Medical management of the okapi is similar to other medium/large ruminants. Okapis are susceptible to many of the diseases common to domestic ruminants. Digestive disorders, rotavirus, jaw abscesses, trauma and overgrown hooves are a few of the most common problems encountered in the zoo community.
Perinatal and Neonatal Care of Okapi
It is recommended that female okapi near term be monitored closely for signs of impending parturition. To reduce
stress, this can be done through the use of remote video cameras. Parturition averages 3 to 4 hours and generally
proceeds
rapidly once a foot is seen at the vulva (1.5 to 2.5 hours). Progression of parturition should be monitored
closely so
dystocias and other problems can be detected as early as possible. Dystocias resulting from uterine inertia
and posterior
presentation have been reported, and have been successfully corrected by manual manipulation and
extraction, using either standing or full chemical restraint. Calves born through assisted births are more at risk for
maternal neglect or
trauma and neonatal problems, so careful consideration should be given to the introduction of
these calves to their dams
and to monitoring their health.
The birth of a single calf is the norm, but twinning has occurred rarely. Normal birth weights are in the 15 to 30 kg
range
with a mean of 22.5 kg (32 to 69.5 lb with a mean of 49.5 lb). Low birth weight calves or calves exhibiting evidence
of immaturity
have a much higher prevalence of neonatal problems and should be evaluated and closely monitored.
Calves commonly double their birth weights in 3 to 4 weeks and triple it by 8 weeks.
Calves that reach these behavioral landmarks slowly should be carefully evaluated and monitored. The birthing area
should have a substrate that provides good footing for the calf to allow standing without struggling or exhaustion and to
prevent injury from slipping and splaying. Okapi calves do not thermoregulate well until they are about 51 to 60 days
of
age (rectal temperatures vary from 37.0° to 39.2°C and average 38°C (98.6° to 102.6°F and average 100.4°F) for the first
90 days of life), so barn temperatures should be regulated. Okapi calves generally delay their first defecation
(meconium
passage) until they are 4 to 10 weeks old. Calves which defecate early should be observed closely for
signs of illness.
Additional behavioral landmarks for calves include:
The neonatal mortality rate of okapi in the North American captive population is about 20%—contributing factors include maternal neglect and trauma, and infectious disease. Maternal neglect or inadequate maternal care can lead to failure to nurse and failure of passive transfer of maternal immunoglobulins. Such calves will be prone to infectious disease, and if intake remains inadequate, will quickly become hypoglycemic and dehydrated.
Diarrheal diseases can cause severe problems in okapi calves, with the principle pathogen being a rotavirus that is
endemic in the
captive okapi population. Other common causes of enterocolitis
in okapi calves are E. coli and coronavirus.
The younger the calf,
the more serious the risk of severe disease or death from diarrheal
disease.
have also caused morbidity and mortality
in okapi calves.
Veterinary neonatal care is recommended to identify health problems
early, guard against specific pathogens known to
affect okapi,
and build the database of available okapi neonatal information.
Since okapi dams have been known to
traumatize calves following
handling, it is imperative that any procedure involving a calf be
carefully thought out, discussed,
planned and considered worthy
of the risk.
Perinatal and Neonatal Procedures:
Isolation and Hygiene: Okapi dams and calves should be kept as
isolated as is possible from other okapi and other
species.
Increased hygiene and sanitation should be instituted to prevent
transfer of pathogens to the calf and dam.
– Nothing substitutes
for good hygiene and sanitation.
Enteric viruses are easily
spread from enclosure to enclosure by fomites (i.e., boots, cleaning
utensils, tires, etc.).
Use of footbaths and dedicated boots, coveralls,
and utensils are indicated. Calving barns and enclosures
should
be cleaned and fed first before keepers enter other enclosures.
— Reduce entry into calving enclosure as much as possible.
Common sense is paramount when designing a sanitation program.
— Don’t do anything that will endanger the calf or calfdam
bond. (Over-cleaning and disturbing the calf ’s nest may disorient
and
stress the calf, new smells from disinfectants may disturb
the dam, etc.)
Keepers should concentrate on preventing
introduction of
pathogens into the calving enclosure rather than
over-cleaning or
sanitizing the calving enclosure. Keeping
calving barns warm
reduces rotavirus and coronavirus survival in the nvironment.
