PUBLICATION 1006
OCTOBER 1962

Control
of

MOW OH

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by W.O.Haufe

l^| Agriculture
m~m Canada

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RESEARCH BRANCH

CANADA DEPARTMENT OF AGRICULTURE

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CONTROL OF CATTLE LICE

W.O. Haufe
Research Station, Lethbridge, Alberta

Chemicals are not the perfect means of controlling lice and other pests
of livestock. Do not assume that routine use of them will replace the need
for good husbandry practices in maintaining the health of animals.

Animals vary in susceptibility to infestation. Nutrition and shelter,
especially during cold weather, also affect an animal's natural resistance
to the rapid development of parasites. First of all, keep animals in comfort-
able, sanitary quarters with adequate nourishment. Then use pesticides as
recommended for the most satisfactory results.

Insecticides are toxic materials for emergency uses. Indiscriminate
use or use in place of proper animal care is misuse.

GENERAL CAUTIONS: Follow closely all the cautions listed on the
insecticide label, especially those on toxicity to livestock, harmful residues
in animal products for human consumption, and hazards to the user in hand-
ling. The interval required between the last application and slaughter for
some of the treatments varies with the material used, the number of applica-
tions, and the amount applied. Keep to the interval given to avoid residues
that would render the meat unfit for sale. You may be held responsible for
misuse of materials.

Handle all insecticides carefully and store them safely to avoid acci-
dental poisoning of animals or humans.

Two species of sucking lice are SYMPTOMS AND ECONOMIC

common on cattle in Canada: the short- IMPORTANCE
nosed cattle louse (cover illustration,

top)1 and the long-nosed cattle louse Lice are usually noticed first on

(cover illustration, bottom). One weakened and unthrifty animals, es-

species of biting louse (cover illus- pecially those wintering outdoors,

tration, middle) is also common. Some animals may be heavily infested

Haematopinus eurysternus (Nitz.).
2

Linognathus vituli (L.).
3

Bovicola bovis (L.).

whereas others in the same herd carry
few or no lice. Therefore, to learn the
full extent of an infestation it is ne-
cessary to examine most or all of the
animals. This is particularly true in
large range herds, since most lousy
animals are irritable and wary and
avoid handlers unless the whole herd
is worked through a chute.

Very lousy cattle, especially
white-faced ones, usually look greasy,
dirty, and rough; they smear them-
selves with blood from scratches and
open sores and from crushed, blood-
engorged lice. When an animal has
many lice for a long time without treat-
ment, the whole body may become
infested, and large patches of skin
may become bare from rubbing.

Lousy cattle spend much time
scratching and rubbing themselves
instead of feeding. Louse- free cattle
may gain from 1/2 to 2/3 pound a day
more than heavily infested ones dur-
ing the first two years of growth.
Calves heavily infested with biting
lice may not gain normally in unfavor-
able falls and winters. The poor
appearance of cattle infested with any
kind of lice may seriously reduce the
market value of either commercial or
purebred stock.

In older cattle, longflasting
heavy infestations cause low vitality.
Sucking lice feed largely on red blood
cells and can reduce their number to
half of normal. Animals weakened by
anemia in this way are unable to with-
stand severe conditions or unusual
exercise and become easy victims of
cold weather, severe conditions of
transportation, and diseases that are
resisted by healthy animals.

IDENTIFICATION AND LIFE
HISTORIES

Sucking and biting lice differ in
habits, and you need to know which
kind your cattle have so that you may
get the best results from control treat-
ments.

Sucking lice may be distin-
guished from biting lice by their slate-
blue color. They are usually found on
mature stock; few nursing calves are
susceptible. They usually have their
heads partly buried in the skin, and
often form dense colonies on small
areas of the animal.

The adult female is about 1/8
inch long and the body is about as
broad as long. The male is slightly
smaller. The head is short in compari-
son with the body.

