Rhino Nutrition Guide

Written by Zutrition . Posted in Mammals, Uncategorized

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Photo Credit:  Wikimedia

Many of the health problems identified in captive rhinos are believed by some to be linked to nutritional factors. Rhinos consume a large number of species of plants with a diverse array of phys­ical characteristics and nutrients. They represent a range of feeding strategies and, consequently, diet, from browsers (or selective feeders) to unselective grazers. Diets in the zoological setting may have possible imbalances in dietary fats (particularly essential fatty acids) and soluble and insoluble carbohydrates, as well as minerals and vitamins for some species.  [1]

 

Nutritional Requirements

Due to similarities in digestive tract morphology, the domestic horse represents the best nutritional model for all rhinoceros species. Until further information is obtained, diets should be formulated using current National Research Council (NRC; 2007) recommendations for horses of various physiologic stages. Minimum nutrient requirements are listed in Table 1 below. [1]

 

Table 1.  Nutrient concentrations in total diets for horses and ponies (dry matter basis: modified from NRC, 2007) [1]

Nutrient Growing Mature/Maintenance Pregnant/Lactating
Digestible Energy (Mcal/kg) 2.45-2.90 2 2.25-2.60
Crude Protein (%) 12-15 8 10-13
Ca (%) 0.6 0.3 0.4
P (%) 0.3 0.2 0.3
Mg (%) 0.1 0.1 0.1
K (%) 0.3 0.3 0.4
Se (mg/kg) 0.1 0.1 0.1
Vit A (IU/kg) 2000 2000 3000
Vit D (IU/kg) 800 300 600
Vit E (IU/kg) 80 50 80

Forage

Good quality forages should provide primary nutrients for all herbivores, with concen­trate feeds used to balance energy, protein, mineral or vitamin needs. Hay storage is particularly important for ensuring proper dietary management. Moldy or dusty hay may cause colic and/or heaves. Large amounts of poor-quality hay should not be fed to rhinos, as it may be so poorly digested that impaction and/or colic will result. Very high-quality legume or small-grain hay may be so readily digested that when fed with concentrates, loose feces or colic may result. [1]

The larger, grazing rhino species should have ad libitum access to grass hay and water. Given the propensity of captive grazing rhinos to become over-conditioned, use of hays or low-glycemic index concentrates are highly recommended for white rhinos (Berkeley et al., 2011). The concentrate portion of the ration should be given in at least two feedings daily for better utilization. When practical, a small feeding of hay should be encouraged prior to each concentrate feeding. [1]

In studies of intake, digestion and passage in zoo herbivores, Foose (1982) measured dry matter intakes of approximately 1% of body mass when white rhinos (n=5) were fed grass hays and slightly higher levels (1.2-1.6% of body mass) when fed alfalfa hay. Diets were 67% digestible (white rhinos eating alfalfa). Thus, a guideline for as-fed diet quantity would be approximately 1.5% of body mass, but the exact quantity of high-fiber pellets will depend on their formulation. Offering sweet feeds in excess of 33% of the total calories in the diet is not advised. Large (>1.0 cm diameter), high-fiber pellets work well with grazing species. [1]

Animals can sometimes be encouraged to consume less palatable forages if hays are soaked in water or sprinkled with molasses. Applesauce has proved to be helpful in administering unpalatable medications and/or supplements. [1]

 

Produce and Browse

Produce generally is not offered to white rhinos in their daily diets (indeed, 15/28 institutions do not offer any at all), but some institutions do feed up to 2.3 kg of produce daily. Produce items that are fed for enrichment, training, or as part of a daily diet are listed below (Table 2). Similarly, browse generally is not offered to white rhinos in their daily diets (16/28 institutions do not offer any). Where it is offered, a few kg of browse might be offered a few times per year up to free choice when the particular forage is growing (Table 2). The most common hays and concentrated pellets fed among white rhinos are noted below (Table 2). Hay is often fed in variable amounts, from 0 kg to ad libitum, depending on the available grazing. Two of the surveyed institutions do not feed any pellets. It is important to remember that all diets should be based on forages, not concentrates. [1]

 


BLACK RHINO BROWSE

The Black rhino is a browser, its main foods being the thin regenerating twigs

of woody growth and legumes. A great variety of plant species are utilised, although

acacia seems to be a favourite (Nowak, 1999). The natural diet of the Black

rhinoceros is characterised by a high fibre and moderate to high protein

content (Claus and Hatt, 2006). They eat a wide range of browse species in any

given habitat, but while over 100 species may be ingested during a year’s foraging,

90% of the diet is commonly made up from fewer than 20 species. Grass is generally

only eaten incidentally while foraging for low-growing herbs, but new soft grass leaf

growth is voluntarily taken (Adcock and Amin, 2006). [2]

Black rhinos are most active during the night-time when most of their

foraging and drinking is done. Foraging also occurs in the cooler hours

of the morning and afternoon, but wallowing and / or sleeping in a cool,

breezy or shady spot is the main activity during the heat of the day (Adcock and Amin, 2006). [2]

Browse may contribute required nutrients that have not yet been quantified and may

also be of benefit to dilute a captive diet that is too digestible (Dierenfeld, 1996).

