ANNUAL REPORTS

At the start of the year the silvery marmosets were still in with the saki monkeys; but the silveries failed to rear two sets of offspring, and the saki infant born in February died at ten days of age. The species were separated in case the mix was causing some sort of stress which might be resulting in the rearing failures. However, twins born to the silvery pair in December also failed to survive. The intrepid free-ranging cotton-top tamarins had to be caged, their latest trick being jumping into the chimp enclosure. The family of Geoffroy's marmosets replaced them, and the pair of Goeldi's monkeys that consistently failed to rear young were put in the other free-range area; three Geoffroy's were born and reared during the year. The female emperor tamarin has proved to be a baby-killer with the charming habit of chewing infants' heads off at birth – but at least we know that the male is a potential breeder.

The Bennett's wallaby enclosure was turned into a new electric-fenced exhibit for the ring-tailed lemurs, which opened in September. The group that moved in were two males, obtained from Marwell in the summer, mixed with our six adult females and three infants from 1997.

Apart from the l'Hoest's guenons, who again produced a still-born infant, all the primate species for which the zoo runs programmes did reasonably well, with infants born to the diana and Hamlyn's monkeys, and to the siamangs. In an effort to breed de Brazza's monkeys, three (2.1) new animals were obtained. Various mixes took place, but by the end of the year the animals were in two pairs, with mating being observed in one pair. At one point both females were together, and got on reasonably well, which is quite unusual for this species. Experiments also took place in mixing the Allen's swamp monkeys. Four additional animals were obtained via Twycross and Bristol Zoos. At the end of the year they were housed in two trios (each 1.2), to try and stimulate breeding. No individuals of this species in the U.K. are presently breeding, and little is known of them in the wild as they inhabit inhospitable swampy areas. Field work which started in Zaire (now the Democratic Republic of the Congo) some three years ago had to be curtailed because of the political problems in that country.

A major improvement in the monkey house was the conversion of the outside cages to high-rise. This started with an extension to the spectacled langurs' cage, which not only gave the animals a lot of extra height, but also allowed `arboreal' access between the inside and outside areas – very comforting to a species that naturally spend their lives in the upper forest canopy. There was a dramatic change in the langurs' behaviour, and they now spend a lot more time in the outside area. By the end of the year the extension of the other cages was nearing completion.

One of the best events of the year was the birth of two red panda cubs; the same pair who had reared one cub in 1996 reared both females born in July. We hope to keep one of the cubs as the basis for another pair in 1999. The species has had a good year in the U.K., with several young born and reared.

The Amur tiger move discussed in last year's report [see I.Z.N. 44:6, p. 356] came to fruition in October when the Russian-born 17-month-old female was collected from London Zoo. She will be mixed with the male when she is a bit bigger, and could breed in late 1998 or early 1999. In February London Zoo hosted an international symposium, Tiger 2000, the first major scientific meeting devoted to tigers in over ten years. In that time the fight to save the five remaining races of tiger has intensified. One important outcome of the symposium was that it brought together tiger experts who are carrying out field work on the different races of tiger. Part of the reason that habitat fragmentation is detrimental to tiger populations is the effect this has had on the availability of prey species. Work carried out in Java, where the tiger became extinct in the early 1970s, is enlightening. Examination of the prey species of the largest surviving carnivore, the leopard, shows that its largest prey are primates. These would be too small to sustain a population of tigers, which needed large deer and pigs to survive, so the demise of its prey species due to habitat degradation brought about the tiger's extinction in Java. Thus determination of the minimum habitat requirements for the tiger's prey species is a vital part of conservation planning.

The South American tapirs produced another youngster, a male. There was still concern over the health of the female white rhino Floozie, and this increased when she aborted a foetus early in the year; but she was again pregnant and in reasonable health at the end of the year. A female pygmy hippo came from Whipsnade to replace our female, Hope, who was sent to start a new pair at London Zoo. The pair of muntjac produced an infant and were mixed with the remaining Bennett's wallabies in Whitson Wood – this could be termed the `British introduced mammal exhibit'. Pudu did well with two youngsters born and reared. All three species of desert antelope did well, particularly the Arabian oryx, who produced the first two (0.2) calves born at Edinburgh. As the elder one was sired by a male in Zürich we will keep her to breed with our male. Three addax were born, of which two survived; nine (4.5) scimitar-horned oryx were born, and two of last year's females went to Fota Zoo in Ireland.

