Hoofstock & Megavertebrate Nutrition

Question 1

What disease problems of hoofstock have been associated with dietary causes?

Answer 1

Chronic weight loss

Rumen acidosis

Chronic weight loss

Rumen acidosis

Rumenitis

Laminitis

Hoof overgrowth

Periodontal disease

Fowler 6 - Nutrition of Browsers

Question 2

How do ruminants obtain their energy?

Answer 2

Basic pathway for creating energy from food in a ruminant:

Forages are fermented by microbes in the ruminoreticulum → Produce fatty acids → Fatty acids provide energy to the ruminant

Question 3

Why is healthy rumen flora important?

How can it be maintained?

What problems arise from an oversupply of simple carbohydrates?

Answer 3

Vertebrates and plant cell wall digestion:

• Vertebrates can’t digest plant cell walls on their own
• Rely on fermentation activity of symbiotic gut bacteria

Challenge is to maintain healthy stable gut flora

This is managed through:

• Maintaining a generous supply of high fiber feeds
• Restricting supply of highly digestible carbohydrates
• Problems with unrestricted carbohydrates
• If fed an oversupply of easily fermentable carbohydrates:
  
  • Foregut fermenters tend to develop:
  • Diarrhea
  • Weight loss
  • Hindgut fermenters tend to develop: Obesity

Question 4

Define the terms browser and grazer

Answer 4

Grazer: Refers to a species that eats primarily monocotyledonous plants (ie: grasses)

Browser: Refers to a species that eats primarily dicotyledonous plants (ie: woody plants and shrubs)

Question 5

How do browsers & grazers differ in obtainin their energy sources?

Name some species examples of each type.

Answer 5

Question 6

What anatomical differences exist between browsers and grazers?

There are 8 of them.

Answer 6

Question 7

What are the differences in digestibility, protein content, pectin content, and abrasive content in monocotyledon v dicotyledon plants?

Answer 7

Question 8

How does browse differ from hay in terms of fermentation times?

How does this affect feeding hay to browsers?

Answer 8

Browse reaches maximum fermentation sooner than grass:

• Browsers have a shorter ingesta retention time than grazers, making them:Less efficient at digesting fiber. Therefore, a browser on hay alone would have to:
• Ingest relatively more hay than a grazer would to get the same nutrition

So why not just feed browsers more hay?

• Because browsers have a wimpy rumen:
• Browser rumen lacks the strong musculature of a grazer, therefore:
• They are unable to ingest enough grass to form a grass mat as is seen in grazers
  
  • Because of this, browsers will preferentially avoid large amounts of grass
  • In addition, overall rumen capacity is smaller, so can not ingest enough hay to meet their energy demands even if they were willing
  • This makes it difficult for a browser to eat enough hay to survive on hay alone

Question 9

Nondomestic ruminants often have problems with inverse calcium phosphorus ratios.

List 5 species that are commonly affected.

Answer 9

Inverse Ca: Phos ratios are common in a lot of zoo ruminants:

• Affects both browsers and grazers:
• However, common species with clinical signs are often browsers or intermediate feeders:
• Including:
  
  • Kudu (Tragelaphus imberbis and T. strepsiceros)
  • Nyala (Tragelaphus angasii)
  • Eland (Taurotragus oryx)
  • Bongo (Tragelaphus eurycerus)
  • Giraffe (Giraffa camelopardalis)

Need to pay close attention to calcium, phosphorus, and magnesium levels in the diet as these all affect the calcium to phosphorus ratios in the body.

Question 10

Discuss the importance of pectins in the nondomestic ruminant diet.

Answer 10

Pectins: High energy source with less acidotic potential than grains

Pectins are found in higher levels in browse than in grasses

Commercially available pectins can also be used to replace grain / corn in pelleted rations as a good source of energy with less acidotic risk

Example of a commonly used pectin: Beet pulp

Question 11

Discuss the abrasive potential of grass v browse.

How does grazer & browser dentition differ?

Answer 11

Abrasive potential of grass vs browse: Grass is generally more abrasive than browse due to a higher acid-insoluble ash content and higher silica content. Importance:

Grazer dentition: Hypsodont

• High crowned teeth designed for eating abrasive foods
• As the teeth grind the food, the tooth surface wears down
• Since the crown is high, it takes years to wear down the tooth to the point of dental disease
• Results in continual wear by abrasion

Browser dentition:Brachydont:

• Low crowned teeth not designed to handle abrasive foods
• Hardest thing they are meant to chew against is the opposing tooth surface
• Tooth surfaces are not intended to wear down smoothly
• Results in eventual wear by attrition, but slow process

Question 12

A 2007 study evaluated the effects of wild and managed diets on giraffe dentition.