Sucking lice spend most, if not
all, of their life cycle on cattle. Al-
though they usually feed in one place
on the animal, they sometimes crawl
to other animals in the same pen or
pasture as well as to stable litter,
bedding, walls, and floors. The eggs,
or nits, are cream-colored and are
attached singly to hairs close to the
skin. They usually hatch in 11 to 20
days, the average period being about
15 days. The newly hatched lice look
much like the mature ones except that
they are much smaller.

The cattle biting louse may be
distinguished from a sucking louse by
its conspicuously red head and light-
cream or yellowish-white body. It is
commonly found under flakes of scurf
as well as on the surface of the skin,
since it feeds on hair, loose scales,
and other sloughed debris. Unlike the

\

sucking lice, it usually moves about noticeably large numbers of lice

on the animal as it feeds and causes throughout the summer, even when

considerably more irritation. It is also they shed their hair,

common on young as well as on mature During the winter, sucking lice

cattle. may form colonies on parts of the ani-

The adult female is about 1/16 mal where they cannot be dislodged

inch long and has a broad, blunt head. by licking, or by rubbing against walls,

Its small size makes it difficult to fences, trees, or other objects. On

detect, but you can see it if you exam- lousy animals, dense colonies are

ine the coat of the animal closely. usually found on the crest; in the

The life history of this louse is simi- folds on the sides of the neck; on the

lar to that of the sucking lice except brisket and inner surfaces of the legs;

that it develops more rapidly. around the ears, scrotum, udder, and

Differences in size and shape hindmost part of the animal; at the

of the two kinds of lice are shown in bases of the horns; and on the tail

the cover illustrations. and tailhead. If neglected, they may

even surround the eyes and nose. In

rapid inspection of large numbers of

DISTRIBUTION AND HABITS rJge aJmals passingtlfrougha chute,

Both biting and sucking lice a few partings of the hair on the dew-
may infest cattle in any of the stock- lap and in the folds of skin on the
raising areas of Canada. The short- side of the neck below the ear usually
nosed sucking louse is usually the expose sucking lice even if the ani-
most abundant on both range and farm mal has few.

cattle in Western Canada, and the Sucking lice move little while

long-nosed sucking louse in Eastern developing under favorable conditions.

Canada. Serious infestations of the But they crawl about on the hair and

short-nosed louse may occur in East- skin before attaching for feeding and

ern Canada on feeder cattle shipped after completing their growth. They

from the west in the fall for finishing, may then move from animal to animal

Lice usually become less abun- by contact or by crawling across walls

dant with the approach of warm, moist and bedding.

weather in spring. Natural shedding Since biting lice move over the
of hair at this time of year may con- hair and skin while feeding, they are
tribute to this decrease. During the generally found on larger areas of the
summer, lice become hard to find on animal than are sucking lice. On
grazing cattle; but from only a few heavily infested animals they congre-
survivors they may increase rapidly gate around the base of the tail, on
in the following fall and early winter, the shoulders and neck, and occasion-
In large herds, especially on ranges, ally on various parts of the body. They
a few head usually have many more may live a week or more off the host
lice than the others and act as 'car- as compared with two to three days
Tiers.' Unlike most cattle, these have at most for sucking lice. Therefore,

biting lice are more likely to spread
within a herd than are sucking lice.
Lice that hatch from eggs sloughed
off on shed hair usually do not live
more than three days without a host.

METHODS OF CONTROL

Keep animals in a favorable
environment with adequate nourish-
ment. Inadequate diets and exposure
to severe weather and hardship in
winter create the conditions for heavy
infestations of lice. Good management
is as important as treatment with
chemicals in preventing infestations.

Because chemicals vary in
effectiveness according to husbandry
practices, certain chemical treatments
may be more successful in some re-
gions than in others. Therefore, plan
chemical treatments carefully to fit
your particular type of feeding opera-
tions and marketing practices.

Helpful Husbandry Practices

The following practices ensure
adequate protection of animals:

1. Keep pens, stalls, feedlots
and barnyards clean and dry. Com-
fortable, thrifty animals help to keep
themselves louse-free by grooming if
they are properly housed.