There were only a few problems with aspergillosis in the penguins, so we really are keeping on top of this age-old penguin affliction with the new drug regime reported last year [see I.Z.N. 44:6, p. 359]. But we saw rather more blocked preen glands than in previous years. Penguins have a large gland at the base of the tail which secretes an oily substance that they use to coat the feathers and keep them in good condition. This gland can get blocked and sometimes infected. Usually it can be cleared by a good squeeze, but occasionally the secretion gets so dried-out and thick that it is impossible to express, and surgery is required. We don't know why we're seeing more of this problem, but an addition of a cod liver oil tablet to the diet does seem to help affected birds.

The hatching and rearing of four king penguins was one of the major achievements of 1997. This was particularly pleasing, because of the failure to hatch any kings during the preceding two years. The timing of egg-laying in king penguins makes them particularly vulnerable to high temperatures during the midsummer period, causing agitation and stress in incubating birds and consequently adversely affecting embryonic development. In an attempt to solve this problem, a technique used for other penguin species at Edinburgh was adapted for kings. All king eggs were removed from adult birds for artificial incubation and replaced with wooden dummies. While some assistance was required on hatching, four of the five chicks that hatched have survived. The dummies were removed and the chicks returned to the adult birds after 24 hours, with full acceptance from both members of the pair. Most birds accepted the manipulation of the eggs and chicks without any problems. In previous years adults with chicks have been either fully or partially penned off from other birds to prevent aggression towards chicks. This year there was no penning, and while some squabbling was observed there were no injuries. It was noted that there has been a high level of stealing and fostering of young by non-breeding birds, particularly as the chicks became more mobile. The king chicks have all been sexed as male, which was disappointing as this year we have also sexed all the adult birds, revealing a male bias of 21 to 11.

The gentoos continued their prodigious breeding, producing 39 chicks of which 30 survived; most of these birds have gone on loan to Belfast Zoo to re-establish their colony. Some of the nine chicks deaths resulted from predation, the first for some years. Some of the pairs of gentoos are extremely productive and very good parents, but others have a tendency to smash eggs or be rather poor at rearing. In order to assist the survival of some of the less well-represented lines within our colony, a small amount of cross-fostering of eggs took place.

For the first time since the new group was established in the present enclosure, the Chilean flamingos produced six chicks, of which four survived. [A detailed account of this breeding is published in the full Annual Report, pp. 61–64.] The removal of the black-faced ibis from the enclosure may have been a factor in this success, and may also have been the trigger for the successful breeding of the ibis. One pair of ibis were transferred to the duck ponds, where they parent-reared two chicks for the first time; previously they had ejected chicks from the nest on hatching. The nest was totally inaccessible to the keepers, and although they were aware that the birds were sitting, it was only when two heads of quite well developed chicks were seen peering over the top of the nest that hatching was confirmed.

A delicate decision was taken about the future of the zoo's night heron colony. Although the free-flying group had been in the zoo since the 1950s, the number of birds had grown to a point where it was not certain that they would remain in the vicinity of the zoo; in addition they were beginning to have an impact on the local amphibian population. It is extremely difficult to catch the adult birds, and also they do not adapt particularly well to the confines of an aviary. So this year's chicks were taken from the nests to an aviary prior to fledging, and then passed on to other collections. This strategy will prevent further expansion and allow for the gradual phasing out of the free-flying group over several years.

The azure-winged magpies bred for the first time. A number of nesting baskets were provided, but these were not acceptable to the birds. They made various attempts to build nests, ultimately settling on a position behind a drainpipe, and constructed an exquisite cup-shaped nest. To reduce disturbance, no attempt was made to check the nest. Five chicks hatched and four fledged from an exceptionally overcrowded nest.

The pair of thick-billed parrots produced two chicks and initially were proving to be conscientious parents. But towards the later stages of rearing, it was noted that one chick was significantly stronger than the other and appeared to be receiving the bulk of the feeding from the parents. For a period of about two weeks the second chick was supplementary-fed in the nest by keepers. The parent birds accepted this reasonably well – with only an occasional altercation with this helping hand – and both chicks fledged.

