Ammonia intoxication in rabbits



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Ammonia (NH3) is a heavy gas, whose presence in greater concentration is toxic. It is formed by bacteria that degrade litter, urine, excrements, and takes place in warm conditions. It is thus more likely to observe NH3 intoxication during the summer months, rather than in the winter.

NH3 is rapidly absorbed by the mucosal cells lining the respiratory tract of the rabbit, where it will be transformed into an alkaline molecule with aggressive properties. This leads to the destruction of the mucociliary epithelial cells lining the respiratory tract, whose role is to protect the respiratory tract against bacterial aggressions.




Typical clinical signs related to upper respiratory tract disease: rhinitis and conjunctivitis.

Although NH3 is a toxic molecule, intoxication is often ignored in the differential diagnosis of respiratory diseases. The problem is seen more often in commercial rabbitries, seldom in private homes where a rabbit is kept in good hygienic conditions.

The prevention of NH3 intoxication is done by regular cleaning of the litter boxes, and a good aeration.

Clinical signs

The disease is characterized by different stages, depending on the length of exposure and the concentration of ammonia in the air.

In the very beginning, typical problems related to upper respiratory disease are observed: nasal and ocular discharge, swollen eyelids and irritation of the corneal surface of the eye, sneezing and snoring, rarely fever.

If the problem is not treated, pharyngeal and tracheal inflammation is observed, followed by lower respiratory tract disease. At this stage, secondary bacterial infection is possible, due to the destruction of the mucociliary barrier and depression of the immune system. At this stage, the disease develops in an acute form, with difficult respiration and sometimes coughing. The rabbit is often anorexic, depressed, shows signs of dyspnea (abnormal or difficult breathing) and cyanosis (blue discoloration of tongue, lips, gums, due to shortage of oxygen in the blood), fever or hypothermia.

The disease is difficult to treat and often becomes chronic, even when the rabbits are transferred to a clean well-aerated environment.

For information of the treatment of bacteria induced respiratory diseases, see: Upper respiratory tract disease in rabbits.

Further Information

1.  Boucher S, Nouaille L. Maladies des Lapins. Manual pratique. Editions France Agricole. 2002. pp 182-183

2.  Kruckenberg SM, Cook JE, Feldman BF. Clinical toxicities of pet and caged rodents and rabbits. Vet Clin North Am. 1975;5(4):675-84. 

3.  Makarenko ON, Skorik LV, Mel'nichuk DA. The characteristics of nitrogen metabolism in the tissues of rabbits with ammonium toxicosis. Ukr Biokhim Zh. 1992; 64(6):105-9.