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Surgical castration of giraffe (Giraffa camelopardalis) has not been commonly performed. Large domestic animal castration has a significant complication rate that includes postoperative mortality. Documentation of castration techniques and complications in large domestic animals occurs regularly. However, literature describing castration experiences with large zoo mammals is sparse. In addition, a suitable anesthetic regimen for surgical castration of giraffe has not been confirmed. Open castration using an emasculator plus ligation was performed in three subadult giraffe weighing 555-711 kg. Scrotal incisions were left open and healed in about 6 wk. One animal developed scrotal dermatitis. No other complications occurred. As slow scrotal healing can increase the risk of ascending infection, partial or complete scrotal closure for giraffe may warrant consideration. Experiences with these animals also suggest that closed or modified closed castration may be considered for giraffe of this size. Thiafentanil, medetomidine, and ketamine plus local lidocaine provided suitable anesthesia for surgical castration.

A full-term ectopic pregnancy was diagnosed in a multiparous, captive gerenuk (Litocranius walleri walleri) following prolonged gestation without parturition. Until 213 days of gestation, fetal viability was determined by transabdominal ultrasound of fetal heartbeat, physical palpation, and visual observations of fetal movements. Survey abdominal radiographs obtained at day 229 of gestation revealed a fully mineralized fetal skeleton in an inappropriate position for parturition. Surgical exploration revealed a full-term, nonviable, male calf contained within fetal membranes attached to the omentum. Histologic examination of the fetal membranes identified lesions compatible with placenta-cotyledon separation occurring prior to surgical removal. No congenital fetal abnormalities or infectious processes were identified. Visual observation of the reproductive tract at the time of surgery revealed no abnormalities or evidence of concurrent pregnancy.

A dose range was determined for anaesthesia of 20 recently boma-captured roan antelope (Hippotragus equinus) with the synthetic opiate A3080 combined with medetomidine and ketamine. A dose of 10-30 micro/kg A3080 (x = 20+/-8 microg/kg) combined with 5-21 microg/kg medetomidine (x = 13+/-7 microg/kg) plus 0.29-1.11 mg/kg ketamine (x = 0.71+/-0.24 mg/kg) was found to be safe and effective for the field conditions in this study. The anaesthesia produced by this drug combination was predictable and characterised by a short induction time, good muscle relaxation, and acceptable physiological parameters for anaesthesia periods ranging from 49-103 min (x = 64+/-19 min). The wide range (3-4-fold) of doses with acceptable results is also an indication that this drug combination has a wide margin of safety in roan antelope, making it desirable for field use. When 2 dose levels (2-3-fold dif ference) were retrospectively evaluated, no statistical difference was found in induction times, and no observable clinical differences in the anaesthetic episodes were seen. Based on this study, the recommended dose range in roan antelope for this combination is 10-13 microg/kg A3080, 5-6 microg/kg medetomidine and 0.3-0.6 mg/kg ketamine. The anaesthesia produced by this combination was rapidly and completely reversed by i.m. or i.v. injections of naltrexone at 30 times the A3080 dose (x = 0.60+/-0.25 mg/kg) and atipamezole at 3 times the medetomidine dose (x = 38+/-20 microg/kg). No residual effects from ketamine were noted following reversal of A3080 and medetomidine. No mortality was associated with this protocol.

Sixteen (10 female, six male) captive-born dama gazelles (Gazella dama) weighing 48 +/- 10 kg (mean +/- SD) were used to evaluate the cardiopulmonary effects of i.m. carfentanil and to validate the use of pulse oximetry in immobilized gazelles. Carfentanil (18.4 +/- 2.2 micrograms/kg i.m.) produced rapid induction (6 +/- 3 min), moderate muscle relaxation, and a significant (P < 0.05) decrease in heart rate (87 +/- 12 beats/min) beginning 5 min following induction and continuing throughout the immobilization period. A decrease in respiratory rates began 15 min following induction (11 +/- 4 breaths/min). Systemic hypertension was present throughout the immobilization period. Arterial blood gas analysis, performed at 10, 20, and 30 min after induction, showed PaCO2 and PaO2 values within normal limits. Arterial blood oxygen saturation (SaO2) was < 95% 10 min after induction. Relative arterial oxygen saturation (SpO2) values indicated by pulse oximetry were generally lower than SaO2 values but reliably demonstrated trends in arterial oxygen saturation as confirmed by arterial blood gas analysis. Periods of hypoxemia were usually indicated by the pulse oximeter reading and confirmed by SaO2 measurements. There was an increase in creatine phosphokinase values (88 +/- 53 U/L to 109 +/- 48 U/L) at 30 min postimmobilization. Naltrexone reversal (1.8 +/- 0.3 mg/kg, half i.v. and half s.c.) was rapid and uneventful, and time to standing was 2 +/- 1 min.

