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EEHV hemorrhagic disease in elephants is often fatal as a result of DIC. Antibody assays and PCR monitoring may help to treat affected elephants in an early stage. This page describes the virus, the disease, its treatment, plasma transfusion, cross matching and standing sedation. To infectious diseases Elephant Endotheliotropic Herpes Virus-Hemorrhagic Disease (EEHV-HD) Compiled by Willem Schaftenaar History: EEHV-HD is caused by a delta-herpesvirus. The virus has evolved with the elephant species and is older than the currently living elephant species. Most (if not all) adult elephants are latently infected with EEHV. Young elephants between 1 and 9 years of age can be susceptable for an often fatal syndrom: EEHV-Hemorrhagic Disease. It is hypothesized that the long half-lifetime of maternal antibodies (EEHV maternal antibodies can circulate for up to 36 months in a calf) protects the calf against developing this syndrome. If this is true, it means that calves need to be exposed to EEHV during the phase in which antibodies are decreasing, but still protecting the calf. Fatal cases in Asian elephants have been reported over 20 times more than in African elephants. One of the hypotheses is that African elephant are shedding the virus much more frequent than Asian elephants, which offers a better opportunity for the calf to build up a solid immunity during the period that it is still protected by maternal antibodies. Asian elephants can carry EEHV1a, EEHV1b, EEHV4 and EEHV5, of which EEHV1a has caused the vast majority of the fatal cases. African elephants can carry EEHV2, EEHV3a, EEHV3b, EEHV6 and EEHV7. EEHV3 and EEHV6 have been associated with fatal cases, while the other African EEHV-subtypes are associated with lymphoid nodules in lungs and skin of African elephants. There is one report of a fatal case caused associated with EEHV3 in an Asian elphant. Like all herpesviruses, EEHV has a latent phase in a so far unknown tissue of the elephant body. For reasons that are not yet known, the virus can be reactivated, probably due to a (temporary) weakening of the elephant's immune system. The virus migrates to the mucous membranes of the mouth, trunk, eyes and the female genital tract. Shedding in semen or mucous membranes of the penis has not yet b een reported. Shedding has been observed in a zoo-kept herd of Asian elephants after the introduction of a bull and on a second occasion after the introduction of 2 females (Titus, 2022). In another zoo, 2 young Asian elephant calves died of EEHV1 within 2 weeks after the introduction of a breeding bull (Dublin zoo, 2024). Both calves appeared to have no antibodies against EEHV1a and EEHV1b. These findings suggest that the introduction of adult elephants in a herd can induce virus reactivation and consequently virus shedding. (Maternal) antibodies Humoral antibodies can be demonstrated by using recently developed antibody assays. A fluorescence based assay (Lips assay) has become available in the USA (Fuery, 2020) and an ELISA-based assay in the Netherlands (Hoornweg, 2021 ) . Serological studies using these assays demonstrated that maternal antibodies remain circulating for up to 36 months in elephant calves (Fuery, 2020). These maternal antibodies are transmitted in the uterus. The long period during which they are circulating at high levels in a young elephant, suggests that this species is able to absorb antibodies excreted by the dam in her milk. This is also suggested by Takehana et al 2024 , who described that the antibody level in a bottle-fed elephant calf decreased within 14 months as compared to 2 other calves in the same herd, in which antibodies remained high for more than 2 years. However, this hypothesis still needs to be proven. EEHV-subspecies and subtype-specificity has been demonstrated for these assays (Hoornweg, 2023 ) . Another finding was that antibodies against EEHV4 were not protective against fatal EEHV1a infections, while antibodies against EEHV1a seem to protect against illness caused by EEHV4 and EEHV5. Hoornweg et al. studied 23 fetal EEHV-HD cases in European zoos and found that all fatalities had low antibody levels against gH/gL of the EEHV (sub)species they succumbed to (Hoornweg, 2024) . During the first 12 months of life, maternal antibodies seem to remain stable at a high level, which seems to protect the calf from developing Hemorrhagic Disease when infected by EEHV. This may explain why clinical EEHV-cases have never been reported below the age of 1 year. This has lead to the hypothesis that young elephants need to be exposed to EEHV while they are still (partly) protected by maternal antibodies. Shedding of EEHV by herd mates is therefore essential for the calf to build up natural immunity. In an elephant that is permanently infected with EEHV, shedding takes place after reactivation of EEHV. In 2 elephant orphanages in Sri Lanka (31 and 93 elephants), all calves had high levels of EEHV-gB antibodies. These 2 institutions never lost a calf to EEHV-HD. This leads to the conclusion that the larger herd sized in these 2 orphanages (compared to zoos increases the likelihood of cantact between EEHV-shedders. Herpes viruses in general can become reactivated during a stressful situation, when the immune system of the host seems to become weaker, possibly under the influence of endogenous glucocorticosteroids. Specific stress inducers that result in EEHV-reactivation are not yet known for elephants. It is tempting to hypothesize that social stress could be one of those factors, as elephants are highly social animals. Zoos generally try to avoid stress situations for their animals, including elephants, especially when there is a young calf in the herd. In the light of the recent findings, the absence of stress might as well work against the development of acquired immunity against EEHV in young calves. The same hypothesis could be valid for elephants in wild situations: if social stress factors are absent in some of the wild situations (less contact with other herds due to habitat fragmentation, less contact with bulls in musth), reactivation frequency of EEHV may be reduced in (sub)adults, preventing calves younger than 12 months from building up immunity during the crucial time frame when they are still protected by maternal antibodies. Clinical signs and diagnosis: 10-14 days before the elephant shows clinical signs of EEHV-HD, the presence of the virus can be demonstrated in the blood by qPCR (EDTA blood sample). It is important to monitor the presence of EEHV in calves between 1 and 9 years of age on a weekly base. As soon as the presence of EEHV has been confirmed, the number of monocytes and platelets are indicative for the further development of the virus in the days to come. When monocytes and platelets are stable and the viral load remains below 5.000 Viral Genome Equivalents (VGE's)/ml, close observation is required. As soon as the viral load in the blood increases or monocytes or platelets drop, immediate treatment is required. If the initial viremia has passed unnoticed, the young elephant may display one or more of the following unspecific symptoms: lethargy, reduced appetite, lameness, abnormal sleeping pattern, soft feces. In more advanced cases petechiae are seen on the tongue, edema on the head and front legs and finally cyanosis (purple tongue). Sometimes the severe symptoms are the first ones to be discovered. Photo: courtesy of Florence Ollivet-Courtois The most relevant tools needed for the diagnosis of EEHV-HD are: qPCR and total WBC, platelet count and blood smear (manual count of monocyte and heterophyls). The monocyte/heterophil (M/H) ratio is an important prognostic indicator for EEHV-HD. A ratio below 1 is reason for great concern and immediate treatment should be started. Blood smears are essential for manual differentiation of the white blood cells and recognition of the morphology. Note that the presence band-heterophils in young elephants is a bad sign! Lactate is an important serum parameter to monitor in a EEHV-HD case. Normal values are between 0--0.11 mmol/L (0-1 mg/dL). Values >0.44 mmol/L (4 mg/dL) are indicative for perfusion problems due to DIC (see below). EEHV-HD patients often have lactate value > 0.22 mmol/L (2 mg/dL) (Wiedner, pers. comm. 2022). Reports from Thailand suggest that a (primary?) infection with EEHV4 is generally associated with intestinal problems (Kittisirikul, 2025). At rectal examination, edema of the rectal mucosa can be diagnosed. This finding is supported by histopathological findings in fatal EEHV-HD cases ( Sripiboon, 2013) . Disseminated Intravascular Coagulopathy (DIC) One of the main reasons an EEHV infection can lead to severe illness or death is the development of DIC in young calves that are not adequately protected by (maternal) antibodies. DIC results from a severe, dysregulated immune response triggered when endothelial cells are damaged by the virus (endothelial glycocalyx degradation). Two independent studies have clearly demonstrated the occurrence of DIC in fatal cases of EEHV-HD (Guntawang, 2021; Perrin, 2021). In the treatment protocol for EEHV-HD, addressing DIC is a top priority. Cytokine Storm? In recent years, researchers have questioned whether a cytokine storm—described in human hemorrhagic fevers such as Ebola and Dengue—also plays a role in the development of EEHV-related DIC in elephants. A recent study reported a significant increase in interleukin-6 (IL-6) and interleukin-10 (IL-10) levels in the tissues and blood of six elephants suffering from clinical EEHV1a-HD (Hoornweg, 2025). Moreover, 2 elephants with clinical EEHV1a-HD that were treated with glucocorticosteroids, had lower serum levels of IL6 and IL10 than those that were not treated and even lower than the assumed reference level. Both elephants survived the clinical EEHV-HD infection. Elevated levels of these two interleukins are commonly associated with cytokine storms, suggesting that this phenomenon may also occur in EEHV-HD. These findings support the theory that the administration of glucocorticosteroids are indicated in the early phase of the hemorrhagic disease. Photo: courtesy African Lion Safari Park Photo: courtesy Amersfoort Zoo Pathological findings at necropsy The most prominent signs of EEHV-HD at necropsy are those that resulted from DIC: cyanosis of the tongue, subcutaneous edema, hemorrhages in most of the organs, joints and muscles, ranging from petechiae to large hematomas. There may also be a hydro-or hemopericardium. Especially in the case of EEHV4, the cecum and colon can be congested, hemorrrhagic and containing abnormal watery dark-brown content. Hemorrhages in the heart, intestines, brain and liver of a yound elephant that died of EEHV1a-HD. Photos by Arun Zacharia Coinfection of EEHV-HD and Clostridium perfringens α, βand ε. One report describes a coinfection of EEHV4 and Clostridium perfringens in a 7-month-old Asian elephant bull calf (Boonsri et al., 2018). The animal died within 2 days after the onset of the first clinical signs. At necropsy, basophilic intranuclear inclusion bodies were identified in the endothelial cells of blood vessels in the heart, lungs, liver, and spleen. This finding is indicative of a primary EEHV4 infection, despite the calf being suckled by its mother. Under normal circumstances, maternally derived antibodies would be expected to confer partial protection; however, this protection may have been insufficient, possibly due to a lack of prior immunity in the dam. Alternatively, the concurrent C. perfringens infection may have predisposed the calf to viral disease by compromising mucosal barriers or inducing systemic stress, thereby reducing the effectiveness of existing maternal antibodies against the virulence of the virus. The same authors also describe a coinfection involving EEHV1a and C. perfringens in a 3-month-old, female, wild-born Asian elephant that died within 6 hours after the onset of clinical signs. Although samples from the heart, lungs, liver, and spleen tested positive for EEHV by polymerase chain reaction, no intranuclear inclusion bodies were observed upon histopathological examination. This discrepancy suggests that, in this case, maternally derived antibodies may have partially inhibited viral replication within endothelial cells, thereby preventing the formation of characteristic inclusion bodies. Nevertheless, the rapid clinical deterioration indicates that other pathogenic mechanisms, potentially including the effects of C. perfringens toxins, may have played a decisive role in the fatal outcome. Taken together, these cases highlight the potential for synergistic interactions between EEHV and C. perfringens infections. Such interactions may exacerbate disease severity through combined effects on vascular integrity, immune function, and systemic homeostasis. Click here for the EAZA elephant TAG EEHV treatment protocol Treatment of EEHV-HD Early treatment of EEHV-HD is essential for the survival of the elephant. The list of recommended drugs is shown below. The clinician should not hesitate to administer all these drugs and should even sedate the sick elephant if needed for its