Browse that could be fed to black rhinos are:

  • Willow (Salix spp)
  • Beech (Fagus spp)
  • Hazel (Corylus spp)
  • Ash (Fraxinus)
  • Birch (Betula spp)
  • Oak (Quercus spp)
  • Hawthorn (Crataegus spp)
  • Robinia (Robinia spp)
  • Poplar (Populus spp)
  • Apple (Malus spp)
  • Cherry (Prunus spp)
  • Pear (Pyrus spp)
  • Prune (Prunus spp)
  • Wild rose (Rosa spp)
  • Blackberry (Rubus spp)

 

Table 2. Food items fed to white rhinoceros. Amounts (kg) reflect daily rations. Some food items are not offered daily but are offered during enrichment and training; other food items are offered free choice [1]

Produce Amount (kg)
Apple 0-0.5
Banana 0-2.2
Beets 0-0.2
Bell pepper 0.28
Bok Choy 0.2-0.28
Cantaloupe 0.13-0.28
Carrot 0-1.5
Cauliflower 0.2
Celery 0-0.23
Cucumber 0.28
Grapes 0.4
Green beans 0.2-0.28
Honeydew 0.13-0.28
Kale 0.2-0.25
Lettuce 0-1 head
Orange 0.3
Parsnips 0-0.2
Pear 0.17-0.3
Pineapple 0.22-0.3
Potato 0-0.75
Pumpkin 0.28
Squash 0-0.23
Sugar Cane 0.28
Sweet Potato 0-0.75
Watermelon 0.13-0.28

from the EAZA Best Practice Guidelines Black Rhinoceros [2]

 

Browse/Grasses1 Amount (kg)
Abies fraseri 8-14
Acacia 0-2/week
Acer1 0-free choice
Alnus 1-10
Albizia 0-free choice
Alpinia zerumbet 8-14
Andropogon
Arundo domax 0-3
Bamboo
Bauhinia 8-14
Bismarkia nobilis 8-14
Broussonetia papyrifera 8-14
Carpinus 1-5
Casuarina equisetifolia 8-14
Celtis 0-free choice
Cenchrus pupureus 8-14
Cersis 0-5
Coccoloba uvifera 8-14
Cocos nucifera 8-14
Coprosma repens 27-36
Cornus1 0-3
Cymbopogon citratus
Elaeagnus 0-7
Elaeocarpus 1
Escallonia 27-36
Ficus 0-10
Fraxinus 1-10
Gleditsia 0-6.8
Gordonia lasianthus 7
Hibiscus 0-14
Ipomoea 0-free choice
Lagerstroemia indica 8-14
Latania loddigesii 8-14
Liquidambar 0-free choice
Lirodendron 0-3
Lonicera japonica1 0-free choice
Malus1 0-10
Miscanthus sinensis 0-5/week
Morus 0-free choice
Musa 0-14
Musaceae 27-36
Myrica 7
Nyssa1 7
Panicum
Pennisetum alopecuroides 0-5/week
Persea borbonia 7
Pinus1 0-3
Phragmites australis 8-14
Phyllostachys 0-free choice
Phoenis canariensis 8-14
Phoenix dactylifera 8-14
Plantanus 0-2.72
Poaceae 8-14
Populus 0-10
Pyrus 2.2-7
Quercus1 0-14
Rhus 0-5
Robinia1 0-10
Rubus 1-5
Sabal palmetto 8-14
Saccharum
Salix 0-free choice
Sassafras 0-2.72
Scheffelera 4-8
Schinus terebinthifolius1
Schizachrium
Spondias mombin
Syagrus romanzoffiana 8-14
Symphoricarpos1 1-5
Tilia 7
Tillandsia usneodes 8-14
Tipuana karoo 8-14
Ulmus crassifolia 0-14
Vitis 1-5
Wodyetia bifurcata1 8-14

from the EAZA Best Practice Guidelines Black Rhinoceros [2]

Some browse species are potentially toxic when offered in large quantities.  Variety and moderation are key.  Animal managers should consult a nutritionist before feeding substantial quantities of any one browse item.

