Husbandry Manual for Asian Lorisines (Nycticebus & Loris ssp.)
 
 

Birth Management and Hand Rearing of Lorisidae

Contributed by Janet Hawes and Jacqueline Ogden

Following the birth of a loris infant, involved staff should work together to evaluate the status of the neonate. In cases where abuse, neglect, or insufficient care is observed or suspected, animal care staff should closely monitor the situation, and discuss options for care and husbandry management.

Hand rearing

The term “hand rearing” encompasses a wide continuum of methods: from total isolation until past weaning age, to peer rearing and early reintroduction to conspecific family groups. In general, the extreme end of the hand rearing continuum appears to be detrimental at least in primates (e.g., Harlow and Harlow, 1962). However, measuring the results of the other end of the rearing continuum is more complex. Many species appear able to recover from hand rearing efforts when they are introduced to conspecifics at a very early age. However, almost all captive managers now support mother rearing whenever possible for all species, both due to the complexities of early introductions, and in the overall best interest of the individuals and the species. The Prosiminan Taxon Advisory Group (TAG) strongly recommends that all institutions develop management programs that increase the likelihood that infants will be mother-reared within a social group.

Post-partum observations and evaluation

Following a birth, close monitoring of the mother and infant is critical. Some institutions such as the San Diego Zoo regularly schedule nighttime observations, allowing the collection of this critical data. Rogers and Davenport (1970) developed a scale for use in evaluating maternal care in chimpanzees immediately postpartum. Although chimpanzees are far removed from lorises, this protocol has general application to observation of primate maternal behavior. This protocol, including a scale from negative to positive maternal care where 0=negative and 4=positive, has been slightly modified to evaluate loris maternal behavior (see Table 10). Obviously, if a female is injuring her infant, it should be removed right away.

Alternatives to hand rearing

If observations of the infant postpartum indicate that the infant is becoming weak, dehydrated, hypoglycemic, and/or hypothermic, and that inadequate maternal care may be the cause, there are several possibilities short of removal for hand rearing. First, if the infant is being held correctly but is not nursing, or the female is not holding the infant in the appropriate manner, milk may be expressed from the mother’s breast to encourage the infant to suckle. Second, if the infant appears to be nursing but nonetheless seems weak, the infant may be pulled for medical evaluation. If the evaluation indicates that the infant is physically well but is not receiving enough nutrition, the mother’s milk may be lacking in nutritive content or volume. The infant can then be returned to the female and supplemented with formula feedings. Alternatively, if another female exists that has milk, crossfostering can be attempted, with proper follow-up care and monitoring. At San Diego, we were

Loris Husbandry Manual

Table 10: Scale of maternal care, where 0=negative care and 4=positive care (modified from Rogers and Davenport, 1970).
 

successful at introducing a young infant to an unrelated female with milk. We continued to monitor the weight of the animal, and because the quality of milk from the female was unclear, we continued to provide supplemental feedings until weaning age.

If alternatives to hand rearing are unsuccessful, hand rearing should be implemented with the goal of early reintroduction to conspecifics. To the best of our knowledge, the following institutions have hand reared loris species: slender loris: London Zoo; Bengal slow loris: San Diego Zoo; Duke Primate Center; pygmy slow loris: Brookfield Zoo, Ogrod Zoologiczny-Poland, Philadelphia Zoo, and San Diego Zoo. We have compiled the following recommendations for hand rearing based on information provided by Brookfield Zoo, Duke University Regional Primate Center, London Zoological Society, Ogrod Zoologiczny-Poland, and San Diego Zoo.
 

