Most available information on cleaning oiled mammals is related to the cleaning of oiled
Enhydra lutris - Sea otter. The same principles are applicable when cleaning other aquatic mammals which rely on their pelage for insulation, such as
Lutra lutra - European otter.
(B335.6.w6)
- Sufficient personnel need to be available for cleaning oiled
mammals: usually two to three people per
animal, but with as many as four or five possibly required for larger
animals. (D208.6.w6)
Pre-washing assessment:
- It should be remembered that the process of being cleaned is
stressful to the animal and that giving the oiled individual chance to
recover strength after capture before being washed is beneficial. (D208.6.w6)
- Before an individual is cleaned it must be assessed by a
veterinarian to determine whether it is in a sufficiently healthy
state to tolerate a cleaning procedure which may last for as long as
three to four hours. (B335.6.w6)
- If anaesthesia will be required for the animal to be washed then it
is important that the individual is in a sufficiently good
condition to tolerate anaesthesia. (D208.6.w6)
- It is recommended that oiled marine mammals should be given
supportive care, including treatment to restore normal body
temperature, to correct dehydration and to provide nutrition, for at
least 24 hours before being washed. (D208.6.w6)
- Species such as Enhydra lutris - Sea otter
also need to be
able to groom after being cleaned. (D208.6.w6)
- A veterinary examination should be conducted prior to cleaning,
considering the animal's general physical condition and strength,
alertness, blood parameters and any abnormalities noticed on general
physical examination. Only individuals passing this assessment should
be subjected to cleaning. (B335.6.w6,
D208.6.w6)
- However, with heavily oiled animals, or those covered with
fresh oil, washing as soon as possible is suggested to reduce exposure
to petroleum hydrocarbons by absorption or with ingestion associated
with grooming. (B335.6.w6,
P14.2.w5, P14.3.w15)
- For Enhydra lutris - Sea otter, it has been suggested that animals found in the
early phase of the spill (first three weeks) should be cleaned
immediately to reduce medical problems caused by exposure to fresh
oil, while a 24- to 36-hour stabilisation period will probably be
beneficial for those taken into care later than this. (B335.4.w4)
- Cleaning is not required for Enhydra lutris - Sea otter
with only light sheening
of oil on the coat and no penetration of oil or water into the
underfur. (B335.4.w4)
Pretreatment of tar patches and thick oil:
- While small areas of tar on non-furred mammals may not need to be
removed, tar should be removed from furred mammals. On non-furred
marine mammals, large areas of tar may need to be removed if they
might interfere with thermoregulation or cause toxicity. (D208.6.w6)
- Warmed (35°C/95-98°F) canola oil, olive oil or methyloleate is
applied to the areas of tar or very firm and thick oil and worked into
the area for up to 30 minutes or until the tar loosens and can be
wiped off. (D208.6.w6)
- Monitoring of body temperature is required during such treatment,
with appropriate treatment for any hyperthermia or hypothermia. (D208.6.w6)
- It is not recommended that patches of tarred fur should be
clipped off since the bald area will cause reduced heat retention
until the fur regrows, which could have serious, even
life-threatening, implications for animals which are highly reliant on
their fur for insulation and in debilitated individuals or those at
less than optimum weight. (D208.6.w6,
P14.3.w15)
Cleaning:
Otters (including Enhydra lutris - Sea otter
and river otters) and fur
seals:
Most information on cleaning oiled mammals related to the cleaning of oiled
Enhydra lutris - Sea otter. The same principles are applicable when cleaning other aquatic mammals which rely on their pelage for insulation, such as
Lutra lutra - European otter
and other river otters,
and fur seals.
(B335.6.w6, D208.5.w5)
- For tarry oil or with other oil which does not come off with
detergent, pre-treatment may be required using light mineral oil or
light olive oil worked into the affected fur and left for 30 minutes
before washing. (D60.7.w7)
Handling:
- [For information on handling of fur seals, see the paragraphs
immediately below, on handling of pinnipeds]
- Chemical as well as physical restraint will normally be required for
otters. (B335.6.w6)
- A combination of light sedation and restraint by a trained handler has been recommended for
Enhydra lutris - Sea otter.
