Since the beginning of the 20th century, Indian rhinos have been kept in zoos and were successfully bred. The estimated wild population size of the Javan rhinoceros (Rhinoceros sondaicus) is less than 100, and about 400 individuals are thought to exist of the Sumatran rhinoceros (Dicerorhinus sumatrensis) (Foose and van Strien, 1997).
The Indian rhinoceros in zoological gardens
Regarding the health status of the Greater One-Horned Rhino, they appear to have relatively good health compared to other rhino species. The pustular dermatitis appears as multiple seropurulent, pisiform to miniature pustules covering most parts of the body.
Foot problems of Indian rhinos in zoos
The animals' behavior appears to play an important role in causing the cracks. Treatment consisted mainly of trimming the overgrown horn wall and debridement of the granulation tissue.
Foot problems of large mammals in zoos
The growth of the horn wall is approx. 1 cm per month and requires regular trimming under most breeding conditions. Elephant pox and foot-and-mouth disease can impair the health of the feet.
Foot problems in intensively managed animals with regard to some selected areas
Cracks are defined as a separation of the horn wall and possibly the coral structures (superficial or deep). Predisposing factors include damp and dirty husbandry conditions, which lead to changes in the horn.
Some histological features of the equine foot
This coronary horn is connected to the corium of the wall through a special fold formation of Str. The frog's horns are softer and the papillae of the leathery skin slightly longer than those in the sole.
Histopathological changes in some selected areas of the equine hoof
The sole is slightly concave, about 1 cm thick, and forms most of the underside of the hoof (Bolliger, 1991). Enlarged tubules were found as pathological changes mainly in the outer zone of the coronary horn.
Cattle and pig hooves
The last horn was in some cases completely detached from the surrounding horn leaflets, leaving a large gap between the two leaflets.
Genetic studies in the captive population of Greater One-horned rhinoceroses
Due to the fact that many other factors contribute to juvenile mortality, which are not associated with inbreeding, Bauer and Studer (1995) concluded that inbreeding has so far not resulted in any significant adverse effects in the captive population. This is based on the fact that there were no further associations between juvenile mortality, survival and inbreeding.
Material and Methods
Zoos and animals within the study group
Two (2/0) animals died and their feet – all from one animal and one forelimb and one hindlimb from the other animal – were taken to the Department of Anatomy of the Veterinary Faculty of the University of Zurich for macroscopic and histological anatomical examination. The feet of two (1/1) black rhinos – one forelimb from a female and one forelimb from a male – and two (1/1) Asian elephants – four feet from each animal – were also brought to the university for research. anatomical research.
Sampling locations and measurement techniques
Processing of the material
Further processing of the blocks was done in the same way as with the horn samples. Collecting horn samples from the animals living in zoos resulted in an additional 300 horn wall and pad samples.
Results
Husbandry
Size and weight
The adjacent figure depicts the anatomical nomenclature for an Indian rhinoceros leg used in this study.
Status of health
Anatomic description of the feet of captive Indian rhinos
From the lateral to the medial edge or apical to the palmar/plantar edge of the sole. The bones are arranged in an almost parallel line with the dorsal surface of the foot. The third phalanx of the central hoof is rather oval and has an elongated shape in the side hoofs.
This connective tissue and even the pad extends apically to the plantar/palmar portion of the sole. The foot pad (Pulvinus digitalis) is very large and takes up 2/3 of the interior space. Corium holds the hoof in place by attaching to the deeper structures of the foot.
The soft part consists of the epidermal layer next to the corium, Str. The coronal horn is the main part of the horn wall and has a very hard consistency.
Anatomic description of the feet of wild Indian rhinos
On the lateral hooves, the pad appears to be connected to the soles by a fold. There is a step between the cushion and the central sole, with the sole protruding from the cushion.
Anatomical structures of Black rhinoceros feet
In the middle part, the horny part is 0.4 cm thick and close to the skin about 0.2 cm. The lateral hooves of the Indian rhinoceros do not extend as close to the pad and central tongue as seen in the Black Rhinoceros.
Microscopical structures of Indian rhinoceros feet
Longitudinal section of the proximal part of the crown; Indian rhinoceros; AB-PAS coloring; magnification: 16x. Histological section of the horn tubule from the middle zone of the coronary horn; Indian rhinoceros;. Histological section of the horn tubule from the inner zone of the coronary horn; Indian rhinoceros;.
Histological cut of the coronary horn in the middle of the wall; The black rhinoceros;. Histological cut of the coronary horn in the middle of the wall; Indian rhinoceros; Histological transverse section of the distal part of the hoof wall; Indian rhinoceros; AB-PAS staining; magnification: 8x.
The linear arrangement of the tubules is lost in the palmar/plantar part of the sole. The linear alignment of horn tubules (a) and intertubular horn (b) is clearly visible.
