Ultrasonography was used to evaluate the duodenum of 6 clinically normal horses. Examinations were performed in horses which each, alternatively, received diets of; 1) concentrates and hay, 2) hay only, or 3) after 36 hours of starvation. The duodenum was constantly visualized just ventral to the right kidney at the 16th and 17th intercostal spaces on a line joining the olecranon and tuber sacrale. Cranial to the 16th intercostal space visibility depended on thickness of interposing liver and lung field interference. Duodenal distensions, contractions and content are described. Starved horses had fewer contractions and distensions than horses on hay, or hay and concentrate diets but the difference was not significant. Duodenal wall thickness ranged from 3–4 mm. Ultrasonographically five layers, corresponding to the mucosal surface, mucosa, submucosa, muscularis propria and serosa, could be identified. A necropsy specimen of the duodenum was evaluated histologically and Ultrasonographically in a water bath for comparison.

Bilateral ovariectomy was performed in 11 mares and unilateral ovariectomy in 2 mares. The horses were standing and sedated for surgery. After appropriate preparation, a laparoscope was inserted into the abdomen through the paralumbar fossa and the ovary was identified and anaesthetised with local anaesthetic via a custom-built needle. The ovary was then withdrawn from the abdomen through a separate flank incision and removed. The abdomen was not distended with gas before surgery. This method proved to be minimally invasive, rapid and effective.

Repair of parotid duct lacerations in 2 horses is described using intraluminal silastic tubing as a stent. The duct was lacerated traumatically at the facial vessel notch (<em>incisura vasorum facialium</em>) in the 1st horse, and iatrogenically after removal of an intraluminal sialolith after development of infection within the duct in the 2nd horse. In both cases, a silastic tube was passed retrograde into the duct <em>via</em> the salivary papilla, past the wound until the end lay rostroventral to the parotid salivary gland. The severed salivary ducts and the wounds were sutured. The external portion of the silastic tube was sutured to the skin and the tube left in place. Recovery in the 1st case was uneventful. In the 2nd case a salivary duct/cutaneous fistula formed at a wound distant from the sutured wound, which healed spontaneously. This technique differs from a similar described technique in that the stent tube exits the oral cavity and is attached to the outer skin surface

A shoe was designed to combine the advantages of a reverse shoe and an adjustable heart bar shoe in the treatment of chronic laminitis. This reverse even frog pressure (REFP) shoe applies pressure uniformly over a large area of the frog solar surface. Pressure is applied vertically upward parallel to the solar surface of the frog and can be increased or decreased as required. Five clinically healthy horses were humanely euthanased and their dismem-bered forelimbs used in an in vitro study. Frog pressure was measured by strain gauges applied to the ground surface of the carrying tab portion of the shoe. A linear variable distance transducer (LVDT) was inserted into a hole drilled in the dorsal hoof wall. The LVDT measured movement of the third phalanx (P3) in a dorsopalmar plane relative to the dorsal hoof wall. The vertical component of hoof wall compression was measured by means of unidirectional strain gauges attached to the toe, quarter and heel of the medial hoof wall of each specimen. The entire limb was mounted vertically in a tensile testing machine and submitted to vertical downward compressive forces of 0 to 2500 Nat a rate of 5 cm/minute. The effects of increasing frog pressure on hoof wall weight-bearing and third phalanx movement within the hoof were determined. Each specimen was tested with the shoe under the following conditions: zero frog pressure; frog pressure used to treat clinical cases of chronic laminitis (7 N-cm); frog pressure clinically painful to the horse as determined prior to euthanasia; frog pressure just alleviating this pain. The specimens were also tested after shoe removal. Total weight-bearing on the hoof wall at zero frog pressure was used as the basis for comparison. Pain-causing and pain-alleviating frog pressures decreased total weight-bearing on the hoof wall (P < 0.05). Frog pressure of 7 N-cm had no statistically significant effect on hoof wall weight-bearing although there was a trend for it to decrease as load increased. Before loading, the pain-causing and pain-alleviating frog pressures resulted in a palmar movement of P3 relative to the dorsal hoof wall compared to the position of P3 at zero frog pressure (P < 0.05). This difference remained statistically significant up to 1300 Nload. At higher loads, the position of P3 did not differ significantly for the different frog pressures applied. It is concluded that increased frog pressure using the REFP shoe decreases total hoof wall weight-bearing and causes palmar movement of P3 at low weight-bearing loads. Without a shoe the toe and quarter hoof wall compression remained more constant and less in magnitude, than with a shoe.

Summary Twelve horses were injected intra‐articularly into the metacarpophalangeal joint and extra‐articularly in the region of the lateral palmar digital nerve with 1 ml air and local anaesthetic to simulate gas accidentally introduced during regional anaesthesia. Half the horses underwent limited exercise after which all horses were radiographed at 15 and 45 min and then every 24 h until all evidence of gas had disappeared. Intra‐articular gas appeared as gas capped radiolucencies (GCR) in the proximal aspect of the joint. Extra‐articular gas appeared as linear radiolucencies (LR) which initially tended to migrate proximally. There was no significant difference in gas resorption in exercised and nonexercised horses. All gas was resorbed within 96 h with most of the gas already gone at 48 h.