Humidifying the air in calving barns also reduces rotavirus survivability.
Proper ventilation in barns reduces aerosol spread of
pathogens. Phenolic disinfectants
are most effective against rotavirus.
—dams
should be acclimated to the smell
of these disinfectants well before calvin so the smell is not new.
Vaccinations:
1. Rotavirus and Coronavirus: Rotavirus and coronavirus are significant enteric pathogens that have caused diarrheal disease
in several okapi collections and death in young calves. A modified-live virus vaccine (Calf-Guard®, Pfizer Animal
Health, Exton, PA 19341, USA) and a killed virus vaccine (ScourGuard 3®‚ (K), Pfizer Animal Health, Exton, PA
10341, USA) are commercially available for prevention of rotavirus and coronavirus infections in calves and both have
been used in okapi. Both vaccines contain only one group A bovine rotavirus serotype (atypical rotaviruses are typically
seen in okapi) so the efficacy under field conditions of both of these vaccines has been seriously questioned. However,
clinical impressions suggest that vaccination does reduce the prevalence of serious clinical infections with rotavirus and
coronavirus in collections in which these enteric viruses are endemic.
Ideally, Calf-Guard®‚ must be given orally to calves immediately after birth, before they suckle colostrum, to provide
active mucosal immunity, but this is impractical and can put okapi calves at risk for maternal aggression or rejection.
Calf-Guard® can safely be used intramuscularly in okapi, but its efficacy by this route is unknown. ScourGuard 3®‚ (K)
was developed for intramuscular use and has been used in both okapi adults and calves. This vaccine has induced moderate
to severe muscular swelling, edema, and pain in individual adult okapis after multiple vaccinations. It is recommended
that okapi that experience a vaccination reaction to ScourGuard 3® (K) not be vaccinated again with this vaccine
(reactions appear to worsen with each successive vaccination). ScourGuard® reactors can be switched to vaccination
with Calf-Guard®, if deemed necessary.
Recommended intramuscular vaccine schedule for rotavirus and coronavirus: Initial vaccination of dams, twice, 3–4
weeks apart followed by a preparturient vaccination given 4-6 weeks before each parturition to boost colostral and lactogenic
antibodies. Calves should be vaccinated at their neonatal examination and at 4, 8, and 12 weeks of age.
2. E. coli: For collections that experience problems with neonatal colibacillosis, dams should be vaccinated during pregnancy
with ScourGuard 3®‚ (K) as described above. An Escherichia coli monoclonal antibody product (Genecol‚ 99,
Shering-Plough Animal Health Corp., Omaha, NE 68103, USA) has been given orally to okapi calves during the first 12
hours of life to prevent adherence of pathogenic E. coli to the intestinal mucosa.
3. Other Vaccines: Other vaccines can be used in okapi calves based upon health risks at each institution and the experience
of each veterinarian. Other vaccines which have been given to okapi calves include tetanus antitoxin, tetanus toxoid,
and polyvalent clostridium bacterins-toxoids.
Neonatal Examination:
This examination should take place within 24 to 96 hours after birth. The exact timing of the examination should
into account the dam’s birth history and post-parturient behavior, the calf ’s attitude and perceived health, and
the institutions
history of neonatal problems.
Adequate time should be given for good maternal-calf bonding. Each impending examination should be thoroughly discussed
between managers, veterinarians, and keepers to reduce the risk of maternal rejection or aggression and trauma to
the calf. Risk of maternal aggression is reduced if the neonatal examination is delayed until the calf establishes nesting
behavior and the dam willingly leaves the calf alone (generally 48 to 96 hours). The dam can then be locked away from
the calf, when she leaves it on her own, and left separated from the calf until the calf calms down and lays down normally
in its nest. The examination should be performed as quickly and efficiently as possible using minimal staff. Care
should be taken not to apply medications topically to the calf that have abnormal scents (e.g., alcohol, etc.), and to
remove human scent from the calf. The re-introduction of the dam should be done with minimal staff present and in a
routine manner, so the dam can see the calf in its nest from a distance when she enters the barn.