An important arrival in the psittacine collection was a sibling pair of green-cheeked amazons (A. viridigenalis) from Chester. This is an extremely rare species and the subject of an EEP. Within the next year or so one of the birds will be swapped for an unrelated partner; it is unwise to pair up parrots at too early an age, as they tend to develop a sibling bond rather than a breeding bond.

A male Rothschild's mynah was diagnosed as suffering from iron storage disease (haemochromatosis), a common problem in mynahs and toucans, where iron accumulates in the liver, causing damage. The bird was very sick, and radiography showed it had a very enlarged liver, which biopsy confirmed was full of iron. Treatment involves a low-iron diet, giving a drug that binds iron in the blood, and also regularly removing blood from the bird. He did very well initially, and we could tell that his liver function was improving, but he died after two months. The stress involved in handling and dosing a wild bird often takes its toll, and makes treatment of wild avian species very difficult and often frustrating.

A major development in the parrot aviaries has been the installation of an alarm system. A number of zoos in the U.K. have been the victims of parrot thieves. The presence of this deterrent will not only protect our current stock but also enable us in the future to hold more rare species of bird – which are even more desirable to thieves.

Eight Indian starred tortoises (Geochelone elegans) arrived from Singapore, where they had been seized by customs. They were all in poor condition, and several had `runny nose syndrome', a problem that can be caused by malnutrition, stress or bacterial infection, or more importantly by a herpes virus. Unfortunately, diagnosing whether the virus is present or not is extremely difficult, and we had to assume they were carrying it. This meant it would be very foolish ever to mix them with our existing tortoise collection, which has never had the virus. Despite the animals becoming apparently very healthy after a few months on a good diet and with good husbandry and antibiotic treatment, we eventually decided that it was safer to send them to other collections that knew they already had the virus, rather than risk infecting our own animals.

A number of new species of lizard entered the collection – collared lizards (Crotaphytus collaris), blue spiny lizards (Sceloporus cyanogenys), black-lined plated lizards (Gerrhosaurus nigrolineatus) and Moluccan blue-tongued skinks (Tiliqua sp.). Some more chameleons were obtained through customs and a pair of jewel chameleons (Chamaeleo lateralis) remained at the end of the year. Reptiles bred included Sinaloan milk-snake, rainbow boa, blue-tongued skink, jewelled lizard (Lacerta lepida), Standing's gecko and Hermann's and Kleinmann's tortoises.

The strawberry poison-arrow frogs (Dendrobates pumilio) bred successfully and could be observed in the reptile house rearing their young. The male, having enticed the female into his bower by calling, guards the eggs. As they hatch, the female carries the tadpoles away to safe and suitable areas.

Autumn brought the completion of the new wolf enclosure, Wolf Territory, which is about fifty per cent bigger in area than the old enclosure, and is surrounded by a new low-visibility fence. The new viewing platform has proved a great success for visitors, who really appreciate the clear view of the wolves. The Territory has taken in a small piece of birch woodland, and they also have access to a large boulder which is their new `council rock' and affords them new views into the main reserve.

European bison numbers remained the same. The bull Glen Orrin and the cow Glen Affric are our oldest herd members, both approaching 20 years of age but continuing to do well; though not dominant, Orrin is still the most impressive member of the herd. The red deer produced 22 calves, but three of these were killed by the bison.

This was a successful year for the capercaillie, with 20 (10.10) chicks reared to adulthood. Twelve birds were put out to other collections as part of the captive-breeding programme for the reinforcement of the wild population.

Once again, more than 40 research projects were conducted at Edinburgh Zoo during the year. The following are some of the topics studied:

– Association, nest-building and reproductive behaviour of gentoo penguins. The zoo's gentoos display the same strong nest-site fidelity and high degree of monogamy as has been observed in wild colonies. It appears that females are more bonded to a mate than to a particular nest-site.

– The effect of rank on agonism and affiliation in ring-tailed lemurs. The females were found to live in a linear hierarchy (where individual A is dominant to B, who is dominant to C and so on). However, no evidence of linear hierarchy was found in the male group. Overall, the females showed a much greater level of agonistic behaviour when compared to the males. There was no correlation in the females between position in the hierarchy and the distribution of affiliative behaviour. Allogrooming appears to serve primarily a hygienic function, since it was not associated with other social behaviours, and individuals tended to groom inaccessible body parts on the receiver of the grooming.

