In rural areas,
pigeons, starlings, and house sparrows are attracted to dairy
farms, where food and shelter are readily available. Populations
of these three bird species usually increase around dairy barns
during winter months, when snow cover limits access to food and
water. Barns provide warm shelter on cold days, and feed troughs
and bunkers provide an easy source of food. During winter, birds
often consume and contaminate large quantities of feed intended
for livestock. Starlings may consume up to 50% of their body
weight in grain each day. Loss of feed may be quite significant.
A flock of 200 starlings may consume 175 pounds of grain per
week, and contaminate even more with their droppings. In addition,
birds may create fire hazards by nesting on light fixtures and
wiring in barns, and their droppings may contaminate bedding
material and water intended for livestock.
Birds may also
pose health hazards to both cattle and humans working in dairy
barns. However, because birds have higher body temperatures than
mammals, most of the bird pathogens do not flourish in healthy,
non-stressed cows or humans. Some noteworthy exceptions occur
in the salmonella and systemic (internal) fungal families.
is a family of bacterial
disease-causing organisms, of world wide distribution and major
economic importance. Many of these pathogens arc capable of spreading
disease to humans. Salmonella infections in birds, cattle, and
humans tend to be intestinal, but generalized infections also
occur. These infections may lead to death, but most are medically
treatable. Young and old cattle tend to be more susceptible,
with two to four week old calves most apt to contract severe
infections. In mature cattle, salmonella may cause abortions,
or a decrease in milk production. There are 81 different types
of salmonella that cause infection in cattle. Salmonella may
be transmitted by direct contact, consumption of fecally contaminated
feed or water, or inhalation.
are fungal diseases
that affect internal organs. Two notable diseases in this group
that infect cattle are histoplasmosis and cryptococcosis.
Both of these disease organisms are found in bird manure. Pigeons
are more commonly associated with cryptococcosis, while starlings
or pigeons may be associated with histoplasmosis. Histoplasmosis
proliferates in less harsh climates, and is more commonly found
in the central Midwest states. It is usually contracted through
inhalation of spores, and causes a respiratory infection that
healthy cattle recover from without medical treatment; however,
it is potentially fatal in humans. Children are more susceptible
to this mold than any other mycotic infection.
Cattle may become
infected with cryptococcosis by breathing spores from an environment
rich in dried bird manure, consumption of contaminated feed or
water, contact with contaminated milking equipment, or through
infusion medications contaminated with bird feces. In cattle,
cryptococcosis appears as a primary infection of the mammary
glands. The mastitis caused by cryptococcosis can be quite severe
and non responsive to medications, as well as difficult to diagnose.
Cryptococcosis may also cause a decrease in milk production,
and loss of appetite. Cryptococcosis usually begins as a respiratory
infection in humans, and may eventually spread to the central
(AT) is another
disease that causes considerable frustration for dairy farmers.
As the name implies, avian tuberculosis is a disease that occurs
primarily in birds, but many also occur in pigs. AT is worldwide
in distribution, but occurs most frequently in the northern temperate
zone, It generally causes no lesions, or only nonprogressive
lesions in lung lymph nodes in cattle. In rare cases AT can cause
generalized progressive lesions in cattle. It may also cause
mastitis. AT is a more common infection in domesticated fowl
than in wild birds, but both are susceptible, and where wild
and domestic birds intermingle, the bacteria is easily transferred.
AT may be transmitted through direct contact with feces, consumption
of feed contaminated with bird droppings, or through inhalation.
The major AT
problem for the dairy farmer isn't the disease itself, but rather
the caudal (tail) fold tuberculosis test, the official surveillance
test for tuberculosis. This test cannot distinguish avian tuberculosis
from bovine tuberculosis, because both cause a swelling of the
tail. If this initial test is positive, the farm is usually quarantined
because of the serious risk of infection to humans and other
cattle, if bovine tuberculosis were actually present. This quarantine
can last from 10 days (most common) to 6 months or more, depending
on additional test results. Occasionally these additional tests
are inconclusive, requiring that indemnity be paid, and the animal
be taken for necropsy and pathological examination. Certain acid-fast
soil bacteria may also cause cattle to react positive to a caudal
to alleviate sanitation and health problems caused by large concentrations
of pigeons, house sparrows, and starlings, three important factors
must be considered: timing of control, persistence in carrying
out control, and diversity of control methods. While pigeons
and sparrows may roost in barns overnight, starlings usually
form large flocks that roost in nearby stands of brush or trees.
The largest numbers of birds are usually present in barns during
the winter, when cold weather causes them to seek shelter and
alternative sources of food and water. Proper identification
of all bird species present is important before any control techniques
are implemented. Most birds are protected by federal laws. However,
pigeons, starlings, and house sparrows are NOT protected by federal
to controlling birds is exclosure and habitat modification. Some
bird problems can be reduced by excluding the in from buildings.
This can often be accomplished by screening or blocking access
areas with 1/4 inch wire mesh or netting. Areas such as vents,
broken windows, and eaves all provide access for birds.
pigeons, starlings, and sparrows may be reduced by destroying
nests and eggs. For best results, nest sites should be checked
every two weeks for re nesting attempts, and nests should be
destroyed before eggs are laid. A long pole with a metal hook
on the end is useful for removing nests built in high rafters
or ledges. This control method should be used in combination
with other control methods, such as exclusion.
In short, birds around dairy barns can be a significant health
hazard, for both livestock and people, and the best means of
damage control is to use a variety of techniques.