 

Hay Amount (kg)
Alfalfa with coastal 20-25
Bermudagrass
Brome w/prairie Up to 22
Coastal bermudagrass 2.5-free choice
Mixed grass 9.3-18
Oat hay w/timothy 9-12
Orchardgrass w/timothy 0-35
Peanut 1
Prairie Up to 18
Sudangrass
Timothy 0-free choice
Timothy w/alfalfa 79.2-free choice
Triple Crown Safe Starch 3-9

from the EAZA Best Practice Guidelines Black Rhinoceros [2]

 

Pellets and Mixes Amount (kg)
Bran 4.6/week
Custom formula herbivore diet 4.6
Elephant supplement 0.5-2.7
Purina Equine Senior 2.9
HMS ADF 16 1.8-9.1
Mazuri ADF 16 2.2-13.6
Mazuri ADF 25 5.4-15
Mazuri Browser Rhino Cube 5.5
Mazuri Wild Herbivore 2.3-20
Mazuri Wild Herbivore Plus 6.5
Moose Maintenance 33
NuZu Low Isoflavinoid
NuZu Low Iron Herbivore 6-7
Open formula 7-10
Herbivore grain
SDZ Global High Fiber 10.8
ADF-25 Herbivore
Uni. of FL Zoo Blend milled at Pennfield 10-13.6
Sweetfeed 7.2/week
TMR Pennfield 0.5/week
Toronto Zoo Formula 6.25
ADF 22%
Wheat Bran 0.5

from the EAZA Best Practice Guidelines Black Rhinoceros [2]

 

Feeding Location

As with all zoo species, feed should be offered on a concrete pad or in livestock troughs or bins. Sand impaction has previously been documented in rhinos (Nouvel and Pasquier, 1946); therefore, feeding directly on the ground is not recommended. To reduce competition for food, individual feeding stations or adequate space at communal feeders is recommended. [1]

 

Concentrates (from EAZA Best Practice Guidelines for Black Rhinos)

When feeding concentrates the pellets should be smaller than 1 cm in diameter for a proper intake of the pellets (Dierenfeld, 1996). The portion of pelleted compound feeds (or other forms of concentrates) in the diet should not exceed one-third of the overall caloric value. It should be possible to deliver sufficient amounts of energy and protein while providing a substantially lower proportion of pelleted compound feeds or concentrates in the diet. Pelleted compound feed may be used to balance mineral, vitamin and in some cases protein requirements. Pelleted compound feeds should only be used to satisfy energy needs when adequate roughage is not available. A pelleted compound feed based on lucerne meal, with a high concentration of vitamins and minerals (except iron) is recommended so that only small amounts need to be fed. When pelleted compound feeds are used it is recommended that it has high-fibre content (crude fibre 20% and acid-detergent fibre (ADF) of 25% of DM) (Clauss and Hatt, 2006). The proportion of concentrates in the diet should be between 1 and 10%. [2]

 

Supplements

Dietary supplements should be unnecessary in properly formulated rations. A possible vita­min-E deficiency has been suggested but not confirmed in zoo rhinos; current recommendations based on natural browse composition suggest that diets should contain 150 to 200 IU vitamin E/kg dry matter. Salt blocks and water should be available at all times. If grown in an area prone to soil selenium (Se) deficiency, forage should be tested routinely for determination of Se content in order to provide data needed for balancing rations (Table 1). [1]

Iron (from EAZA Best Practice Guidelines for Black Rhinos)

Over supplementation of iron is of particular concern in Black rhinos because this can cause several uncommon diseases. The recommended amount of 50 mg iron/kg DM for horses will probably be exceeded by the hay mixes described, and also by most pelleted feeds used. The use of tannin might reduce the excessive iron absorption. But there is no quantitative proof regarding supplementation of tannin in captive rhinos. According to Clauss and Hatt (2006), who assessed the results of studies regarding the effect of tannin supplementation in other species, the iron absorption will probably reduce by increased dietary tannin content. Extra supplementation with iron is not recommended (Clauss and Hatt, 2006). One Black rhino collection uses supplementation of tannin. [2]

Fatty Acids (from EAZA Best Practice Guidelines for Black Rhinos)

The supplementation of linolenic acid (n-3) could be necessary to balance the amount of linoleic acid (n-6) and linolenic acid (n-3). This could be done by feeding fresh forage like freshly cut grass and browse, by increasing the proportion of grass or lucerne hay in the overall diet, by using concentrates that are based on lucerne meal rather than grain or soy products or by including linseed or linseed oil in the concentrates (Clauss and Hatt, 2006). [2]

