Infectious Bovine Keratoconjunctivitis Cattle Pinkeye

W 472

INFECTIOUS BOVINE KERATOCONJUNCTIVITIS
CATTLE PINKEYE
Lew Strickland, DVM, MS, DACT, Extension Veterinarian
Department of Animal Science

Infectious bovine keratoconjunctivitis (IBK),
more commonly known as pinkeye in cattle,
is a highly contagious bacterial infection of
the eye. Although pinkeye is a non-fatal
condition, it has a tremendous economic
impact on the US cattle industry. Not only do
calves weigh 36-40 pounds less at weaning,
pinkeye also can affect prices received for
cattle at sale because of price discounts. The
magnitude of the discount, which can be
quite large, will depend on the severity of the
infection. Some estimates place the cost to
the beef industry of decreased productivity
and animal value due to pinkeye at $150
million annually due to lower production (i.e.,
growth), sale value and treatment costs.

Cause
Although pinkeye is most often the result of
infection of the surface of the eye by the
bacterial organism Moraxella bovis (M. bovis),
several other viruses and bacteria also have
been associated with the disease. Infectious
bovine rhinotracheitis virus (more commonly
referred to as “IBR”), Mycoplasma bovis, and
Moraxella bovoculi (M. bovovuli) all may
enhance the risk for infection, as well as
increase ocular and nasal discharge that may
facilitate the shedding of M. bovis. The
surface of M. bovis has hair-like structures
known as pili, which extend from the main
body of the bacteria. The pili allow the
bacteria to attach to the conjunctiva of the
cornea and colonize, causing inflammation of
the tissue lining of the lid and chamber of the
eye. Ultimately, the degree of inflammation

may become severe enough to cause
ulceration of the cornea that may eventually
rupture, resulting in potential blindness. Seed
heads, dust, pollen and UV light are
environmental factors that increase the risk
for development of pinkeye in cattle. These
irritants scratch the cornea of the eye and
allow for easier attachment of the M.
bovis bacteria. Such irritants increase
secretion of tears from the eye, which
attracts face flies (Musca autumnalis) that
can spread the bacteria that cause pinkeye.

Transmission
Once exposed, the M. bovis organism resides
on the eyes and in the nasal cavities of
infected cattle. Asymptomatic carriers can
harbor the organism for a period that may
exceed one year. Transmission occurs
through contact with secretions infected with
M. bovis. This may be direct contact, through
face flies, or contact with an inanimate object
such as the rough or frayed rubber covering
of a mineral feeder contaminated with M.
bovis. Face flies are the vector primarily
responsible for transmission, as they travel
from animal to animal and up to several miles
in search of a meal. They feed on the watery
tearing from cattle's eyes, and in the process
spread the bacteria that can cause pinkeye
from animal to animal. Face flies travel to
several animals per day, so they have the
potential for rapid of spread M. bovis
throughout a herd. However, not all cattle
exposed to M. bovis develop clinical signs of
the disease.

Infectious Bovine Keratoconjunctivitis

Clinical Signs
There are four stages of pinkeye, with clinical
signs ranging from conjunctivitis, excessive
tearing, photosensitivity, ocular pain,
squinting of the eyelid, corneal edema, and
corneal ulceration to corneal rupture and
blindness. Depression of appetite is due to
ocular discomfort or visual disturbance that
results in an inability to locate food. The
typical clinical course may vary from a few
days to several weeks in duration. Most
corneal ulcers in cattle with pinkeye heal
without loss of vision; however, corneal
rupture and permanent blindness often
occurs in the most severe cases. Typically,
recovery occurs in three to five weeks.

Stage 1: Affected eyes have excessive

tearing and photophobia (increased
sensitivity to light). They will blink frequently
and the sclera (white portion of the eye) will
turn red due to inflammation. Typically, a
small ulcer develops in the center of the
cornea that appears as a small white spot.

Stage 1

Edema in the cornea will result in a slightly
cloudy gray appearance.

Stage 2: As the clinical signs progress, the

ulcer spreads across the cornea. The cornea
becomes increasingly cloudy as additional
inflammation occurs. Portions of the iris are
detectible, but compromised vision is
possible. Blood vessels from the outside
portion of the cornea begin to grow across
the cornea to assist with healing. The cornea
now appears pink, which is how the disease
received its name.

Stage 3: The ulcer continues to progress and
covers most of the cornea while
inflammation continues to spread into the
inner parts of the eye. The interior of the eye
fills with fibrin and white blood cells. This
gives the eye a yellow appearance versus the
typical brown color.

Stage 3

Stage 2

All images courtesy of Virginia
Cooperative Extension.
Stage 4

The University of Tennessee Institute of Agriculture

Corneal scar

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Infectious Bovine Keratoconjunctivitis

Stage 4: The ulcer extends completely

through the cornea, and the iris is protruding
through the ulcer. The iris will form adhesions
to the cornea even after healing. The
recommend treatment is to enucleate
the eye.

Corneal scar: Once the ulcer has healed

(except Stage 4) the blood vessels recede;
however, the eye may continue to be a
cloudy blue color for a short period.
Eventually the eye appears clear again with
a white scar that slightly impedes vision.

