Feeding Browsers

Nutrient content of Carolina willow (Salix caroliniana) browse components fed to exotic herbivores

Michael L. Schlegel1*, Alejandra Renjifo2, and Eduardo V. Valdes2

1Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA and 2Disney

Animal Kingdom, PO Box 10000, Lake Buena Vista, FL 32830 USA

Disney's Animal Kingdom Theme Park receives over 150 metric tons of Carolina willow browse (Salix caroliniana) yearly from an onsite 25 ha farm which is harvested from April to October. Willow is fed primarily to browsing species such as giraffe (Giraffa camelopardalis), lowland nyala (Tragelaphus angasi), mountain bongo (Tragelaphus eurycerus isaaci), southern black rhinoceros (Diceros bicornis minor), as well as to African elephants (Loxodonta africana africana). Based on the species that willow is offered, these animals consumed only the leaves; leaves, small stems, and bark; or in the case of black rhinoceros, the entire branch. Although information is available on the nutritive content of leaves and edible stems of willow species, there is little information on other components of the plant such as bark and wood. The objective of this study was to evaluate the nutritive content of the components of Carolina willow. Bundles of willow were harvested in April, August, September, and October 2003; and stored at 4.4 °C until sampled. Each bundle of willow was weighed (average = 6.82 kg, n = 4) and divided into components. These components included: leaves, green stems, stems less than 0.5 cm, stems 0.5 <= 1.0 cm, stems 1.0 <= 2.0 cm, and stems greater than 2.0 cm. Stems were further separated into bark and wood resulting in 10 components. Each component was weighed to determine bundle component proportion and subsampled for proximate, fibre fraction, and mineral analysis at a commercial laboratory. Bundles averaged 5% green stems, 20% leaves, 21% bark, and 54% wood on a dry matter basis. Wood from stems less than 0.5 cm had the highest DM content. Leaves had the highest and wood had the lowest crude protein content. Acid detergent fibre was the lowest in bark from stems less than 2 cm and the highest in wood. Bark had the highest calcium content with wood having the lowest. Phosphorus was higher in green stems than bark and wood from stems greater than 0.5 cm. Based on the extent to which each species consumes willow browse, the nutritive value will vary. Additionally, the effect of season on nutrient composition of Carolina willow browse is unknown.

Author's address:
M. Schlegel
University of Florida
6641 Bannerl Lake Cir, Apt 9201
32821-7359 Orlando
e-mail: schlegel@animal.ufl.edu

Nutrient content of Carolina willow (Salix caroliniana) browse components fed to exotic herbivores

Developing adequate diets for browsing ruminants: Investigations on the okapi (Okapia johnstoni)

J. Hummel1,2,3, K. Johansen4, M. Clauss3, W. Zimmermann1, C. Nþrgaard5

1Zoo Köln, Germany, 2Institute of Animal Nutrition, University Bonn, Germany, 3Institute of Animal Physiology, Physiological Chemistry and Animal Nutrition, LMU MÒnchen, Germany, 4Ebeltoft Zoo, 5Copenhagen Zoo, Denmark

As many other browsing ruminants, the okapi is regarded as a rather difficult species to be fed in captivity. Efforts have been made to evaluate intake and digestibility of diets fed in different EEP zoos. Typical diets of okapis in European zoos consist of alfalfa hay as roughage source, grain based concentrates and considerable amounts of produce (Crissey et al., 2000). In this study, we wanted to evaluate diets with a higher amount of an alternative concentrate (unmolassed beet pulp) concerning their energy content, and whether additional browse has an influence on overall intake or the roughage proportion of diets.
The study was done at two facilities, including 5 male and 2 female okapis. Intake and faecal output was quantified over a period of at least 8 days. Five sampling periods with variation in diets were done at facility 1 and two test diets were used at facility 2. Proximate and detergent composition was analysed for the samples. Metabolizable energy intake was estimated via a regression equation for domestic ruminants.
The digestibility of the traditional diets was relatively high (65-72 %), supplying the animals with sufficient amounts of metabolizable energy (0.6-0.8 MJ ME/[kg BW0.75*d]). Diets higher in unmolassed beet pulp and diets higher in unmolassed beet pulp and browse also had a high digestibility. Intake of ME in these diets was estimated to be adequate. Digestibility of fibre was high in the diets higher in unmolassed beet pulp (aD NDF: 54 – 61 %). Additional browse did not have an unequivocal effect on overall intake and roughage proportion, although it was the most preferred food of the study animals.
Traditional diets for browsing ruminants include a high amount of starch based concentrate and alfalfa hay as the only roughage source. They are regarded to be susceptible to the following problems: Alfalfa hay may not always be palatable to the animals, and a high intake of starch or sugar rich concentrates makes digestive upsets more probable. Diets high in unmolassed beet pulp are regarded to reduce the probability of digestive upsets (Van Soest 1987), and browse is generally the most preferred feedstuff for browsing ruminants. Since the diets including considerable amounts of these feedstuffs apparently provided the animals with sufficient energy they can be considered as valid alternatives to other feedstuffs used for okapis in captivity.

