A. De Moor

Evaluation of excision, cryosurgery and local BCG vaccination for the treatment of equine sarcoids

Ninety-five horses with sarcoids were subjected to three types of treatment: surgical excision (conventional or carbon dioxide laser), cryotherapy or local BCG vaccination. The type of treatment was selected on the basis of the size, location and clinical appearance of the tumours. The choice between conventional and laser excision was empirical. A successful outcome was obtained in 1 1 of 14 (79 per cent) of the horses treated by cryosurgery, 18 of 27 (67 per cent) treated by BCG vaccination, 18 of 22 (82 per cent) treated by conventional excision, and 20 of 28 (71 per cent) treated with a carbon dioxide laser. For both excision methods, rigorous measures were taken to avoid autoinoculation and to ensure a wide margin of normal skin. The probability of local recurrence after excision was significantly higher for large sarcoids and sarcoids which had previously failed to respond to treatment. In 10 of the 31 horses with remaining sarcoids, some or all of the untreated sarcoids were observed to regress spontaneously.

A preliminary study on the effects of atropine sulphate on bradycardia and heart blocks during romifidine sedation in the horse.

Romifidine (STH 2130-Cl or Sedivet) is an ά2-agonistic imino-imidazol sedative for intravenous use in horses recently developed by Boehringer Ingelheim, Vetmedica GmbH. An exploratory study was done in nine warm-blood horses, randomly divided into three groups, which received different dosages of romifidine (0.04, 0.08 and 0.12 mg/kg of body weight (BWT) intravenously (i.v.)) with at least one weeks interval between tests.Romifidine induced a marked bradycardia accompanied by second degree atrioventricular (AV) block and some sinus blocks at all tested dosages. A placebo (NaCl 0.9% i.v.) given 5 min before and after romifidine did not affect the cardiac disturbances induced by romifidine.A low dose of atropine sulphate (0.005 mg/kg of BWT i.v.) given 5 min before romidifine counteracted the bradycardia and caused a normal to increased heart rhythm at all romifidine dosages. A higher dose of atropine sulphate (0.01 mg/kg of BWT i.v.) administered 5 min before sedation induced a tachycardia (average 70 beats/min) at all romifidine dosages and completely prevented the bradycardia and the heart blocks. The positive chronotrope effects of atropine sulphate were attenuated by increasing doses of romifidine.The effects of atropine sulphate (low or high doses) given 5 min after romifidine only appeared after 5 min. Both dosages counteracted the bradycardia and suppressed the heart blocks.No atropine-dependent side effects were observed in non-fasted horses. The degree of the romifidine induced sedation was not affected by the use of atropine sulphate given before or after romifidine.

Haemodynamic changes during sedation in ponies.

The cardiovascular changes induced by several sedatives were investigated in five ponies with a subcutaneously transposed carotid artery by means of cardiac output determinations (thermodilution technique), systemic and pulmonary artery pressure measurements (direct intravascular method) and arterial blood analysis (blood gases and packed cell volume).The cardiovascular depression (decrease in systemic blood pressure and cardiac output) was long lasting (>90 min) after administration of propionylpromazine (0.08 mg/kg intravenous (i.v.)) together with promethazine (0.08 mg/kg i.v.). The phenothiazine-induced sedation was not optimal.α2-Agonists (xylazine (0.60 mg/kg i.v.) and detomidine (20 μg/kg i.v.)) induced initial but transient cardiovascular effects with an increase in systemic blood pressure and a decrease in cardiac output for about 15 min. Second degree atrioventricular blocks and bradycardia were seen during this period. The cardiovascular depression was more pronounced during detomidine sedation.Atropine (0.01 mg/kg i.v.) induced a tachycardia with a decrease in stroke volume but did not alter the cardiac output or other cardiovascular parameters. It prevented the occurrence of the bradycardia and heart blocks normally induced by xylazine or detomidine. Atropine potentiated the initial hypertension induced by the α2-agonists sedatives (especially detomidine). The decrease in cardiac output induced by xylazine, and to a lesser extent by detomidine, was partially counteracted when atropine was given in advance.The atropine-xylazine combination seemed the best premedication protocol before general anaesthesia as it only resulted in minor and transient cardiovascular changes.