Salt lick (from EAZA Best Practice Guidelines for Black Rhinos)

Black rhinos have been found to have higher endogenous faecal sodium losses. To counter sodium deficiency salt licks (suitable for horses) should be available ad libitum (Clauss and Hatt, 2006). [2]

 

Problematic Diets

High-quality alfalfa as an exclusive forage is unnecessary and may lead to mineral imbalances, colic and diarrhea. There is some evidence that white rhinos are more sensitive to phytoestrogens, such as those found in alfalfa hay and some pellets, than greater one-horned rhinos (Tubbs et al., 2012), but the implications of this sensitivity for white rhino reproductive success are still being evaluated. The consumption of fresh red maple browse has been associated with hemolytic anemia in horses and should therefore be avoided. [1]

 


Hemolysis (from EAZA Best Practice Guidelines for Black Rhinos) [2]

Due to the predilection to hemolysis in the Black rhino, Dr Donald Paglia of the University of California at Los Angeles has suggested avoiding exposing them to drugs and compounds that are known to induce hemolysis in enzyme-deficient human populations. All of the following compounds should be avoided.

  • Pharmaceutical compounds: antimalarials, sulfonimides, sulfones, nitrofurans, acetanilide, chloramphenicol and some vitamin-K analogs
  • Chemical compounds: wood preservatives, rodent-control poisons and other pesticides, strong cleansers particularly those containing naphthalene
  • Food: favabeans

Other drugs have been associated with hemolysis but with an uncertain or doubtful role. These drugs include aspirin, phenacetin, aminopyrine, acetaminophen, probenecid, vitamin C, dimereaprol, p- aminosalicylic acid and 1-DOPA. Any exposure to creosote should be avoided. In view of the hemolysis induced in horses by the consumption of certain oak and red maple leaves, as well as wild onions and members of the Brassica (kale) family in other domestic species, consumption of these species should be avoided (Fouraker and Wagener, 1996). A long term treatment with chloramphenicol in Black rhinos had no impact on urine quality or a haemolysis. Continuous vitamin E and C supplementation is recommended as prophylaxis especially during the winter (Göltenboth and Klös, 1995).


Hand-Rearing

A limited number of rhino calves have been and are currently being raised using various formulas. Reports and published information must be carefully scrutinized for measures of success and methodology in milk-sample analysis. The following information uses the ungulate hand-rearing chapter in the AZA Infant Diet Notebook as a base for general feeding guidelines and formula selection (Reiter et al., 1994). This recommendation is to be used as a guideline for stan­dardization of a hand-rearing diet. [1]

Milk Composition and Formula Selection

Based on available data, rhinoceros milk is more dilute than milks of other ungulate species. It is low in solids, low in protein, very low in fat and high in sugar compared with milk of equids, bovids and cervids (Oftedal, 1984). Formula selected should mimic mother’s milk in composition as much as possible (Table 3). In Table 4, Formula One has been used to raise a calf to one year of age; Formula Two more closely mimics mother’s milk. In Europe, Mazuri® makes a rhino milk replacer for white rhinos. Land O’Lakes® Mare’s Match® has been used to supplement a greater-one horned rhino calf at San Diego Zoo Safari Park and possibly could be used for hand-raising white rhino calves (powder:H2O = 1:6 but formula may need to be mixed at a more dilute ratio (1:8) for the first few days to avoid problems with constipation). The San Diego Zoo Safari Park has used a low fat cow’s milk: nonfat cow’s milk: lactose powder: water (27:9:1:1 by weight)(Blakeslee and Zuba, 2002). [1]

 

Table 3. Nutrient compositions of rhino milk (Gregory et al., 1965) and recommended formulas (% as-fed basis). [1]

Formula Solids Protein Fat Sugar
Rhino milk 8.8 1.4 0.2 6.6
Formula 1 10.3 3.3 0.3 5.9
Formula 2 8.3 1.7 0.2 6.6

 

Table 4.  Composition of Rhino Hand-Rearing Formulas [1]

Ingredients Parts by Volume
  Formula 1 Formula 2
Water 32 9
Skim Milk 32 9
Karo Syrup 1 1

 

Though rhinoceros’ milk is different from cow’s milk, the latter may still be appropriate for hand-rearing rhinos if used in combination with other ingredients. Cow’s milk is low in iron; consequently, an iron source such as Fer-In-Sol®  should be added to the formula at two drops per 100 g of formula. In addition, infant vitamins, such as Major® Multi-Vita Drops®, should also be added to the formula at two drops per 100 g of formula. Some infant vitamins, such as Mead Johnson® Poly-Vi-Sol with Iron®, contain added iron. San Diego Zoo Safari Park uses Probios® (2 tbsp) and Lixotinic® (0.44 ml /kg body weight) as daily supplements added in the first bottle. The animal may also benefit from the addition of Lactaid® at one drop per 100 g of formula. Lactaid® aids in carbohydrate diges­tion and helps prevent possible gastrointestinal tract distress. [1]