treatment. Repetitive sedations have been given to sick calves without negative effects. If butorphanol is used to obtain sedation, it should not be antagonized as it will help to relieve the pain in the patient. Circulatory support: Rectal fluids: Luke-warm water 10-20 ml/kg BW TID or QID, up to every 2 hours NB: As repeated rectal fluid administrations may be needed, the anus of the elephant may become sensitive to these procedures. Rx: mix 15 ml lidocaine 2% with some lubricant and carefully apply on the anus. Wait for 10 minutes before placing the tube in the rectum for the administration of fluids. Repeated rectal exploration may be cause painful irritation of the anal sphincter and perianal skin. Adding lidocain to the lubricant may facilitate the exploration. Crystalloids: IV as a bolus of 0.3-4 ml/kg BW When blood or plasma is available, the administration of those products has preference over crystolloids. Whole blood transfusion: Indicated in case of anemia or severely delayed coagulation. The advantage of whole blood administration lays in the rapid availability: no waiting time for preparing plasma. A practical strategy is to collect sufficient blood from a donor elephant to make it available for whole blood (1-2 L) and save the rest to prepare it for plasma transfusions. Dosage whole blood transfusion: 1-2 L. Cross matching needs to be done prior to the transfusion. Plasma transfusion: IV bolus of 0.5-2 ml/kg BW (after minor cross matching of donor and recipient blood) For plasma transfusion in elephants see: Emergency care for elephants clinically ill from Elephant Endotheliotropic Herpes Virus–hemorrhagic disease (EEHV-HD, EAZA Elephant TAG, compiled by Fieke Molenaar (ZSL-Whipsnade zoo), Mads Bertelsen and Kathryn Perrin (Copenhagen zoo), Imke Lueders (GEOLifes), Lauren Howard (Houston zoo), Willem Schaftenaar (vet adv. EAZA Elephant TAG, 9 February 2021) Plasma is currently considered one of the best supportive therapies to provide, as platelets, clotting factors and potentially protective antibodies can thus be provided. Note that the freezing process activates platelets, which may render them useless at the time of transfusion. Therefore - where possible - freshly collected plasma is preferred. The following should be considered for plasma transfusions: If frozen plasma is available, this can be given in an early stage of the disease to save time (despite the activated and spent platelets). Blood collection from an adult elephant (plasma donor) should be initiated to provide fresh plasma as soon as possible. Cross-matching the donor animals with the recipients, especially if one donor will be used on multiple occasions. For more information about plasma transfusion: click here Anti-inflammatory treatment : Gluco-corticosteroid drugs are indicated in case of suspicion of DIC. Recent research could demonstrate an increase of interleukin 6 (IL6) and interleukin 10 (IL10) in tissues of elephants that succumbed to EEHV-HD and below-normal levels in blood of 2 survivors that were treated with glucocorticosteroids (Hoornweg, 2025). Dexamethasone: Used in 2 EEHV1a-HD survivor cases: Case 1: started with 0.2 mg/kg (200 mg) IV and continued daily for 12 days (final dose 0.007 mg/kg = 7 mg). Case 2: 2 mg/kg iv SID for 5 days, followed by 1 mg/kg iv SID for 2 days Triamcinolon : 0.067 mg/kg IV SID for 1-3 days (used in 1 EEHV1a-HD survivor case). Methylprednisolone sodium succinate: 0.5 mg/kg IV or IM; much higher doses are used for treatment of shock in horses: 10 - 20 mg/kg IV. Please note that in human medicine DIC (e.g. in Covid-19 cases) is treated with Dexamethasone 0.1mg/kg SID for 7-10 days ( https://www.who.int/news-room/q-a-detail/coronavirus-disease-covid-19-dexamethasone#:~:text=Recommendation%201%3AWHO%20strongly,medication%20for%20another%20condition .) Antiviral treatment: Several antiviral drugs are routinely used, although none of these have proven to be effective; preliminary studies are suggesting that the TK-gene of EEHV does not make the virus sensitive for the group of “ciclovirs” that is currently used. Famciclovir has been used most frequently, followed by ganciclovir. In the absence of the former antivirals, aciclovir has been given in several cases. Famciclovir: 15 mg/kg orally or rectally, TID Aciclovir: 15 mg/kg BID orally, rectally or IV (Ganciclovir: 5 mg/kg BW BID 5 mg/kg IV, BID, each dose given slowly diluted in 1 liter of NaCl. NB Ganciclovir is not preferred, as it is considered a potential human carcinogen, teratogen, and mutagen) Antibiotic treatment: A broad-spectrum antibiotic is recommended as the integrity of the intestinal wall may be disrupted and gut bacteria may leak into the abdominal cavity. Pain management: Pain management (opioids, NSAIDs) is recommended if there are clear signs of pain or discomfort Butorphanol (first choice): 0.008-0.014 mg/kg IM Q 4 hrs Flunixin: 0.25 to 0.5 mg/kg IM SID Omeprazole: 0.7 to 1.4 mg/kg PO SID Immunostimulating drugs: Immunostimulants have been used in one case of EEHV1a-HD: Interferon alpha 2a or 2b (25 mIU/2.5 ml Intron A, Merck or 4.5 mIU/0.5 ml Roferon A, Roche) were administered at 27–33 mIU intramuscularly once a day on days 1–12 then every 48 hours to day 20, administered by dart on days with no treatment session, incomplete delivery on days 8 and 14. Bacterial plasmid DNA in a liposome carrier (Zelnate DNA immunostimulant, Bayer HealthCare LLC) was given to the same elephant (2 ml intramuscularly on days 0, 4, 7 and 12). It should be noted that the same elephant was also given anti-inflammatory treatment (dexamethasone). WS personal note: It should also be noted that interferon levels are expected to be elevated in case of a cytokine storm. As there is no scientific proof of the benefits of interferon treatment in EEHV-HD, care must be taken to use any interferon-containing drug formulation! Adjunctive drugs: Oxygen should always be standby and administered as soon as signs of hypoxemia are seen. Furosemide (1 mg/kg IM ) has been given occasionally. Vitamin C, routine used in Asia (dos age depends on product; use equine dose). Vitamin E (dosage depends on product; use equine dose). Monitoring the course of the disease: The serum lactate level gives an indication of the organ perfusion. In EEHV-HD patients, the lactate level is often higher than 2 mmol/L (normal value: 0-1 mmol/L). Rehydration by the fluid administrations will help to decrease an elevated lactate. Platelet counts during the treatment course are helpfull in evaluating the success of the treatment. The administration of whole blood and plasma will compensate partly the loss of platelets and also provide antibodies if the donor is an adult elephant. It is advisable to make sure that the donor does have antibodies. Blood pressure : in severe EEHV-case, the blood pressure may decrease or decrease. Fluid administration may help to stabilize the blood pressure. When the patient has a vascular shock, the blood pressure may be low. A fast administered bolus of rectal fluids (0.5-5 ml/kg BW) within 15-30 minutes may help to increase the blood pressure. To standing sedation Treatment of EEHV-HD Cross-matching procedure Based on design elaborated by Houston Zoo, Inc. Step one: Prepare a 3-5% red cell suspension. 1. Collect blood from both donor and recipient in EDTA. 2. Centrifuge the tube and separate the plasma from the red cells. Save both. 3. Place 1 drop of recipient red cells into a small (2-5 ml) clean test tube. 4. Add approx. 1-2 ml of normal saline to the tube with the red cells (or 1 drop RBC to 40 drops saline) 5. Centrifuge at 2500 RPM for 20 seconds. 6. Remove the supernatant, leaving the red cell button on the bottom. 7. Repeat steps 4-6 three times (for a total of 4 washes). 8. Add 1 drop of newly washed recipient red cells to a new test tube. 9. Add approximately 20-40 drops of saline and mix to suspend the red cells. This should be an approximate 3-5% cell suspension to work with. Step two: Minor cross-match (for plasma transfusion). 1. Add 1 drop of the recipient’s 3-5% red cell suspension to a labeled test tube. Add 1 drop of the recipient’s 3-5% red cell suspension to another labeled test tube to be used as a control. 2. Add 2 drops of donor plasma or serum to the test tube. 3. Add 2 drops of saline to the control tube. 4. Incubate these tubes at 37oC for 15 minutes. 5. Centrifuge the tubes for 20 seconds at 2500 RPM. 6. Observe the supernatant for signs of haemolysis. If present in the cross-match tube and not the control tube, the match is not compatible. If present in both, start again with a new cell suspension. 7. If no haemolysis, then gently rock the test tube back and forth to re-suspend the cell button. Observe the cell button while rocking the tube and grade for the presence of agglutination. Grade on a 0-4 scale where 0 is no agglutination and 4 is heavy clumping. Record your results. Step three: Major cross-match (for whole blood transfusion). 1. Add 1 drop of the donor’s 3-5% red cell suspension to a labeled test tube. Add 1 drop of the donor’s 3-5% red cell suspension to another labeled test tube to be used as a control. 2. Add 2 drops of recipient’s plasma or serum to the test tube. 3. Add 2 drops of saline to the control tube. 4. Incubate these tubes at 35-37oC for 15 minutes. 5. Centrifuge the tubes for 20 seconds at 2500 RPM. 6. Observe the supernatant for signs of haemolysis. If present in the cross-match tube and not the control tube, the match is not compatible. If present in both, start again with a new cell suspension. 7. If no haemolysis, then gently rock the test tube back and forth to re-suspend the cell button. Observe the cell button while rocking the tube and grade for the presence of agglutination. Grade on a 0-4 scale where 0 is no agglutination and 4 is heavy clumping. Record your results. Anchor 1 References: Boonsri K, Somgird C, Noinafai P, Pringproa K, Janyamethakul T, Angkawanish T, Brown JL, Tankaew P, Srivorakul S, and Thitaram C. 2018. Elephant Endotheliotropic Herpervirsus associated with Clostridium perfringens infection in two Asiane elephants ( Elephas maximus ) calves. Journal of Zoo and Wildlife Medicine 49(1): 178–182, 2018 Fuery, A, Pursell,T., Tan, J, Peng, R, Burbelo, P.D., Hayward, G.S., Ling, P.D.2020. Lethal Hemorrhagic Disease and Clinical Illness Associatedcwith Elephant Endotheliotropic Herpesvirus 1 Are Caused by Primary Infection: Implications for the Detection of Diagnostic Proteins. J. Vir. Volume 94 Issue 3. Guntawang T, Sittisak T, Kochagul V. ,Srivorakul S., Photichai K., Boonsri K., Janyamethakul T., Boonprasert K., Langkaphin W.5, Chatchote Thitaram C. and Pringproa K. 2021. Pathogenesis of hemorrhagic disease caused by elephant endotheliotropic herpesvirus (EEHV) in Asian elephants (Elephas maximus ). Scientific Reports (2021). 11:12998. https://doi.org/10.1038/s41598-021-92393-8 Hoornweg TE, Schaftenaar W, Maurer G, van der Doel PB, Molenaar F, Chamour-Galante A, Vercammen F, Rutten V and de Haan CAM. 2021. Elephant Endotheliotropic Herpes Virus is omnipresent in elephants in European zoos and an Asian elephant range country. Viruses 2021, 13, 283. https://doi.org/10.3390/v13020283. Hoornweg TE, Perere VP, Karunarathne NS, Schaftenaar W, Mahakapuge AN, Kalupahana AN, Rutten VPMG, de Haan CAM. 2022 . Young elephants in a large herd maintain high levels of elephant endotheliotropic herpesvirus-specific antibodies and do not succumb to fatal haemorrhagic disease. Transboundery and Emerging Diseases 69-5 . https://doi.org/10.1111/tbed.14644. Hoornweg TE, Schaftenaar W, Rutten VPMG, de Haan CAM. 2024. Low gH/gL (Sub)Species-Specific Antibody Levels Indicate Elephants at Risk of Fatal Elephant Endotheliotropic Herpesvirus Hemorrhagic Disease. Viruses. 2024; 16(2):268. https://doi.org/10.3390/v16020268. Hoornweg TE, Schaftenaar W, IJzer J, Mulder MMP, Lugtenburg M, van Beest A, de Haan CAM and Rutten VPMG (2025) Elevated IL-6, IL-10, and IFN-g levels in fatal elephant endotheliotropic herpesvirus – hemorrhagic disease cases suggest an excessive proinflammatory cytokine response contributes to pathogenesis. Front. Immunol. 16:1645752. doi: 10.3389/fimmu.2025.1645752 Howard L.L. & Schaftenaar W. 2017. Elephant Endotheliotropic Herpes Virus. In: Fowler’s Zoo and Wild Animal Medicine Current Therapy, Volume 9. Kittisirikul N, Angkawanish T, Langkaphin W, Chaopong O, Thaitam B and Sripiboon S. 2025 Challenging management of clinical EEHV4 infection in an adult Asian elephant. 21st International Elephant Conservation and Research Symposium. Fort Worth IEF, December 5-8. Luz S & Howard L.L. 2017. Elephant Endotheliotropic Herpesvirus (EEHV) in Asia. Recommendations from the 1st Asian EEHV Strategy Meeting (On behalf of the Asian EEHV Working Group), second edition. Perrin KL, Kristensen AT, Bertelsen MF, Denk D. 2021. Retrospective review of 27 European cases of fatal elephant endotheliotropic herpesvirus‑haemorrhagic disease reveals evidence of disseminated intravascular coagulation. Scientific Reports (2021) 11:14173, https://doi.org/10.1038/s41598-021-93478-0. Sripiboon S, Tankaew P, Lungka G and Thitaram C. 2013. The occurrence of Elephant Endotheliotropic Herpes Virus in captive Asian elephants (Elephas maximus ): first case of EEHV4 in Asia. Journal of Zoo and Wildlife Medicine 44(1): 100–104, 2013. Takehana K, Hoornweg TE, Schaftenaar W), Rutten VPMG, de Haan CAM, Matsuno K. 2024. Elephant endotheliotropic herpesvirus gB-specific antibody levels in sera of Asian elephants (Elephas maximus) in Japanese zoos. J Vet Med Sci 86(12): 1279–1283, 2024 doi: 10.1292/jvms.23-0503. Titus SE, Patterson S, Prince-Wright J, Dastjerdi A, Molenaar FM. 2022. Effects of between and within Herd Moves on Elephant Endotheliotropic Herpesvirus (EEHV) Recrudescence and Shedding in Captive Asian Elephants (Elephas maximus ). Viruses, 14(2) 2022. doi:10.3390/v14020229. Wissink N. et al. 2018. Using in-house hematology to direct decisionmaking in the successful treatment and monitoring of a clinical and subsequently subclinical case of Elephant Endotheliotropic Her Vitus 1B. J. of Zoo and Wildlife Med., 50(2): 498-502 For more information see: http://eehvinfo.org/ To page top

