Don Gillespie is the reptilian curator at DVM El Paso Zoo when asked about UVB lighting he had this to say......






Why the Active UV Heat lamp is an important advance.
(Satisfying Reptilian Vitamin D3 Requirements Indoors)

Confusion abounds in popular magazines regarding reptiles, lights, and vitamin D. Requirements are unknown except for a few lizards and some must get vitamin D3 from an ultra-Violet (UV) source instead of the diet. Various lamps are labeled as full-spectrum whether they are or not. Light output is stated in very general terms of output but effective distance and exposure time are not mentioned. Direct sunlight is the ultimate solution for maintaining proper vitamin D3 levels in diurnal (day-time) lizards. Considerations of housing or climate may limit direct sunlight exposure to part of the year or none. The best measure of any UV lamp is the ability to maintain or elevate 25 -hydroxyl vitamin D3 blood levels. This is the standard used for man and many animals. A study of vitamin D3 in large monitors in the wild and captivity has established normal and deficient vitamin D3 level for these species. Monitors in the normal group had direct sunlight access part to all of the year or other significant UV exposure such as UV-permeable acrylic skylights in their housing area. Monitors in the deficient group were inevitably kept indoors with no artificial UV source or with perhaps an UV source too far away to be effective for the animal. Thus a solid standard could be used in evaluating the effects of Active UV Heat in vitamin D3 "synthesis for these species.

A female crocodile monitor (Varanus salvador) had no Ultraviolet (UV) light source or dietary vitamin D3 supplementation for several years. The animal was exposed to a 300-watt flood Active UV Heat bulb for four months at a ceiling high distance (2.0 to 2.2 meters). 2.5-hydroxy vitamin D3 levels were low-normal (100 nmol/L) as compared to other large monitors with exposure to direct sunlight. Then the animal was given UV through a focus-spot 160-watt Active UV Heat bulb at the same distance (2.0-2.2 meters) and vitamin D3 blood levels were measured again 30 days later. Vitamin D3 levels had continued to climb to mid-normal range (157 nmol/L). Daily exposure averaged 8-10 hours.

There were other significant improvements in this animal condition. A strong improvement occurred in the animal appetite to include only balanced prey items, which had not been previously possible. This species yellow spots became a bright gold as achieved with exposure to abundant natural sunlight. Three other crocodile monitors in this collection also demonstrated enhance natural colors under these lights. In one other zoo both a water monitor (Varanus salvador) and Komodo dragon (Varanus komodoensis) have been documented with normal to fairly high levels of vitamin D3 with use of the Active UV Heat lamp at distances of 4-7 feet away.

Consistently there has been a need in reptile exhibit lighting for a bulb that could project ultraviolet for some distance (many fluorescent UV-B lights project over an effective distance of only 12-18 inches). It would be even better to utilize incandescent fixtures. The Active UV Heat bulb does this on a real time basis for large monitors. Added advantages of heat and excellent visible-light spectrum make this bulb ideal for most reptile enclosures. Anecdotal experience with appetite problems that resolved after lamp use with a crocodile monitor and python would suggest problem feeders in variety of reptile species would benefit from it use.

--- Don Gillespie, DVM El Paso Zoo

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