A. Liesegang1 and K. Baumgartner2

1Institute of Animal Nutrition, Zürich, Switzerland; 2Nürnberg Zoo, Nürnberg, Germany

The Morelet‘s crocodile is a relatively little known species from the Atlantic coast of Mexico and northern Central America. It`s length rarely exceeds 3 m and has it has a characteristic broad snout. These animals live primarily in freshwater habitats, particularly marshes, swamps, ponds and lagoons, but in some areas this species can be found in brackish water areas. They are seldomly held in zoos and scientifical data including nutritional requirements are scarce. Calcium and phosphorus are very important minerals in reptile nutrition, but many diets in zoos are still not sufficiently balanced. To achieve optimal growth, including a healthy skeleton, a wellbalanced supply with these minerals and also vitamin D is the prerequisite. The present case report is intended to share our experiences. In Nürnberg Zoo, three Morelet‘s crocodiles hatched for the first time in a european zoo in December 1999. The animals had an average weight of 31.9 g. They had access to artificial UV light. The dietary management prooved to be difficult. Firstly feeding recommendations are rarely found in the literature and secondly it was a challenge to feed anything at all to the freshly hatched crocodiles. The diet constisted of crickets and once or twice a week of baby mice. No supplementation was given. Occasionaly the animals received chicks and fresh meat strips. After 3 ½ months with an average body weight of 125.8 g, the animals were x-rayed, because one had a broken leg. Radiography revealed severe signs of rickets in all three animals. The animal with the fracture was treated with a T-bustersplint bandage. In addition, the diet was enriched with mineral and vitamin supplements. After 6 weeks radiography revealed a healed fracture and physiological ossification in all animals. The crocodiles had an average length of 528.3 mm and a weight of 445.3 g. Previous studies described that Ca and P play an important role in the nutrition of reptiles (Allen, 1989; Allen et al., 1993). It is very important for growing animals to give them enough vitamin D and calcium with a Ca:P ratio of a least 1:1. From the literature it is known that crickets have a calcium content of 0.47 % and a Ca:P ratio of 0.49 (Dennert, 1997). Recommendations for other reptiles are (much) higher (Donoghue and Langenberg, 1994). Nevertheless crickets prooved to be the most appropriate food for our animals. In their natural habitat growing Morelet‘s crocodiles also eat insects, as well as small fish, and worms. Considering the small size of the young reptiles, crickets also fulfil practical feeding purposes. In conclusion this case report demonstrates a quick recovery of crocodiles with rickets following diet supplementation with minerals and vitamins. Mineral requirements of juvenile Morelet‘s crocodiles appear to be comparable to other reptiles. A diet consisting of crickets with or without a combination with meat always requires supplementation since the Ca content and the Ca:P ratio are too low.


M. Linssen1, S. M. Mwasi2, I.M.A. Heitkönig2, C.B. de Jong2 and B.B.H. van Wijk1

1Animal Management, Van Hall Institute, P.O. Box 1528 Leeuwarden, The Netherlands; 2Tropica Nature Conservation and Vertebrate Ecology Group, Wageningen University, Bornsesteg69, 6708 PD Wageningen, The Netherlands.

The diets of wild ungulates are related to the cover of the vegetation they feed on in their natural habitats. Ungulates in captivity can not be fed on their original natural resources. Discussions on the composition of diets for captive animals to ensure that their health, welfare and reproduction are not damaged by poorly or wrongly compiled diets are going on to date. The trend to provide captive animals with natural surroundings in Zoos should also include a diet as natural as possible. Ex-situ ungulate species management can make use of the results in-situ research techniques. In Lake Nakuru National Park situated in the Rift Valley Province of Kenya, research is done combining feeding behaviour studies and the technique of faecal analyses to confirm the actual food consumed and digested by different ungulates species grazing and/or browsing in their natural environment. Results from this type of research contribute to the composition of natural diets for ungulate species in captivity. The purpose of faecal analyses is to identify plant/grass-species and to measure the abundance of these species as a percentage of the total faecal contents of a specific collected dung sample. Related to habitat vegetation composition this provides useful data on diet composition for ex-situ ungulate species management. The technique of faecal analyses and its use is presented, based on an example of research on faecal analyses on two competing ungulate species in Lake Nakuru National Park, the African Buffalo (Syncerus caffer) and the Defassa Waterbuck (Kobus ellipsiprymnus).