Monitoring fecal quality in elephants includes regular control on parasites, consistency and fiber length. Fecal quality reflexes molar condition, food passage speed and presence of parasites. Intestinal infections can cause abnormal feces. Increased fibre length can indicate poor mastigation due to abnormal molar wear. Fecal quality control Compiled by Christian & Linda Schiffmann The physiology of defecation in elephants Elephants are megaherbivores with a mean retention time of about 24 hours (Rees 1982; Hackenberger 1987). Elephants do defecate on average around 12-16 times per 24 hours with a mean amount of five fecal boluses per defecation (Coe 1972; Ratnasooriya et al. 1994). Being hind gut fermenters, the plant fibers of their diet are shed in the feces exactly the size as they have been swallowed after being chewed. Therefore, fecal particle size is correlated to chewing efficiency in elephants. With respect to this physiology, fecal quality offers a valuable opportunity to assess an elephant’s digestive health. Accordingly, regular fecal check is strongly recommended as an integral part of continuous health monitoring in elephants under human care. Aspects to be assessed through regular fecal checks We recommend checking the following criteria for elephant feces in the indicated intervals: fecal consistency, structure and bolus size – on a daily basis fecal particle size – monthly coproscopy in order to detect intestinal parasites – 1-4 times a year (depending on regional parasite prevalence and housing conditions). In addition, fecal samples can be used to determine glucocorticoid metabolites and reproductive hormones, if this information is relevant for management decisions or scientific research. Fecal consistency, structure and bolus size Although fecal consistency and structure may slightly vary depending on diet composition, it usually allows the building of well-shaped and evenly sized boluses (Fig. 1a). Ideally, the boluses are compact and can be taken from the ground without breaking into pieces. They have a brown color which can tend towards slight green or yellow depending on the roughage fed. Gastrointestinal disorders as well as short-term stress may lead to reduced fecal consistency resulting in varying degrees of diarrhea (Fig. 1b-e). Not well-masticated food stuff (e.g. seeds, fruits) can be observed in the fecal boluses (Fig. 1f), as well as foreign materials which have been swallowed intentionally or unintentionally. These indicators provide information on which material the elephant has access to and on his (potentially abnormal) feeding behavior. Fecal bolus size varies with age and therefore size of an elephant (Coe 1972; Morrison et al. 2005; Leopardi et al. 2013). Elephants with improper chewing efficiency (e.g. due to molar issues), may show heavily enlarged fecal boluses as a consequence of poorly masticated roughage (Fig. 2). Such mega boluses may cause abdominal pain or even lead to constipation. In addition to the bolus size, also the total amount of feces during a 24h cycle should be checked. Showing an increased or decreased amount of feces may hint to digestive disorders or inappropriate feed intake in an elephant. Even the distribution of fecal boluses in the habitat of an elephant may tell you a story. As an example, geriatric individuals suffering from severe degenerative joint disease may not interrupt their lying rest to defecate, which can be recognized by the pattern of their defecations (Fig. 3). Taking this together, macroscopic fecal check as a daily routine can provide experts in charge with a multitude of valuable information on elephants’ (digestive) health status. Figure 1. Fecal consistency in elephants may vary from well-shaped firm boluses in a healthy situation (a) to different degrees of diarrhea with reduced fecal consistency (b-e). Unchewed parts such as corn may offer additional information on an elephant’s food intake on the previous day (f). Picture a: Photo Courtesy of Martin Kristen. Pictures c,d and e Photo Courtesy Patrycja Kasprzak. Figure 2. Mega boluses of different sizes (cell phone for size comparison) and in relation to regularly formed fecal boluses (upper right). Note the large plant fibers contained in the mega boluses (left). Photo Courtesy of Martin Kristen. Figure 3. Defecation pattern of an elephant suffering from severe degenerative joint disease and therefore avoiding to interrupt its lying rest for defecation. Healthy elephants do get up from recumbency in order to defecate. Fecal particle size Chewing efficacy has been shown to vary during an elephant's lifetime, presumably due to continuous changes in the molar grinding surface caused by the physiological process of molar progression (Schiffmann et al. 2019). Fecal particle size as an indicator for chewing efficacy can be used to monitor these physiological changes over time and to detect pathological alterations (Fig. 4). A simple sieving method allows the determination of fecal particles by focusing on the largest fibers. This method is practical in the field and has been shown to correlate well with a sophisticated approach in the lab (Schiffmann et al. 2023). A concise description of the procedure is given in Figure 5. It is recommended to document the detected size of the ten largest fibers photographically (Fig. 6). This enables the monitoring of fiber length of an individual elephant over time. Of course, this information should be completed with parallel monitoring of the molar status, which can also be documented photographically (Fig. 7). Figure 4. Obvious difference in fecal particle size between two female Asian elephants on the same diet, but with varying chewing efficacy. While one female with a healthy molar status was able to chew roughage as needed (a), the other female suffered from molar issues and struggled to chew properly (b). Figure 5. Guidance for a simple sieving protocol to determine fecal particle size in elephants. Figure 6. The size of the ten largest fibers can easily be documented photographically. Figure 7. Ideally, molar status in the upper and lower jaw should be monitored and documented on a regular basis. We recommend a frequency of three months for photographic documentation. Coproscopy for the detection of intestinal parasites Basically, African as well as Asian elephants are susceptible for clinical gastrointestinal parasite infestation. Most relevant gastrointestinal parasites for elephants do belong to the trematoda, cestoda, nematoda and protozoa (Vimalraj and Jayathangaraj 2013; Abeysekara et al. 2018; Chel et al. 2020). Severe parasite loads are reported in free-ranging as well as captive elephants in the range countries with the potential for fatal outcomes (Kinsella et al. 2004; Obanda et al. 2011; Nishanth et al. 2012; Hing et al. 2013; Vimalraj and Jayathangaraj 2013; Lynsdale et al. 2017; Abeysekara et al. 2018; Kingori et al. 2020). They seem less relevant in modern zoos. Prevalence of gastrointestinal parasites seems significantly higher in free-ranging elephants compared to elephants living in human care (Abeysekara et al. 2018; Abhijith et al. 2018). The composition of parasites seems to shift from helminth-dominated in free-ranging elephants to mostly protozoa in captive elephants, presumably due to regular anthelminthic treatment in human care (Abeysekara et al. 2018). Based on these reports, the recommended monitoring interval heavily depends on the geographic region and the housing conditions in particular regarding feed hygiene (Fig. 8). In Western zoos annual to biannual coproscopy seems a reasonable protocol, if appropriate hygienic conditions are ensured. Figure 8. Providing roughage in top-feeders (e.g. hay nets) can significantly reduce contamination of food items and ensure hygienic conditions. Especially for Asian elephants, these feeders should not be too high (like on this photo) as this may place too much strain on the flexibility of the spine, which could result in damage to the spinal joints. In order to cover the intestinal parasite species relevant for elephants, the fecal sample should be examined both by sedimentation as well as flotation. Table 1 gives an overview on which detection method is appropriate for which parasite species. Various treatment options are available (Fowler and Mikota 2006). If anthelmintic treatments are administered a subsequent coproscopy should be conducted to confirm the effectiveness of the treatment (Lynsdale et al. 2015). Table 1. Appropriate detection methods for the parasite classes most relevant in elephants Summary Regular fecal checks provide a non-invasive, simple and cheap opportunity to monitor an elephant’s molar and digestive health. Fecal consistency, structure and fiber length provide valuable information and should be checked on a regular basis. In combination with parasitology in the lab on an interval appropriate for the parasite prevalence in the region, these fecal checks present an important part of health monitoring in elephants under human care. References Abeysekara N, Rajapakse RPVJ, Rajakaruna RS (2018) Comparative cross-sectional survey on gastrointestinal parasites of captive, semi-captive, and wild elephants of Sri Lanka. Journal of Threatened Taxa, 10, 11583-11594. http://threatenedtaxa.org/index.php/JoTT/article/view/3406 Abeysinghe KS, Perera ANF, Fernando P (2012) Developing a practical and reliable protocol to assess nematode infections in Asian elephants. Gajah, 37, 22-26. Abhijith TV, Ashokkumar M, Dencin RT, George C (2018) Gastrointestinal parasites of Asian elephants (Elephas maximus L. 1798) in south Wayanad forest division, Kerala, India. Journal of Parasitic Diseases, 42, 382-390. https://link.springer.com/article/10.1007/s12639-018-1012-0 Baines L, Morgan ER, Ofthile M, Evans K (2015) Occurrence and seasonality of internal parasite infection in elephants, Loxodonta africana, in the Okavango Delta, Botswana. International Journal for Parasitology: Parasites and Wildlife, 4, 43-48. Chel HM, Iwaki T, Hmoon MM, Thaw YN, Soe NC, Win SY, Bawm S, Htun LL, Win MM, Oo ZM, Masum MA, Ichii O, Nakao R, Nonaka N, Katakura K (2020) Morphological and molecular identification of cyathostomine gastrointestinal nematodes of Murshida and Quilonia species from Asian elephants in Myanmar. International Journal for Parasitology: Parasites and Wildlife, 11, 294-301. Coe M (1972) Defaecation by African elephants (Loxodonta africana africana (Blumenbach)). East African Wildlife Journal, 10, 165-174. Fowler ME, Mikota SK (2006) Biology, Medicine, and Surgery of Elephants. Iowa, USA, Blackwell Publishing. Hackenberger MK (1987). Diet digestibilities and ingesta transit times of captive Asian (Elephas maximus) and African elephants (Loxodonta africana). Guelph, University of Guelph. MSC Thesis. Hing S, Othman N, Nathan SKSS, Fox M, Fisher M, Goossens B (2013) First parasitological survey of endangered Bornean elephants Elephas maximus borneensis. Endangered Species Research, 21, 223-230. http://www.int-res.com/abstracts/esr/v21/n3/p223-230/ Kingori E, Obanda V, Chiyo PI, Soriguer RC, Morrondo P, Angelone S (2020) Patterns of helminth infection in Kenyan elephant populations. Parasites & Vectors, 13, 145. Kinsella JM, Deem SL, Blake S, Freeman A (2004) Endoparasites of African Forest Elephants (Loxodonta africana cyclotis) from the Republic of Congo and Central African Republic. Comparative Parasitology, 71, 104-110. Leopardi S, Keratimanochaya T, Solmi F, Roberts J (2013). Estimation of a linear model capable to predict age of Asian elephants (Elephas maximus indicus) using dung bolus circumference. Proceedings of the International Conference on Diseases of Zoo and Wild Animals, Vienna, Austria. Lynsdale CL, Franco dos Santos DJ, Hayward AD, Mar KU, Htut W, Aung HH, Soe AT, Lummaa V (2015) A standardised faecal collection protocol for intestinal helminth egg counts in Asian elephants, Elephas maximus. International Journal for Parasitology: Parasites and Wildlife, 4, 307-315. http://www.sciencedirect.com/science/article/pii/S2213224415300031 Lynsdale CL, Mumby HS, Hayward AD, Mar KU, Lummaa V (2017) Parasite-associated mortality in a long-lived mammal: Variation with host age, sex, and reproduction. Ecology and Evolution, 7, 