Partial tibial neurectomy in 113 Belgian blue calves with spastic paresis

One hundred and thirteen double-muscled Belgian blue calves (69 males and 44 females) with spastic paresis (52 unilateral and 61 bilateral) were treated surgically by partial tibial neurectomy under caudal epidural anaesthesia. Telephone inquiries made at least three-and-a-half months later established that good results were obtained in 83.2 per cent of the calves; a considerable improvement was reported in 4.4 per cent which still had intermittent spastic contractions; severe hyperflexion of the hock necessitating early slaughtering was recorded in 4.4 per cent of the calves; and in 8 per cent there was little or no improvement.

Conservative and surgical treatment of tibial fractures in cattle

Ninety-five cattle with tibial fractures, all but one with a uni-lateral fracture, were examined between 1990 and 1994. The feasibility of repairing the fracture was assessed radiographi-caily, also taking into account the bodyweight and value of the animal. Twenty-two cattle were slaughtered. Conservative treatment with stall confinement and/or a splint or cast was applied in 18 cases, with satisfactory results in eight of them (44 per cent). They were fattened to normal bodyweight, but they all had a severe deformity of the affected leg. In 55 ani-mals, the fractures were fixed externally with Steinmann pins and methylmethacrylate bridges under image-intensi-fied fluoroscopy. Ten of them could not bear weight on the affected leg and were slaughtered before the pins were removed. In the remaining 45 animals the pins were removed after a mean (sd) period of 71 (14) days. Four ani-mals re-fractured the affected leg shortly after the pins were removed and six others were slaughtered prematurely because of inadequate weight bearing. The results were suc-cessful in 35 cases (64 per cent). Slight deviations of the affected leg and/or the contralateral leg were often observed. The overall survival rate of the cattle with tibial fractures was 45 per cent.

Decreased number of α-motoneurons in the cervical intumescence of calves with Arthrogryposis Multiplex Congenita of both thoracic limbs

The number of α-motoneurons in the spinal cord segments C6 to Th2 of five calves with Arthrogryposis Multiplex Congenita (AMC) and of five normal calves was compared. A statistically highly significant reduction in the number of α-motoneurons in segment C6 was observed in the affected calves. Two hypotheses to explain the effect of these findings were proposed. Firstly, it was thought that AMC may result from paresis of some muscles of the girdle, shoulder and elbow. Secondly, it was postulated that the decrease in the number of α-motoneurons in C6 may have induced a radial nerve dysfunction resulting in AMC.

Surgical treatment of urethral dilatation in seven male cattle.

The surgical treatment of urethral dilatation in the perineal region of seven young Belgian blue bulls is described. Urethrostomy under local anaesthesia in the standing animal resulted in a successful outcome in three of them. The possible aetiological factors and consequences of this syndrome are discussed.

HAEMODYNAMIC, METABOLIC AND PHYSICAL RESPONSES TO A NEUROLEPTANALGESIC-GLYCERYL GUAIACOLATE COMBINATION IN THE HORSE

A commercial neuroleptanalgesic acepromazine-etorphine combination administered intramuscularly to four horses produced a severe tachycardia and an increase in muscular tone, together with hypoxaemia, hypercapnia, metabolic acidosis associated with an increase in the packed cell volume and hyperglycaemia. No electrolyte changes were found. After reversal of the action of etorphine with diprenorphine, there was a prolonged decrease in the calcium and phosphorus serum concentrations and decreases in the packed cell volume and the total protein serum concentration.In a second experiment on the same four horses, glyceryl guaiacolate (10 g/100 kg body weight intravenously) was given as soon as the horses were anaesthetized with acepromazine-etorphine. The muscular rigidity disappeared and the tachycardia was less evident. There was a more pronounced hypoxaemia but the changes in the other parameters were similar to those in the first experiment.It was concluded that the neuroleptanalgesic-glyceryl guaiacolate combination is not a safe anaesthetic procedure in horses.

Influence of halothane anaesthesia, after xylazine premedication, on serum calcium concentration in the horse

In 20 horses breathing spontaneously, xylazine premedication followed by 1.5 h of halothane anaesthesia caused a significant decrease of the total serum calcium concentration. The ionized and complexed calcium fraction showed a non-significant increase. A significant decrease in total serum calcium also occurred in another group of ten horses during halothane anaesthesia with automatic artificial ventilation. The ionized and complexed calcium fraction remained at a constant level in these animals. A possible explanation for, and several consequences of, this calcium decrease are discussed. Determination of the serum calcium concentration might be indicated in some horses during halothane anaesthesia.