fractures are ussually open

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Fractures are usually open, and there is almost always a local infection and osteomyelitis

associated with this condition. Therapy is difficult if the condition has progressed for days or weeks.

Good results have been obtained htrough surgical debridement and removal of infected bone.

Vertebral compression fractures occur rarely in trained animals as a result of commonly

employed back-arching behavior. Affected animals exhibit soreness amd reluctance to utilize their

pelvic limbs. Radiographic examination reveals the fractures that are usually located in the lumbar

area. Therapy consist of rest for up to a year.

Genitourinary diseases

Cetaceans

Renal problems are relatively rare in dolphins, altough the syndrome of prerenal azotemia

does occur following certain conditions. Since the renal circulation is technically part of the

peripheral vascular bed, vasoconstriction with shunting of blood away from the kidneys can occur,

and under conditions of extreme stress or shock, may result in renal anoxia and renal failure. Clinical

findings include elevation of serum creatinine, reduction of urine output, rise in urine specific

gravity, proteinuria, and a urine sediment containing casts and renal ephitelial cells. The animal

quickly becomes anorectic, depressed, and unresponsive. Unless treated, death ensues within

several days. Therapy includes rehydration of the animal, preferably through an intraperitoneal

catheter. An angiocath needle serves nicely for this purpose. Up to four liters of fluids may be

administeres safely to an adult dolphin within one hour, with up to 50 per cent of animals blood

volume being delivered over 24 hours. Care should be taken to monitor the animal for urine

production and for signs of congestive edema.

Pinnipeds

Sea lions and seals may suffer from the same prerenal azotemia syndrome as dolphins. The

same general causes, clinical findings, pathogenesis and therapy apply.

Renal calculi are relatively common in harbor seals and elephant seals and are seen

occasionally in sea lions. There does not seem to be pain or inflammatory response associated with

their presence. Calculi are often found after a long, debilitating ilness but have also been observed in

wild healthy pochid seals.

OPHTHALMOLOGICAL DISEASES

Cetaceans

The primary ocular disease is keratitis or conjunctivitis, which usually occurs in response to

trauma. Corneal lacerations that occur during capture or transportation are the most common


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causes. Bacterial conjunctivities may complicate the wound. The condition is often better left

untreated, as therapy can be traumatic.

Pinnipeds

Corneal ulteration and conjunctivities are the most common ocular diseases of pinnipeds .

They are as likely due to poor water conditions as they are to trauma. The clinical course is similar to

that in dolphins. Some lesions have been treated with subconjunctival injections of antibiotics or

corticosteroids, but this form of therapy has not resulted in any more success then no treatment at

all. Some benefit may be attained by the systemic administration of antibiotics. Most lesions resolve

without complications, but severe cases lead to ulceration and eye rupture.

REPRODUCTION

J.Sweeney

The reproductive system of marine mammals is not well understood, nor are the husbandry

requirements of pregnant, parturient, and neonatal animals. Gestation periods of cetaceans have

become known through observations of copulatory and subsequent parturient events. In pinnipeds,

most species exhibit definite pupping periods followed almost immediately by mating activity. We

now believe that nearly all marine mammals, except for some of the large whales, have a one-year

gestational cycle. In some pinnipeds, e.g., the northern fur seal and the harp seal, whose migratory

habits take them far away from solid substrate for all but a few short months of the vein, this annual

cycle is facilitated by delayed implantation of the fertilized ovum. Little or no information is available

on the ovarian cycle and ovulation in most species. A hormonal cycle has been demonstrated in the

mate, dolphin that suggests a semi-annual increase in gonadal activity in fall and spring months. This

same periodicity appears to mark the female gonadal cycle, as it is during these periods that increased

copulatory activity has been observed. Most captive dolphin calves are born at these corresponding

periods a year later.

This discussion focuses on the medical aspects of reproduction and specifically on problems of

pregnancy diagnosis, parturition, and neonatal management. Discussion is limited to three species,

the bottle-nosed dolphin. the California sea lion, and the harbor seal.

PREGNANCY DIAGNOSIS CETACEANS

Through the use of various electronic devices, the diagnosis of pregnancy can be confirmed

long before physical verification is possible. Such devices are especially useful in view of the fact that, to

date, no dependable blood hormone assay has been developed for this purpose.

