Farm Animal Health: Spraying the Hen House, Lameness in Horses, Saddle Sores in Horses and More

article image
Veterinarian Andrea Looney answers common questions about animal health and conditions.

Dear Andrea:

I have 45 chickens ranging in age from 10 months to two
years. Last year I sprayed the henhouse once a month with
malathion to keep away lice and mites brought in by
visiting wild birds. I’m not keen on using the malathion.
What are your suggestions?

-Molly StanleyAddress withheld by

Dear Molly:

The most common species of mites which infect chickens are
the chicken mite, the northern fowl mite, and the tropical
fowl mite. There are over 40 species of lice that can be
found on poultry. Mites are smaller than lice and while
mites feed on blood alone, most lice can feed on bits of
feather, skin, and blood. Both can cause anemia,
unthriftiness, and even death, especially in young birds.
The chicken mite is particularly serious in warmer parts of
the States. Adult female mites lay eggs within 12-24 hours
of attachment. Some females are so hardy that they can
survive up to 30 weeks or more without food. These mites
can affect turkeys, pigeons, canaries, and several species
of wild birds. Sparrows are thought to transmit the mite.

Malathion is an organophosphate, which are among the most
effective pesticides when used correctly. However, chickens
overdosed with malathion may experience muscle tremors and
even seizures, and it goes without saying that people have
become more concerned about the potentially hazardous
effects of pesticides on the food chain.

Pyrethrins are also effective pesticides and are considered
a more organic form of miticide since they are derivatives
of the chrysanthemum. Permethrin, a pyrethrin derivative,
can be used to treat both the birds and the house at
concentrations of 0.05 percent. This will prevent mite
infestation for up to eight weeks. The most effective
treatment, however, is routine cleaning and monitoring of
both all incoming birds and the facility itself.

First, the litter should be changed on a regular, frequent
schedule. The nest boxes should be sealed yearly with
varnish or paint. Roosts should be treated with
preservative two or three times per year. The house should
be cleaned out and all cracks and crevices steam-cleaned
and treated with a pesticide once the birds are removed.
The building should be closed up tight for an hour or two
following fumigation and then adequately ventilated for an
additional hour before returning the birds. Regular yard or
pasture rotation is essential to the health of any
livestock or poultry.

Pesticide treatment of the birds themselves is essential,
especially to the point that the skin is wet. Yet if the
housing is neglected, treatment won’t be complete. Checking
and treating the house, feed and egg crates, cases, and
flats along with all your chicken-house clothing and boots
is of great importance. If one area is neglected, it is of
no use to treat the rest. Houses are the most affected, yet
least aggressively treated, areas.

Dear Andrea:

We own a few Hampshire feeder pigs who have had distorted
snouts since birth. What’s the cause of this?

-Jake McColly Joliet, IL

Dear Jake:

Several bacteria are commonly found in the upper air
passages of pigs. These bacteria have special appendages that allow them to firmly attach to cells inside
the nasal cavity. Some bacteria and the toxins that they
produce irritate the nasal cells so much that the nose
tissue is severely damaged. This produces the
mild-to-severe coughing, sneezing, nose rubbing, and
obvious snout distortion for which the disease is known. At
times, black tear streaks can be seen running from the
eyes. In severe cases, the rhinitis, or nasal inflammation,
can result in pneumonia as well.

Mild occurrences of this disease–known as atrophic
rhinitis-pose minimal economic consequences to pork
producers, and often do not warrant the expense of
treatment. Severe outbreaks or recurrence of signs however,
require urgent action. To treat this disease requires
strategy. Since the disease is extremely contagious, don’t
introduce any new pigs to your herd if you can help it. In
fact, when purchasing, try to buy those pigs vaccinated
against the disease or less severely affected. Injectable
and oral antibiotics in feed and water may help halt
disease progression. One of the most appropriate ways to
treat the disease, however, is to prevent it via reduced
stress. For pigs, this means in particular improved
ventilation, decreased dust, and increased hygiene via more
efficient manure removal.

Dear Andrea:

I’m a first-year vet student, specializing in large
animals, at University of California. I’m finding that
there are hundreds of causes of lameness in horses. In
fact, there have been books written in volumes on this
subject alone. One day I hope to be an expert, but, until
then, what basic things can I do to prevent and treat
lameness in my horses?