– Social behaviour of diana monkeys. This is an interesting species to study, as the females appear to be very active in defending the group's territory in the wild. As relatively little is known about the behaviour of the species, studies of them in captivity are of particular importance.

– Management of the Chilean flamingos and how this interacts with breeding success. Observations appear to suggest that it is critical that the birds experience a certain duration of rainfall (natural or artificial) followed by a dry period to stimulate nesting and reproduction. Visitors may have a disturbing effect on the behaviour of the birds, but keeper activity within the enclosure seems to have no adverse effect on the birds.

– A behavioural study of the interactions of white-faced sakis and silvery marmosets who were housed together. Mixed species exhibits such as this can be argued to have a number of advantages over traditional single-species exhibits, including greater educational value, more effective use of space, and visual and other stimulation for the species housed together. However, it is important to assess how successful a mixed-species exhibit is in terms of the welfare of its occupants. and that was the aim of this study. [As mentioned above, these species have now been separated.]

– Incubation in king penguins. In the past a number of eggs have been discovered broken from unknown causes; so this study attempted to identify factors that could potentially lead to egg breakage. The principal risk identified was an incubating penguin being aggressively interacted with by another king penguin.

– Whether the type of text presented on a sign influences how many people read it. This study was conducted by constructing information signs for the snow leopards: the same photo was used on each sign, but the text varied. It was found that the public were much more likely to read signs that presented information in a light-hearted and concise manner.

– Tool-use and grip in chimpanzees. The aim was to determine how, if at all, chimpanzees altered their hand-grip on a tool depending on the degree of precision required. The experiment was conducted by allowing the apes to dip for yogurt, using sticks, from pots of different widths; the narrower the width, the more difficult the task, and hence a change of grip would be expected. It was found that chimpanzees do indeed alter their grip of a stick relative to the precision of the task being performed, and also, as with other studies, that the females and youngsters were the most prolific and adept tool-users.

– A short-term study of the ring-tailed lemurs' response to an electric fence, which proved to be valuable in providing information prior to moving the lemurs to a paddock-style enclosure.

– Whether any aspects of the behaviour of nesting gentoo penguins affect hatching rates or chick survival. It was found that time spent on the nest was a good predictor of hatching success. The researchers found no behavioural correlates of chick-rearing success, but the age of the birds and duration of the pair-bond were good predictors of rearing success – basically, older birds (except those over 20 years old) and those with long-lasting pair-bonds were more successful at chick-rearing.

– Reproduction in rockhopper penguins. This study was a repeat of one conducted last year into the effects of simulating breeding migration in this species [see I.Z.N. 44:6, p. 359]. It was found that levels of bowing, allogrooming and aggression decreased during the course of the study (i.e. from the start of the breeding season onwards). When the males were first placed back in their enclosure (i.e. `migrated'), they displayed much appeasement behaviour. The arrival of the females was marked by an increase in vertical trumpeting behaviour and stone collection for nest construction. However, this year only one fertile egg was produced and no chicks were hatched; so the thesis concludes that further factors influencing reproduction need to be investigated.

– Whether the amount of time visitors view sequences of cages is dependent on the similarity of species in those cages. It has been hypothesised that, if zoo visitors are presented with a row of different monkey species, for example, then viewing times will decrease as they move along the row. No evidence of this so-called `saturation effect' was found, though the researcher acknowledges the need for a more in-depth study.

– The behaviour and temperament of big cats housed at Edinburgh and Colchester Zoos. One of the main aims of this study was to evaluate whether keepers' assessments of big cat personality correlated in any way with the behaviour of the cats. A good correlation between these two variables would allow `rapid behavioural assessment' (RBA) of zoo animals, and this could be extremely useful from a management of species point of view. (This technique is being extensively tested in the U.S.A. by Kathy Carlstead of the National Zoo in Washington, D.C.)

– How social status and scent-marking behaviour are related in ring-tailed lemurs. Olfactory communication in mammals is poorly understood and may influence a wide range of social behaviour from territorial defence to maintaining the social hierarchy. In this study no relationship was found between the frequency of scent marking and social status in either sex. However, a temporal correlation was found between the incidence of agonistic behaviour and the status of the scent-marker; for example, a dominant individual would attack a subordinate and subsequently perform scent-marking behaviour. So this behaviour may have a role in maintaining the dominance hierarchy.