What did they find?

Answer 12

Clauss M, et al. 2007. Tooth wear in captive giraffes: mesowear analysis classifies freeranging specimens as browsers but captive ones as grazers. JZWM 38(3): 433-445.

• Looked at tooth wear in museum specimens: 20 free ranging and 41 captive giraffe
• Found that free-ranging giraffe had attrition wear, typical of a browsing species but captive giraffe had abrasion wear, typical of a grazing species.
  
  • Suspected cause:
    
    • Silica content higher in captive vs wild giraffe diets
    • Captive diet is often low in browse (and alfalfa), but higher in grass hay and pelleted compounds
• Importance: May related to shorter life span:
  
  • Captive giraffe generally die around 15 years of age, don’t reach maximum life span of 26-30 years that is listed in the literature
  • May be related to inability to utilize diet that is offered

Question 13

How do browsers and grazers differ in regards to fecal particle size.

Answer 13

Importance of fecal particle size:

• Fecal particle size is a direct function of chewing (comminution) efficiency.

Hummel, J., J. Fritz, E. Kienzle, E. P. Medici, S. Lang, W. Zimmermann, W. J. Streich, and M. Clauss. 2008. Differences in fecal particle size between free-ranging and captive individuals of two browser species. Zoo Biol. 27: 70–77

• Evaluated feces from the following four captive and wild animals for mean fecal particle size
  
  • Ruminant browser: Giraffe
  • Ruminant grazer: Aurox (primitive cow)
  • Non-ruminant browser: Tapir
  • Non-ruminant grazer: Przewalksi’s horse

Results:

• Captive grazers had a smaller MPS than wild grazers
  
  • Likely associated with pellets in captivity that are already ground
  • Indicates that teeth of grazers are equally efficient at chewing captive and wild diet components
• Captive browsers had larger MPS than wild browsers
  
  • Indicates that the teeth of browsers are less efficient at chewing captive diet components compared to wild diet components
  • Roughage offered in zoos likely very different from natural diet
  • Larger particles may contribute to bezoars and intestinal blockages
  • Offering of roughage only diets in captivity to ruminant browsers may result in not enough energy intake b/c they are unable to break it down efficiently

Question 14

Discuss the consequences of keeping a browser on a grazer diet long term.

Answer 14

Browsers kept on a grazer diet over a long period of time develop:

• More tooth wear than a grazer
• Less effective particle reduction leading to formation of phytobezoars
• If offered large amounts of concentrates:
• Tend to eat more concentrate and less grass leading to obesity and/or acidosis
• If offered large amounts of grasses and grass hay:
• Tend to end up in a negative energy balance due to inability to fully utilize grass plants

Question 15

Describe the ideal ration for ungulate herbivores.

How does that differ for browzers and grazers?

Answer 15

Ideal Rations for all Ungulate Herbivores

• Should be composed of:
• Adequate roughage
• High fiber pellet
  
  • Good pellet for any herbivore (including browsers) is one that:
    
    • Is based on forage meal to ensure high fiber content
    • Uses unmolassed beet pulp as an energy source
  • Pelleted diet should not be composed of:
    
    • Sugars and starches such as found in commercial fruits and grains

Browser Example Recommendations

• Wild Herbivore Line:
  
  • Mazuri’s diet for intermediate and browser herbivores
  • Basic description:
    
    • Starch content: Low (<4%)
    • Fiber content: High (>20%)
• Recommended ration:
  
  • 1.5 to 2.5% of BW per day in addition to:
    
    • Grass or legume hay
    • Supplemental browse

Grazer Example Recommendations

• Commercial herbivore pellets (ex: ADF-16) containing:
• Protein at: 12-18%
• Acid detergent fiber at: 16-25%
• Easily digestible starches including:
  
  • Alfalfa meal
  • Yellow corn
  • Wheat middlings
  • Molasses
• Recommended ration:1% BW per day in addition to:
  
  • Free choice grass hay

Question 16

What diseases have been linked with nutrition in giraffe?