Treatment
Early treatment of cattle with pinkeye is
important, not only for successful outcome of
the affected animal, but also to reduce the
shedding of the bacteria which will decrease
the risk of transmission to other cattle.
Moraxella bovis is often susceptible to overthe-counter oxytetracycline (LA200, LA300,
Biomycin). Medications such as ceftiofur,
tulathromycin and florfenicol will require a
prescription from a veterinarian.
Intramuscular antibiotic therapy is usually
effective, especially during the early stages
of the disease. When severe corneal
ulceration exists, protect the eye from UV
light, flies and other irritants with eye
patches, or by creating a third eyelid flap. A
veterinarian or someone adequately trained
should perform this procedure.
Sub-conjunctival local injection is one of the
more popular therapies to treat more severe
cases of pinkeye. However, recent studies
illustrate that topical uses of intramammary
cloxacillin and intramuscular injections have
a similar healing time to local injections
of penicillin.
Sprays and topical ointments are only
effective if used multiple times daily, which
generally is not possible for most producers.
In addition, many of the commercially
available ophthalmic ointments have very
long withdrawal times or are illegal to use in

The University of Tennessee Institute of Agriculture

cattle. Give all injections in the neck or in
front of the shoulder according to Beef
Quality Assurance recommendations. Consult
a veterinarian before using any other
medications. Never use any medication
containing nitrofuracin, as its use in cattle has
been illegal since May 2002. If treating
several animals, wash your hands or change
gloves between animals so you do not
spread the bacteria to other cattle.

Prevention
An ounce of prevention is worth a pound of
cure in this situation, but can be timeconsuming. Since face flies are responsible
for transmission, a solid fly control program
is imperative! Management practices that
reduce the risk factors associated with
pinkeye are the most effective tools in
decreasing the incidence of disease. An
appropriate vaccination program that
includes infectious bovine rhinotracheitis
(IBR) and bovine viral diarrhea virus (BVDV)
along with a good nutrition/mineral program
will decrease the incidence of pinkeye.
Appropriate grazing, along with clipping
pastures, will prevent seed-head
development, reducing irritation to the eyes
of cattle. Inanimate objects can also serve as
an irritant to cattle eyes. Check mineral
feeders and other areas for frayed or sharp
edges that can easily damage the cornea and
potentiate disease. To decrease the effect of
UV light, breed for eyelid pigmentation and
ensure shaded areas are available to cattle.
Commercial and autogenous pinkeye
vaccines are available. However, they should
not be the sole means of preventing pinkeye.
Due to the numerous strains of M. bovis,
vaccinations have not proven to be
consistently effective in prevention.
Vaccination is only one part of pinkeye
prevention strategies. Combine the
management practices mentioned above to
reduce the incidence of disease.
Pinkeye is an economically devastating
disease that can be frustrating to a cattle

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Infectious Bovine Keratoconjunctivitis
operation. A well-designed
prevention/treatment program will assist in
minimizing economic losses. If you have any
questions, or need help in developing a
program, contact your veterinarian or local
Extension agent.

References

Whitter W.D., Currin J., Currin N. Pinkeye in
Beef Cattle. Virginia Cooperative
Extension Publication 400-750.
Cornell University College of Agriculture and
Life Sciences; Veterinary Entomology
vet.entomology.cals.cornell.edu/arthropo
d-identification

Snowder GD, Van Vleck LD, Cundiff LV, et al.
2005. Genetic and environmental factors
associated with incidence of infectious
bovine keratoconjunctivitis in preweaned
beef calves. J Anim Sci 83:507.

Eastman TG, George LW, Hird DW, et al.
1998. Combined parenteral and oral
administration of oxytetracycline for
control of infectious bovine
keratoconjunctivitis. J Am Vet Med Assoc
212:560.

George LW, Ardans A, Mihalyi J, et al. 1988.
Enhancement of infectious bovine
keratoconjunctivitis by modified-live
infectious bovine rhinotracheitis virus
vaccine. Am J Vet Res 49:1800.

Angelos JA, Dueger EL, George LW, et al.
2000. Efficacy of florfenicol for treatment
of naturally occurring infectious bovine
keratoconjunctivitis. J Am Vet Med Assoc
216:62.

Pugh GW Jr, Hughes DE, Packer RA. 1970.
Bovine infectious keratoconjunctivitis:
interactions of Moraxella bovis and
infectious bovine rhinotracheitis virus.
Am J Vet Res 31:653.

Dueger EL, Angelos JA, Cosgrove S, et al.
1999. Efficacy of florfenicol in the
treatment of experimentally induced
infectious bovine keratoconjunctivitis.
Am J Vet Res 60:960.

Pugh GW, Hughes DE, Schulz VD. 1976.
Infectious bovine keratoconjunctivitis:
experimental induction of infection in
calves with mycoplasmas and Moraxella
bovis. Am J Vet Res 37:493.

Lane VM, George LW, Cleaver DM. 2006.
Efficacy of tulathromycin for treatment of
cattle with acute ocular Moraxella bovis
infections. J Am Vet Med Assoc 229:557.

Pugh GW Jr, Hughes DE. 1975. Bovine
infectious keratoconjunctivitis: carrier
state of Moraxella bovis and the
development of preventive measures
against disease. J Am Vet Med Assoc
167:310.

Abeynayake P, Cooper BS. 1989. The
concentration of penicillin in bovine
conjunctival sac fluid as it pertains to the
treatment of Moraxella bovis infection. (I)
Subconjunctival injection. J Vet
Pharmacol Ther 12:25.
Kirkpatrick J.G., Lalman D. Pinkeye in Cattle
Infectious Bovine Keratoconjunctivitis
(IBK) Oklahoma Cooperative Extension
Service Publication VTMD-9128.

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