2. Before bringing in louse-free
animals, see that their new quarters
are free of lice. If the quarters have
been occupied by lousy cattle in the
last three days, clean and then spray
or wash them with a suitable insecti-
cide. Use an economical residual
insecticide (4, Table 1) at the same
concentration recommended for use on

cattle. Spray the walls and floor with
enough material to wet all surfaces,
or scrub them with a stable broom
dipped in the insecticide. Do not
spray bedding.

3. In the fall, inspect cattle
before putting them in feedlots or
barns or when moving them to winter
feeding areas. Spray all cattle with
an insecticide, preferably one that is
effective with one application.

If careful inspection is imprac-
tical, as in some special ranching
operations, spray all the winter stock
when sorting animals for sale. In
Western Canada, as a general rule
complete this treatment between
September 15 and October 31 for best
results. Fall treatments in southern
Alberta may be delayed until Novem-
ber if the weather is favorable; but
the later treatments have less preven-
tive value against winter infestations
in other parts of the prairies.

In cold seasons, long, thick hair
keeps the insecticide from reaching
the skin unless increased care and
labor and high-pressure equipment are
used. High-pressure sprays are best
applied during warm weather. Then
treated animals have time to dry be-
fore exposure to chilling night tem-
peratures, which may induce or aggra-
vate respiratory infections.

If preventive fall applications
are thorough and well timed, they are
equally effective on range, feedlot,
and barn cattle.

In spraying, wet the animals to
the skin and cover all parts. Pay
special attention to the underline and
protected parts such as the escutcheon

and brisket, where lice (especially
sucking ones) usually congregate.
One or two colonies of sucking lice
missed on an animal may be enough
to reinfest it quickly after the spray
has lost its effect.

You may prefer to use the less
expensive insecticides for economy
if labor and convenience in handling
animals are not the more important
factors in cost of production, i.e., for
sheltered animals on small farms.
DDT, lindane, chlordane, and toxa-
phene are low-cost materials but must
be applied at least twice in the fall
to ensure lasting protection through
the winter. Make the second applica-
tion of these materials 12 to 16 days
after the first, to kill lice that hatch
in the interval.

For most commercial operations,
especially on ranches in southern
Alberta and British Columbia, it is
economical to use an organophosphate
insecticide in a single application.
Malathion, Co-Ral, ronnel, or Ruelene
is satisfactory. Lower labor costs and
lower losses in weight because of
handling compensate for the higher
costs of materials. Further, when an
organophosphate is applied in late
fall no follow-up treatment is needed
in cold weather.

4. In the spring, inspect animals
before letting them out to pasture,
especially on the range. Otherwise,
highly susceptible cows with calves
may become severely infested by late
summer. These animals may act as
'carriers' and reinfest the herd in the
fall when normal animals are more
easily infested. Shedding of hair in

early spring may help to reduce num-
bers of lice on moderately infested
animals. If infestations are still no-
ticeable in late spring, consider these
animals as 'carriers' since they do
not normally rid themselves of lice
during the summer months. Treat
these animals with one of the organo-
phosphate insecticides, and see that
the treatment has been satisfactory
before putting them out to pasture
with other animals.

Since it is difficult to control
lice satisfactorily on 'carrier' ani-
mals, it is sound practice to cull
habitually lousy ones, especially from
breeding stock, and market them at
the earliest opportunity.

Spring treatment is most bene-
ficial on infested cows mothering
calves. Severe infestations usually
cause anemia. Anemic cows are poor
milk producers and their suckling
calves fail to reach the desired weight
at weaning time in the fall.

5. In winter, cattle require spe-
cial attention if they become lousy
during cold weather. Limit treatment
to hand washing or scrubbing with a
suitable insecticide (Table 1) in
sheltered quarters, or to dusting with
an insecticide powder if shelter is not
available. During mild weather in
winter, use a high-pressure spray out-
doors for large groups if they have
time to dry before they are exposed to
a freezing temperature or cold winds;
in southern Alberta, for example,
chinook weather may be used to ad-
vantage. If you separate heavily in-
fested animals from the herd during

and shortly after treatment, fewer lice
will spread to untreated animals.