Answer 16

Diseases Linked to Nutrition in Giraffe include:

• Rumen acidosis
• Chronic wasting
• Peracute mortality syndrome / serous atrophy of fat
• Energy malnutrition
• Hoof disease
• Inverse serum calcium and phosphorus levels
• Mortality caused by cold stress
• Overall poor body condition
• Urolithiasis
• Chronic energy deficiency
• Dental disease
• Pancreatic disease

Question 17

What does the diet of giraffes in the wild consist of?

Are they glassified as a grazer or a browser? Why?

What problems exist with the historical diets of managed giraffes?

Answer 17

Natural Diet of Giraffe

• In the wild, consume:
  
  • Foliage (main item)
  • Wild fruits
  • Flowers
  • Bark
  • Thorns
  • Seed pods

Grazers or Browsers?

• Traditionally categorized as browsers
• However, have some similarities to grazers:
• More omasal laminae
• Rumen well connected to abdominal wall
• Advanced compartmentalization of the rumen
• Larger body size
• May be more accurate to categorize them as intermediate feeder

Historical Captive Diet

• Typically consists of:
  
  • A complete feed - Ex: Low fiber pellet like ADF16
  • Hay - Typically alfalfa or alfalfa-grass mixes
  • Browse
    
    • Small portion, often only for enrichment
  • Produce
    
    • Small portion for enrichment, training
• Problems with this diet:
  
  • High in soluble carbohydrates
  • High in protein
  • Low in total fiber

Question 18

Discuss peracute mortality syndrome in giraffes.

Answer 18

Etiology: Negative energy balance leading to complete collapse from emaciation

History prior to death varies from:

• No premonitory signs
• Short history of illness
• History of stressful event

Pathology:

• Emaciation with serous atrophy of fat **Key finding
• Pulmonary edema
• Petechial hemorrhages
• Intestinal ulceration
• Myocardial degeneration

Question 19

Discuss the diets that were initially offered to giraffes, what they choose to actually consume, and what current recommendations exist for giraffe nutrition.

Answer 19

Initial Giraffe Diet Recommendations

• When first brought into captivity, giraffe were often fed like cattle (typical grazer diet). However, in the 1970s, Peracute Mortality Syndrome was first recognized as a syndrome triggered by a negative energy balance.
  
  • Suggested higher levels of easily digestible carbohydrates may decrease incidence
  • Several early studies noted higher levels of nitrogen in browser rumens than grazer rumens
  • Suggested a higher protein diet may be needed
• Out of this, came the initial giraffe diet recommendations:
  
  • Low fiber, high protein diet with easily digestible carbohydrates:
  • Adult non-lactating animals = 15-18% protein
  • Calves and lactating animals = 18-20% protein
• ADF-16 (or similar product) was often utilized.
  
  • Suspected benefits in giraffe nutrition:
  • Low fiber pellet
  • Relatively high protein (17%)
  • Supply high levels of readily fermentable carbohydrates (starch) due to ingredients:
    
    • Alfalfa meal
    • Yellow corn grain
    • Wheat middlings
    • Molasses

But what do giraffe actually eat?

• Giraffe offered low and high fiber pellets plus alfalfa hay selectively ingest:
  
  • Pellets and alfalfa with higher levels of neutral detergent fiber (NDF) and acid detergent fiber (ADF)
  • Pellets and alfalfa with lower levels of gross energy
• This is contrary to the idea that giraffe as concentrate selectors should select a low fiber, easily digestible diet. Suggests that browsers such as giraffe should be fed a diet:
  
  • High in fiber
  • Low in protein

Current Recommendations

• Should include:
• Low-starch, moderate protein, high fiber complete feed
  
  • <5% starch, ~30% ADF
  • 50 – 75% of daily caloric requirements
• Hay
  
  • Legume or legume-grass mix
  • 25-50% of daily caloric requirements
• Woody browse
  
  • Up to 25% of daily caloric requirements
• Produce
  
  • Offered only for training and enrichment
  • Should include items low in starch and calories including lettuce, green beans, carrots

Question 20

How do serum concentrations of fatty acids differ between wild and managed giraffes?

Answer 20

Schmidt DA, et al. 2009. Serum concentration comparisons of amino acids, fatty acids, lipoproteins, vitamins A and E, and minerals between zoo and free ranging giraffes. JZWM 40(1): 29-38.