10904-10915. Morrison TA, Chiyo PI, Moss CJ, Alberts SC (2005) Measures of dung bolus size for known-age African elephants (Loxodonta africana): implications for age estimation. Journal of Zoology, 266, 89-94. Nishanth B, Srinivasan SR, Jayathangaraj MG, Sridhar R (2012) Incidence of endoparasitism in free-ranging elephants of Tamil Nadu State. Tamilnadu Journal of Veterinary & Animal Sciences, 8, 171-173. Obanda V, Iwaki T, Mutinda NM, Gakuya F (2011) Gastrointestinal parasites and associated pathological lesions in starving free-ranging African elephants. South African Journal of Wildlife Research, 41, 167-172. Punya MS, Shyma VH, Reshnu VC, Vijayakumar K, Vinodkumar K, Ambily R, Zachariah A (2021) Gastrointestinal parasites of captive Asian elephants in Kerala. Journal of Veterinary and Animal Sciences, 52, 312-315. Ratnasooriya WD, Molligoda PS, Molligoda WHM, Fernando SBU, Premakumara GAS (1994) Absence of synchronization either in defaecation or urination of the Sri Lankan elephant (Elephas maximus maximus) in captivity. Ceylon Journal of Science, 23, 47-51. Rees PA (1982) Gross assimilation efficiency and food passage time in the African elephant. African Journal of Ecology, 20, 193-198. Schiffmann C, Hatt JM, Hoby S, Codron D, Clauss M (2019) Elephant body mass cyclicity suggests effect of molar progression on chewing efficiency. Mammalian Biology, 96, 81-86. Schiffmann C, Schiffmann L, Bonillo J, Blukeviciute I, Gozalbes Aparicio E, Paniagua J, Ribera G, Ruiz M, Torro M, Clauss M (2023) A simple approach to monitor faecal particle size in the Asian elephant - A proof of concept study. Gajah, 56, 30-35. Thewarage LD, Dissanayake DSB, Perera US, Bandara AT, Perera BVP, Wickramasinghe S, Rajapakse RPVJ (2020) Morphology and molecular characterization of Parabronema smithii (Cobbold, 1882) (Nematoda: Habronematidae) from wild Asian elephant (Elephas maximus maximus) of Sri Lanka. Acta Parasitologica, 65, 504-517. Vanitha V, Thiyagesan K, Baskaran N (2011) Prevalence of intestinal parasites among captive Asian Elephants Elephas maximus: effect of season, host demography, and management systems in Tamil Nadu, India. Journal of Threatened Taxa, 3, 1527-1534. http://threatenedtaxa.org/ZooPrintJournal/2011/February/vanitha.htm Vimalraj PG, Jayathangaraj MG (2013) Endoparasitic infections in free-ranging Asiatic elephants of Mudumalai and Anamalai Wildlife Sanctuary. Journal of Parasitic Diseases, 39, 474-476. To page top

The dermatology-page will direct you to the chapters about skin wounds, skin abscesses, skin infections, tempral gland infection and temporal gland surgery. To case report index Dermatology Skin wounds Abscesses (needs your input) Skin infections (needs your input) Cutaneous filariasis Vaginal vestibulotomy Temporal gland impaction Temporal gland impaction/surgery

This case report describes an open fracture of the mandible in a young Asian elephant, that resulted in a severe infection. The elephant was humanely euthanized. To bone fractures Case report Mandibular fracture Date: 2020 Place: 13th Asian Society of Conservation Medicine Virtual Conference History •Coconut-sized abscess on left mandible •Asymmetric buccal margins •Tongue ulceration •Periodontitis •Endodontitis •Foul-smelling caseous material •Malocclusion Diagnostic results •Radiography 70kVp, 10mAs •Lateral and intraoral bisecting angle •Soft tissue swelling •Callus formation Conclusion: Left sided comminuted fracture at the body of the mandible. Unilateral mandibular fracture on left side → Malocclusion → Failure of 𝑀3 extrusion on right side → Impeded eruption of caudal molar on right side → Abnormal eruption of 𝑀5 on right side → Excessive molar abrasion on the left side → Compromised mechanical digestion of food → Anorexia → Malnutrition Treatment The animal was not a release candidate, and keeping the animal in captivity for a prolonged period nor permanently was not an option. Therefore, the authorities opted for euthanasia. Read the poster To page top

This chapter describes tusk fractures, conservative and treatment by partial pulpectomy and filling with glass ionomer cement and tusk extraction. To dentistry To dentistry Tusk fractures Rose et al. 2022: Elephant tusk fractures are a management and medical challenge that can escalate into life-threatening complications. Out of 459 elephants included in a survey, 85 elephants incurred at least one fracture during a period of 10 years. The most common causes of fractures were conspecific interactions (44.6%), caught tusk in an enclosure or enrichment item (28.4%), and a strike by the elephant of a tusk with an object (12.2%). For social causes, unstable hierarchy (45.5%) and specific agonistic interactions (36.4%) were the most frequently cited fracture causes. Steel gates were associated with 23.8% of fractures caused by enclosure elements. Management changes including tusk trimming, enrichment, training, and re-arranging social groups were found to be important in reducing subsequent fractures, with odds ratios showing that a second tusk fracture was 6.37 times more likely to occur if no management changes occurred after the first fracture. The data of this survey suggests that targeted management strategies in herds with maturing males, unstable social dynamics, and/or high-risk enclosure elements could reduce the frequency of tusk fractures. In 2024, a working group called Elephant Dental VETS, initiated by members of the EAZA Elephant TAG, began a collaborative effort to develop guidelines for responding to cases where an elephant breaks its tusk. This work resulted in a document outlining treatment procedures for tusk fractures. The document also includes valuable advice on preventing tusk injuries and will be updated regularly as new scientific insights become available. Click here to download the guideline Clinical cases Treatment options Tusk fracture in 36 months-old calf Tusk fracture repair in 9 yr-old bull Tusk fracture in 4 yr-old African elephant Tusk fracture repair procedure Conservative treatment (Tusk extraction) Reference Rose, J.B.; Leeds, A.; LeMont, R.; Yang, L.M.; Fayette, M.A.; Proudfoot, J.S.; Bowman, M.R.; Woody, A.; Oosterhuis, J.; Fagan, D.A. Epidemiology of Traumatic Tusk Fractures of Managed Elephants in North America, South America, Europe, Asia and Australia. J. Zool. Bot. Gard. 2022, 3, 89-101. https://doi.org/10.3390/jzbg3010008

This case report describes a colic episode in an adult Asian elephant. Salmonella sp. was identified in a fecal sample taken during this period of colic. - colic -Salmonella To salmonellosis CAse report Next case Colic and Salmonellosis in an adult Asian elephant History This adult multiparous female had been on GnRH-vaccine for over 4 years. Because of chronic joint disease, the elephant had been on phenylbutazone for over 1 year in combination with omeprazol. Sudden onset of apathy, anorexia and hardly drinking water. Normal feces. Occasionally the elephant goes into a sitting position or lateral recumbancy, showing moderate straining activities. After this labor-like behaviour, herd mates investigate the perineal area of the elephant with their trunk. Differential diagnose: Labour, colics (intestinal, uterine or urinary) Treatment The administration of phenylbutazone was discontinued No specific treatment was given on the first day. Treatment results During the night the elephant became more active and the symptoms decreased. The next morning, the animal behaved normal. Diagnostic notes Salmonella sp. was cultured from the feces on the day it showed the above mentioned symptoms To page top

Reproductive tumors and cysts are frequently seen in aging nulliparous elephants. Diagnosis is based on ultrasound examination. The anomalies may finally result in infertility. If leiomyomas need treatment (because of blood loss), Gonadotrophin Releasing Hormone (GnRH) vaccins can be used to down-regulate the estrous cycle, which will result in reduction of the size of the leiomyomas. To reproduction Reproductive Tumors and cysts Prevalence of tumors and cysts Abegglen et al. (2022) published an overview of reproductive tumors in elephants: "Asian elephants in particular are often diagnosed with benign uterine tumors called leiomyomas or fibroids (the term typically used to describe these lesions in humans). While malignant tumors overall are rare in elephants, when they do occur, the reproductive tract is disproportionately affected. Benign and malignant reproductive tract tumors are known to affect reproduction and pregnancy in other animals, and even tumors outside of the reproductive tract can have significant negative impacts on reproductive success." In a literature study of the same authors the following reproductive anomalies were found in (aged) Asian elephants : Uterine leiomyoma Uterine adenocarcinoma Anaplastic carcinoma (uterus) Carcinoma in situ in endometrial polyp Peripheral neuroectodermal tumor (uterus) Angiosarcoma (uterus) Anaplastic sarcoma (pelvic mass of presumed uterine origin) Ovarian carcinoma Ovarian cysts Hyperplastic endometrial disease Vestibular cysts Vaginal leiomyoma Hyperplastic, polyploidy or papillomatous mucosal lesions of vagina/vulva Vagina polyps Vulvar polyps Uterine polyps Uterus undifferentiated malignant neoplasm The vast majority of reproductive pathologies in Asian elephants consists of uterine leiomyomas, followed by hyperplastic endometrial disease and cyst s. Reproductive tumors and cystic changed found in African elephants are: Endometrial cysts Ovarian carcinoma Bilateral multilocular serous ovarian cystadenoma Hyperplastic endometrial disease Vestibular cysts Vestibular polyps Vagina polyps Polyps and Hyperplastic endometrial disease are the most frequently encountered reproductive anomalies. Symptoms and diagnosis Most elephants suffering from the above mentioned disorders are aged and nulliparous . There are no hard data about the impact of these abnormalities on the reproduction. No doubt that large areas of affected uterine surface may reduce implantation options for the embryo. The same applies to hyperplastic endometrial disease. Large polyps in the distal reproductive tract can impede copulation by blocking the passage of the penis. Symptoms are rarely observed. Occasionally blood loss can be observed in severe cases of leiomyomas. Diagnosis The only way to diagnoses these reproductive disorders is by transrectal ultrasound examination. Location and severity of the abnormalities can be evaluated when they can be reached during this examination. Figure 1: Transrectal examination in a 12 yr-old Asian elephant showing the early stage of an embryo in the left uterine horn and a large leiomyoma in the right uterine horn, clearly compressing the endometrium. The embryo developed normally and the elephant produced several calves after this diagnose was made. Figure 2: Leiomyoma (55 cm diameter) in an Asian elephant that produced 6 calves. (Courtecy: Planckendael Zoo) Figure 3: Transrectal examination in an adult African elephant showing a cyst in the cervix uteri. Figure 4: Transrectal sonogram (4-2MHZ) of the uterus (UT) with a cystic (CY) degenerated endometrium. The rectal wall (RW) appears as a moderate echoic strip on the top of the sonogram (Fowler & Mikota 2006) Treatment of severe cases of leiomyomas Female elephants suffering of chronic pathological conditions in the reproductive tract (leiomyomas) may benefit from a permanent shut-down of the estrous cycle by the administration of gonadotrophin releasing hormones (GnRH) vaccins. The following schedule should be used: A minimum of 450 μg of a GnRH vaccine (i.e. 3ml of Improvac©, Zoetis Animal Health)* deep intramuscularly once per month for 3 months. Thereafter booster vaccinations are given every 6 months (please note that some individuals may not respond and thus, require higher doses of up to 1000 μg protein conjugate or more frequent injection, in this case, please contact the v et advisors). Other available commercial products/brand names are Improvest©, Equity© and Bopriva©, depending on country. References Abegglen, L.M.; Harrison, T.M.; Moresco, A.; Fowles, J.S.; Troan, B.V.; Kiso,W.K.; Schmitt,D.; Boddy, A.M.; Schiffman, J.D. 2022. Of Elephants and Other Mammals: A Comparative Review of Reproductive Tumors and Potential Impact on Conservation. Animals 2022, 12, 2005. https:// doi.org/10.3390/ani121520052022 Reproductive Tumors and Potential Impact on Conservation Boedeker et al. 2012. Effects of a gonadotropin-releasing hormone vaccine on ovarian cyclicity and uterine morphology of an Asian elephant (Elephas maximus). Journal of Zoo and Wildlife Medicine 43(3): 603–614, 2012. Landolfi JA, Gaffney PM, McManamon R, et al. Reproductive tract neoplasia in adult female Asian elephants (Elephas maximus). Veterinary Pathology. 2021;58(6):1131-1141. https://doi : 10.1177/03009858211031843 Lueders et al. 2019. Use of gonadotrophin releasing hormone (GnRH) vaccines for behavioural and reproductive control in managed Asian elephant Elephas maximus and African elephant Loxodonta africana populations. Int. Zoo Yb. (2019) 53: 138–150. Thitaram et al. 2018. Monitoring and controlling ovarian activity in elephants. Theriogenology 109, 42-47.

