An indoor temperature of 18 – 20oC should be maintained. Indoor temperatures of greater than 30oC should be avoided.
Various heating methods have been used successfully including radiators, hot water pipes, radiant panel heaters, hot air blowers and under-floor heating. If under-floor heating is used it is advisable for it to be installed in the area of the enclosure most likely to be used for sleeping, but not throughout the whole facility. This provides the animals with a thermal gradient and gives them a degree of choice as to where they are most comfortable sleeping. Some institutions have reported increased dust and ammonia fumes in houses where under-floor heating is used, so increased ventilation may be required to compensate. Indoor facilities should be maintained with good ventilation while avoiding draughts.
Some institutions have used heavy duty plastic hanging strips on the doorways allowing animals free access to both indoors and outdoors whilst minimising heat loss and draughts. Animals can be habituated to these by installing one trip at a time. Most animals accept them within two – three weeks.
Thermal imaging cameras can be a useful tool in assessing surface temperatures in different parts of the indoor enclosure and identifying and eliminating cold spots. This is particularly useful when preparing an enclosure for a winter calving. One institution has experienced hypothermia in a newborn calf due to it lying on a cold floor. Use of deep straw (30 – 40cm) to cover the floor around the time of birth and during calf rearing is another method of reducing cold spots and recommended by one highly successful institution.
Natural daylight cycles seem to be adequate for rhinos. However, if an animal is to be held indoors for more than twelve hours (e.g. during winter in cold-climate institutions), facilities should provide artificial or natural light sources to stimulate natural cycles. Skylights or windows providing natural light should be included whenever possible.
Water should be available in each indoor area. Both standing water and wall mounted self-filling water troughs have been used. In order to avoid drowning when young calves are present, any water troughs set into the floor should either be replaced with one off the ground or drained of all but a few centimeters of water.