(B335.6.w6)
- Physical restraint alone may be preferred for individuals which are hypothermic or extremely
lethargic. (B335.6.w6)
- The handler should grasp the skin between the shoulder blades and
maintain control of the animal's head movements. (B335.6.w6)
- North American river otters (Lontra canadensis - Canadian otter)
have been washed
while anaesthetised with 4 mg/kg tiletamine-zolazepam (Telazol)
intramuscularly, with up to two supplemental doses of 5 mg/kg ketamine
intramuscularly.
(J2.28.w2, P14.5.w14)
- Anaesthesia of Enhydra lutris - Sea otter
for cleaning has been carried out using
0.09-1.12 mg/kg fentanyl, plus 0.55 mg/kg azeperone or 0.09 mg/kg
acepromazine, plus 0.1-0.2 mg/pg diazepam. (B22.33.w9)
- Fentanyl (0.22 mg/kg) plus diazepam (0.07 mg/kg) is recommended for
adult Enhydra lutris - Sea otter, with reversal of the fentanyl at the end of the
procedure, using naltrexone (0.44 mg/kg recommended but a dose three
to four times the dose of fentanyl may be required). (D208.6.w6)
- Gaseous anaesthesia [with isoflurane] may have increased mortality in oiled
Enhydra lutris - Sea otter: it is suggested that inhaled oil vapour coated the
trachea and
bronchi and, on use of the isoflurane, was dissolved by this
anaesthetic and moved deeper into the respiratory system with
resultant distress, toxicosis, respiratory failure and, the day
after anaesthesia, death. (J4.208.w1,
B23.59.w8)
Washing:
- It has been recommended that at least two people are used for applying detergent and washing the fur.
(B335.6.w6)
- A team of four to six people per washing table is recommended, with
one person, equipped with heavy gloves, just to hold the head and
forearms. (D208.6.w6)
- An ophthalmic ointment should be applied to the eyes prior to
starting washing to give the eyes protection from both oil and
detergent. (B335.6.w6)
- Detergent should be kept out of the animal's eyes, nose, mouth and
ears during washing.
(B335.6.w6)
- As with oiled birds, Fairy Liquid/Dawn (Procter & Gamble) is the recommended detergent and a dilution of 1:16 with water
is recommended.
(B22.33.w9, B335.6.w6,
J30.66.w2); 5%
Dawn/Fairy Liquid is recommended. (D208.6.w6)
- Constant monitoring of body temperature using a flexible rectal probe is
recommended during the whole washing procedure. (B335.6.w6)
- Water used for washing should be at or near normal core body
temperature (38.4°C). (P14.5.w14)
- For Enhydra lutris - Sea otter, water controlled to a temperature of 28 to 32°C
(80-89°F) is recommended, allowing alteration in reaction to
rises or falls in the individual's body temperature. (B335.6.w6,
D208.6.w6)
- For river otters, water at or near normal body
temperature may be preferred to reduce cooling of the otter.
Washing North American river otters (Lontra canadensis - Canadian otter) in 24°C
water was shown to reduce core body temperature at a
rate of about 0.1°C per minute, while this
did not occur in otters washed in water of 39°C (near normal
core body temperature, 38.4°C). (J2.28.w2,
P14.5.w14)
- Water should be adjustable, allowing use of
cooler water if otters become too hot (e.g. reduce water
temperature from 39°C to 34°C for river otters reaching a
core temperature of 41°C. (J2.28.w2)
- For fur seals (Otariidae - Sea lions (Family)), thermoneutral (98°F/37°C) water
and 5% Dawn detergent is recommended. (D208.5.w5)
- Cooler or cold water is required if the animal becomes
hyperthermic during washing. (D208.5.w5)
- Experiments with fresh pelts showed that exposure
to fresh water increased the thermal conductance of river otter (Lontra canadensis - Canadian otter) fur to about 2.4 times that seen in air (8.76 +/-
0.68 W/m C, compared to 3.49 +/- 0.16 W/m C in air) and in salt
water thermal conductance was increased further. Similarly for
mink (Mustela vison - American mink) thermal conductance was 7.83 +/- 0.62
W/m °C in fresh water compared to 3.23 +/- 0/08 W/m °C in air and
there was also a further increase in thermal conductance in salt
rather than fresh water. In comparison, an Enhydra lutris - Sea otter pelt showed only a 0.2% increase in thermal conductance
when immersed in water (4.47 +/- 0.61 W/m °C conductance in fresh
water, compared with 4.25 +/- 0.66 W/m °C in air) and no
significant further increase in conductance for sea water (p
<0.001). (P60.1.w39)
- Detergent should be gently massaged into the oiled area of pelage then rinsed out with fresh water.