Uses of Insecticides

Effective insecticides, rates of
application, and uses are listed in
Table 1 (inside front cover). The
recommendations are only for use
against cattle lice.

Table 2 (inside back cover)
gives the amounts of insecticide to
add to 100 imperial gallons of water
to have spray mixtures of the exact
strengths desired; the amounts of
powdered materials are given on the
basis of weight and those of emulsible
concentrates on the basis of liquid
volume. This table may be used also,
with Table 1, to estimate the amount
of concentrate needed for a given num-
ber of animals.

Mix materials exactly at the
concentrations recommended. The
dosages are given for best results.
Increasing the dose does not kill more
lice. It may cause pronounced ill
effects on the animal, and may make
the meat unfit for sale because of ille-
gal residues.

Most insecticides deteriorate in
prolonged storage. If stored from sea-
son to season, especially in opened
packages, they may not give satis-
factory control.

CAUTIONS: Note the following
cautions as well as those on page 3.

Do not use wettable powders as
dusts on animals. The animal may
absorb an overdose of toxic materials
through the skin if soaked by rain
after treatment. Be safe by using only

materials that are labeled for use on
animals as dusts.

Do not mix different materials
even though they may be recommended
for use separately on animals. In spe-
cial cases a combination of chemicals
is more effective against a pest, i.e.,
the common treatment for lice and
ticks (See "Multipurpose Treatments,"
p. 11). Other insecticides may interact
in the animal and be much more potent
than either alone. Therefore, do not
mix materials unless the label states
that the two formulations are compat-
ible for use on livestock. For the same
reason, do not treat animals for lice
with an insecticide if they have been
treated recently with another. Either
use a material that is effective against
both pests or allow an interval of two
to three weeks between applications.

Especially if you handle insect-
icides often, take care not to get any
on your skin or to inhale the vapor. If
you handle different insecticides, they
may interact in your body and be much
more toxic than any of them alone.
The toxic effects persist in man for
long periods. Use waterproof clothing
and respirators with adequate filters.
Always remove your clothing and
launder it before wearing if it is con-
taminated with an insecticide. If you
wash animals by hand, wear clean
rubber gloves, preferably unlined ones,
and a rubber apron.

Sprays. — Plan louse-control op-
erations in advance and do not spray
in cold weather unless you can protect
the animals until they are dry.

For effective, economical, time-
saving treatments, use any type of

8

pump that can deliver 6 gallons a min- barn animals by the head to a fence

ute at a nozzle pressure of 400 pounds or a wall, leaving enough space to

per square inch. With such a pump move them with the force of the spray

you can readily handle large groups and thoroughly wet all parts of their

of cattle. Weed sprayers and some bodies.

general-purpose sprayers that cannot A 4- or 4%-foot spray gun is a

deliver pressures above 200 p. s.i. may handy size for treating animals in

not wet the animal right to the skin. pens. If the gun has a shut-off and an

The amount of spray required adjustable- angle nozzle controlled at
for adequate wetting varies widely, or near the handgrip, it is more readily
depending on weather, season, and handled and wastes little insecticide,
condition of the hair. Two gallons per Disk sizes should not exceed No. 4
head is enough to wet the largest and (4/64 inch) for most sprays recom-
most heavily coated animal in winter, mended. No. 3 (3/64 inch) disks are
One gallon is enough for full-grown best for emulsible materials in cone-
animals in early-fall applications on pattern sprays. Disks should be re-
short-haired animals. Late-fall and placed regularly, especially when
winter applications on thick-coated wettable powders are used in high-
animals require an average of \lA gal- pressure sprayers. Worn or large disks
l°ns' waste spray materials, especially in

Economy in the use of spray treating large herds. Nozzles of any

materials depends largely on the abil- design, including those with a fan

ity of the spray operator and on the spray, are satisfactory if they allow

facilities for holding cattle. Cattle rapid and thorough wetting of the

cannot be sprayed thoroughly for lice animals to the skin.