· Crissey, E. S.; Dierenfeld, E.; Kanselaar, J.; Leus, K.; Nijboer, J. (2000): Feeding guidelines proposal for okapis – a joint European and North American project. In: J. Nijboer, J.-M. Hatt, W. Kaumanns, A. Beijnen, U. Gansloßer (eds.): Zoo Animal Nutrition. FÒrth, Filander-Verlag.257 -270.
· Van Soest, P. J. (1987): Soluble carbohydrates and and the non-fiber components of feeds. Large Animal veterinarian 42: 44-50.

Author’s address:
J. Hummel
Zoo Köln
Riehler Str. 173
50735 Köln
e-mail: Juehummel@aol.com

The use of near infrared spectroscopy (NIRS) to evaluate browsing and grazing materials in order to optimise the feeding to zoo animals

J.A. Lowe, G. Dodson

Ringstead, Kettering, Northants NN14 4BX, UK

The use of near infrared spectroscopy (NIRS) to predict the chemical composition of feedingstuffs is widely used in the agriculture and the petfood industries. Both of these industries however rely on the development of either specific or general prediction equations based on the mathematical manipulation of the observed spectra of a large sample size in relation to the known chemical analysis of the samples.
Animals in captivity often do not have access to the browse or grazing plants that they would in their natural wild habitat. Finding a suitable material as a substitute depends upon experience of the keepers and zoo nutritionists and in many cases the choice is limited and dependent upon that material which is available locally.
Routine detailed chemical analysis of the available material as well as of the natural browse or grazing is both expensive and not always practicable. The chemical evaluation, particularly of the dietary fibre components and non-starch polysaccharides, of these ingredients is not routinely carried out in many laboratories. Thus establishing which locally available materials most closely match the material available in the wild is difficult. NIRS offers a rapid, flexible and cheap method of evaluating browse and gazing materials.
The conventional use of NIRS relies upon prior determined calibration equations, which when samples are limited and, or prior chemical analysis is unavailable is not possible. We propose an alternative approach that involves the comparison and manipulation of the spectra itself without relating it to the wet chemical determination of the product.
The individual spectra of a material can be regarded as a “fingerprint” of the chemical structure of a food, thus the subtraction of an identical or closely related spectra from this would result in a spectra which would approximate to a straight line. It is thus possible to use a computer to carry out iterative subtractions of varying proportions of combinations of the spectra of available browse or grazing material from the spectra of a sample of “ideal” material to establish a mix of available material that would match the ideal material. Matching the spectra in such a way would mean that the resulting combination would be nutritionally very close to the ideal material. This technique would permit the development of a more closely related nutritional supply of grazing or browse material without the need for detailed and comprehensive chemical analysis. It could also be used to pinpoint areas where the available combination would fall short of providing key macro-nutritional components.