(D60.7.w7,
D208.6.w6,
B335.6.w6)
- Cycles of washing and rising are suggested, until there is no
longer any oil visible in the rinse water and no odour of petroleum. (B335.6.w6,
D208.6.w6)
- For an Enhydra lutris - Sea otter
it has been suggested that at least 40 minutes of washing and four to eight litres of
1:16 detergent solution
- would be required for oil removal; a longer time may be required if there is heavy oiling,
weathered oil, or tar balls. (B335.6.w6);
washing may take 40 to 60 minutes. (D208.6.w6)
Rinsing:
- After application of detergent the pelage must be rinsed using fresh water at moderate pressure (30-40 psi
suggested, using spray nozzles) and 28-32°C
(82-90°F). (B335.6.w6)
- This temperature may be raised or lowered depending on the individual's body temperature.
(B335.6.w6)
- Water used for washing should be at or near normal core body
temperature (38.4°C). (P14.5.w14)
- Hard water (high calcium concentration) will require softening using a commercial water softener.
(B335.6.w6)
- For fur seals, rinsing with soft (3 - 5 grains) water at
30-40 psi using a shower spray is recommended. (D208.5.w5_
- Rinsing for about 40 to 60 minutes may be required to ensure the detergent has been removed and assist in restoring the fur's natural water
repellency. (B335.6.w6,
D208.6.w6)
- Normal fur, or fur which has been adequately washed and rinsed, will develop a striated
appearance, visibly different from the matted appearance of oiled fur.
(B335.6.w6)
Drying:
- Complete drying of the fur after washing is important. In
North American river
otters (Lontra canadensis - Canadian otter)
it was shown that failure to completely dry the fur can contribute to
a fall in core body temperature even after washing in water of the
correct temperature. (J2.28.w2,
P14.5.w14)
- Absorbent paper towels or clean cotton towels are most effective for removal of the bulk of the water, replacing towels as they become moist.
(D60.7.w7,
D208.6.w6,
B335.6.w6)
- Once the bulk of the water has been removed the fur may be dried using
commercial, temperature-controlled pet blow driers. (B22.33.w9, B335.6.w6,
D60.7.w7,
D208.6.w6)
- For Enhydra lutris - Sea otter
and fur seals drying in a pen using
industrial pet driers set at a temperature of 20°C (68°F) (room
temperature) are recommended. (B335.6.w6,
D208.5.w5)
- Cooler air may be required as drying progresses, to avoid
hyperthermia developing. (D208.6.w6)
- For river otters: hand-held human hair driers have been used to dry North American river
otters (Lontra canadensis - Canadian otter),
with four hair driers used simultaneously on one animal. (J2.28.w2)
- After drying the otter should be left in a cage in a critical care room until it has recovered from sedation.
(D208.6.w6)
- The animal should be kept in a dry pen such as a kennel with a
slatted floor until fully recovered and any urine or faeces
immediately washed away. (D208.6.w6)
- Close monitoring for signs of hypothermia or hyperthermia as
well as dehydration and degree of alertness is
recommended during this time. (B335.6.w6,
D208.6.w6)
- After recovery from sedation/anaesthesia, small blocks of ice to eat
can be offered (to relieve stress as well as dehydration), then food.