in some chutes. A small pen that holds

.i . . . I 11 i Aerosol bombs, — Synergized py-

tnree to six animals and leaves enough / o r/

r .1 i ji rethrin mists, available in aerosol

space tor the operator to handle a '

j l n i *l bombs, are useful in treating a few

spray gun and reach all parts ot the ' &

i • i r i j lousy milking cows. They are effect-

animals is best tor range stock and J & J

i I j ive only when used inside a stable or

large herds. J

rpi r li i. ,.. t a closed barn and when the lice are

the tall application tor prevent-

. r tc M.- hit with the mist,

ing winter infestations is effective

only if all, or most, of the underline, Hold the bomb within a few

escutcheon, and brisket of the animal inches of the animal and cover in-

is wet as well as the back and sides. fested areas by ruffling the hair and

The lower parts mentioned are the directing the mist into it. Careful

centers of the initial build-up and application indoors reduces the number

spread of lice. Therefore some con- oi lice in winter, but the bombs are

fining devices such as squeezes and not economical for large numbers of

chutes are not suitable for thorough animals or for fall applications to

single-application operations. Tether prevent infestations.

An alternative for a few lousy
milking cows is to apply a pyrethrin
emulsible concentrate mixed with
water. The mixture may be prepared
easily in small amounts and applied
with a hand sprayer.

Washes. — Washes are econom-
ical occasionally for a few lousy
animals but are expensive in time and
labor for large herds. Power spray
equipment is more economical in large
livestock operations.

However, washes prepared from
emulsible concentrates or wettable
powders are more easily applied than
dusts when the coat is thick and
shaggy. If thoroughly applied, washes
can be the most effective treatment.

In winter, treat the animals in a
warm place. Be sure to scrub them
enough with a stiff-bristled brush to
wet the skin. Give special attention
to areas along the escutcheon and
underline, between the legs, and on
the brisket and neck although these
are hardest to reach.

Dusts. — Dusting is less effect-
ive than other methods of application
but the materials cost less. When lice
are a perennial problem in a herd, use
dusts only for emergency treatment in
severe winter weather.

DDT, lindane, chlordane, rote-
none, and most other dusts are inef-
fective, especially against sucking
lice, unless they are rubbed or brushed
through the hair to reach the skin. As
with other external applications, the
areas along the underline where lice
congregate must be treated to achieve
satisfactory control. A hand brush
with long, thick, flexible bristles is

useful in tapping or brushing the dust
through the hair, especially on parts
of the animal with dense colonies of

ice.

Applying dust only to the back
is ineffective because few, if any,
lice are found near the back line. For
this reason, dusting by hand may not
give protection throughout the winter
even when done often. Power dusting
equipment gives more thorough appli-
cation and better results, but it is
practical only in large ranching and
feedlot operations.

If lice are still numerous after
three applications of dust, treat the
animals thoroughly with a wash in a
warm shelter.

Internal treatment. — When one or
a few very lousy animals need prompt
treatment to prevent serious debility
during severe winter weather, give
them a systemic insecticide by mouth.
Boluses, or pills, are no longer on the
market but can be prepared by veterin-
arians. They eliminate the expense
and inconvenience of preparing heavy
equipment and spray materials for
treating a few animals. Or a systemic
insecticide may be prepared as a
suspension in water and given as a
drench (Table 1) from a narrowneeked

bottle.

Dips and spray-dips. — For single

fall applications some insecticides

may be used to treat cattle in dipping

vats, or with spray-dip machines if

this equipment is available. These

methods entail more hardship and

rough handling for animals than others.

The losses in weight from rough hand*

10

ling and physical injury may offset
the gains obtained by controlling the
lice. Use only insecticides specifi-
cally labeled for dipping vats and
spray dips.