The recent application of ultrasound diagnostic instruments has been extremely useful in

cetacean obstetrics. The doppler sonography unit uses continuous acoustic energy in the form of a

beam that is reflected off moving matter, e.g., red blood cells, producing an audible sound. When the

bearn is directed towards the heart or great arteries of the fetus, the resulting sounds reflect the fetal

heart rate. The rate is usually constant and far more rapid in the fetus (140 bpm) than in the mother


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(60 to 80 bpm). The transducer of the unit is placed on the surface over the left abdominal quadrant of

the mother, since most pregnancies in smaller cetaceans are left horn pregnancies. No ill effects have

been noted with this instrument, which also offers the convenience of portability. The doppler

unit has added value as an indicator of intrauterine fetal viability.

Radiographically visible ossification of the fetal skull and spine occurs early in the second trimester

of pregnancy. The technique is of limited value; it requires a suitable x-ray unit and involves

considerable handling of the subject. There is also the potential danger of harmful irradiation to the

developing fetus.

Physical signs of pregnancy in the adult we not always obvious. Particular attention should be

paid to enlargement of the abdominal girth, enlargement of mammary glands (around six months),

dilatation of vaginal membranes (around nine months), and fetal movements (around ten months).

Pinnipeds

Pregnancy diagnosis in pinnipeds of all species is limited to the morphological features of enlarged

abdominal girth. Food consumption usually increases and, as labor nears, distinct behavioral

alterations occur. Doppler ultrasonography maybe utilized in the smaller pinnipeds, providing proper

restraint is available. It must be kept in mind that restraining pregnant animals may itself be harmful.

PARTURITION

CETACEANS

Table 25-9 shows the result of a survey, in which 31 per cent of 88 captive dolphin pregnancies

resulted in stillborn calves. Most of these were full-term fetuses. The majority of these were from

recently captured pregnant cows, but a significant percentage were bred in captivity. There is no

suitable explanation for this high number of stillbirths, yet there is general agreement that the causesomehow relates to a variety of environmental stresses. Of the parturition itself, the duration of labor

appears to be critical. The mean paturition time of successful dolphin births was 54 minutes, while

those resulting in stillborn calves had a mean time of 240 minutes. Generally, if parturition took

longer than two hours, fetal mortality resulted. The cetacean fetus is normally in a breech position at

parturition, though successful cephalic presentations have also been reported.

PINNIPEDS

Although no data are available for a definitive accounting of parturition in captive pinnipeds, it

is generally evident that among California sea lions, a high percentage result in stillbirth. Again,

environmental factors likely play an important role. Some parturient successes have been noted inEuropean zoos, where there are relatively stable social groups within reasonably good facilities.

Enclosures that provide ample haul-out space with an area of seclusion for the parturient cow have

accounted for the most successes. In harbor seals, successful births are relatively more common. The

fetus is normally in a cephalic presentation at parturition. For many years at the New York Aquarium,

one could set a chronometer by the January 16 births of at least one gray seal in the established

colony of two cows and one bull.

MANAGEMENT OF THE NEONATE

CETACEANS


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Roughly one half of the live birth dolphin calves born in captivity have survived to one year of

age (Table 29). Of this relatively high first year mortality, the greatest death rate occurs within the

first month, during which approximately 23 per cent of the live-born calves die, and thereafter there

is a sharp decline to 2 per cent per month for each of the remaining 11 months. Although the reasons

for these mortality figures are still speculative, there appear to be primary environmental factors that

relate directly to successful infant rearing.

Unquestionably, pool size is of major importance. Those oceanariums that have breeding

animals in large enclosures have had better success. One certain feature of such enclosures is that

they enable mother and calf to escape from harassment. Recorded observations of many newborn

mortalities suggest that most of these occur as a result of aberrant behavior between mother and

infant, poor suckling habits or the absence of milk, and accidental or deliberate trauma to the

infant by the mother or other animals within the enclosure. These behavioral abnormalities are likely

attributable to environmental problems. First-birth mothers appear to exhibit more difficulty rearing

their calves.