– Factors causing bumblefoot (plantar pododermatitis) in the zoo's penguins. This is characterised by damage to the skin on the bottom of a bird's foot, and can be a debilitating and painful condition. It is often associated with bacterial infections. Clinical identification of bumblefoot in penguins is straightforward. However, sub-clinical evidence of the condition is hard to obtain, because the birds cannot be handled without stressing them. The study involved examination of feet and behavioural observations. It was found that the macaroni and rockhopper penguins had a much higher incidence of bumblefoot than the gentoos. The results also indicated that within the gentoo population older birds, especially females, were particularly prone to the condition. In terms of behavioural differences, infected birds show behaviours that relieve weight-bearing on the feet (e.g. lying, sitting and swimming), and tend to use areas of the enclosure with smooth substrate

Curators' Report (by James M. Dolan, Ph.D., Director of Collections)

The creation of `Heart of Africa' at the Wild Animal Park was a major project for all concerned, bringing together diverse species of mammals and birds from various habitats – dry savannas, wetlands and forests.

For the Park's bird department, this year brought the first hatching in the Northern Hemisphere of a southern bald ibis. Seven California condor chicks hatched, which brings the Society's total number of hatches of this critically endangered species to 59; through such captive-breeding programs, the species now numbers more than 150 birds, compared to fewer than 30 in the early 1980s. Other notable hatches included five pink-backed pelicans, five species of hornbills (red-knobbed, wrinkled, Papuan, black and Abyssinian ground), two Asian woolly-necked storks and one Rüppell's griffon.

This was also a prolific year for the Park's mammal department, which welcomed the 14th birth of a lowland gorilla and the 20th birth of an okapi. Among the deer and antelopes there were many new additions to the herds. While studies continue on rhinoceros reproduction, the Park's herd of Indian rhinos had its 27th birth and the East African black rhino herd had its 9th birth. The Park's new residents include a tamandua and the rare and beautiful banded linsang from Asia.

In the Zoo's bird department, there were three hatchings of the rare Micronesian kingfisher, a species that is extinct in the wild; the total captive population hovers around 50. For the second year in a row, five chicks were reared from the Empress of Germany's bird of paradise (Paradisaea raggiana augustaevictoriae); San Diego Zoo is one of only two zoos in the U.S.A. to raise this species. The Cuban amazons hatched and reared six chicks. We are happy to report that two Pesquet's parrot chicks hatched and were hand-reared, the only chicks of this species produced this year in the United States.

Among mammals at the Zoo, there were several significant primate births. Two northern douc langurs were the 43rd and 44th such births at the Zoo and the only births for this species in the U.S. in 1997. François' langurs also had two births, the 38th and 39th at the Zoo, which was the first institution to breed this species outside China. Azizi, the Zoo's seventh gorilla birth, was born to Alvila, the first gorilla born at the Zoo. Our European river otters are the only breeding pair in the U.S., and their male cub born in January was the first such birth in this country. Our fifth koala birth of the year – and the 86th for the Zoo – came in December; more than 30 koalas are now housed at other zoos around the world, on loan from San Diego. The Zoo was also the first to breed Sichuan takins outside of China, with four Sichuan and two Mishmi takins born in 1997.

There were several firsts for the reptile department in 1997, among them the acquisition of three new species of New Caledonia geckos in the genus Rhacodactylus. Two pairs of Mount Kenya vipers are also new to the Reptile House collection; this rough-scaled viper will eventually be on display in a montane rainforest exhibit. Our womas produced nine young, and the Chinese crocodile lizards and Fiji Island iguanas produced third-generation offspring. Boelen's python from New Guinea returns to the Zoo's collection for the first time since the 1970s. Another exciting addition came with two giant Indian soft-shelled turtles, with a carapace that measures more than three feet (90 cm) across when fully grown. The Galapagos tortoise herd was bled for DNA analysis by Ed Lewis of the Henry Doorly Zoo in Omaha, Nebraska, for studbook purposes and in order to set up subspecies breeding group.

Center for Reproduction of Endangered Species (by Werner P. Heuschele, D.V.M., Ph.D., Director of CRES)

The nine divisions of CRES had a busy and productive year, with major conferences and workshops hosted by the staff and several dozen research projects under way at the Zoo, the Wild Animal Park, and overseas.