Jennifer Stuart Davis, CA

Dear Jennifer:

Living arrangements have much to do with injury. Late
summer pastures, once plush, are now filled with flies and
dried mud, cracked and hardened from the sun. Animals
turned out daily are usually not shod, and they may stomp
at flies and run awkwardly on the uneven ground, increasing
the likelihood of hoof bruises and cracks, both of which
invite bacterial infection. Uneven terrain may also bruise
soles and increase the risk of sprain, strain, and

Pay close attention to horses turned out to pasture and
consider having front feet shod during fly season and in
dry weather. Likewise, damp or wet footing found in areas
of flood, swamp, or high humidity can cause a horse’s foot
to expand, creating gaps at the white line (junction of
sole and hoof wall). Small pastures with many horses are
usually knee deep in manure at certain points, and bacteria
or parasites thrive here simply waiting for a chance to
invade a damp and injured hoof.

Use a hoof pick to clean manure and dirt from the hoof on a
regular basis. Carefully examine the hoof wall and
frog/sole to check for stones or plant matter. Puncture
wounds often appear as black spots which are extremely
sensitive to pressure. To locate an abscess, the
veterinarian will probe the hoof, sole, frog, and heel with
fingers and a hoof tester to find the precise spot of entry
of a penetrating object. The horse will commonly flinch
when it is pressed. Using a sharp hoof knife, a window is
created (usually less than half an inch in diameter) around
the wound or suspect area to allow infection to escape.
This is called “paring out” the wound. Soaking the foot in
warm Epsom salt baths and cleaning with hydro gen peroxide
helps keep this window open from drainage, and kills
bacteria. I am in favor of keeping small wounds un covered,
as ban daging often promotes wicking of material into the
wound and may also prevent proper drainage.

Conformation plays an incredibly large part in lameness.
Some horses with flat or thin soles, worn heels, or thin,
weak walls are susceptible to hoof injury. Horses with
upright pasterns-i.e.: not enough angle from heel to hoof,
contracted tendons, or knee deformities-are also
particularly prone to further damage to foot and hoof.
Regular visits from the farrier are important, especially
in horses with conformational faults, as corrective shoeing
is not only protective to the hoof, but can guard against
stress and pain in the rest of the leg and body during
exercise. Check the shoes frequently to see if they are
loose or in need of resetting, which should be done every
812 weeks. If the hoof grows quickly, the shoes can
actually cause harm by forcing an unnatural angle to the
pastern. Lameness so caused is usually temporary and
resolves with new shoes, but can become permanent if left
unattended due to abnormal stresses placed on the rest of
the leg.

Proper nutrition plays a great part in prevention of hoof
injuries and lameness. Whether the animal is an elite
athlete or a backyard companion, the types and amounts of
roughage, grains, and vitamins/minerals should be tailored
to exercise/stress needs in order to avoid problems with
either obesity or poor body condition.

Especially important in avoiding lameness problems is
assuring adequate levels of electrolytes (sodium, chloride,
potassium, magnesium) thiamine, biotin, selenium, and
vitamins C and E in a horse’s diet. Constantly available
fresh water, especially at this time of year, is a must.
Horses fresh from exercise should not be allowed to drink
until adequately cooled down to avoid lameness or muscular,
cardiovascular, and colic (gastrointestinal) problems.

Proper exercise is essential. Temperatures in late summer
near 100 degrees or combined with high humidity (greater
than 50 percent) can cause a horse to sweat excessively,
increasing chances of muscle strain, sprain, tying up, heat
prostration, and simple exhaustion. Whatever the exercise,
try to preserve mental and physical condition, offering a
variety of workouts while minimizing the amount of stress
the animal feels. Help cope with seasonal weather extremes
by scheduling heavy workouts early in the day, before the
sun, temperature, humidity, and insect population are at
peak. Check equipment to be sure it fits well and there is
no wear or grime at key contact points. You’d never believe
how much lameness occurs because of faulty harnesses,
saddles, bridles, and other tack. Avoid particularly
difficult maneuvers on uneven ground and allow adequate
warm up before and cooling out after work.

Needless to say, lameness is likely to crop up again later
in life in any horse with a history of lameness ,
especially if the owner doesn’t pay attention to some of
the keys outlined above. Ninety percent of lameness occurs
in the foot and hoof, and a majority of these are found in
the horse’s front legs. There’s a great deal of truth in
the old statement, “No foot, no horse.” Prevention and
sound management on the farm are the key to avoiding
lameness and saving your horse (and you!) from days of
pain, stress, and soreness.