Mortalities of older infants, e.g., one month to one year, occur as a result of a variety ofproblrms including trauma, infections, and possibly nutritional difficulties.

There are few who would disagree that infant dolphins are rather delicate. Handling and

physical restraint can be life-threatening and should be avoided. Male infants appear to be particularly

prone to this "capture shock" and because of this should not be handled before at least six months

of age.

P I N N I P E D S

The suckling period of infant pinnipeds other than the walrus is of shorter duration than that

of the dolphin. Sea lions begin eating fish at around six months of age and harbor seals at or before one

month. If necessary, such infants can be placed on an exclusive fish diet just a few weeks after birth.

The pups appear to adapt well to a variety of physical environments and are far less fractious to

handling.

The predominant problems in rearing sea lion pups occur within the first two weeks of life. In

some exhibits, parturient cows are forced to deliver their pups onto inadequate, overcrowded haul-out

areas. Such pups succomb either to trauma or drowning as they fall into the water prematurely. If

there is no suitable haul-out space and sheltered protection from the other animals, pregnant cows

should be removed from the exhibit with care to note the pups' adaptability.

Harbor seals appear to adapt well, even to overcrowding, and swim readily very soon after

birth. This species has been reared successfully in many zoos and aquaria.

CLINICAL PATHOLOGY OF MARINE MAMMALS

W. Medway

andJ. R. Geraci

GENERAL CONSIDERATIONS

Most laboratory, values for marine mammals are not yet refined to the point where normal

ranges can be given within narrow limits. Many of the studies that have provided these data were

the result of long-term repeated analyses on captive animals, some healthy, others presumed to be

healthy. In some cases the sample size has not been large enough to bear any statistical weight.

Studies on wild-caught specimens have yielded seemingly ideal data, but these do not always

correlate with the data from captive animals. Captivity demands physicological adjustments that canbe reflected in blood values. For example, wild dolphins and seals often have a higher circulating red


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cell mass than their counterparts in captivity, owing to greater oxygen demands in the natural envi-

ronment. White cell counts in beluga whales have been shown to increase by more than 20 per cent

within just a few weeks of captivity. Stress elevates circulating blood cell mass in some seals but not in

cetaceans; the latter do not have spleens large enough to be effective as blood reservoirs.

As in other animal species, variation in collecting, handling, and analytical technique must be

taken into account when interpreting clinical laboratory results. Seal blood collected into Na-EDTAfor routine hematology shows a progressive increase in packed cell volume (PCV) due to swelling of

erythrocytes. Automated cell counting equipment does not always perform well on animals such as

ringed seals and hooded seals, which have an extremely high red cell mass (PCV, 60 per cent). Some of

the human standards used in clinical chemistry, such as for serum albumin, give erroneous results when

applied to dolphins. In taking these factors into account, this chapter is intended to provide only broad

guidelines for "normal" values. Only those parameters that have been shown to be clinically useful

are discussed.

HEMATOLOGY (Table 25-10)

RED BLOOD CELLS

The circulating red cell mass is variable with cetaceans and pinnipeds. These differences

appear to correlate with an animal's diving capability; higher values are found in pelagic or deep

diving species. Following some period of acclimatization in captivity, the values reduce somewhat.

Increase in PCV and hemoglobin (Hb) generally signals dehydration, which nearly always

accompanies a period of fasting or lowered food intake. This is especially evident in young, rapidly

growing animals. Up to U per cent increase in PCV can be seen in seals following stress, as, a result of

release of splenic stores into the general circulation. Lower red blood cell (RBC) values, indicative of

areams, can be the result of blood loss or reduced red cell formation. In cetaceans, low-grade

normocytic anemia can be seen in association with infections and nonspecific (nondiagnosed)

disorders. It is often accompanied by an elevation in the number of circulating reticulocytes and does

not appear to respond to iron therapy. Such nonspecific, as yet nonresponsive anemias are a common

finding in some dolphin colonies. Microcytic anemia due to blood loss is seen in cetaceans with bleeding

gastric and duodenal ulcers. In suspected cases, blood examination should be accompanied by fecal

examination for occult blood and gastric lavage. This condition is less frequently encountered in pin-

nipeds.