The examination
should consist of the following:
Failure of Passive Transfer of Maternal Immunoglobulins (FPT):
Calves with evidence of FPT (based on neonatal
blood work) should be observed closely for evidence of illness during the first
month of life. These “at-risk” calves should
be considered for plasma transfusion to boost serum immunoglobulin levels. Institutions
breeding okapi should consider
maintaining a frozen plasma bank for such occasions. Calves with FPT will need anywhere from
50 to 200 ml
plasma/Kg body weight to raise immunoglobulins to acceptable ranges. The success of plasma transfer in raising
serum
globulins can be evaluated by measuring serum globulins and performing serum electrophoresis before and after transfusion.
Quarantine for okapis should be accomplished in a large animal quarantine facility if such a facility exists. Alternatively,
the animal could be isolated from other ruminants and cared for by separate staff for the duration of the quarantine period.
Pre-shipment tests should be carried out prior to transfer of the animal and repeated during the quarantine period to
look for any travel-induced medical concerns.
Routine testing for parasites is recommended followed by treatment as needed. Annual vaccinations in some situations
may be advisable depending on institutional and individual history. Acquiring blood samples opportunistically is recommended
for baseline data.
To perform medical procedures, several methods have been used successfully. If the procedure is relatively non-invasive
(TB test or read, blood draw) and the individual has an approachable temperament, a standing immobilization can be
undertaken. Previous training to acclimate the individual to tactile contact is necessary in these circumstances. If the animal
is not approachable or not acclimated to direct contact, or the procedure is more involved, a full immobilization is
warranted. As with many ruminants, the risk of regurgitation, possibly resulting in inhalation pneumonia, is a serious
concern. Individuals should be fasted from food and water for a specified amount of time as directed by the veterinarian.
The procedure room should provide good footing and smooth walls to minimize possible injury to the animal. Animal
care staff should be prepared to help position the animal as needed to facilitate the procedure and to minimize risk to the
animal.
Some individuals have been acclimated to allow minor yet repeated hoof trims without the use of immobilizing drugs or
a restraint chute. This acclimation process usually begins when the animal is young and continues into adulthood. It is
possible that by utilizing a protective barrier, which allows access to the animal, more procedures could be undertaken
with minimal or no tranquilization. This type of acclimation is in development in a few of the managing institutions.
Both San Diego Zoo and the Wild Animal Park utilize a restraint box for procedures which is working well for them.
Animals walk through the box on a daily basis and are desensitized to touch and confinement as part of their normal
routine. Drop chutes have not been utilized for okapis to date. Geriatric animals generally suffer from ailments similar
to bovids. Arthritis is relatively common. Medication offering pain relief may be warranted. Solid flooring with good
traction is important. Rubber flooring or thick bedding may also be warranted.
References:
Andra K: personal communication.
Bennett, CL and S Lindsey: Preliminary findings on the behavioral budgeting of two okapi calves during the first six
months of life. American Association of Zoological Parks and Aquariums Regional Proceedings, Wheeling, West
Virginia, pp. 751-758, 1989.
Bennett, CL and S Lindsey: Some notes on the physiological and behavioral ontogeny of okapi (Okapia johnstoni)
calves. Zoo Biology 11(6):433-442, 1992.
Citino, SB: Rotavirus and Coronavirus Infections in Nondomestic Ruminants. In: Fowler, ME and RE Miller (eds.):
Zoo and Wild Animal Medicine: Current Therapy 4, W.B. Saunders Co., Philadelphia, pp. 605-612, 1999.
Lindsey, S, Bennett, CL, Pyle, E, et al: Calf management and the collection of physiologic data for okapi (Okapia
johnstoni). Int Zoo Yearbook 33:263-268, 1994.
Lukas, J (ed): Okapi Metapopulation Workshop, White Oak Conservation Center, Yulee, Florida, 1996.
Raphael, BL, Sneed, L, and J Ott-Joslin: Rotavirus-like infection associated with diarrhea in okapi. J Am Vet Med
Assoc 189(9):1183-1184, 1986.
Raphael, BL: Okapi medicine and surgery. In: Fowler, ME and RE Miller (eds.): Zoo and Wild Animal Medicine:
Current Therapy 4, W.B. Saunders Co., Philadelphia, pp. 646-650, 1999.
Reason, R.: Preliminary Observation on Growth and Development in the Okapi (Okapia johnstoni) at Brookfield Zoo,
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