Author’s address:
J.A. Lowe
Ringstead, Kettering
Northants NN14 4BX
United Kingdom
e-mail: DRDOG234@aol.com

Digestibility and roughage intake in a group of captive giraffes (Giraffa camelopardalis reticulata)

S. Schmucker, A. Hörhager, L. Kolter,

Zoologischer Garten Köln, Germany

Adequate feeding and nutrition of giraffes is a constant topic of debate and discussion in zoo community. Giraffes are adapted to browse on digestible leaves by intense lip and tongue movements. While some reports, based on post mortem findings, mention low or missing fat reserves indicating energetic undernutrition, other reports present data on oral disturbances, which are regarded to be caused by insufficient stimuli due to inadequately low intake of forage and high intake of produce and concentrates high in metabolizable energy. The latter are fed in addition to the roughage offered to meet nutritional requirements. Here we present data on composition, intake and digestibility of a diet low in easily digestible carbohydrates offered to the giraffes at Cologne Zoo.
The study group consisted of 3 adult females and 2 subadult females (3 and 1.5 years old). The diet was composed of lucerne hay ad lib., fresh browse (winter: leafless; summer: with leaves), dried chestnut leaves (only winter), fresh lucerne/grass mixture (only summer), different concentrates (pelleted zoo compounds, unmolassed beet pulp, soybean extraction chips) and some produce. Feed intake was quantified over 8-12 days on two occasions (representing summer and winter feeding conditions).
The proportion of roughage in the diet was 65 % in winter and 73 % in summer (on a dry matter base). Dry matter digestibility was 52%. The frequency of oral activities (activity/kg DM) differed considerably between feedstuffs. Intake of the whole group was evaluated to be lower in winter than during summer feeding. All animals were considered to be in a good condition. Compared to published data, the high proportion of forage consumed by the studied giraffes is remarkable. Thus sufficient energy provision could be managed despite a forage intake of 65-73 %. This agrees with recommendations proposing a forage proportion of 60-70 % for giraffe diets (Lintzenich and Ward, 1997). The results will be discussed with respect to nutrition and its potential effect on feeding behaviour.

Lintzenich, B.A.; Ward, A. M. (1997): Hay and pellet ratios: Considerations on feeding ungulates. Fact sheet 006 in: Nutrition advisory handbook.

Author’s address:
S. Schmucker
Zoologischer Garten Köln
Riehler Str. 173
50735 Köln
e-mai:Lydia Kolter:lkolter@zoo-koeln.de

Browse provision for captive herbivores: design and management of a browse plantation

S. Höllerl1, B. Stimm1, J. Hummel2,3, M. Clauss3

1Institute of Silviculture and Forest Management, Munich, Germany
2Zoological Garden Cologne, Germany
3Institute of Physiology, Physiological Chemistry and Animal Nutrition, Munich, Germany

Many herbivorous zoo animals are known or are suspected to benefit from provision with serious quantities of browse material. However, for many zoological institutions, the reliable supply of browse is problematic: on the one hand, harvesting browse is a labour-intensive process; on the other hand, browse resources may be limited and subject to conditions that cannot be controlled by the zoological facility – such as urban browse cutting operations, or access to forests in the vicinity.
Therefore, ideally, zoological institutions that keep browsing animals and that do not have reliable access to browse guaranteed by third parties, should maintain or contract their own browse plantation. Although this concept has been pursued by individual facilities for a long time, general interest in such resource management has increased recently.
In this contribution, we explain the different necessary steps of planning, starting and maintaining a browse plantation for the purpose of regular harvesting. We give quantitative information on the size, plant density, expected browse yield etc. that allow the calculation of the necessary resources (in terms of land and logistics) for a targeted amount of browse. Combined with estimates of recommended browse provision to different zoo animal species, this information allows the planning of a browse plantation tailored to any given needs.

Author‘s address:
Marcus Clauss
Institute of Animal Physiology, Physiological Chemistry and Animal Nutrition
Schönleutnerstr. 8
85764 Oberschleissheim