WHITE BLOOD CELLS

Because of the wide variation in white cell counts within a colony, "normal" values should be

established for each animal. Many institutions routinely sample on a periodic basis in order to establish

such baselines. Leukopenia has been observed in harbor seals immediately prior to the onset of seal

pox, a known viral disease. Whether it is a usual response to viral diseases in marine mammals is not

known. This response has also been seen following a protracted and fatal illness associated with aninfectious disease in a dolphin. Leukocytosis in dolphins is associated with tissue damage; increases

of 30 to 40 per cent above normal, due to a rise in neutrophils, is a common sequel to shipping,

especially if it is accompanied by complications. Postshipping leukocytosis is often treated unnecessarily

as an infectious problem. In seals, leukocytosis can be observed in stress. It is associated with a two-fold

increase in neutrophils, a 70 per cent decrease in lymphocytes, and depressed eosinophils. Infectious

processes elicit a neutrophilic response in cetaceans and pinnipeds. White blood cell counts as high as

60,000/have been observed in a dolphin with abdominal abscesses. Less pronounced elevations are

usually encountered, and if prolonged, are associated with an increase in the percentage of immature

neutrophils. Chronic infections are accompanied by a lymphocytic and monocytic response.

Leukocytes is in seals does not always signal a severe problem. One apparently healthy ringed seal has

been observed with fluctuating white cell counts in excess of 20,000/gl over a period of one year. Ceta-ceans have a high percentage of circulating eosinophils. The reasons are unknown. Eosinopenia


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accompanies stress in seals, and can be seen in conjunction with stress and debilitating diseases in

cetaceans.

BLOOD CHEMISTRY

The literature on enzymes is confusing indeed. The units for designating enzyme levels are

too numerous to be of value in establishing guidelines. Moreover, most of the units are notintercovertible. Enzyme levels are influenced by organ specificity, and by release during blood

sampling-associated stress, as well as by blood handling techniques. Table 25-11 shows reference

values for plasma enzymes in two phocid seals and the bottlenosed dolphin. Otariid values can be

expected to correlate closely with those of phocids. The principal locations of each enzyme have

been established, and follow the general pattern observed in domestic animals. Unit designations

are consistent between species.

Glutamic oxaloacetic transamonase is widely distributed in tissues, and is not useful as a

specific indicator of liver damage in any of the species examined. In seals, it becomes elevated as a

result of handling stress, and is influenced by the amount oEvermlysis in the blood sample. Glutamic

pyruvic transaminase, alkaline phosphatase, omithine carbamyl transferase, and sorbitol dehydro-

genase are liver specific and though little work has been done on release of enzymes into the

circulation following experimental organ damage, it can be reasonably assumed that elevations of

these enzymes reflect hepatic damage. Elevations of GOT, GPT, and OCT have been found in

association with carbon tetrachloride toxicity in phocid seals, and trematode-induced liver damage

in dolphins. They are also found to be significantly elevated for months at a time in healthy , harp

seals through no known cause. The enzymes creative phosphokinase and aldolase are principally

found in muscle. Leucine aminopeptidase and gamma glutamyl transferase are kidney specific

and would be expected to increase in urinary concentration and not in blood, as a result of kidney

tubular damage. Values for lactic dehydrogenase are highly variable in marine mammals, and are oflittle use diagnostically. Plasma electrolytes (Table 25-12) are useful aids in helping to assess the

state of hydration of an animal, and in diagnosing a serious condition in phocid seals, characterized

by low circulating sodium levels. Prolonged fasting can lead to hemoconcentration and increases in

circulating sodium to values in excess of 180 mEq/l. Therapy should be aimed at re-establishing

water balance. Pinnped hyponatremia is a disease of phocid seals held in fresh water. It is related to

stress and is characterized by circulating sodium levels below 147 mEq/l, an associated decrease in

chloride, and possible changes, up or down, in potassium levels (see Nutrition and Nutritional

Disorders). There are few other known conditions that principally involve electrolytes. Potassium is

sometimes elevated following severe physical exertion in seals and dolphins. Blood urea nitrogen

levels inmarine mammals are generally high, especially in cetaceans. If BUN is to be used as an

indicator of a renal disorder, it should be used in conjunction with creatinine, which is generally

found in the range of up to 1 mg/dl. Uric acid levels are peculiarly high in young phocid seals (2 to 5

mg/ dl), in seals with prolonged illnesses associated with dehydration (up to 12 mg(dl) and in the

freshwater dolphin (10 to 12 mg/ dl).

