Intravascular catheters were placed in the umbilical, uterine and maternal peripheral circulations of 16 Jersey cows between 240 and 260 days of gestation. Foetal plasma cortisol, blood gases and pH, and maternal plasma oestrogen, progesterone and cortisol were measured in ten animals during late pregnancy and throughout spontaneous parturition; all delivered live foetuses although parturition was earlier than normal and the placenta was generally retained. The gradual pre-partum rise in foetal plasma cortisol during the last week of gestation (from 10\p=n-\20 ng/ml 7 days before parturition to 51 \ m=+-\5 ng/ml in the last 3 h before delivery) was much less marked than the abrupt increase immediately after birth when the cortisol concentration invariably doubled. Maternal plasma oestrogen rose from 0.35 \ m=+-\ 0.04 ng/ml to 1\m=.\20\ m=+-\ 0.11 ng/ml during the week before parturition. Progesterone concentrations remained stable until a sudden fall 1\p=n-\2 days before delivery. The slight alterations in maternal plasma cortisol during this period were not statistically significant. The maternal plasma oestrogen levels were higher in the uterine vein than in the periphery, whereas uterine venous progesterone concentrations were significantly lower than in the peripheral circulation.The hormonal changes associated with the artificial induction of labour were investigated by the administration of cortisol, dexamethasone or corticotrophin to the foetus (four animals). In each case premature delivery occurred 5-6 days later; the maternal hormonal changes were very similar to those in untreated catheterized cows. These findings contrasted sharply with the known, rapid effect of dexamethasone given directly to cows in late pregnancy. This action of dexamethasone was confirmed in two catheterized cows (at 257 and 260 days of gestation); one dose of 25 mg (i.m. to the cow) was sufficient to cause delivery within 40 h. No changes in foetal plasma cortisol concentration occurred until the increase immediately after delivery but the usual maternal hormonal changes were telescoped into a sudden rise in oestrogen and fall in progesterone. The changes in foetal and maternal hormone levels during induced and naturally occurring parturition are discussed in relation to findings in other species.

The prevalence of feline polycstic disease in Persian cats presented to the University of Melbourne between February and August 1999 was 45%. Exotic cats were found to have the slightly higher incidence of 50%.

Observation of orthopaedic findings on yearling repository radiographs showed generally excellent agreement on the absence of findings, but variable agreement on the presence of findings. Agreement was good for larger and easy to categorise radiographic findings. More accurate definitions and training need to be developed to improve agreement within and between observers for orthopaedic findings with poor or fair to good agreement.

A technique using two interbody washers and a transvertebral screw was utilised to distract the cervical vertebrae and so decompress the spinal cord in 17 dobermann pinschers and three great danes with cervical spondylopathy. Neurological dysfunction was graded (1 to 5) according to the degree of hindlimb ataxia. Myelography showed evidence of spinal cord compression at C6‐7 in all dogs and at C5‐6 in six dogs. Twenty‐three compressive lesions were reduced when traction was applied to the cervical spine. Seventeen dogs improved following surgery and of these 10 improved by two or more grades. Follow‐up radiographic studies indicated resorption of end‐plate bone and eventual fusion of the vertebral bodies. Displacement of the screw into the vertebral canal, remodelling of the vertebral canal, fracture of C6 ventral spinous process and breakage of the screw were implant associated complications. The distraction‐fusion technique with modifications appears to be an effective procedure for the management of cervical spondylopathy in dogs in which the compressive lesion is soft tissue in nature.

Three cases of intramural haematoma of the small colon of horses are presented. In all cases the haematoma obstructed the lumen and caused an accumulation of faeces and gas. The horses were in shock and had acute abdominal pain. Exploratory abdominal surgery revealed the haematomas and showed them to be associated with chronic infection and terminal rupture in one animal which was subsequently killed, and an iatrogenic perforation of the terminal small colon in another which survived after intestinal resection. In the remaining horse, which died without recovering after intestinal resection, no cause was found.

Osteochondrosis is a failure of the normal process of endochondral ossification. In the elbow joint there are three manifestations of osteochondrosis, namely osteochondritis dissecans of the medial condyle of the humerus, ununited coronoid process and ununited anconeal process. This paper describes a series of sixty‐eight cases diagnosed at a referral centre over a 10‐year period. Ununited coronoid process and OCD of the medial condyle are not readily diagnosed because the lesions are difficult to demonstrate radiographically, but signs of degenerative joint disease of the elbow in young dogs of the medium to large breeds is strongly suggestive. Surgical treatment is indicated and the surgical approach to the medial aspect of the joint is described.

The occurrence of osteochondrosis in a breeding colony of labrador retrievers during an 11year period was investigated. Management practices and environmental factors were similar for all dogs. In 1247 progeny, elbow lameness was recorded in 259 dogs (21 per cent) and lesions of osteochondrosis on the coronoid process and, or, medial condyle of the humerus were confirmed in 189 dogs (15 per cent). None of 39 labrador crossbred dogs were affected. The incidence in progeny varied between different sires and dams and was associated with the severity of radiographic evidence of elbow arthritis in sires and dams with dams contributing significantly more than sires, suggesting a 'maternal' effect. tT. A. Mason's current address is 26

A transvertebral screw and interbody washer technique was used to stabilise the vertebrae and maintain the intervertebral space in 34 adult dobermann pinschers with cervical spondylopathy. The long term success of the procedure was 50 per cent. Pre‐operatively three dogs were considered mildly ataxic, 16 moderately ataxic, 13 severely ataxic and two non‐ambulatory. Thirty dogs had radiographic changes of calcified disc, vertebral malalignment or narrow intervertebral disc space and all dogs had myelographic abnormalities in the caudal cervical spine. Vertebral malalignment and narrow intervertebral space correlated closely with myelographic cord compression. However, compressive lesions were not identified in 11 cases on plain films. Follow‐up was available on 30 dogs of which 25 showed neurological improvement. This was temporary in 10 cases which were destroyed two weeks to three years following surgery.