(B335.6.w6, D208.6.w6)
- Once dry, animals can be placed in an outdoor pen. (D208.6.w6)
- Once the animal has a stable core body temperature, is eating, and
is showing normal
grooming behaviour, it can be transferred to a pen with an appropriate pool (seawater for
Enhydra lutris - Sea otter).
(B335.6.w6)
Note: Cleaning of oiled Enhydra lutris - Sea otter
pelts has been shown to reduce
the lipid content of the pelage (from 7.4 mg lipid per gram of fur down to
just 2.0 mg/g), although proper cleaning and rinsing did restore water
repellency. Thermal conductance of pelt samples was returned to normal by
cleaning but conductance in live otters is increased. (J30.60.w1,
J30.66.w1, J30.66.w2)
At least eight days were required following oiling and cleaning before
average oxygen consumption returned to normal, indicating a return of the
normal insulative quality of the fur. (J30.60.w1)
Pinnipeds:
- Cleaning should be carried out immediately for individuals covered
with fresh oil, in order to reduce exposure to inhaled vapours. (P14.2.w5,
P14.3.w15)
- In other circumstances, maintenance for 24 hours, allowing
evaluation of the animal's overall condition, is recommended prior to
cleaning. (P14.2.w5,
P14.3.w15)
- A general physical examination should be carried out prior to
cleaning, including assessment of the overall condition, heart rate,
lung auscultation, checking the colour of the mucous membranes,
checking the eyes and, if required for research, taking a sample of
oiled fur for analysis. (P14.2.w5)
- Fur seals have only a thin layer of blubber and rely on their pelage
for insulation; cleaning of these species is more like cleaning
otters. (D208.5.w5)
See above for information on cleaning fur seals (together with
information on cleaning otters).
Restraint
- Physical restraint may be sufficient for cleaning of neonatal phocid
seals such as harbour seals (Phoca
vitulina - Common seal). (B377.13.w13,
P14.2.w5, P14.3.w15)
- For medium-sized phocids, diazepam (0.2 mg/kg) may be used to
provide sedation allowing safe handling. (P14.2.w5, P14.3.w15)
- For larger pinnipeds, full anaesthesia may be required for safe
handling during the cleaning process. Injectable anaesthetics may be
used and, if required, inhalation anaesthesia may be used to prolong
the anaesthetic. (P14.2.w5, P14.3.w15)
- Note: Use of inhalant anaesthetics is not recommended
in mammals covered with fresh oil, due to the risk of recently
sequestered toxic hydrocarbons becoming remobilised. (P14.2.w5, P14.3.w15)
- Additional doses of injectable anaesthetic agents to prolong
anaesthesia are not recommended. (P14.2.w5,
P14.3.w15)
- Twelve hours of fasting prior to anaesthesia will reduce the risk of
vomiting and aspiration. (P14.3.w15)
- Preanaesthetic treatment with atropine (0.02-0.04 mg/kg atropine
sulphate) is recommended to prevent pulmonary oedema and bradycardia).
(P14.3.w15)
- Heart rate, respiratory rate and temperature should be monitored
during the wash, particularly in anaesthetised animals. (P14.2.w5)
Prewash
- For large areas of tar, pretreatment with mayonnaise, worked into
the pelage and left for 30 minutes has been recommended. (P14.3.w15)
- See also general recommendations for mammals given above.