If the neonate is less than 24 hours old, colostrum diluted 50% with water or an electrolyte solution for ungulates, such as Replenish®, should be administered for the first 24 hours. Though species-specific colostrum is preferred, cow colostrum may be used. San Diego Zoo Safari Park uses Land O’Lakes® Colostrum Replacement® in the first 24 hours after nursing followed by a mix of 50% colostrum and 50% formula during the next 24 hours, and then 100% formula until weaning. Products such as Colostrx® and Seramune® Oral may also be used. To avoid gastrointestinal distress, a diluted formula should be offered beginning on day two. The formula can be gradually increased to full concentration depending on the animal’s health, including weight gain and stool condition. Prior to feeding, the formula should be warmed to approximately 37°C (99°F). Rhinoceros calves prefer their milk cooler than many other ungulates. [1]

Feeding Regimen

The calf should be stabilized and hydrated before any feeding. Quantity fed should range from 10 to 13% of body weight (BW). Animals should be fed every two hours. Because infants suckle during daylight hours, feeding should be equally spaced in a 12-hour period not to exceed 3 to 4% of body weight at any one feeding. It is recommended that feeding begin with 10% of body weight split equally into 12 feeds one hour apart during daylight hours. The quantity of formula fed should be adjusted daily based on the animal’s weight. Animals should be weighed at the same time each day. Fresh water should be available at all times. [1]

Table 2.23. Example feeding regimen, provided by San Diego Zoo Safari Park. [1]

Week 1 & 2 6am, 8, 10, 12, 2, 4, 6, 8pm (18-20% BW) 8 feedings
Week 3 & 4 6am, 8, 10, 12, 2, 4, 6pm (17-19% BW) 7 feedings
Week 5 & 6 6am, 8, 10:30, 1, 3:30, 6pm (16-18% BW) 6 feedings
Week 7 & 8 6am, 9, 12, 3, 6pm (14-16% BW) 5 feedings
Week 9-14 6am, 10, 2, 6pm (12-14% BW) 4 feedings
Week 15 No more increases to daily volume
Week 15-30 6am, 12, 6pm (8-12% BW) 3 feedings
Week 30-40 (5-7% BW)
Week 41 (3-4% BW)
Week 52 Start dropping amount on all bottles
Week 60 Weaned

 

If diarrhea occurs, the quantity of formula fed should be decreased or the formula diluted until stool condition returns to normal. If diarrhea is persistent, an electrolyte solution can be used to dilute the formula, replacing some or all of the water. In addition, the number of feedings can be increased to lessen the quantity fed at any one time. [1]

Formula can be prepared ahead of time and warmed as needed. Water should be boiled to decrease possible contamination due to pathogens and refrigerated before being added to the formula. The formula should be refrigerated and used within 72 hours. Prior to feeding, the formula should be warmed to the animal’s body temperature. Calf nipples work well with large species. Bottles should be boiled before use. Diluted bleach may be used as a disinfectant. Formula left over from each feed should be discarded. [1]

Weaning

Weaning may begin as early as six months if necessary and should be completed in one year. Weaning is a slow process involving carefully monitoring of body weight and solid food consump­tion. Animals should have access to solid food at all times. A nutritionally complete pellet diet such as Calf Manna (Manna Pro Products, LLC., Chesterfield, MO, USA), horse feeds or high fiber ungulate pellets, in addition to high-quality grass hay, is appropriate. Formula may be decreased by gradually eliminating the number of feeds or decreasing the amount offered per feed and gradually decreasing the number of feeds. [1]

 

 

[1]  Excerpted from 2014 Rhino Husbandry Manual, Lara Metrione and Adam Eyres (editors) International Rhino Foundation, Association of Zoos and Aquariums Rhino Advisory Group

[2]  EAZA Best Practice Guidelines Black rhinoceros (Diceros bicornis)

Editors: Dr Mark Pilgrim and Rebecca Biddle MBiolSci., NEZS Chester Zoo

Contact information: Chester Zoo, Cedar House, Caughall Road, Chester, CH2 1LH, 01244 389 879

Email: b.biddle@chesterzoo.org / m.pilgrim@chesterzoo.org

Name of TAG: Rhinoceros TAG TAG

Chair: Dr. Friederike von Houwald

Edition: 1

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