Causes and prevention of foot problems in Greater one‐horned rhinoceros Rhinoceros unicornis in zoological institutions

Abstract

Greater one‐horned rhinoceros Rhinoceros unicornis have been successfully maintained by and bred at zoological gardens in the past half century. Despite this success, decades ago it was recognized that this species frequently develops foot lesions. Such damage can impair the health and well‐being of an individual, and contribute to a reduction of its lifespan. The death of a breeding bull or cow will have an effect upon the success of the breeding programme. Various studies have been carried out to determine the types and causes of foot problems in Greater one‐horned rhinoceros with the aim of identifying long‐term solutions to this health concern. The most effective method for preventing lesions and improving the health of the feet in rhinoceros is to utilize an appropriate substrate (e.g. 50 cm‐deep untreated wood chips) in both outdoor enclosures and indoor stables.

Body condition scoring system for greater one-horned rhino (Rhinoceros unicornis): Development and application

“…Obesity is considered a contributing factor once the disease is established, delaying the healing of the affected feet. At one facility with very intensive monitoring of foot health, an improvement and prophylactic effect with a change from hard substrate to a deep layer of woodchips in both the indoor and outdoor enclosure was observed [von Houwald, 2016], and a different questionnaire than the one used in the present study, filled in by eight zoological institutions, indicated fewer foot problems in those facilities that had instigated similar changes [von Houwald, 2016]. By contrast, in the present study, BCS and enclosure characteristics (such as the proportion of soft and hard substrate) did not differ for animals without and with mid-to long-term foot problems.…”

“…Chronic pododermatitis (CP) is a multifactorial disease, where suboptimal husbandry (especially inadequate flooring and a lack of pools) is probably the most influential etiologic factor, as this condition is not described in free‐ranging animals and the incidence in the captive population is high; cracks, non‐healing fissures, ulcers between the sole of the central toe and the adjacent pad, and pad overgrowth characterize this condition [von Houwald, , ; Atkinson et al, ]. Obesity is considered a contributing factor once the disease is established, delaying the healing of the affected feet.…”

“…Additional information on individual animals was taken from the studbook (e.g., reproductive history, age), from Hermes et al [], and from the survey results. Based on the veterinary information provided, animals were considered as having mid‐ or long‐term foot problems (during the last 4 years) typical for GOH‐rhinos if the information listed, for example, cracks, fissures, foot pad overgrowth [von Houwald, ]; animals reported to have, for example, “lameness around the knee” or “fractured metatarsal bone” or a condition that healed within a short time period were not considered as having “foot problems.” For those facilities that responded with amounts of different diet items offered per animal on a daily basis, a total dry offer of the winter feeding regime was estimated by adding dry diet ingredients (hay, pelleted feeds, grains, bread) to the sum of fresh diet items (fruits and vegetables); following Flores‐Miyamoto et al [], the latter were corrected for a moisture content of 85%.…”

“…Monitoring the weight of an animal continuously over time is probably the best option to check for changes in nutritional status, but using body weight only may be difficult, because the average body weight for stages of growth, maintenance, or pregnancy, have yet to be defined, and because of inter‐individual variation. Also, it evidently requires the availability of scales, which are considered a prerequisite for any new GOH‐rhino facility [von Houwald, , pers. comm.…”

Husbandry, management and breeding of the Greater one‐horned rhinoceros Rhinoceros unicornis at Zoo Basel

“…In order to control the parasitic load, the rhinoceros were kept inside on concrete substrates and easy‐to‐clean floors were provided outside. Unfortunately, this type of hard substrate led to the occurrence of foot problems (von Houwald & Flach, ; von Houwald, ). Bulls suffered from severe foot problems and, as a consequence, some of them died at a young age (14–20 years), which led to a loss of breeding bulls in the captive population (von Houwald, ).…”