Major projects for the analytical chemistry division included analysis of animal scents in primates, reptiles, felines and bears. In collaboration with the ecology and behavior divisions, staff worked to identify the chemical components found in the scent gland of male giant pandas, used by them to mark territory. They also investigated cholesterol levels in lowland gorillas and reproductive hormones in black rhinoceroses.

The behavior division worked on 14 projects, which included a complete study of the giant pandas' behavior during the female's estrus in the spring of 1997. Research indicates that scent-marking plays a strong role in panda reproduction. Birth control was evaluated for the lion-tailed macaques, and it was found that vasectomies in males may affect subsequent reproductive behavior in females, reducing their cycling frequency. Another major project involved studying the young polar bears during enrichment of their exhibit in order to decrease or eliminate pacing and head-tossing behaviors. Work also continued with California condors and Hawaiian forest birds. We were happy to report the first births of red pandas at this facility in more than 43 years.

The comparative physiology division changed its name to the ecology division in 1997, which better reflects its research goals: to understand interactions between organisms and their environment, including the factors that influence species' distribution and abundance. Important work continued with critically endangered West Indian iguanas in the wild. At CRES, more studies were done to develop non-invasive methods to assess hormone levels to aid researchers in determining the sex of young lizards. Locally, the coast horned lizard, a threatened species, received attention as habitat suitability was evaluated.

The endocrinology division had an extremely busy year, as the number of research projects within the U.S. zoo community and around the world has increased. Two successful meetings were organized by this division: the First International Symposium on Vertebrate Sex Determination and a workshop to discuss establishing an all-male gorilla habitat at the Wild Animal Park. Staff also collaborated on a project in Nepal to assess the impact of pollution in Royal Chitwan National Park. Hormonal evaluations to pinpoint the timing of ovulation in the giant panda were ongoing. Reproductive cycles were monitored in female bonobos and stress hormones in the males, and two studies were initiated in Uganda to assess stress levels in mountain gorillas. A multi-institution study continues on rhinoceros reproduction. The division is also working with Wild Animal Park animal care staff on contraceptive methods for some of its collection.

The genetics division, which includes molecular genetics and cytogenetics, had a good year during which relationships were strengthened in the scientific community, through governmental conservation activities, and with the general public. Its Frozen Zoo now contains samples from more than 4,240 individuals of 369 species and subspecies. During 1997, its storage capacity was expanded with new equipment, which allowed the banking of genetic material from an additional 271 individuals by the cytogenetics staff. Genetic evaluation is critical for endangered species and helps us to establish and maintain self-sustaining populations in captivity and in the wild. For those threatened species not closely related to humans and domestic animals, progress is slower, but significant programs are under way for giant pandas, black rhinos, and the Arroyo toad, a local endangered species.

The pathology division is uniquely positioned to be actively involved in research, conservation, animal health, and animal management. Its staff are also involved in teaching and training students, pathologists, and other professionals. Major conservation and research efforts for 1997 involved Hawaiian forest birds, San Clemente Island loggerhead shrikes, and California condors. This division tries to maximize the information gained from the tissue and biological specimens they examine, sharing this information with other institutions and professionals. This all benefits teaching efforts, animal conservation, and other scientific investigations.

Reproductive physiology staff collect, evaluate, and freeze valuable genetic material in the form of sperm, eggs, and embryos. They are constantly creating new protocols that allow for successful collection and freezing of germ plasm in different animal species. In January 1997 they hosted an international workshop on reproduction in the giant panda, along with the behavior and endocrinology divisions, with emphasis on estrus detection, artificial insemination, and other health issues. A long-term study was initiated to determine the causes of reproductive failure in cheetahs, as well as to design hormone protocols to stimulate estrus and ovulation, and some encouraging results were seen with hormone therapy in female cheetahs. Studies continued with black bears – an important, non-endangered model for artificial reproduction in the giant panda – at Bear Country, U.S.A., in Rapid City, South Dakota.

The virology/immunology division continued major work with diseases in captive-raised black rhinos and cheetahs, which suggests involvement of viral agents that may affect the immune system. Molecular analysis of genes involved in immune recognition and those of several viruses are conducted, both to identify individual animals that may be more susceptible to certain agents and to establish a basis for improved diagnostic tests.

The infectious diseases division carried on studies with malignant catarrhal fever among the hoofed stock at the Wild Animal Park.