- Small areas of tar do not need to be removed. (P14.3.w15)
Washing
- Thermoneutral water (about 98°F/37°C) should be used. (D208.5.w5)
- If the animal becomes hyperthermic during washing, cold water
should be used. (D208.5.w5)
- Detergent is applied undiluted, or mixed 50:50 with water so that it
is easier to work into the hair/oil, and rubbed in until the oil is
seen to be removed. (D208.5.w5)
- Washing may take 10-30 minutes depending on the type and extent
of oil, the efficiency of personnel and the species and health of
the individual animal. (D208.5.w5)
- Galapagos sea lions Zalophus wollebaeki (Otariidae - Sea lions (Family))
oiled during the Jessica oil spill in 2001, were cleaned using
liquid detergent and water; mucous membranes were cleaned using milk. (J313.47.w1)
- For harbour seal (Phoca
vitulina - Common seal) pups oiled during the Exxon
Valdez oil spill, dilute detergent (Dawn) was ineffective, but
lathering with full-strength detergent, followed by rinsing with
fresh water, repeated until no more oil was visible on the seal or
in the rinse water, was effective. (B377.13.w13)
- Dawn detergent (Proctor and Gamble) at a 1:16 dilution with water
has been recommended. (P14.2.w5, P14.3.w15)
Rinsing
- Rinsing can be started under restraint with the animal at the wash
station, but finished with the animal unrestrained in a pen, using a
pressure nozzle. (D208.5.w5)
- This reduces the time of restraint. (D208.5.w5)
- Rinsing should continue until no oil or detergent is visible in
the rinse water coming off the animal. (D208.5.w5)
- Water may be thermoneutral or, if there are signs of
hyperthermia, cold water may be used. (D208.5.w5)
- Cold tap water may be used for most pinnipeds to reduce the
possibility of hyperthermia due to restraint. (P14.2.w5)
- Warm water should be used for neonates and debilitated animals to
avoid hypothermia. (P14.2.w5, P14.3.w15)
Drying
- Drying may not be required for healthy adults. (P14.2.w5, P14.3.w15)
- Healthy adults can be placed directly into outdoor pens and
allowed to dry naturally. (D208.5.w5)
- Drying using cool air blowers is recommended for neonates and for
debilitated individuals. (P14.2.w5, P14.3.w15)
Insectivorous Bats (Microchiroptera) Chiroptera - Bats (Order):
- Oil contamination of the fur of bats is not infrequent in insectivorous bats presented for rehabilitation in the UK. (B284.9.w9)
- Oil may be removed by washing with a dilute solution of dish-washing
detergent (washing up liquid). (B284.9.w9)
- An alternative method avoiding washing involves working a quantity of sunflower-based
margarine (vegetable spread) into the affected area of fur, then
cleaning the mixture off using cotton buds. The bat may be left to
groom the remaining margarine off the fur. (B284.9.w9,
V.w47)
- Kaolin and pectin gel may be given orally to minimise toxic effects
from oil ingested prior to cleaning. (B284.9.w9)
Hedgehogs (Erinaceidae - Hedgehogs, moonrats (Family)):
- Oil may be removed by washing the hedgehog in warm water with
detergent, as for birds. (V.w47)
Beavers:
- Beavers (Castor - (Genus))
were stabilised for about 12-24 hours before washing. (P14.4.w4)
- Animals were anaesthetised for restraint during washing. (P14.4.w4)
- Beavers were initially bathed in 3 to 5% detergent solution at 90-95°F to remove
gross oil. (P14.4.w4)
- Animals were restrained, still sedated, on a rubber-coated steel mesh rack over a
sink and cleaned by working detergent solution into the fur by hand,
rinsing with warm water at 95°F using a high-pressure nozzle, and
repeating until all oil was removed. (P14.4.w4)
- Following washing the beavers were rinsed thoroughly until water
started to "bead" of the
underfur. (P14.4.w4)
- The beavers were briefly dried with towels, then given subcutaneous fluids and left
in a padded cage under an infra red lamp to dry and recover from
anaesthetic. (P14.4.w4)
- 24-48 hours after cleaning, they were moved to outdoor pens with pools for
swimming and, if necessary, encouraged to swim several times daily to
regain full waterproofing. (P14.4.w4)
Other mammals:
- Other mammals such as raccoons (Procyon lotor - Common
Raccoon) and muskrats (Ondatra zibethica, (Muridae - Rats, mice, voles, gerbils etc. (Family)))
have been washed in a detergent (Dawn, Proctor &
Gamble) solution, at 1% detergent or if required higher strengths,
using water at 95°F, followed by rinsing with a high pressure nozzle
and drying using pet driers, with or without initial towel drying. (P
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