Feeding practise of roe deer in Zoo Goldau- a case report

A. Liesegang1, M. Wehrle2
1Institute of Animal Nutrition, ZÒrich, Switzerland, 2Goldau Zoo, Goldau, Switzerland

Roe deer require more energy per unit of body mass for maintenance compared with that required by larger animals, since energy requirement increase proportional to metabolic weight. As the gut capacity can not cope with the high energy requirements, roe deer increase energy and protein intake. To optimise energy and protein intake they select easily digestible forage (highly digestible protein and carbohydrates), with a high proportion of soluble plant cell contents like young leaves and buds of various plants in the forest. These animals belong to the ruminant feeding types called “concentrate selector“. For this reason, the feeding of these animals in captivity is very demanding. Due to the selective feeding behaviour, the digestive system shows several morphological and physiological particularities: relatively small forestomach, a short retention time of ingesta, relatively large salivary glands producing high volumes of saliva, and a highly developed ventricular groove. These animals use both the fore- and hindgut as sites for the fermentaion of dietary carbohydrates. In captivity, it is difficult to feed these animals with species-specific rations, especially in wintertime, since it is not easy to compose a diet consisting of natural browse. In addition, roe deer have a reluctance to eat hay in contrast to other ruminants. For this reason the diet often consists of pellets, fruits, and vegetables.
In addition roe deer are highly susceptible to endoparasites. There may be a coherence between the feeding problems and this susceptibility to helminths and coccidiae.
It was the aim of this study to create a diet for roe deer with different feedstuffs at Goldau Zoo that contained higher portions of browse. This diet is supposed to be more natural than the diet fed before.
The roe deer group in Goldau Zoo included 3 adult animals (1.2, 7, 10 and 2 years old) with 2 juveniles. The enclosure was 1000 m2 large with natural meadow in the forest and several trees. The feeding place was roofed. The animals had free access to water. The health status of the animals was monitored with parasitology and from observation.
The diet fed first contained a high amount of roe deer pellets with high crude protein and low crude fiber contents. The proportion of crude fiber derived from structured feeds (hay, silage) was rather low. No hay was consumed by the animals, but a silage containing twigs and leaves was eaten during winter. The animals showed high incidence of endoparasites like helminths and coccidiae. The diet was changed thereafter. The change of diet started in August 2003. Some amount of the roe deer pellets was replaced by sugar beet pulp which has a lower crude protein content, but a higher crude fiber content. Instead of a grass-rich hay, a hay rich in herbes (Alpine meadow altitude 1800m , cut only once per year, no fertilizer used) was used. Additionally, molassed hay pellets were introduced. The animals accepted this diet much better and ate more. The palatability of the crude fiber and structure-rich ration was increased. The new silage only contained the leaves without the twigs. In table 1 the crude protein content and crude fiber content is listed. Although the crude fiber content could be increased, the crude protein content remained high. The proportion of crude fiber derived from structured feed was much higher compared to the old diet. Interestingly already in January 2004, the number of treatments against endoparasites could be reduced, since the loading of the faeces with worm eggs was reduced.

Table 1: Feed comsumption before and after feed changes
Before: amount (g/animal and day) Crude protein (% TS) Crude fibre (% TS) ADF (% TS) NDF (%TS)
Roe deer pellets* 400 15 3
Vegetables/fruits 100 2.3 10
Hay (not accepted) 0 10 27 37 59
Foliage (summer) 600 15 17
Foliage silage leaves and twigs (winter) 30 16 16
Chestnut (winter) 200 2.5 3.7
Gras (in enclosure) Ad lib.

After: amount (g/animal and day) Crude protein (% TS) Crude fibre (% TS) ADF (% TS) NDF (%TS)
Roe deer pellets* 50 15 3
Vegetables/fruits 100 6 8 14.1 16.3
Lucerne pellets* 50 18 24
UFA 256+ 200 7.5 23 27 35
Sugar beet pulp 100 10 21
Hay rich in herbs 100 9 26 33 56
Hay pellets+ (molassed) 150 9 27 30 41
Foliage (Sommer) 600 15 17
Foliage silage only leaves (Winter) 100 15 19 38 49
Chestnut (Winter) 200 2.5 3.7
Grass (in enclosure) Ad lib.
*Protector, Lucens, Switzerland
+Ufa, Sursee, Switzerland

In conclusion this case report demonstrates a quick change of appetite in a roe deer group after changing the diet to a fiber-rich diet, which is still high in crude protein. Also the excretion of endoparasites in the faeces was decreased, probably due to the fact the animals were healthier, ate more and revealed a better function of their intestinal tract according to a more species-specific diet. It has been stated that the mechanical characteristics of a diet are much more important than the chemical characteristics. So, additionally the structure of the changed diet seems to fit better to the
ration the roe deer, as a special browser, can deal with.