Physical needs

Housing

Some zoological parks have central nursery facilities, whereas others may hand rear animals adjacent to the natal groups. Regardless, upon determination that hand rearing is required, the infant should be placed inside an isolette incubator set at 90° F (32° C). At the San Diego Zoo, the humidity is typically set to low; alternatively, the Philadelphia Zoo uses high humidity. The infant should be provided with an appropriate surrogate and a hot water bottle to simulate the maternal body. Surrogates are typically either plush animals or soft material such as artificial fur. All

Formula and Nipple Selection

Upon arrival, a veterinarian should evaluate the neonate. Dehydration, sepsis, and hypothermia should be corrected appropriately. Infants should not be fed if they are hypothermic. Obtaining a body temperature on an animal of this small size is extremely difficult, and it may be necessary to rely on touch to assess relative body temperature.

Initially it is safest to offer formula in a tuberculin syringe to provide more control. Special care and

Loris Husbandry Manual

attention should be paid in the first days to avoid aspiration of formula into the lungs. This is especially important due to the small size, active nature, and frequent vocalization of loris neonates. Neonates should be fed on the surrogate with the aid of a blanket to steady the body and limbs. In weak or injured neonates, the first feedings should be of pedialyte solution, until patent swallowing reflex is observed. When neonate and caregiver are settled into a comfortable routine, it is appropriate to try the animal on a nipple. We have found that the only nipple small enough and of the appropriate turgor is the short size macropod nipple. These nipples can be ordered (Multi-purpose short teats #T-3, Order from: Geoff and Christine Smith, 15 O’Shannassy St., MT Pritchard NSW, Australia 2170, 02-823- 9874), and are attached to the smallest size nip pet nurser bottle, although other institutions have made their own nipples from latex (Sodaro, 1993). Great caution should be taken when first trying nipples. In particular, it may be necessary to slow down the flow of the formula; one method for doing this is to hold the bottle horizontally. If the individual does not tolerate the nipple well, a syringe feeding method can be employed throughout the hand rearing process. At the Philadelphia Zoo these methods were combined. The macropod nipple was attached to a syringe of appropriate volume, and the animal was syringe-fed throughout hand rearing.

Table 11. Infant diet schedule.
 

*During initial feedings the animal’s hydration and blood glucose levels must be monitored closely. If the animal is dehydrated or hypoglycemic, some institutions combine formula with Pedialyte or D5W. Others supplement with subcutaneous fluids.

The diet and feeding schedules obtained from institutions that have hand reared lorises showed considerable variation. Those schedules utilized by the San Diego Zoo that met with success in both pygmy and slow lorises are outlined in Tables 11 and 12. Many responding institutions included sweet gruel mixtures in the diet, generally including baby food, bananas, peaches, yogurt, and so on. Some institutions successfully use such diets as transition between straight formula and solid food. For example, the Philadelphia Zoo feeds a mixture of esbilac, baby cereal flakes, and a small amount of banana by dish. At San Diego we have avoided these sorts of mixtures, due to the incidence of caries in older animals, and possible influence of such sweet diets on general nutrition.

Additionally, most institutions add insects, such as crickets and mealworms, to the neonatal diet.

*q2h=every two hours, and so on.
 

Physical Needs: Species-Specific Concerns

Feeding. Loris neonates that are being hand reared vocalize frequently, particularly during any interaction or stimulation, such as when they are being fed. These neonates also are “squirmy,” and attempt to burrow into their surrogate or blanket, and reach out to grasp the nipple or syringe tip. Loris babies can aspirate easily, especially in the first few days of life. Aspiration is a particular risk when animals are vocalizing or moving during feedings. Therefore, special care should be taken not to rush feedings, and to wait until the neonate is sufficiently settled prior to feeding. One method of settling an overstimulated neonate is through grooming. For grooming, the handler may either use their fingers or a slightly damp gauze pad or soft brush. Initially, lorises should be offered formula via syringe, until they are nursing reliably and are comfortable with handling. As always, handlers need to be constantly alert for any change in respiration. Any such change should be reported to veterinary staff. However, when keepers and veterinarians are evaluating such changes, veterinarians should be made aware that at San Diego, nursery attendants heard one particular vocalization that actually sounds like a “raspy lung.” Although there was initial concern about aspiration, it was later determined it to be a vocalization rather than respiratory difficulty.

