Hi X,
The photoperiods are important for intact ferrets and for ferrets that
have been spayed or neutered.  For intact ferrets the photoperiod is what
controls the breeding season.  In the springtime as the days become longer
(ie.more light) the melatonin level is decreased.  Ferrets shed, put on
their summer coat, and lose some weight.  Plus the breeding season starts.
In the fall as the days become shorter (ie less light and more darkness)
the melatonin level is increased.  Ferrets shed, put on their thick winter
coat, and gain their winter weight.  Plus the breeding season ends.
 
Now for pet ferrets that have been spayed/neutered, the photoperiod is
also important.  The adrenal glands are "acting like ovaries or testicles"
because they have LH receptors on them.  Thus if they are kept indoors
with artificial lights on at night time, they are being kept in "long
day" photoperiods (like spring/summer time).  This stimulates the adrenal
glands.  With chronic stimulation the adrenal glands produce the sex
hormones, and this may cause adrenal gland disease with time.
Unfortunately most pet ferrets are spayed/neutered at an early age, kept
indoors under "long day" photoperiods, and are at risk for adrenal gland
disease.
 
Keeping your ferrets in a fall/winter like photoperiod (8-10hours of
light,14-16 hours of dark) may help prevent the stimulation to the adrenal
glands and adrenal gland problems.  Treatment with melatonin simulates a
fall/winter photoperiod which causes a decrease in the LH levels which
stops the stimulation to the adrenal glands.  This in turn stops the
overproduction of the sex hormones by the adrenal glands.  So the big
picture is to keep your ferrets in a dark room at night time!  Try to
keep them in the dark just like they would be if outdoors during the
fall/winter time!
 
Hope that answers your question,
Jerry Murray, DVM
[Posted in FML issue 3664]