouroquinolone,
in cattle for the treatment of bovine respiratory disease associated with the
Pasteurella haemolytica, Pasteurella multocida and Haemophilus sommus.

This product has a trade name of Baytril 100 Injectable Solution for the
treatment of Bovine Respiratory Disease (BRD), is an Rx drug, and is
administered by injection. This product is “Not for use in dairy cattle greater
than 20 months of age. Use of enrofloxacin in this class of cattle may
cause milk residues.” Baytril 100 is still prohibited for use in lactating dairy
cows and should be segregated on the dairy farm from those drugs used for
lactating animals. Extra-label use of flouroquinolones in food animals has

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