This chapter describes the feeding ingredients, fibre, protein, fatty acids, minerals, vitamins, food presentation and diet examples. -Nutrition -Elephants Nutrition Written by Christian Schiffmann & Marcus Clauss Contents of this chapter: General feeding ecology and feeding behaviour Digestive physiology Nutritional management of elephants in captivity and recommendations for feeding Feed storage and preparation Feed items Staff behaviour Food analyses Examples for daily ration quantities Diet monitoring Fecal quality control References General feeding ecology and feeding behaviors Both elephant species are herbivores and consume a wide variety of plant material including grasses, leaves, twigs, fruits, barks, herbaceous material and soil (Sukumar 1990; Kabigumila 1993). A thorough review of diet breakdown, feeding behaviour, seasonal variation and summary data on broad nutrient ranges in natural diets for African elephants (Loxodonta africana) is covered in Sach et al. (2019). Variance between species does occur, with Asian elephants consuming a greater proportion of grasses in the diet when available (Sukumar 1990; Cerling et al. 1999). However, in our view, this does not mean that elephant species should be considered fundamentally different in their nutritional ecology. Although described as generalist herbivores, consuming over 400 species of plants, it appears populations may vary regionally and seasonally in their plant choice. However, it is clear that elephants are predominantly seasonal grazers and browsers with fruit, barks and soil being consumed as secondary food choices (Kabigumila 1993). The natural diet is characterised by a high fibre content (crude fibre 30-50%) and a low to moderate protein content (crude protein 8-12%). In summary, elephants are designed to eat large quantities of nutrient poor fibrous material which passes quickly through the gastrointestinal tract. Several studies indicate free living elephants of both species spend a considerable proportion (48-76.4%) of their day feeding, although where feeding conditions are improved and food availability increased, elephants have been seen to reduce the total amount of time spent feeding (Dougall and Sheldrick 1964; Beekman and Prins 1989). There is debate surrounding the feeding pattern; several reports indicate that elephants feed almost continuously throughout a 24-hour period (Laws 1970; Beekman and Prins 1989). However, there is also evidence that elephants feed in distinct peaks (Sukumar 1990). It is thought the feeding pattern may vary depending upon food availability, temperature (time spent in shade) and migration (usually to water). It has been suggested that free-ranging elephants make use of specific sites where they eat soil (geophagy) in order to cover their nutritional requirements of minerals (Holdo et al. 2002; Holdo and McDowell 2004). The body weight ranges overlap; however, Asian elephants (Elephas maximus) tend to be lighter than African elephants (Loxodonta africana). The weight range of wild adult Asian elephants is 1,800-5,000 kg compared with a range of 2,700-6,000 kg for adult African elephants (Wittemyer 2011). Individual body weights are influenced by age, sex, health, food availability and according to recent findings by the molar state (Schiffmann et al. 2019b). General feeding Back to Top Digestive physiology Digestive physiology With respect to their high-fibre and low-energy diet, elephants express a relatively high daily dry matter intake of 1-2% of body weight (Ullrey et al. 1997; Clauss et al. 2003). Feeding trials have shown a significantly reduced digestibility in elephants compared to horses (Clauss et al. 2003). Although heavily dependent on the provided diet, digestibility in elephants seems to range between 40 and 60% of dry matter. But even a digestibility as low as 22-32% has been detected in free-ranging African elephants (Rees 1982). According to an experimental study, digestibility decreases with increasing fiber content of an elephant’s diet (Clauss et al. 2003). Studies have demonstrated that passage of food through the elephant’s digestive tract is rapid compared to other monogastric hindgut digesters such as horses. Total gut transit time is 11-46 hours (Bax and Sheldrick 1963; Rees 1982; Hackenberger 1987; Loehlein et al. 2003), and they have a correspondingly low digestive efficiency (Clauss et al. 2003; Hatt and Clauss 2006). Elephants have a single stomach and a short but voluminous hindgut fermentation chamber (similar to equids), inhabited by anaerobic bacteria and protozoa similar to those found in the rumen and reticulum of the ruminant. These micro-organisms digest plant fibre that otherwise could not be used, since elephants, like other herbivores, have no fibre-digesting enzymes of their own (Ilmberger et al. 2014). Microbial fermentation of plant fibre in the hindgut provides the main energy source for these animals. They are adapted to eat complex plant fibres and thus in captivity, high fibre components must contribute a very significant part of their diet. As herbivores, elephants fulfil their needs in vitamins through their plant diet. This is the case for fat soluble as well as water soluble vitamins. Our knowledge on vitamin nutrition in elephants is still very limited and further research is needed (Fowler and Mikota 2006). Monitoring the quality of the feces is an important part of the health surveillance in each individual elephant. Body mass (BM, kilograms) and length measurements (meters) of an African (Loxodonta africana ) and Asian (Elephas maximus ) elephant (Clauss et al. 2007). Back to Top Nutritional management Nutritional management of elephants in captivity and recommendations for feeding Within each zoo, captive elephant diets should be formulated in line with the zoo’s dietary management programme using the skills of zoo nutritionists, curators, veterinary staff and keepers. The diet should be reviewed at least annually by appropriate staff, and proposed modifications raised in line with the individual institution’s diet management strategy. Forage consisting of grass, hay and browse should be the staple dietary ingredient, comprising a minimum of 80% of the total dry matter (Ullrey et al. 1997). Nutritionally appropriate pellets should be fed according to the individual dietary needs, but in the range of no more than approx. 20% of the total dry matter. Exceeding this may lead to excess energy consumption. Dietary items that deliver readily digestible energy, such as grains, bread, fruits, vegetables and low-fibre pellets should not be used in any significant quantity, although they may have uses for the administration of medication, or in geriatric animals. We want to emphasize that training should generally not be used as an excuse to feed unnatural feeds such as bread, fruits or sweets, and that training can often be done successfully using fresh green vegetables as well. This is not because a single piece of fruit is dangerous, but because often, one excuse leads to another. Excluding these items as training incentives is thus based on the concern about dietary drift. All food fed to the animal as part of the daily routine as well as used for training, enrichment or public activities must be included in the daily diet ration calculations. A review of the nutrient recommendations for both elephant species was published by Sach et al. (2019). Although species-specific differences may be present in the physiology of African and Asian elephants, evidence-based findings on corresponding requirements for are lacking and further research is recommended (Bechert et al. 2019). Hence, based on the current knowledge we consider our recommendations to be valid for both elephant species kept in European facilities, and emphasize that the difference to other herbivores is much greater than that between the two elephant species. Back to Top Feed storage Feed storage and preparation As with all animal feed, appropriate storage conditions are essential to retain product quality, including appropriate insect and rodent control measures. All food storage must be designed in such a way to enable safe access by staff and limit wastage. A clear system for stock control and product traceability must be implemented. Forage – must be protected from the weather (wet) and with good ventilation to prevent mould and degradation Browse- must be protected from weather (wet) to prevent mould/degradation and consumption from other pest species Pellets - purchased supplies should not exceed the amounts needed over a 4 to 6-month period to prevent degradation of vitamins, assuming ideal storage conditions. Most vitamins within pelleted feeds are stabilized for shelf life of up to 1 year – products must be individually checked and an inventory with record of expiry date, maintained within the animal feed store. Produce – must be kept under refrigeration Feed items Feed items Back to Top Forages 1. Fresh grass paddocks Ideally, access to grass paddocks should be provided to all elephants within the collection, although this may not be possible for some zoos due to space limitations, and in those with paddocks, not consistently throughout the year due to weather limitations. Paddocks must have appropriate drainage, especially around high use areas, such as gateways and feeding stations to maximise the amount of time in which they may be used by animals. A paddock management system must be in place for maintaining the paddock and preventing overgrazing. The time taken for elephants to consume small amounts of food via grazing is extremely important from a behavioural perspective and can assist in increasing the proportion of an elephant’s time spent foraging. For facilities without copious grass paddocks, implementation of a comprehensive feeding enrichment as a substitute is imperative. The latter may present an opportunity to compensate for limited space as recently reported by Scott and LaDue (2019). 2. Hay and fresh forages Grass hay is an ideal forage source for species adapted to eating plants high in fibre. It is important that the hay is of high hygienic quality, properly dried and cured. Hay should look green, and be free of weeds, insects, mould, twine, wire or any other foreign objects. Hay must be visually inspected before a delivery is accepted, and should be rejected if found to be substandard (mouldy, excessively dry and dusty, off-colour). During the process of unloading a delivery, this testing should continue, and not only be applied to the first few bales or batches that may have been deliberately chosen by the merchant to give a good impression. Given that elephants should have hay available at all times, and that obesity rather than energy deficiency is the primary concern, the hay used should be of a low nutritional quality (e.g., crude protein 5-8%, neutral detergent fibre 60-70%, acid detergent fibre 40-50 % in dry matter). Ideally, the grass should have been cut at a very late growth stage, with long, lignified stems. Hay typically used for production animals, with cut at an earlier growth stage with soft, pliable stems and a high proportion of grass leaves, is not ideal for elephants due to its high energy content. Because hay suitable for elephants is typically not produced for the hay market, and because farmers cannot sell the same amount of hay if cutting their fields as late as reasonable for elephant hay compared to what they could sell cutting the same field several times, prospective contracting of farmers and fostering long-term relationships is recommended. Notably, local farming conditions, e.g. subsidies for an extensive land use with late cuts, will influence costs and practicalities. Considering differences in the dietary needs of individual elephants (e.g. breeding vs. non-breeding females), it is recommended to have various badges of hay with differing energy content/digestibility on site. Differences in energy requirements should rather be met by different hay qualities than by the addition of other feedstuffs. Hay of peculiar grass species, such as reeds, has been used successfully by some elephant facilities. For the use of fresh forage, the same principles apply (grass of late maturity stage with long, lignified stems). If at all possible, the use of fresh forage should receive priority over dried forage, but will be necessarily limited to the non-winter season. Reedgrass or elephant grass, or other tall grasses, may be suitable. In theory, using whole maize plants without the cobs would also represent a suitable elephant feed. When feeding fresh forages, their dry matter content needs to be accounted for in ration calculation. 