The fmdmgs of Girjes et al(1992) indicate that the koala has a variable response to chlamydial infection, and that, at least in in-vitro experiments, koalas are able to produce antibodies capa- ble of neutralising chlamydial infection. It is therefore possible that in populations with endemic chlamydial infection overt clinical disease may not be normally produced, and it may be relatively unimportant to the health status of the koalas, as found in the present study. Nonetheless, the population will include koalas from which chlamydia can be isolated, and from which anti-chlamydia1 antibodies can be detected.

A comprehensive survey by Brown er al(1984) indicated that prevalence of infection was likely to be lower in areas where koalas were under least pressure from habitat alienation. Using a radiographic technique, the prevalence of cystitis was 5% at Springsure, compared with increased levels in populations in near-urban environments. It would appear that while infection rates may be similar in different areas, the likelihood of infection manifesting itself as overt ocular or urogenital infection, or as reduced fertility (Browner al1984), increases with the pressure of habitat alienation.

Funding for this project was provided by The University of Queensland Koala Fund and the Central Queensland Koala Study.

References BoboL,MunozB,VasUdiR,QuinnT,MkochaH andWestS(1991)Loncer

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Treadmliis in equine pfacflce

Motor-driven treadmills that are now available are sophisticated to allow horses to be walked, trotted, cantered and galloped comfortably and safely. Rose RJ and King CM (1993) Comp Cont €duc15:875-878 discussed the use of treadmills in equine practice in 4 main ways: to assess gait; to assist the dynamics of upper respiratory function; to measure physiological indexes of exercise capacity; and to rehabilitate horses with limb injuries.

The use of treadmills in equine practice will increase because many problems in equine athletes are apparent only in conditions of high-intensity exercise and because they provide a unique method of assessing cardiorespiratory and metabolic function during exercise.

Diagnosis of chiamydiai infection in koalas

Girjes AA et a/(1993) Vet Rec 133:136-141 developed a test to detect anti-chlamydia1 antibodies in sera from koalas infected with C psittaci. The immunodot blot test was compared with existing tests and shown to be the most sensitive test forthe identification of chlamydial infection in koala serum samples. It was rapid (about 16 h) and inexpensive. However, for the assay of swab material from koalas, gene probe analysis remains the most sensitive method of detection of chlamydiae.

Cfi6-6ifing and other sfefeofypies Stereotypy is defined as a repeated, relatively invariant sequence of movements with no obvious function.

Equine stereotypies include stall-walking, crib-biting, wind-sucking, weaving, swaying, pawing, stall-kicking, head-shaking, head-nodding, and tonguedragging, all repetitive movements that are not essential for locomo- tion, eating, cleaning the body or social communication. Stereotypies waste energy and some may lead into injury or disease. They appear commonly with confinement, frustration or an uncontrollable change of the environment.

Broom DM and Kennedy MJ (1 993) Equine Vet Educ5:151, reviewed the causes of stereotypies in horses. There is some indication that genetic factors may have a role. High concentrate, low volume, roughage-deficient diet is suspected to be a factor. lnsuff icient space and lack of social stimulation probably contribute, as well as the presence of other horses that display stereotypical behaviour. Some neurological disorders can be expressed as stereotypies. The common feature seems to be frustration over insufficient control of the environment.

The authors emphasise that stereotypies indicate poor welfare of the animals and the prevention and the correction of the problem should be aimed at the cause. Improving the housing and management is of primary importance compared with attempts to stop the behaviour by restrictions or surgery. It may be necessary to correct feeding, provide adequate exercise, encourage social contacts and alleviate boredom.

In an accompanying case report, Kennedy MJ, Schwabe AE and Broom DM (1993) Equine Vet€duc5:142, take a closer look into 10 cases of cribbiting and wind-sucking, and at attempts to correct the stereotypical behaviour.

428 Australian Veterinary Journal Vol. 70, No. 11, November 1993