Blood glucose (Table 25 -12) in cetaceans and some pinnipeds is somewhat higher than most

mammalian species. This is believed to be an adaptation for deep and prolonged diving to assure

adequate nutrient supplies to the brain. The values we highly variable within species, and even

within individuals, depending on the state of activity of the animals and the fasting interval before

sampling.Plasma iron (Table 25-12) represents the iron being carried by transferrin, either to a storage


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depot or to the site of hemoglobin synthesis. In most mammals, the plasma iron represents about

one third to one half satum, tion of the protein iron binding capability of blood. Plasma iron and the

unbound iron binding capacity (UIBC) are usually measured simultaneously. The normal ranges

from one study on dolphins are as follows:

Fe 116-320 Agidl

UIBC 100-564 ggldl

% Sat 17-63 ug/dI

Pilot whales and beluga whales have comparable values. Lowered plasma iron can be expected in

iron deficiencies, active erythrogenesis, and in the course of infections. Increases occur during

increased red cell destruction, or decreased blood formation. Increased UIBC follows acute chronic

blood loss and is seen in iron deficiency; a decreased UIBC occurs during acute and

chronicinfections.

Total proteins and the separation of pre, tein fractions are receiving increased interest in the stud,

of mechanisms of disease (Table 25-13). The albumin values and consequently the AG ratios in

cetaceans are somewhat higher than those seen in domestic species. Hyperalbuminemia has not

been reported in any species. On the other hand, hypoalbuminemia can occur under a variety of

conditions, including lack of adequate diet, protein losing enteropathy, inadequate synthesis

through hepatic dysfunction, kidney loss, etc. Globulins represent three distinct groups: alpha, beta,

and gamma. The excursions of the alpha and beta fractions are nonspecific; they may become

elevated in any chronic disorder. Normally they are considered to be, the transfer or carrying proteins

of the blood. The gamma globulin fraction usually becomes elevated after antigenic stimulation such

as that associated with chronic microbial disease. Paraproteins have not been identified in any

aquatic mammals, as yet

FECAL CHARACTERISTICS

Feces should be examined for color, consistency, and parasite segments, larvae, and ova. The

latter can be detected using routine procedures, i.e., direct smears, flotation, and sedimentation.

Pinniped feces are usually formed and are dark brown in color, Animals on squid diets often

have soft feces. Some trainers' routinely add squid to the diet as a cathartic. Fasting seals show

evidence of mucoid excreta, which can range in color from yellow to orange and green.

Cetacean feces are normally dark greenish-brown and hav e t hic k l iqu id firm consistency.

They dissipate rather quickly in water. In cases of maldigestion or malabsorption, the feces may be off-

colored, foamy, and will float. Frothy light-colored feces have been reported from a dolphin with

clinical jaundice.

URINE CHARACTERISTICS

Examination of urine is an integral part of the evaluation of the urinary system. Unfortunately,

there are few reports in the literature dealing with results of such examinations in marine mammals.

Most quantitative studies require that a 24-hour urine sample be collected. This is not possible in a

cetacean without placing an indwelling catheter; it is easier in a pinniped, but requires the use of a

metabolism cage. For these reasons, every opportunity should be taken to examine urine

collected incidentally from animals restrained for other purposes.


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Pinnipeds and cetaceans on a fish diet excrete urine that is yellow to amber in color, usually

clear, but occasionally cloudy and has an acid pH (6.0). In a study on fur seals, it was shown that the

concentration values for sodium, potassium, and chlorine are relatively low, in the same range as

man. Pinniped, generally seem to be able to concentrate urine, however, and experimental work has

shown that the sea lion presented with a formulated diet high in sodium chloride can excrete a urine

more concentrated in both sodium and chloride than seawater.

fractures are ussually open

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