3. Browse Browse is an essential dietary component, both nutritionally and from a behavioural perspective. It must be fed daily to all elephants throughout the year and may contain twigs, branches and stems up to entire tree logs. Consuming browse increases foraging time and has additional benefits for dental health. A plan must be in place for adequate browse provision throughout the year, including the winter months when leafy material is not available. Browse can be preserved for other species by silaging, freezing or drying, but for elephants, due to the volumes required, this is mostly not feasible. Rather, stems and twigs without leaves should be provided on a daily basis, as well as evergreen species such as evergreen oak(Quercus ilex), bramble (Rubus fruticosus) or stinging nettle (Urtica spp.). Feeding conifers has proven successful for some collections. It may be logistically beneficial to additionally use branches that have been plucked clean of leaves and small twigs by other species of the same zoological institution for final consumption by the elephants, given that no hygienic concerns speak against this. 4. Straw Straw can be a suitable low-caloric fibre addition to the diet of elephants and can be mixed in with the hay ration to prolong foraging time, especially in high feeding nets. Due to the high amount of forage required by elephants, mixing of hay and straw generally appears the less feasible option compared to the acquisition of long-stem grass hay of low nutritional (but high hygienic) quality. If mixing of hay and straw is done, the ratio should be determined in accordance with the dietary needs of the individual elephant. Like hay, straw must be of high hygienic quality, free of weeds, insects, mould, twine, wire or any other foreign objects and should be visually inspected before a delivery is accepted. Wheat or barley straw should be preferred, because oat straw typically contains a higher energy content. 5. Lucerne The elephants’ requirements for bulky, low-energy roughage can be easily met with grass hay and straw, so that the more costly lucerne hay is typically not required. The feeding behaviour of elephants makes a loss of leafy material particularly likely when dealing with lucerne hay. Therefore, fresh lucerne or lucerne haylage would be considered more suitable due to the reduced leaf losses. Fresh lucerne or lucerne haylage might be used to increase the calorie and protein content of a specific animal’s diet under specific circumstances such as with geriatric animals or animals of compromised health. However, providing a grass hay of higher nutritional quality most likely is a more feasible solution. For all forage items, gradual changes with a slow introduction of new material over the course of two weeks is recommended. In other words, the amount of the new diet item should be gradually increased so that only after one week, it represents 50% of the forage portion, and is given as the only forage only after the second week. Other feed items 6. Pellets Except for special circumstances of particularly low forage quality or mishaps (e.g., sudden detection of forage spoilage due to roof leakage), there should be no need to provide elephants with pellets for maintenance energy requirements. A variety of pelleted feedstuffs is available. Some are manufactured specifically for elephants and are designed to be fed in very small quantities, with forage making up most of the diet (hay, grass, browse, straw). These pellets provide high levels of vitamins, minerals and protein, in a concentrated form so only a small amount is required to meet the elephants’ nutritional needs. A combination of such a product with forages represents an easy and comparatively safe approach, because potential variation especially in the mineral composition of the forages is of little concern, given the baseline provision by the mineralized pellet. With this approach, the individual provision of specific amounts to each individual, according to its body mass, is prerogative. It is advised that pellet selection is made by the zoo’s nutritionist or, if no nutritionist is on staff, by a nutritional consultancy service, which is sometimes also provided by renowned manufacturers. To avoid digestive upsets, the introduction of any pellet into the diet should be gradual (increasing slowly over 2 weeks). 7. Fruits and vegetables (produce) These should be fed in very limited amounts (less than 1 kg per elephant per day) and be documented as part of the daily diet ration. Produce is comparatively expensive, and amounts fed should not be required to contribute to vitamin and mineral provision. Even small quantities of higher sugar fruits, however, may significantly contribute to energy levels in the diet, adding to the risk of obesity. High sugar fruits should be replaced with vegetables – ideally leafy greens. In appropriate quantities, their use in training may be valuable. As it is easy to condition animals to the use of high-sugar items, but difficult to then reverse the conditioning, it appears prudent to refrain from the use of such items from the very beginning, and establish the use of leafy greens as training items. 8. Bread This should be avoided – should this be required for the administration of medication, use must be monitored. 9. Bran Elephants can be reluctant to consume unfamiliar foods- therefore it is appropriate to offer potential carriers for medication such as a bran mash periodically, so they will be consumed when needed. However, it should not be necessary to offer such items daily. 10. Vitamin and mineral supplements The dietary concentrations of minerals and vitamins recommended for horses should in the most part be sufficient for elephants (Ullrey et al. 1997). Mineral deficiencies have rarely been reported and are best avoided through the adequate use of appropriate forages, supplemented with pelleted feed, rather than additional external supplementation where consumption is more challenging to ensure and monitor. In specific situations such as an expected birth, the monitoring of serum calcium levels is recommended in order to avoid dystocia due to hypocalcemia (Hermes et al., 2008). Although the species-specific vitamin D and calcium metabolism in elephants is not fully understood so far (Childs-Sanford et al., 2020), efficacy of a dietary calcium supplementation has been reported (van Sonsbeek et al., 2013). Back to Top Staff behaviour Food analysis Staff behaviour In particular when changing the diet of elephants, it may be appropriate to avoid eating those diet items (apples, bread) within their range of vision. In doing so, negative reactions by the elephants may be avoided. Food analyses Typically, it is recommended to analyse all feeds on a regular basis. However, the question each zoo has to ask itself is, how will that information be used. Analysing feeds appears mainly reasonable if there is a nutritionist on staff that makes use of that information. Yet, even with a nutritionist on staff, or the use of a consultancy service, it may be a more cost-efficient approach to design a diet based on forages and a concentrated pelleted food that covers a range of possible nutrient values of the forages, rather than adapting the pelleted component each time a batch of forage is analysed. Having stated the potentially limited use of nutrient analyses, there is no excuse at all not to perform hygienic assessments of all feeds delivered to the zoo. Even if there is no nutritionist on staff, or even if there is no dedicated commissary manager, it cannot be excused if there is no personnel trained in evaluating the hygienic quality of forages, vegetables and pellets. In particular for forages, given their relevance and bulk in herbivore diets, personnel dedicated to evaluating and either accepting or rejecting a delivery, and dedicated to proper storage and assessment of storage quality, is indispensable. Food presentation Food presentation It is commonly accepted that feeding in captivity must mimic feeding behaviour of wild counterparts. A variety of complex feeding opportunities to prolong foraging time throughout the day and night must be provided. Provision for food delivery in evening/early morning must be made when personnel is typically absent. With respect to the temporal occurrence of major sleep periods, no additional food should be presented between midnight and 6.00am to avoid sleep disturbance (Schiffmann et al. 2018b), which is evidently not difficult to achieve. Keepers must periodically monitor this via night-time video recording of all animals, to ensure all animals are able to obtain access to food and ensure feeding events do not encourage anticipatory or stereotypical behaviours. Examples for daily ration quantities Please note that the following daily rations serve as examples, making individual adaptation necessary before application. Ideally, a zoo should have a nutritionist on staff. If that is not the case, this task may fall to a veterinarian with some basic nutritional training, or can be outsourced – for a simple ration calculation – to a nutritional consultancy, of which there is a growing number in Europe. Alternatively, several manufacturers of zoo diets also provide nutritional consultancy. As with any business, the credibility of the service should be assessed, by asking for references from other zoos, and by plausibility checks. In particular, advice that appears to be tuned to use a maximum of pellets should be viewed with caution. Target overall diet composition (ingested roughage and non-roughage items) may be in the area of crude protein 10%, neutral detergent fibre 60%, acid detergent fibre 40 % in dry matter. Accurate calculation of the quantities required to cover the individual needs of an elephant would require constant analysis of the diet as well as monitoring roughage intake (by measuring offer and refusals) to allow estimation of the proportion of roughage and non-roughage diet items, which is impractical – all the more so if the recommendation of multiple feeding stations spread across the whole enclosure is heeded. Hence, continuous monitoring of an elephant’s physical condition by weighing and body condition scoring is strongly recommended (Schiffmann et al. 2019a). Subsequently diet composition and quantities can be adapted accordingly. Examples of ration Back to Top A Adult breeding female, body mass: 3´348kg, Body Condition Score (BCS): 5/10 Estimated daily dry matter intake [kg]: 3´348kg * 0.015 -> 50.22kg B) Adult breeding male, body mass: 5´278kg, BCS: 7/10 Estimated daily dry matter intake [kg]: 5´278kg * 0.01 -> 52.78kg C) Geriatric (non-breeding) female, body mass: 2´934kg, BCS: 4/10 Estimated daily dry matter intake [kg]: 2´934kg * 0.015 -> 44.01kg D) Sub-adult male/female, body mass: 2´237kg, BCS: 8/10 Estimated daily dry matter intake [kg]: 2´237kg * 0.01 -> 22.37kg Calculations based on the following parameters: maintenance requirement of daily dry matter intake 1-1.5% of an elephants body mass (Ullrey et al. 1997). Dry matter hay: 90% (Ullrey et al. 1997); recommended quantity pellets: elephant pellets, KasperFaunafood: 1kg/1´000kg BM per day. Diet monitoring Diet monitoring Appropriate monitoring of body condition and weight is essential and should be conducted at least four times per year. Visual body condition scoring has been demonstrated as a practical and simple monitoring tool (Fernando et al. 2009; Schiffmann et al. 2018a; Chusyd et al. 2019) and is of peculiar importance if weighing is not feasible. Records must remain with the animal throughout its life and be recorded as appropriate e.g. via ZIMS. Consequences of obesity in captive elephants are extremely serious and will affect the animal’s long term captive health and welfare. There is strong evidence that obese animals are at increased risk of foot and joint lesions, altered metabolic markers and reduced reproductive success with increased labour length, dystocia, stillbirths and ultimately cow and calf death (Olson 2004; Freeman et al. 2009; Chusyd et al. 2018; Norkaew et al. 2018). Where animals are not achieving an optimum Body Condition Score (BCS), a documented plan must be in place to achieve this with records kept of progress made. Daily, keepers must monitor diet consumption and report variations as appropriate. Individual diet plans must be made for each elephant and recorded. Regular fecal check Regular fecal check is strongly recommended as an integral part of continuous health monitoring in elephants under human care. Click here for more information. Fecal quality control References References Bax P, Sheldrick D (1963) Some preliminary observations on the food of elephant in the Tsavo Royal National Park (east) of Kenya. East African Wildlife Journal 