Back rubbers, — Back rubbers
impregnated with insecticides vary
greatly in effectiveness depending on
design, weather, and especially ani-
mals' acceptance of the equipment as
a scratching device. Since there is no
control of the dosage on individual
animals, some devices may be un-
satisfactory in ridding herds of lice
and preventing reinfestation. Some
animals may not use the device, espe-
cially when other scratching surfaces
such as fences, trees, and shelters
are available. Even the animals that
use them may continue to carry lice
on the inaccessible underparts of the
body. Back rubbers are useful in pre-
venting heavy infestations in large
feedlot operations if animals are
trained to use them.

Use a formulation labeled for
use on back rubbers such as 25 percent
emulsible ronnel at 1 gallon in 21
gallons of diesel or No. 2 fuel oil, or
5 percent emulsible toxaphene in
diesel or No. 2 fuel oil, or 2 percent
emulsible malathion in highly refined
mineral oil (5 ounces of 50 percent
malathion in 1 gallon of oil).

Do not mix the insecticide with
used motor oil. Do not use emulsions
of insecticides for back-rubber mixes
unless the label states that the formu-
lation is suitable for back-rubber
application.

MULTIPURPOSE TREATMENTS

When cattle have other external
parasites as well as lice, a single
treatment may often be used against
both pests. The following treatments
are recommended when lice are found
with the pests indicated.

Winter Tick

Especially in the Alberta foot-
hills, herds are occasionally infested
with the winter tick and it may be
desirable to treat cattle for this pest
when making applications against lice
in midwinter. For this purpose use
lindane or toxaphene (Table 1). Cattle
in areas heavily infested by the tick
may be better protected with a com-
bination of 0.5 percent toxaphene and
0.025 percent lindane. This treatment
is applied as a spray or wash only
during mild weather, or on animals
that are sheltered until dry. Use 0.5
percent lindane dust on animals out-
doors if the weather is severe.

Cattle Grubs

If cattle become very lousy in
March or April, both lice and cattle
grubs may be controlled with a rote-
none spray or wash. Treatments for
grubs with Co-Ral, ronnel, and Ruelene
(Table 1) in the fall generally also
prevent lice from becoming serious
later in the winter.,

4
Dermacentor albipictus (Pack.).

Hypoderma lineatum (de Vill.) and
H. bovis (L.).

11

Mange

Lice (especially biting forms)
may infest animals that have mange.
Use lindane for control of both the
mange mite and the lice when the two
occur together in a herd. Some animals
may continue to scratch and show dis-
comfort after treatment for lice and
the treatment is often assumed to be
ineffective. Examine these animals
carefully. If you find no lice the irrita-
tion may be due to mange mites, which
can only be detected by examination
of skin scrapings. Certain mange di-
seases are notifiable to authorities
for the health of animals.

RESISTANCE OF LICE
TO INSECTICIDES

Occasionally lice on some groups
of cattle become resistant to certain
insecticides. This may happen when
dusts are used often year after year.
If you use dust every winter, you may
find that DDT and perhaps lindane
are unsatisfactory. When this happens,
use chlordane or malathion spray as
soon as the weather permits. If you

use an effective spray in the fall, you
are less likely to have this problem.
Also, avoid using DDT on animals
that persistently carry many lice. It is
good practice not to use the same in-
secticide for several years in succes-
sion if effective substitutes are avail-
able. Check the adequacy of method
and equipment before attributing poor
results to the insecticide, for failure
is often traceable to faulty applica-
tion.

INQUIRIES

For more information, consult
your local agricultural representative.
If extension services are not avail-
able, write to the Scientific Informa-
tion Section, Canada Department of
Agriculture, Central Experimental
Farm, Ottawa.

Some brand names are used in
this publication because the chemical
names are difficult for general use
and there are no official common
names for the active ingredients.

12

LIBRARY / BIBLIOTHEQUE

AGRICULTURE CANADA OTTAWA K1A 0C5

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Copies of this publication may be obtained from :
INFORMATION DIVISION

CANADA DEPARTMENT OF AGRICULTURE

Ottawa

First published May 1957

1st revision February 1960

2nd revision October 1962

THE QUEEN'S PRINTER AND CONTROLLER OF STATIONERY

OTTAWA, 1962

25M - 29595 - 10-62 CAT. NO. A43 - 1006