Author’s address:
Annette Liesegang
Institute of Animal Nutrition
Winterthurerstr. 260
8057 ZÒrich
e-mail: aliese@vetphys.unizh.ch

The formulation of a beet pulp-based pelleted food for captive wild ruminants and preliminary experiences.

C. Berndt¹, A. Klarenbeek¹, T. Heijckman², J. Hummel³, M. Clauss4

1Dierenpark (Zoo), Emmen, the Netherlands 2Van Cooten Diervoeders b.v., the Netherlands, 3Zoological Garden of Cologne, Germany, 4Institute of Animal Physiology, Physiological Chemistry and Animal Nutrition, Munich, Germany.

A major challenge in captive wild ruminant nutrition is the simultaneous provision of an adequate
energy supply and the prevention of rumen acidosis . Pectins and other soluble fibre components are a readily available energy source for ruminants, but their fermentation is not, in contrast to starch or
sugars, prone to result in an acidotic rumen condition (3).
Therefore, the inclusion of feeds with a high pectin content in the diet of captive wild ruminants has been promoted recently (2,4). The acquisition of a new pair of moose (Alces alces) at Emmen Zoo, Netherlands, in March 2003, led to the formulation of a new pelleted food with this concept in mind. Objectives of pellet formulation were a high proportion of pectin-rich ingredients, a low proportion of starches and sugars, a mineral composition with a high copper content considered appropriate for cervids and other wild ruminants except sheep, and the inclusion of sodium bicarbonate as a buffering substance to provide additional protection against rumen acidosis.
An evaluation of the effects of the pellets were noted so far. Compared to earlier years, the skin condition of the impala group was judged to have improved. While beet pulp may cause problems due to swelling in the oesophagus in horses and therefore should be offered soaked, it is commonly fed un-soaked to domestic ruminants. The pellet was offered unsoaked to all 99 animals; only in one case (a giraffe bull) were problems observed in the form of regurgitation/vomiting approximately 15 minutes after food intake, which is believed to be due to an oesophageal stricture.
The formula consists of beet pulp/ citrus pulp (22.5%), soy products (22.5%), lucerne meal (22.5%), sunflower hulls (12.5%), wheat (8%), molasses (2.5%), cellulose powder (2.5%), linseed (2.0), vitamin/mineral premix (2.2%), sodium bicarbonate (1%). The calculated analysis of this product is (on a dry matter basis): crude protein 16.8%, crude fat 5.7%, crude fiber 22.3%, crude ash 8.5%, starches and sugars 16.4%, NDF 40.7%, ADF 26%. Subtracting protein, fat, ash, neutral detergent fiber and starch/sugars from 100% leaves a residual of 12%, which will mostly represent the pectin fraction. Copper is added at 22 mg/kg dry matter.
The pellet has been fed to 3 moose, 13 giraffes (Giraffa camelopardalis), 44 impalas (Aepyceros melampus), 3 Lesser kudus (Tragelaphus imbebris), 4 pudus (Pudu pudu) and 32 guanacos (Lama guanicoe) for nearly two years. The pellets were accepted readily by all individuals.

· Clauss M, Kienzle E, Hatt JM. Feeding practice in captive wild ruminants: peculiarities in the nutrition of browsers/concentrate selectors and intermediate feeders. A review in: Fidgett et al. (eds) Zoo Animal Nutrition Vol. 2, Filander Verlag FÒrth, Germany, 27-52.
· Hummel J, Hörhager A, Nawrocki D. Wìhlerische Laubfresser- angemessene Ernìhrung von Giraffen und Okapis im Zoo. Kölner Zoo 2003; 46: 67-80.
· Van Soest PJ. Soluble carbohydrates and the non-fiber components of feeds. Large Animal Vet 1987; 42-44-50.
· Van Soest PJ. Allometry and ecology of feeding behaviour and digestive capacity in herbivores: a review. Zoo Biology 1996; 15: 455-479.

Author’s address:
C. Berndt
Dierenpark Emmen,
Hoofdstraat 18
7801 BA Emmen
the Netherlands