Use of liquid magnesium in rabbits
with chronic sludge
Esther van Praag, Ph.D.
MediRabbit.com is funded solely by the
generosity of donors.
Every donation, no matter what
the size, is appreciated and will aid in the continuing research of medical care
and health of rabbits.
Rabbit urine always contains a
certain amount of sediments. This is absolutely normal,
rabbits' systems work in this way to excrete the excess of calcium in their
The presence of some sediment in the urine of rabbit
is normal (left). A thick paste that becomes a solid millimeter thick cake when drying
is called sludge (right). The presence of sludge in the bladder is irritating
Up to now, sludge in rabbits has been treated by
flushing the bladder at regular intervals, e.g. every 6 months. The rabbit is
anesthetized and a catheter is introduced into the bladder before flushing.
Since the procedure is accompanied by pain, the rabbit needs to be given pain
relief medication for a few days. Rabbits with chronic sludge and repeated
flushing show longer recovery times after each new attempt to clear the
Sludge can be treated via a non-invasive procedure.
An effective way is the administration of subcutaneous fluids, followed by a
diuretic drug like furosemide. One time is usually enough, although it can be
repeated in the next 24 hours.
Recently, it was discovered that liquid magnesium
may clear sludge over a longer period of time.
Scotchie is a 6 year
old house rabbit. He has been battling bladder sludge for a while, at least 5
years, and needed bladder flushes regularly. These radiographs were taken
before liquid magnesium was administrated and show that his bladder is full
After the last bladder flushing in January (first 2
radiographs), we started giving him 1cc of liquid magnesium daily in his
water. This was recommended by Megan Mather, a rabbit owner who sprinkles
liquid magnesium over fresh vegetables before feeding them to her rabbits
Amount: About 1 to 1.5 ml/cc are added to 500 ml of
fresh water (20oz) every morning.
At his next
vet checkup in October (10 months later), there was no sludge at all.
magnesium does not help, several other products can be tried to treat sludge.
Since they decrease the pH of the urine, they should not be used over longer
periods of time. These products include:
Feeding fresh or dried cranberries daily or
non-sweetened cranberry juice. The properties of cranberry may, furthermore,
prevent the onset of cystitis (bladder infection).
Vitamin C. For smaller animals, the intake of Vit C is up to 100 mg, probably best between 25-50 mg/kg
rabbit once a day. Part of the Vit C will be
converted in oxalates, which may start a stone, but studies showed that high
intake of Vit C did not contribute to the formation
of stones. The use of Vit C in rabbits remains controversial
Use of citrate based products (e.g. Polycitra®) in order to change the pH of the urine, in
rabbits that suffer from chronic urinary tract infection or uroliths (bladder stones). The daily dosage in dogs is:
150 mg/kg per day. It has been used in rabbits and seems to have delayed the
formation of new stones. Long-term use of this urine acidifier may be harmful
to the rabbit.
Use of acidifiers like ammonium chloride (200
mg/kg/day, PO, TID) and DL-methionine (1,000-1,500 mg/cat/day, PO) may help
acidify the urine. Long-term use of this urine acidifier may be harmful to
My gratitude goes to Barbara Schmeitz (USA), Rachel Ihlenfeldt (USA), Megan Mather (USA) and Ros Lamb (UK) for the information on liquid magnesium, their
suggestions, and for sharing the x-rays of Scotchie.