• 32 free ranging giraffe and 20 zoo giraffe evaluated
  
  • Zoo giraffes fed primarily alfalfa based pellets, alfalfa hay, and browse
  • Free ranging animals:
    
    • Omg3 to Omg6 ratio: 0.48
    • Higher levels of omega-3 fatty acids compared to captive giraffe
    • Omg3s are typically produced by rumen microbes digesting forage
  • Zoo animals:
    
    • Omg3 to Omg6 ratio: 0.1
    • Higher levels of omega-6 fatty acids compared to free ranging giraffe
    • Omg6s are usually obtained from grains
• Suggests that giraffe diets should aim to provide more components that favor the production of omega 3 FAs over omega 6s.

Question 21

What diet changes can be provided to giraffes during colder weather months?

Answer 21

Cold weather is a commonly listed predisposing factor for peracute mortality syndrome in giraffe. Ideally, animals will be fed an ideal ration all year long and not be in a negative energy balance when approaching winter.

However, energy requirements may increase as much as 24% in giraffe in winter conditions, so supplementation may still be needed.

Current recommendations are to increase calorically dense items during periods of high energy demand rather than simply increasing diet overall.

Question 22

List the five species of rhino and their nutritional foraging strategy.

Answer 22

Question 23

Describe the recommendations for rhino diets across the taxa.

Answer 23

Generalized Nutrition Recommendations

• Recommended % BW as fed: 1-3%
• Recommended % BW as DM: 1-2%
• Total % of diet to come from pelleted source: 33%

Forage vs concentrate:

• Forage should be used as the primary nutrient source of all rhino species
• Concentrates should be used supplementally to balance energy, protein, mineral, and vitamin needs
• Avoid cereal grains in pellets when possible
• Avoid abrasive pellets due to link with dental damage and tooth wear

All rhinos should have ad lib access to:

• Hay (with the possible exception of the Indian rhino, more on this below)
• Clean water
• Salt

Note about trace mineral blocks:

• Generally not recommended, especially in iron sensitive species

Frequency of feeding:

• At least twice daily due to relatively fast GI transit time

Other types of supplementation:

Particular attention should be paid to mineral and vitamin balances, particularly in regards to Vitamin E

• Vitamin E appears to be lower in captive rhinos than other mammals
• Recommend ensuring at least 150-200 IU/kg per day.

Obesity:

• Common complication in captivity. Recommend frequent BCS assessments with a variety of staff members including: keeper, veterinarian, nutritionist, and manager.

Protein:

• High protein diets have been linked to laminitis in several species. Be sure to pick a protein content that is appropriate for the specific species being fed.

Question 24

Describe the effects of improper diets on rhinoceros dentition.

Answer 24

Severe dental plaque build up commonly seen in captive rhinos:

• Several potential causes have been suggested including:
• Excessive starch and sugar contents in the pellets and produce
• Abrasive pellets leading to damage in the teeth allowing for calculi build up
• Relationship to proliferative gingivitis:
  
  • Severity of proliferative gingivitis is not always associated with the degree of calculus accumulation
• Proliferative gingivitis is commonly seen in black rhinos in captivity

Question 25

Describe the ideal diet of Ceratotherium simum.

What nutritional problems are common in this species?

Describe the estrogen content of various hays.

Answer 25

Classified as a grazer

Wild diet:

• Consume a variety of grasses depending on season
• High levels of crude fiber: ~36%
• Low to moderate crude protein: 4.5-14.9% DM
• However, monocot grass species in human care are more limited in variety

Captive diet:

• Primary energy source in captivity should be from a high quality grass hay such as timothy, coastal bermuda, etc
• Avoid legume hays (alfalfa, lucerne, etc)
• Complete balanced pelleted feed should be used to supplement grass hay
• Frequently required as a portion of the diet considering seasonal needs and hay quality
• Recommended to supplement with forage based pellets rather than grain-based ones

Enrichment and training items:

• Produce commonly used for enrichment and training
• Avoid foods high in simple sugars like ripe bananas, corn, melons, etc.
• Be sure all items are included in the total overall diet tracking to avoid unintentional weight gain

Reproductive challenges in white rhinos and nutrition:

• Reproductive challenges are commonly documented in white rhinos in captivity and are suspected to be related to:
• Obesity
  
  • High levels of digestible sugars and energy negatively impact energy and glucose response and promote obesity
• Possibly high phytoestrogenicity:
  
  • Dietary estrogenicity and fertility of captive-born female southern white rhinos had a low to moderate negative correlation across multiple institutions
  • Hays lower in estrogens should be preferred, such as: timothy, bermuda.
  • Hays higher in estrogens should be avoided, such as: alfalfa, sudan

Question 26

Describe the ideal diet of Rhinoceros unicornis.