1: 40-53 Bechert US, Brown JL, Dierenfeld ES, Ling PD, Molter CM, Schulte BA (2019) Zoo elephant research: contributions to conservation of captive and free-ranging species. International Zoo Yearbook 53: 1-27 Beekman JH, Prins H (1989) Feeding strategies of sedentary large herbivores in East Africa with emphasis on the African buffalo, Syncerus caffer. Journal of African Ecology 27: 129-147 Cerling TE, Harris JM, Leakey MG (1999) Browsing and grazing in elephants: the isotope record of modern and fossil proboscideans. Oecologia 120: 364-374 Childs-Sanford, S. E., Makowski, A. J., & Wakshlag, J. J. (2020). The vitamin D status of Asian elephants (Elephas maximus) managed in a Northern temperate climate. Journal of Zoo and Wildlife Medicine, 51, 1-12. Chusyd DE, Brown JL, Hambly C, Johnson MS, Morfeld KA, Patki A, Speakman JR, Allison DB, Nagy TR (2018) Adiposity and reproductive cycling status in zoo African elephants. Obesity 26: 103-110 Chusyd DE, Brown JL, Golzarri-Arroyo L, Dickinson SL, Johnson MS, Allison DB, Nagy TR (2019) Fat mass compared to four body condition scoring systems in the Asian elephant (Elephas maximus). Zoo Biology: Clauss M, Loehlein W, Kienzle E, Wiesner H (2003) Studies on feed digestibilities in captive Asian elephants (Elephas maximus). Journal of Animal Physiology and Animal Nutrition 87: 160-173 Clauss M, Steinmetz H, Eulenberger U, Ossent P, Zingg R, HummEl J, Hatt JM (2007). Observations on the length of the intestinal tract of African Loxodonta africana (Blumenbach 1797) and Asian elephants Elephas maximus (Linné 1735). Eur J Wildl Res (2007) 53: 68–72 Dougall H, Sheldrick D (1964) The chemical composition of a day´s diet of an elephant. Journal of African Ecology 2: 51-59 Fernando P, Janaka HK, Ekanayaka SKK, Nishantha HG, Pastorini J (2009) A simple method for assessing elephant body condition. Gajah 31: 29-31 Fowler ME, Mikota SK (2006) Biology, Medicine, and Surgery of Elephants. Blackwell Publishing, Iowa, USA Freeman EW, Guagnano G, Olson D, Keele M, Brown JL (2009) Social factors influence ovarian acyclicity in captive African elephants (Loxodonta africana). Zoo Biology 28: 1-15 Hackenberger MK (1987) Diet digestibilities and ingesta transit times of captive Asian (Elephas maximus) and African elephants (Loxodonta africana), MSC Thesis University of Guelph, Guelph Hatt JM, Clauss M (2006) Feeding Asian and African elephants Elephas maximus and Loxodonta africana in captivity. International Zoo Yearbook 40: 88-95. Hermes, R., Saragusty, J., Schaftenaar, W., Göritz, F., Schmitt, D., & Hildebrandt, T. B. (2008). Obstetrics in elephants. Theriogenology, 70, 131-144. Holdo RM, Dudley JP, McDowell LR (2002) Geophagy in the African elephant in relation to availability of dietary sodium Journal of Mammalogy 83: 652-664 Holdo RM, McDowell LR (2004) Termite mounds as nutrient-rich food patches for elephants. Biotropica 36: 231-239 Ilmberger N, Güllert S, Dannenberg J, Rabausch U, Torres J, Wemheuer B, Alawi M, Poehlein A, Chow J, Turaev D, Rattei T, Schmeisser C, Salomon J, Olsen PB, Daniel R, Grundhoff A, Borchert MS, Streit WR (2014) A comparative metagenome survey of the fecal microbiota of a breast- and a plant-fed Asian elephant reveals an unexpectedly high diversity of glycoside hydrolase family enzymes. PLoS ONE 9: e106707 Kabigumila J (1993) Feeding habits of elephants in Ngorongoro Crater, Tanzania. Journal of African Ecology 31: 156-164 Laws R (1970) Elephants and habitats in North Bunyoro Uganda. Journal of African Ecology 8: 163-180 Loehlein W, Kienzle E, Wiesner H, Clauss M (2003) Investigations on the use of chromium oxide as an inert, external marker in captive Asian elephants (Elephas maximus): passage and recovery rates. In: Fidgett A, Clauss M, Ganslosser U, Hatt JM, Nijboer J (eds) Zoo animal nutrition, vol 2. Filander, Fuerth, Germany Norkaew T, Brown JL, Bansiddhi P, Somgird C, Thitaram C, Punyapornwithaya V, Punturee K, Vongchan P, Somboon N, Khonmee J (2018) Body condition and adrenal glucocorticoid activity affects metabolic marker and lipid profiles in captive female elephants in Thailand. PLoS ONE 13: e0204965 Olson D (2004) Elephant husbandry resource guide Rees PA (1982) Gross assimilation efficiency and food passage time in the African elephant. African Journal of Ecology 20: 193-198 Sach F, Dierenfeld ES, Langley-Evans S, Watts M, Yon L (2019) African elephants (Loxodonta africana) as an example of a mega-herbivore making movement choices based on nutritional needs. PeerJ: Schiffmann C, Clauss M, Fernando P, Pastorini J, Wendler P, Ertl N, Hatt JM (2018a) Body condition scores of European zoo elephants (Elephas maximus and Loxodonta africana): Status quo and influencing factors. Journal of Zoo and Aquarium Research 6: 91-103 Schiffmann C, Hoby S, Wenker C, Hard T, Scholz R, Clauss M, Hatt JM (2018b) When elephants fall asleep: A literature review on elephant rest with case studies on elephant falling bouts, and practical solutions for zoo elephants. Zoo Biology 38: 1-13 Schiffmann C, Clauss M, Hoby S, Hatt JM (2019a) Body Condition Scores (BCS) in European zoo elephants´ (Loxodonta africana and Elephas maximus) lifetimes - a longitudinal analysis. Journal of Zoo and Aquarium Research 7: 74-86 Schiffmann C, Hatt JM, Hoby S, Codron D, Clauss M (2019b) Elephant body mass cyclicity suggests effect of molar progression on chewing efficiency. Mammalian Biology 96: 81-86 Scott NL, LaDue CA (2019) The behavioral effects of exhibit size versus complexity in African elephants: A potential solution for smaller spaces. Zoo Biology: Sukumar R (1990) Ecology of the Asian elephant in Southern India - II. Feeding habits and crop raiding patterns. Journal of Tropical Ecology 6: 33-53 Ullrey D, Crissey SD, Hintz H (1997) Elephants: nutrition and dietary husbandry. In: Allen M, Edwards M, Roocroft A (eds) Nutrition Advisory Group Handbook, pp 1-20 Van Sonsbeek, G. R., van der Kolk, J. H., van Leeuwen, J. P. T. M., Everts, H., Marais, J., & Schaftenaar, W. (2013). Effect of calcium and cholecalciferol supplementation on several parameters of calcium status in plasma and urine of captive Asian (Elephas maximus) and African elephants (Loxodonta africana). Journal of Zoo and Wildlife Medicine, 44, 529-540. Wittemyer G (2011) Order Proboscidea. In: Wilson DE, Mittermeier RA (eds) Handbook of the Mammals of the World - Volume 2. Lynx Edicions, pp 50-79 Back to Top

Serum chemistry data in elephants can provide valuable information about organ function (liver, kidney, muscles, intestines, pancreas) and disease conditions (inflammation, infection), hormone levels and toxins. Proteins, AST, ALT, GGT, creatinine, bilirubin, CK, LDH, Ca, P, glucose, Na, Cl, K are part of the comprehensive chemistry panel. To lab diagnosis Blood chemistry Reference values blood Serum/plasma chemistry Refractometry Serum/plasma Chemistry Serum quality Ser um quality Serum chemistry data may help determining the function of certain organ systems. The reliability of the results largely depend on the quality of the sample. Before running any biochemistry tests, the blood should be well clotted, preferably without hemolysis (shown as red colorat ion of the serum). Chemistry data are usually obtained from serum. Some tests can also be run usi ng plasma. Before using plasma, this option should be checked with the test instructions. Test tubes to be used: red-topped serum-tubes with or without a clotting activator. The color of the serum should be light yellow. The figure below shows different serum characteristic: Hemolysis: Red to brown color due to hemolysis (destruction of erythrocytes). This can have a pathological origin or can result from poor sampling/handling; the red-brown color can also be caused by myoglobin after massive muscle damage (rhabdomyolysis) Milky white color due to presence of fat particles in the serum (physiologic shortly after eating or pathological condition) Yellow color due to the presence of bilirubin (liver damage ->icterus). Blueish-red color due to methemoglobin (low venous oxygen saturation). Lipemia Lipemia, which can be a natural occurrence if the elephant has just eaten, can alter several test results. Calcium, phosphorus, total bilirubin or hemoglobin may be falsely elevated. When using a refractometer to measure the total protein remember that the serum must be clear. If not the value may be falsely elevated. Albumin, sodium and potassium may be falsely lower. Lipemia also enhances hemolysis which in turn can affect lab results. But there is a solution: If you refrigerate your sample the lipemic portion will separate and you can use the clear aliquot below the lipid layer. Normal and lipemic elephant serum Reference values Normal serum chemistry values are determined by species, age, gender and reproductive status of the elephant. It is important to have an understanding of the limitations of laboratory values. The term “reference value” is now considered a more appropriate term than “normal value.” Ideally reference values should be established from studies using a minimum of 30 healthy animals and stated selection criteria. Few elephant studies have been conducted to meet this standard. One report describes chemistry results for different genders of Asian elephants used for logging in Myanmar (Santo, 2020). Moreover, many reference ranges are laboratory specific. So it is best to use one laboratory that can help to develop reference ranges for your elephants. Another important point is that a test result that falls outside of the reference is not necessarily clinically significant. Lab values are information that must be used with all the other information that you have when you are faced with a sick elephant. Establishing a baseline during health and performing sequential tests during illness will give the most reliable information. You also want to use a lab that has good quality controls. If you change labs it is advisable to get new healthy baselines. V ery odd results should always be double checked at the same lab. To page top One study in 10 healthy Asian elephants showed that most Asian elephant hematology and biochemistry parameters are highly individual, requiring individual normal values for accurate interpretation (Perrin, 2020). Test result units Another complicating factor when looking at serum chemistry values is that there is a lack of uniformity regarding units and this can be confusing. Most U.S labs use conventional units whereas in Europe they use SI units. There are conversion factors to go from one system to the other but the conversion factor is test specific – so each test has a different conversion factor. You can find SI conversion calculators online, i.g. ht tps://www.amamanualofstyle.com/page/si-conversion-calculator. Liver The liver plays an important role in the following processes: Protein synthesis and degradation (albumin, clotting factors) Carbohydrate and lipid metabolism Breakdown of hemoglobin Storage (fat soluble vitamins) Detoxification Liver enzymes: Aspartate aminotransferase (AST; SGOT) Alkaline phosphatase (ALP) γ-glutamyl transferase (GGT) Bilirubin Bile acids (?) BSP excretion (bromsulphthalein) AST (SGOT) Aspartate aminotransferase, previously known as serum glutamic oxaloacetic transaminase (SGOT) occurs in all cells. Highest levels are in the liver, cardiac muscle, and skeletal muscle. If AST is elevated then you should also look at the creatine kinase (CK) value. If the CK is normal then AST is likely of liver origin. If the CK is elevated or there is obvious muscle trauma then AST may be of muscle origin. Also AST may falsely increase if the sample is hemolyzed. ALP Alkaline phosphatase is also found in all cells with the highest levels in liver, bone, kidney, intestine, and placenta. ALP is not a sensitive indicator of liver disease in the horse and this probably holds true for elephants although research would be needed to confirm this assumption. ALP may increase with disorders such as rickets. ALP levels are normally higher in young animals including elephants. ALP may indicate colostrum absorption. Non-steroidal anti-inflammatory drugs may cause ALP to elevate. GGT Gamma glutamyl transferase (GGT) is liver specific in horses and pigs. Whether it is liver specific in elephants is unknown. GGT is an indicator of cholestasis (the interruption of bile excretion). GGT has been shown to increase in musth bulls and it has been used together with ALP as an indicator to evaluate passive transfer of antibodies to neonates via colostrum. Bilirubin There is not much information about bilirubin in elephants. There are two forms: unconjugated and conjugated bilirubin. The unconjugated is the main form in horses so this may be true for elephants but we don’t know for