It is important to consider the amount of formula lost through unsuccessful attempts at hand feeding when gauging the total intake and formula calculations. When syringe feeding, the total amount of one feeding may be only 0.2ml. Therefore, each drop wasted or dribbled out of the mouth can represent a significant amount of formula with regard to the total daily intake. Handlers should consider these small increments and make adjustments accordingly.

Loris Husbandry Manual

Elimination. Manual stimulation is recommended until the infant is reliably urinating and defecating on its own (approximately four weeks of age). During the first two weeks, some institutions (including San Diego) report that this species has infrequent stool, and may not pass stool for two to five days. Alternatively, others report regular stool production beginning on the first or second day. After this time, they begin stooling reliably once daily. Stool character is uniformly firm and at times appears dry.

Drinking. Caution should be taken when offering water in a vessel or bowl, due to the animal’s small size. Initially, a water vessel should be selected that is very shallow, such as the cap to a medicine bottle or plastic pet food lid.

Weight. It is sometimes difficult to assess vitality on a creature of this size. As a result, particular attention should be paid to the animal’s weight. Weight is an excellent indicator of overall health status in lorises. Weights should be taken on an accurate scale, preferably sensitive to the onehundredth gram.Weights should be taken at the same time each day, preferably before the first feeding of the day. Solids can be weighed before and after feeding to determine amount consumed.

Surrogate selection. Surrogate selection is another important aspect of hand rearing. An adequate surrogate should have several characteristics: 1) The surrogate should ideally be of appropriate size and color to simulate the maternal body; 2) It should be pre-washed and carefully tested to insure that none of the nap or fur can be easily pulled out (some artificial fur is very fragile and sheds continuously regardless of the number of washings); 3) The surrogate should be free of any ornamentation which could be removed or ingested by the infant, including ribbons, bows, etc.; and 4) Several surrogates should be purchased so that there is always a clean dry surrogate ready to use.
 

Social Needs

It is ideal to begin a reintroduction of any hand reared loris infant as soon as possible after climatization is achieved. Determination of how quickly reintroduction commences will depend on location of the nursery. At San Diego, the nursery is far removed from the loris facility. As a result, this makes visits to the loris facility more difficult, particularly before the neonate is able to thermoregulate, thus lengthening the reintroduction process. Alternatively, at facilities such as the Philadelphia Zoo, neonate lorises are raised in the same area as the adult lorises, allowing speedier reintroductions. In Philadelphia, when the neonate is removed from the incubator it is placed directly in a cage inside the loris enclosure, facilitating the reintroduction process. Regardless of each institutions’ particular facilities, the overriding goal is to attempt reintroductions as soon as possible.

The reintroduction site should be free of drafts and cold air, and should include a stable heat source for the neonate. The first step is to provide visual exposure and to accustom the neonate to the new facility or enclosure. Ideally, the visual introduction should be started in an enclosure similar to the one that will eventually house the animal, so that it can learn to use the space before the final introduction. At the Philadelphia Zoo, this is accomplished by placing the infant in a cage inside the loris enclosure. Alternatively, a “howdy” cage can be set up next to the loris enclosure, depending on your facility design. In any case, the howdy cage should be made comfortable for the neonate, including placing the surrogate inside.

Summary

The primary goal of any hand-rearing attempt should be to raise an infant that can be resocialized and that will behave appropriately with conspecifics. The earliest possible reintroduction, combined with continuous monitoring for health problems, has proven the most successful in this regard.

Figure 25: Female N. pygmaeus with twins at San Diego Zoo.

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Management of Lorises in Captivity. A Husbandry Manual for Asian Lorisines (Nycticebus & Loris ssp.) Edited by: Helena Fitch-Snyder and Helga Schulze. Compiler: Lena C. Larsen

Last amendment: 2 January 2003