What nutritional issues are common in this species?

Answer 26

Greater One-horned rhino - Also known as the Indian Rhinoceros, they are classified as an intermediate feeder.

Wild diet:

• Wide variety of diet
• 139 species of plant, 39 families
• 6 yr study in Assam India
• Only 24% of the diet was grasses
  
  • Remainder included:
    
    • Trees
    • Shrubs
    • Herbs
    • Aquatic plants
    • Agricultural products

Captive diet:

• Found to benefit from limited intake: < 1.1% of BW on a DM basis
• Due to propensity for obesity and associated disease states including:
• Chronic foot problems
• Up to 25% of the captive population in one international survey
• Uterine leiomyomas

Obesity common in this species:

• Multi-institutional study digestibility study found that some roughage only diets without added concentrates still exceeded energy needs for greater one-horned rhinos. This suggests that ad libitum hay may not be ideal for this species

Importance of vitamins / minerals:

• Zinc and biotin are known to play a role in hoof health in horses and potentially elephants, unsure of significance in rhinos but may be beneficial to supplement
• Roughage only diets would likely need a specific blend of mineral supplementation to meet the needs of Indian rhinos
• *MORE WORK NEEDED regarding optimal balance of minerals and vitamins in greater one-horned rhinos.

Question 27

Describe the ideal diet for Diceros bicornis.

Answer 27

Black Rhino - Classified as a browser.

Wild diet:

• Entirely fresh browse
• 240 species of plant

Captive diet:

• Pelleted feed
• Alfalfa and grass-legume hay mixtures
• Browse
• Some produce for enrichment

Conclusion: Recommended captive diet for black rhinos

• Low iron pellet
  
  • Low in starch and soluble sugars
  • NDF values 40-60%
• Alfalfa or grass-legume mixes
  
  • Should be limited due to:
    
    • High protein, calcium, and iron in many harvests
    • Also has a tendency to cause diarrhea and colic
• Browse
  
  • As large a portion of the diet as possible
• Minority of enrichment items:
  
  • Avoid high sugar items due to propensity for obesity
  • Avoid produce items that increase iron absorption

Question 28

What are the diseases of unknown origin in Black Rhinos?

What role does nutrition play in these processes?

Answer 28

Several diseases of unknown etiology in black rhinos likely have some nutritional component. These include (but are not limited to):

• Iron storage disease / Iron overload disorder
• Hemolytic anemia
• Idiopathic hemorrhagic vasculopathy syndrome

Disease in these cases is suspected to be an interplay of:

• Stress
• Lack of antioxidants
• Improper fatty acid balance
• Excess dietary iron
• Excess starch and other glucose supplies
• Inadequate fiber
• Lack of polyphenolic antinutrients (tannins)
• Low phosphorus levels
• Several of these things may predispose to multiple diseases

Stress:

• Includes oxidative and environmental
• Oxidative stress:
• Reduced capacity to neutralize oxidants in rhinos, particularly the black rhino
• May imply that antioxidant supplementation should be considered as a preventative measure in black rhinoceros
• Vitamin E supplementation (as mentioned in the general guidelines section)

Improper fatty acid balance: Clauss M, Dierenfeld ES, Bigley KE, et al: Fatty acid status in captive and free-ranging black rhinoceroses (Diceros bicornis), J Anim Physiol Anim Nutr 92(3):231–241, 2008.

• Looked at European-held black rhinos (2008)
• Positive correlations found between amount of grain based products in the diets and the amount of omega-6 polyunsaturated fatty acids
• Omega-6 polyunsaturated fatty acids:
• Excess levels are established precursors to proinflammatory pathways
• May exacerbate inflammation in an already oxidant – sensitive species

Question 29

Discuss Iron Storage Disease in Black Rhinos.

What methods are available for reducing iron in this species?

Answer 29

Iron Storage Disease / Iron Overload Disorder / Hemochromatosis:

• Excessive iron in circulation is stored in the liver. Overtime this can be come pathologic.
• Importance of diet for ISD:
  
  • Grasses (and the associated soil that is ingested) tend to be high in iron
    
    • Therefore, grazers evolved mechanisms for dealing with an iron rich diet
  • Browse tends to be low in iron
    
    • Therefore, browsers evolved mechanisms for dealing with an iron restricted diet
    • More “concerned” about how to save iron, rather than how to get rid of it
    • Because of this, most do not have good mechanisms for removing excess iron from the body
    • Therefore, the excess iron builds up in the liver (hemosiderosis)
    • Eventually reaches a level that causes pathologic changes (hemochromatosis)
• Three main mechanisms to decrease incidence of iron storage disease:
  
