Ferret Photo-Sensitivity Study Update
By Mary Van Dahm
No, this doesn’t refer to ferrets that are camera shy! This refers to the effects of light and dark cycles on ferrets.
We have long suspected that early neutering could have some effect on ferrets, but it didn’t provide a complete picture for many of the adrenal cases we were seeing. Since we already knew that light and dark periods have an effect on the ferret breeding cycle, was it possible that light affected ferrets physically in other ways?
Most members of the mustelidae family are nocturnal (active at night) or are active during the early morning or late evening hours when the sun is just below the horizon. Many members of this family live in burrows during the day to avoid the heat and light of the sun. The average time spent in actual light is just a few hours a day and it is often subdued. This is totally different than the lighting cycles that we subject our pet ferrets to. Most ferret owners tend to keep their pets in sunlit rooms during the day and then subject them to more light in the evening when lights are turned on in the house.
The purpose of our study was to determine if this extended light period had anything to do with the prominence of adrenal disease in ferrets. We also wanted to consider the possibility of whether the age at which the ferret was neutered had any effect on the incidence of adrenal disease, but this was to be considered a by-product of the light study.
We took 30 ferrets aged 3 months to 2-1/2 years and separated them into 6 groups. Each group contained 1 or 2 ferrets that were early neuters, 2 ferrets that were altered at puberty (6 to 9 months) and 1 or 2 ferrets that were altered between 1-1/2 and 2-1/2 years of age. The late altered ferrets (juveniles and adults) were all animals that came into our shelter from different parts of the country. They came in at random as give-ups. They came from breeders in Illinois, Indiana, Iowa, Kentucky, Michigan, Missouri, and Wisconsin. We hoped that having ferrets from different backgrounds and bloodlines would reduce the possibility of a genetic susceptibility to the disease tainting the test.
The ferrets were set up in such a way that they had a sleeping room with no windows at all in it and the lights were only turned on for short periods of time to clean cages. Three playrooms were set up so that each shift could have about 12 hours of playtime. The ferrets received light for a short period of time (about 6 hours) each day. A combination of indirect fluorescent tight and indirect natural light (from a north window)were used.
All of the ferrets were free fed a mixture of Totally Ferret, IAMS kitten
food, Eukanuba cat food, Marshalls ferret food, and an occasional scoop
of Purina Kitten Chow or Cat Chow as a treat. They were also offered ‘ferret gruel’ daily – a mixture of whatever crumbs were left in the bowls from the day before moistened with water and with a dash of Ferretone, brewers yeast, ProBalance and shark cartilage added.
To date, (almost 5 years from the start of the study) only 3 of the ferrets involved in the study have developed signs of possible adrenal disease (Mostly thinning hair on the tail). One of these ferrets has a very low glucose level and is on a high dose of prednisone, which may be aggravating her adrenal glands. The other two had somewhat bad coats to begin with – even as juveniles – so there is a possibility that their hair loss is a hereditary condition and not adrenal disease that is causing their poor coats since they are both sisters. Six ferrets have gone in for non-adrenal related surgeries (hair balls, cystic spleens, insulinomas). The ages of these ferrets ranged from 3-1/2 years to 6-1/2 years at the time of surgery. These ferrets all had completely normal adrenal glands. Two of these ferrets were early alters.
Unfortunately some of the ferrets from the study are no longer with us. One died from lymphoma, two died of heart disease, one died of kidney failure, and one had liver disease. Ages at death ranged from 2-1/2 years to 6-1/2 years. Post mortems showed that all of the ferrets had healthy adrenal glands. None of these ferrets were early alters.
The rest of the group is still going strong, although a few have developed insulinoma. Our oldest ferret is 7-1/2 years old now. He is a late alter. Our oldest female is 6-1/2 years old and she is an early alter.
As God reclaims his little clowns, we will continue to do post mortems and record the conditions of the adrenal glands at that time.
In conclusion: Judging from the information collected so far, I feel very strongly that light plays an important role in the early onset of adrenal disease in ferrets. Perhaps excessive light causes an overly active adrenal gland (hyperplasia). If nothing changes in the ferret’s environment to reduce the light exposure, the hyperplasia develops into true adrenal disease or even cancer.
I can’t say at this point if light is the whole answer. There may be other factors that we have yet to discern, but light seems to be a strong factor. This may also be evident in the number of ferret shelters that I have talked to who notice that most of the ferrets that stay there for any length of time seem to develop signs of adrenal disease. Long hours of light or irregular lighting (as volunteers come and go at different hours) may be having an effect on the shelter residents. In those cases there is no easy solution to this problem.