Dear Andrea:

Our horse has terrible sores over his withers. We use a
saddle pad when exercising him. What else can we do?

-Paul Tucker Davenport, IA

Dear Paul:

Several factors help create saddle sores, those crusting
blisters located behind the animal’s shoulders, on the
withers (between the shoulder blades), and on sides of the
chest. Foremost of the causes of saddle sores is improper
saddling. Some saddles are made to fit only a sawhorse,
never an animal. An ill-fitting saddle, pad, or girth,
coupled with a heavy or awkward rider, and some dirty tack,
can turn the nicest horse into a painful, uncooperative
snide. Saddles are often sold by dealers who do not
understand your horse’s anatomy in

particular and are anxious to sell the tack, not fit the
animal. Check your saddle carefully to be sure that it’s
centered on the withers. Pressure sores over or behind the
withers are often caused by a saddle that is too low on the
back. Sores along the spine itself are often caused by
cheaply made saddles that are nailed together underneath
(with nails still evident) or by saddles with a high arch
that bounce on the spine during exercise.

Be sure to brush the back of the animal–even if there
is no time to brush the rest of the horse-prior to saddling
or applying any type of equipment. Likewise after exercise,
it helps immensely to wash the area under and around the
saddle, massaging areas of high contact. The saddle should
be cleaned with soft detergent (Murphy’s oil soap) and
leather conditioner on a regular basis. Saddle pads quickly
absorb sweat and debris, and also need to be changed if not
washed frequently.

When actually saddling the horse, place the saddle a bit
forward on the withers and slide it back, snugging it into
place with the girth. This will eliminate hair bunching
inappropriately and causing sores. After the girth is
cinched, be sure that there is no fold of skin trapped
underneath it. If necessary, stretch the front legs out one
at a time, as if shaking hands with the animal to pull the
folds smooth.

Once a sore has developed, the quickest cure is to give the
horse’s back a rest. In fact, if the horse needs to be
ridden, bareback is best. Otherwise, use different forms of
exercise and equipment which will not come near the injured
area. Experimenting with different saddles may help down
the line. But with an open sore, new tack may exacerbate
other painful areas, as the horse has learned to compensate
and shift weight appropriately to move under the painful
tack already. Rest is essential, as is cleanliness. Hot
packing and carefully drying, as well as preventing fly
contamination, will help. Most dressings occlude air which
is conducive to healing the broken skin. You can use a
horse with a saddle sore if you cut a pad so that no part
touches the sore, and place another pad over this one.
However, beware, as this pad arrangement slips easily and
usually causes old sores to worsen and new ones to appear.

Dear Andrea:

I have a five-year-old mixed terrier/shepherd who limps
very badly and has trouble getting up and standing any
length of time. She can no longer jump on the bed or couch.
What can I do?

-Rose M. Jolly Kendall Park, NJ

Dear Rose:

There are a number of problems which affect the back and
hind limbs of dogs, causing them a great deal of pain or
inability to exercise. The first step in diagnosing them
would be through manipulations performed by your
veterinarian. Once you know where the problem
originates-muscles, bones, tendons, ligaments,
nerves-X-rays are probably in order. Your veterinarian may
want to perform more specialized studies such as scans, dye
studies, or muscle activity measurements, to identify the
severity of the problems.

In general, many shepherd and shepherd-mix dogs suffer from
a variety of spine, hip, and knee problems. The array of
conditions is so vast that it’s difficult to pinpoint a
treatment to fit all. Weight reduction through an
appropriate diet–not simply decreasing the amount of
food-is important in treating most orthopedic problems. The
more weight, the more difficult it is for the animal to
heal appropriately.

In addition, pain relievers are often necessary. You can
use aspirin if your dog has had no bleeding and
gastrointestinal problems; dosages vary per specific animal
metabolism and weight. There are many veterinarians who
recommend essential fatty acids for arthritic problems.
These come in many formulations and are extremely
beneficial for dogs with skin, coat, and arthritis
problems. I happen to believe that many of these animals,
regardless of specific arthritic problem, would benefit
from certain joint fluid precursors, or cartilage extracts,
called polysulfated glycosaminoglycans, which can be given
in oral or injectable forms.

Exercise should be restricted to short, frequent walks
while repair of injured tissue takes place. Rest is
essential; physical therapy can be performed at home, and
if done correctly, helps the animal “warm up” for limited
exercise or “cool down” appropriately. Several surgical
options have become available, although your vet is best
able to make decisions on whether this is appropriate