  • Decrease iron in diet offered
  • Decrease iron absorption from the diet
  • Remove iron from circulation

Preventing iron storage disease: Decreasing iron in diet offered

• Methods to decrease iron in the offered diet:
  
  • Low iron pellets
    
    • Difficult to produce at low enough levels due to the process involved with milling grains
  • Minimize legume-grass hays
  • Increase browse component
  • Avoid foods high in iron for enrichment
• Goal:
  
  • Diet does not exceed 300 mg/kg DMB
• Added consideration regarding legumes and iron:Plant ferritin:
  
  • A plant protein that holds up to 4500 atoms of iron
  • Exists only in legumes
  • Plant ferritin is absorbed whole through clathrin-mediated endocytosis
  • May indicate that legume iron stores can be absorbed outside the typically understood regulated absorption in the gut

Preventing iron storage disease: Decreasing the absorption of iron from the diet

• Methods to decrease iron absorptionAvoid items that promote iron absorption
• Vitamin C (ascorbic acid)
• Citric acid
• Add items that bind iron prior to absorption or inhibit it’s absorption
• Tannins, including tea leaves, red wine mash, coffee grounds, etc

Preventing iron storage disease: Removing iron from circulation

• Methods to remove iron from circulation:Phlebotomy
• Majority of iron in the body is present in hemoglobin in the RBCs
• Chelation therapy
• Binds iron in the blood and allows for excretion of the iron with the chelation agent

Question 30

Discuss the hemolytic anemia of black rhinos including potential etiologies and how they can be addressed.

Answer 30

Hemolytic Anemia:

• Historical peak incidence in the 1990s, but has been decreasing in incidence since then. There have been 47 known occurrences, with mortality rates high at ~75% of animals.
• Several hypothesized causes (but only focused on nutritional considerations here):
  
  • Hypovitaminosis E
  • Hypophosphatemia

Suspected nutritional causes of hemolytic anemia: Hypovitaminosis E

Vitamin E:

• Alpha-tocopherol
• Important in maintaining membrane integrity relative to oxidant stress
• Hypovitaminosis E
  
  • Decreased membrane integrity leading to hemolysis of RBCs
• Vitamin E in captive vs free-ranging rhinos:
  
  • Lower circulating blood levels of vitamin E in captive animals despite adequate dietary levels (compared to a horse model)
  • May reflect a biochemical deficiency or a variation in the bioavailability of the different forms of the vitamin
    
    • Form of Vitamin E in the diet greatly affects the bioavailability
    • Different species vary in the way they utilize the different forms of Vitamin E
• Additional considerations for Vitamin E:
  
  • Different species may be different in their dietary requirement depending on the portion of the plant they typically ingest
  • Higher vitamin E levels have been demonstrated in the leaves than the twigs of browse plants
  • Vitamin E increases with chlorphyll degredation during plant maturation and would be expected to be higher in photosynthezising leaves
  • May be important in captive animals on a diet high in produced and dried forage versus fresh browse

Suspected nutritional causes of hemolytic anemia: Hypophosphatemia

• Low serum phosphorus levels are commonly seen in captive black rhino
• Low phosphorus inhibits glycolysis
• Reducing the amount of available ATP
• Predisposes red cells to oxidative stress

Question 31

Discuss Idiopathic Hemorrhagic Vasculopathy Syndrome in Black Rhinos

Answer 31

Idiopathic Hemorrhagic Vasculopathy Syndrome

• Acute onset of severe localized swelling of the limbs, face, and neck
• Often associated with a non hemolytic anemia
• Clinical signs also include:
  
  • Lethargy, respiratory stridor, laminitis, nail sloughing, aural hematomas, oral ulcers, skin ulcers
• Recurrence of clinical signs post recovery is common
• Often associated with a high mortality rate
• Unknown cause, but:
  
  • Treatment with fatty acids and phosphorus does appear to shorten the course of disease
  • Suggests that these two nutrients may play a role in the development of the disease

A note about hypophosphatemia in general in black rhinos:

• Appears to be a common concurrent finding in many black rhino diseases (not just hemolytic anemia)
• Unsure of significance:
  
  • May be a contributing cause to disease
  • May be a secondary effect of disease
  • May be unrelated
• Regardless, routine phosphorus supplementation is often recommended in black rhinos