Objective: To determine the effects of an i.m. administered carfentanil-xylazine combination on cardiopulmonary variables and plasma catecholamine concentrations and to validate use of pulse oximetry in bongo antelopes., Animals: 8 healthy adult females., Procedure: Antelopes were immobilized with carfentanil citrate (8.3 micrograms/kg of body weight, i.m.) and xylazine hydrochloride (0.79 mg/kg, i.m.). Hematologic values and plasma biochemical and catecholamine concentrations were determined at the beginning and end of immobilization. Immediately after induction of immobilization and every 15 minutes thereafter, cardiopulmonary variables were determined., Results: Induction time after carfentanil-xylazine administration was 6 +/- 2 minutes. At 15 and 45 minutes after immobilization and thereafter, significant decrease in heart and respiratory rates, respectively, were observed. After 15 minutes of immobilization, all antelopes had developed mild hypoxemia, which resolved after nasal insufflation with 100% oxygen. Pulse oximetry readings underestimated arterial blood gas values, but reliably indicated trends in arterial oxygen desaturation. Antelopes developed hypoxemia after oxygen administration was terminated at the end of the procedure, prior to reversal of immobilization. Norepinephrine concentrations increased significantly (P < 0.05), and 3,4-dihydroxyphenylacetic acid concentrations decreased significantly at the end of the anesthetic event. Immobilization of all antelopes was reversed, using antagonists naltrexone and yohimbine hydrochloride. Time to standing was 3 +/- 1 minutes, and renarcotization was not observed., Conclusions and Clinical Relevance: The carfentamil-xylazine combination at the dosage used induced hypoxemia, pronounced arterial hypertension, and significant increase in plasma norepinephrine and decrease in plasma 3,4-dihydroxyphenylacetic acid concentrations in bongo antelopes. Supplemental administration of oxygen is recommended. Pulse oximetry is a useful tool to monitor trends in arterial oxygen desaturation, but does not substitute for arterial blood gas analysis.

Blood, testicular biopsies and electroejaculates were collected from adult male impala, free-ranging in the Kruger National Park (Republic of South Africa), during the breeding (rut; April-May) and nonbreeding (September-October) seasons. Blood samples were collected at 5-min intervals for 120 min from anaesthetized males (n = 7 impala/group) treated intravenously with saline, gonadotrophin-releasing hormone (GnRH: 1 microgram/kg body weight) or human chorionic gonadotrophin (hCG: 10 or 30 iu/kg). Semen was collected from six more animals during the breeding season and 12 animals during the nonbreeding season using a standardized electroejaculation protocol. Ejaculates obtained during the nonbreeding season were of inferior quality to those collected during the breeding season, and were characterized by lower sperm concentrations, poorer sperm motility and more morphologically abnormal sperm forms. Within season, there were no differences in testosterone secretion between the two hCG doses, and these responses were similar to those observed after GnRH, but during the rut, testosterone secretion stimulated by both GnRH and hCG was approximately nine times greater than during the nonbreeding season. This seasonal increase in testosterone production was associated with a doubling in testicular volume and concentrations of luteinizing hormone (LH) receptors. Although concentrations of testicular follicle-stimulating hormone (FSH) receptors were similar between seasons, receptor content increased during rut as a result of increased testicular volume. In contrast to testosterone secretion, basal LH and FSH secretions were unaffected by season and GnRH-induced gonadotrophin secretion was reduced during rut.(ABSTRACT TRUNCATED AT 250 WORDS)