Pathological alterations in the feet of captive Indian rhinos
This granulation tissue bulges out on the sides of the central hoof, which becomes clearly visible when the animal is standing. Out of the 19 rhinos, I observed that 8 animals had numerous hematomas located on the surface of the substrate. Depending on the severity of the cracks, I divided the animals into three different classes.
The cracks on the hind legs extend either the entire width of the pad or are very deep (> 3 cm). They run from the coronary band to the weight-bearing border of the horn wall and can vary in width and length. The skin shows signs of inflammation along the coronary band and the thickness of the horn wall decreases.
In some cases the central hoof of the hind legs showed scratches on the sides. The horn walls of the forelegs are less affected, but also show signs of abrasion.
Pathological alteration of feet of wild Indian rhinos
Histopathological alterations of the horn structures in certain hoof segments
Histological cross-section through the middle zone of the coronary horn; histopathological findings: small cracks between the cortical cells of the keratin tubes and the intertubular keratin cells; Indian rhinoceros; AB-PAS staining; magnification: 20x. Histological cross-section through the outer zone of the coronary horn; histopathological findings: small cracks between the cortical cells of the keratin tubes and the intertubular keratin cells; Indian rhinoceros, AB-PAS stain, magnification: 20 x. These horizontal cracks start at the beginning of the cushion structures adjacent to the sole.
The intertubular horn on the sole adjacent to these cracks, by comparison, showed no changes at all. The pathological changes are less evident in the palmar/plantar part of the pad, but still present. In some zoos, attempts have been made to improve horn quality by supplementing the food with biotin.
Most of the animals were supplemented over the years and the effect could only be assessed through the personal reports of the keepers and veterinarians. Due to the stronger structure of the horn, it was a general conclusion that the animals needed more frequent foot care.
Selected microscopical and histopathological findings in the Black rhinocer- os foot
These cracks do not occur as often as observed in the pad of the Indian rhinoceros.
Discussion
- Stages of development
- Secondary causes
- The Indian rhinoceros: A ‘Sole-Walker’
- Comparison of foot problems in Indian rhinos with other species
- Special features of the feet of Indian and Black rhinos
- Recommendation to husbandry, treatment, and prevention
- Conclusion
Cracks will form within the weakened horn walls and in the apical part of the footpad, a highly sensible area. Since mating lasts a long time (usually one day with several copulations, each lasting about 1 hour) and is a rather rough event (chasing, lifting and biting the female), most males will show a worsening of the cracks in the footpads afterwards . . The soles are concave and the edge of the sole, next to the cushion, is raised.
In the central hoof, the sulcus protects the cranial part of the cushion from loading. The horn of the sole of the foot is of inferior quality compared to the structures in the sole. Over time, they will affect the health of the feet and leave them vulnerable to further impact.
This thesis cannot be transferred to the Indian rhinoceros, as the pathological changes in the coronary horn appeared mainly in the last third of the horn wall. The anatomical features of the horn structure of their feet look different compared to zoo animals.
Summary
Zusammenfassung
BUDRAS K.-D., HULLIGER R.L. und SACK W.O., 1989: Licht- und Elektronenmikroskopie der Verhornung im laminaren Bereich des Pferdehufes mit Hinweisen auf Hufrehe, Am. GEYER H., SCHULZE J., STREIFF K., TAGWERKER F. und VÖLKER L., 1984: Der Einfluss von experimentellem Biotinmangel auf die Morphologie und Histochemie von Haut und Klauen von Schweinen, Zbl. GULDENSCHUH G., STUDER P. und ROSEMARY D., 2000: Haltungsrichtlinien für das Große Panzernashorn (Rhinoceros unicornis Linné 1758), zuerst.
JOSSECK H., ZENKER W. und GEYER H., 1995: Hufhornanomalien bei Lipizzanern und die Wirkung von Nahrungsbiotin auf makroskopische Aspekte der Hufhornqualität. MÜLLING Ch., BRAGULLA H., BUDRAS K.-D. und REESE S., 1994: Strukturelle Faktoren, die die Hornqualität und bevorzugte Krankheitsherde auf der Fußoberfläche von Rinderhufen beeinflussen, Schweiz. VÖLLM J., PAGAN O., BURNENS A., KUHNERT P. und PLETSCHER M., 2000: Ein Fall von ausgedehnter exsudativer Dermatitis bei einem Panzernashorn, European Association of Zoo and Wildlife Veterinarians (EAZWV), Paris, Frankreich, S . .
WIRZ-HLAVACEK G., STUDER P., and ZSCHOKKE S., 1998: International pedigree of the greater one-horned rhinoceros (Rhinoceros unicornis Linné 1758), 10th edition, published by Basel Zoo, Switzerland. ZENKER W., JOSSECK H., and GEYER H., 1995: Histological and physical assessment of poor hoof horn quality in Lippizzaner horses and a therapeutic trial with biotin and placebo, Equine Vet.
Acknowledgement
Curriculum Vitae