W. Loehlein1, E. Kienzle 1, H. Wiesner2 and M. Clauss1

1Institute of Animal Physiology, Physiological Chemistry and Animal Nutrition, Munich Veterinaerstr.13, D-80359 Munich, Germany; 2Zoological Garden of Munich, Munich, Germany

Digestibility studies in zoo herbivores that are kept in groups are often confounded by the fact that the intake of hay, which is usually offered to the whole group, cannot be measured on an individual basis. This problem can be solved by using a double marker method with an internal and an external arker. In elephants, the internal marker lignin has repeatedly been used successfully; however, no external digestibility marker has been reliably established for this species. Seven captive Asian elephants were fed 500 g of chromium oxide per animal as a pulse-dose. Faeces were collected in toto for 60 hours afterwards. The amount of faeces from each single defecation was weighed, and a representative subsample was taken for chromium analysis. All faeces defecated during night hours were treated as a single defecation unit. With the individual chromium concentrations and the total weights, the recoveries of the chromium marker could be calculated, and the passage rates for these animals were determined. Additionally, four animals in an elephant orphanage in Sri Lanka were fed the same amount of chromium oxide. For these animals, only the passage rates could be determined. The average first marker appearance was 24 hours, and the average last marker excretion 54 hours after marker feeding. On average, the elephants excreted 3.9 kg faeces/100 kg of body mass and day. The average chromium oxide recovery was 97 %. The results confirm that chromium oxide is a reliable external digestibility marker in Asian elephants. The passage rate data compares well with other data from the literature. Like other perossidactyls, the elephant uses the digestive strategy of passing large amounts of low quality forage through its gut within a short period of time.


C. Mascini1, J. Nijboer2, W.L. Jansen3, B. van Wijk1 and T.R.Huisman1

1Van Hall Institute, P.O. Box 1528, 8901 BV Leeuwarden, The Netherlands, 2 Biological and Veterinary Department Rotterdam Zoo, 3000 AM Rotterdam, 3 Department of Nutrition, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80152, 3508 TD Utrecht

As part of a more comprehensive study which aims to get more insight into the nutritional value of browse in zoo diets, interviews were conducted with staff responsible for zoo nutrition in 10 Dutch zoos. Almost all respondents indicated that they experienced the following problems with browse: irregular availability, lack of reliable nutritional data and storage problems. Respondents also indicated that they would like to get more insight in the possibilities to replace browse in the present rations. (Kool and Smit, 2000) The obvious approach towards replacing food items in a diet is to look for products with comparable nutritional properties and suitability as environmental enrichment. fowever in a zoo setting it is possible that there are also other factors which play a role. One of these possible factors is the public's attitude towards the feeding of the animals and the food items used. On three different days a total of 300 Rotterdam Zoo visitors were interviewed on the subject gorilla and giraffe feeding. Knowledge of facts about the feeding of these animals was explored by asking respondents thirty questions about the necessity of ration components, the animal's feeding behaviour and the specific function of certain diet components. Furthermore eight questions were asked to find out how important the visible availability of browse in animal enclosures is for zoo visitors. Results showed no significant differences in knowledge about gorilla and giraffe feeding between ear cardholders and other visitors. Only 24 % of the respondents thought that banana’s are not a necessary item in gorilla diets. When the same question was asked about fruit in general only 6 % expressed the view that this is not a necessary component in Gorilla diets. Slightly more then 60% of the visitors thought gorillas need branches and leaves in their diet. Only 17% considered concentrate as a necessary diet component. More than 75 % of the respondents stated that branches are necessary for playing behaviour. About 60 % of the respondents thought that browse is important for teeth cleaning. Fruit is a necessary component for giraffes according to 37% of the visitors. For vegetables this figure is 46 %. Over 75% expressed the view that both hay and leaves are an important diet component. Only 35% of the respondents agreed upon the statement: “ The digestive system of the giraffe is similar to the digestive system of cattle”. A majority of the visitors (56%) stated that they would find the animal enclosures less attractive when no browse would be fed. Thirty four percent indicated that this would seriously affect their pleasure in visiting the zoo. Although this study had an indicative character, results show that it could be worthwhile to put effort in educating the public on the background of choices made in the composition of zoo diets. Visitors do not only enjoy a zoo visit because of the animals but also because of the environment the animals are exhibited in. This study indicates that the diet offered is an important part of this environment for the visitors.


M. Schils1, R. Smeets1, E. Bruins2, P.Veenvliet1 and T.R. Huisman1

1Van Hall Institute (Dept. of Animal Management), Postbus 1528, 8901 BV Leeuwarden; 2Artis Zoo, Postbus 20164, 1000 HD Amsterdam

Aldabran giant tortoises (Dipsochelys spp) are kept in over hundred zoos and institutions around the world. Many of these animals live there already for decades. Despite this, surprisingly little is known about the exact nutritional requirements of these animals. However there is certainly a need for more knowledge on this subject since quite a few institutions reported possible nutrition related disorders like geophagy, muscle weakness, loose stools, constipation and carapace inflammation. To obtain more insight in the current status of captive Aldabran spp nutrition, a survey was conducted among zoos, which were known to keep these animals. Questionnaires were sent to almost 100 zoos and institutions. The respondents were asked to answer general questions about the animals and their husbandry, diet composition, general health status, UV-lighting regime and possible nutrition related disorders.

Over 30 % of the questionnaires were returned. The information presented in the returned forms was used to calculate the nutritional content of the diets fed with the help of various food tables and compared against data on the in situ food intake found in literature. Preliminary results show a considerable spread in diets offered (i.e. predominantly domesticated fruit and vegetables or predominantly grass, hay and other roughage’s.) and nutritional content. Possible implications of this in connection with reported nutritional disorders will be discussed. All obtained data will furthermore be used to present an overview of the current state of captive Aldabran spp. nutrition.