sure. Unconjugated (indirect) bilirubin is mainly hemoglobin released from old erythrocytes. It is bound to albumin and transported to the liver where it is conjugated. Conjugated (direct) bilirubin is secreted into bile, transferred to the intestine, converted to urobilinogen by intestinal bacteria, and excreted. Elevated bilirubin may be caused by hemolysis; hepatocellular disease that results in reduced functional mass; and intra - or extrahepatic cholestasis or bile duct obstruction. Unconjugated bilirubin predominates in horses with hyperbilirubinemia regardless of etiology whereas in ruminants unconjugated bilirubin is typical. In one report, elevated total bilirubin (4.94 mg/dl) was observed in a female Asian elephant with colic caused by over-zealous feeding of produce. Values for indirect and direct bilirubin were 3.7 mg/dl and 1.2 mg/dl respectively. Tests of hepatic uptake, conjugation and excretion of bilirubin. Diagram from Lattimer, K.S., Mahaffey, E.A., and Prasse, K.W. 2003. Clinical Pathology 4th edition. Blackwell. P.199. Bile acids Bile acids assist with fat digestion. In most species, bile acids are stored in the gall bladder and released into the intestine. However, elephants do not have a gall bladder. There is controversy whether elephants have bile acids. In several cases bile acids were shown to increase in elephants with TB. Bromsulphthalein (BSP) excretion test In the BSP test a dye is injected IV and measured at several points in time post-injection. In the horse, the half-life is 3.5 minutes. Slow clearance time may indicate cholestasis. Although levels have been shown to increase with liver flukes in elephants, it is not a very practical test. Kidney Blo od Urea Nitrogen ( BUN) and creatinine are the main enzymes used to evaluate kidney function in mammals. BUN Elevations in blood urea nitrogen concentration may be due to prerenal causes like inadequate renal perfusion, shock, or diminished blood volume; renal causes like glomerular-nephritis; or postrenal causes like urinary tract obstruction. Blood Urea Nitrogen makes up approximately 75% of the total non-protein nitrogen (NPN) fraction of the blood. BUN is the major end product of protein nitrogen metabolism. It is synthesized by the urea cycle in the liver from ammonia which is produced by amino acid deamination. Urea is excreted mostly by the kidneys, but minimal amounts are also excreted in sweat and degraded in the intestines by bacterial action. Creatinine Creatinine only elevates when disease is severe and there is marked kidney damage. Unfortunately, in elephants these enzymes are not always useful to predict kidney disease. Creatinine may be lower in young elephants; higher in musth bulls. Serum osmolality/urine osmolality. The osmolality reflects the total number of electrolytes in a fluid. To keep the number constant, the kidney excretes the surplus that is present in the liquid fraction of the blood and the osmolality ratio between these two fluids should be <1. If the kidneys fail to maintain this equilibrium, the serum-urine osmolality ratio becomes > 1. Serum dimethyl arginine (sDMA). In domestic animals sDMA is a marker for endothelial dysfunction and early diagnose of renal disease (declining glomerular filtration rate). In one case report it was associated with kidney failure (polycystic kidney disease). To page top These values are from an Asian bull elephant with capture myopathy. The elevations in SGOT and CK are dramatic. ALT (SGPT) did not increase as much but is probably significant. The elevations in BUN and creatinine may have been related to capture myopathy however this bull was chained to a tree and not given access to food or water post-capture so these changes may reflect dehydration. Muscles Muscle enzymes are: Creatine Kinase (CK) Lactate Dehydrogenase (LDH) Aspartate Aminotransferase (AST; SGOT) Alanine Aminotransferase (ALT; SGPT) Evaluating muscle enzymes can help to diagnose muscle pathology. Conditions that may cause elevated muscle enzyme levels include prolonged recumbency, rhabdomyolysis (also called over-exertion, or tying up syndrome), and clostridial myositis. Bacterial endocarditis, and aortic thrombosis are other causes as well as Vit E/Se deficiency and capture myopathy. Working elephants may be at risk for muscle over-exertion disorders especially as the planet heats up. In all of these conditions, muscle cell membranes rupture and enzymes are released into the blood. Conditions that may lead to increased muscle enzymes in serum are: Prolonged recumbency Rhabdomyolysis Clostridial myositis Bacterial endocarditis Aortic thrombosis Vitamin E/ selenium deficiency Capture myopathy Creatine kinase (CK) CK is critical to muscle energy production. Highest levels are in skeletal muscle, cardiac muscle, and brain. Most CK in the serum is of muscle origin and it is the most sensitive indicator of muscle damage. CK rises quickly – within hours. It also returns to normal quickly as long as there is no on-going damage. Levels that remain high indicate an on-going disease process. Hemolysis interferes with the test and causes falsely elevated values. Lactate d ehydrogenase (LDH) LDH is present in all tissues. Muscle, liver, and red blood cells are the usual sources. LDH is not as useful for determining muscle damage because it is not muscle specific. If LDH is elevated and there is no muscle injury then liver problems should be considered. Like CK, LDH will be falsely elevated in the presence of hemolysis. Aspartate aminotransferase (AST) AST was previously known as serum glutamic oxaloacetic transaminase (SGOT). Muscle and liver are the major sources. It is another enzyme to check if muscle damage is suspected. Alanine aminotransferase (ALT) ALT, also known as serum glutamic pyruvic transaminase or SGPT, is considered muscle specific in large domestic animals. Increased levels have been associated with myopathies in a number of species. ALT will increase in recumbent elephants that are down for a long time. Severe muscle damage can occur in case of Capture Myopathy: To page top Calcium Ionized calcium This electrolyte that is involved in many chemical reactions in the body. The active form is ionized calcium (Ca2+) and this parameter gives the best impression of the available calcium. To measure ionized calcium, special heparinized tubes are needed . Ionized calcium should be > 1.5 mmol/L (>5 mg/dL). Low ionized calcium levels are associated with prolonged parturition and dystocia. Total calcium Non-ionized calcium is predominantly conjugated with albumins and expressed as total calcium. Higher levels of total calcium have been reported in very young elephants and in elephants with TB and severe kidney disease. Many pregnant captive elephants develop subclinical hypocalcemia if calcium is not supplemented during pregnancy. When parturition starts, the demand of calcium is high as it essential for uterine contractions that open the cervix and help expel the calf. Calcium is also high in milk. Calcium supplementation during pregnancy is recommended to form a stock supply. However, releasing stock-calcium ions from the bones is a very slow process, so the blood itself should contain enough calc ium conjugated to albumin to supply the uterus and body muscles for these hours of high demand. Total calcium levels lower than 1.5 mmol/l (6 mg/dl) result in recumbency and levels less than 1 mmol/l (4 mg/dl) will result in death. Low total calcium levels are associated with prolonged parturition and dystocia. Total calcium should be 2.8 +/- 0.2 mmol/L (11 +/- 0.8 mg/dL). Other minerals and electrolytes Sodium (Na) Potassium (K) Chloride (Cl) The reference ranges of these electrolyte in elephants are similar to other species and can best be compared with horse values. To page top Proteins Elephants have a higher to tal protein serum level than most mammals; albu min is lower, and globulins are higher. The ratio of albumin to globulin was shown to be lower in one study that compared elephants with and without TB however the number of TB positive elephants in the study was low. Protein electrophoresis separates the albumin and globulin fractions. There are not many reports in elephants. Protein electrophoresis may be useful to monitor inflammatory conditions or problems like TB, herpes, and others. Acute Phase Proteins Acute phase proteins (APPs) are components of the innate immune system that are markers for infection, inflammation, neoplasia, and tissue injury in humans and domestic animals. APPs are produced by the liver in response to cytokines released from leukocytes. They are initially released into serum 24–96 hr following an acute inflammatory stimulus, where they function to promote healing, reestablish homeostasis, and inhibit microbial growth. The main ones are C-reactive protein (CRP) , serum amyloid (SAA) and haptoglobin (HA) . In one study serum samples from 35 healthy Asian elephants were analyzed for these 3 APPS and levels between the values in healthy and unhealthy elephants were compared (Isaza et al., 2014). From this and other studies it seems that SAA may be the most responsive APP in elephants. The APP values in this study in Asian elephants are shown here: C-reactive protein 12.4-122 nmol/l (1.3-12.8 mg/l) Serum amyloid 0-47 mg/l Haptoglobin 0-1.1 mg/l Glucose Glycolysis of glucose in serum or plasma will decrease the glucose level starting shortly after blood collection. Serum or plasma should therefore b e separated from the red blood cells within 30 minutes after collection. Glycolysis can be prevented by using a Na-fluoride tube for blood collection. Significantly lower levels have been noted in one study comparing TB culture positive and negative elephants. In horses, hypoglycemia may be seen with hepatic failure or bacteremia. There is one report of diabetes mellitus in a 50-yr-old Asian elephant (van der Kolk 2011). Hyperadrenocorticism and hyperthyroidism have not been reported in elephants. Increased blood glucose in elephants is likely to be transient. Some of the causes of transient hyperglycemia could be a cute severe colic acute stress, p ost-postprandial, certain drugs (s teroids, x ylazine, p henothiazine) . Hypoglycemia can occur in n eonatal elephants and in cases associated with m alnutrition, m alabsorption, s epsis, e xtreme physical exertion, a dvanced liver disease or n eoplasia. Amylase and lipase Ranges for these enzymes vary tremendously depending on the methodology and the lab so at this point in time they are not very useful tests for elephants. Amylase may increase in case of pancreas, gastro-intestinal, liver and kidney disease Lipase may increase in case of pancreas or kidney disease. One case of pancreatitis in an elephant has been described so far (pers. comm. Susan Mikota, 2023). Lactate Lactate is an important serum parameter to monitor severe, life-threatening conditions in elephants, like septicemia, Disseminated Intravascular Coagulopathy in a EEHV-HD case. Normal values are between 0--0.11 mmol/L (0-1 mg/dL). Values >0.44 mmol/L (4 mg/dL) are indicative for perfusion problems due to DIC. EEHV-HD patients often have lactate value > 0.22 mmol/L (2 mg/dL) (Wiedner, pers. comm. 2022). A comprehensive elephant serum chemistry panel should include: Total protein Albumin BUN Creatinine AST (sGOT) ALT (sGPT) GGT Bilirubin Bile acids (?) CK LDH Na Cl K Ca P Lactate To page top References Steyrer C, Miller M, Hewlett J, Buss P and Hooijberg EH (2021) Reference Intervals for Hematology and Clinical Chemistry for the African Elephant (Loxodonta africana). Front. Vet. Sci. 8:599387 Santos DJ, Franco dos J, John, Nyein UK, and Lummaa VM. 2020. Sex differences in the reference intervals of health parameters in semi-capt ive Asian elephants ( Elephas maximus ) from Myanmar. J.Zoo&Wildl Med 51(1): 25–38 Debbie JG and Clausen B. 1975. Some hematological values of free-ran ging African elephants. Journal of Wildlife Diseases, 11(1):79-82. Isaza R, Wiedner E, Hiser S, Cray C. 2014. Reference intervals for acute phase protein and serum protein electrophoresis values in captive Asian elephants (Elephas maximus ). J. of Vet. Diagn. Invest. 1-6 Perrin, KL, Kristensen AT, Gray C, Nielsen SS, Bertelsen MF, Kjelgaard-Hansen M. 2020. Biological variation of hematology and biochemistry parameters for the Asian elephant (Elephas maximus ), and applicability of population derived reference intervals. Journal of Zoo and Wildlife Medicine, 51(3) : 643-651. Van der Kolk JH, Hoyer MJ, Verstappen FALM, Wolters SABI, Treskes M, Grinwis GCM and Kik MJL (2011). Diabetes mellitus in a 50-year-old captive Asian elephant (Elaphas maximus ) bull, Veterinary Quarterly, 31:2, 99-101. Https://doi.org/10.1080/01652176.2011.585793 To page top