A comparison of the effects of carbon dioxide and medical air for abdominal insufflation on respiratory parameters in xylazine-sedated sheep undergoing laparoscopic artificial insemination

AIMS: To determine if abdominal insufflation with medical air will improve oxygenation and ventilation parameters when compared to insufflation with CO₂ in xylazine-sedated sheep undergoing laparoscopic artificial insemination (AI).

METHODS: Forty-seven sheep underwent oestrus synchronisation and were fasted for 24 hours prior to laparoscopic AI. Each animal was randomised to receive either CO₂ or medical air for abdominal insufflation. An auricular arterial catheter was placed and utilised for serial blood sampling. Respiratory rates (RR) and arterial blood samples were collected at baseline, after xylazine (0.1?mg/kg I/V) sedation, 2 minutes after Trendelenburg positioning, 5 minutes after abdominal insufflation, and 10 minutes after being returned to a standing position. Blood samples were collected in heparinised syringes, stored on ice, and analysed for arterial pH, partial pressure of arterial O₂ (PaO₂), and CO₂ (PaCO₂). The number of ewes conceiving to AI was also determined.

RESULTS: Repeated measures ANOVA demonstrated temporal effects on RR, PaO₂, PaCO₂ and arterial pH during the laparoscopic AI procedure (p<0.001), but no difference between insufflation groups (p>0.01). No sheep experienced hypercapnia (PaCO₂>50?mmHg) or acidaemia (pH<7.35). Hypoxaemia (PaO₂<70?mmHg) was diagnosed during the procedure in 14/22 (64%) ewes in the CO₂ group compared with 8/23 (35%) ewes in the medical air group (p=0.053). Overall, 15/20 (75%) ewes in the CO₂ group conceived to AI compared with 16/22 (72.7%) in the medical air group (p=0.867).

CONCLUSIONS AND CLINICAL RELEVANCE: There were no statistical or clinical differences in RR, PaO₂, PaCO₂, pH, or conception to AI when comparing the effects of CO₂ and medical air as abdominal insufflation gases. None of the sheep experienced hypercapnia or acidaemic, yet 42% (19/45) of sheep developed clinical hypoxaemia, with a higher percentage of ewes in the CO₂ group developing hypoxaemia than in the medical air group. Based on the overall analysis, medical air could be utilised as a comparable alternative for abdominal insufflation during laparoscopic AI procedures.     

Ergovaline does not alter the severity of ryegrass staggers induced by lolitrem B

AIM: To investigate a possible interaction between lolitrem B and ergovaline by comparing the incidence and severity of ryegrass staggers in sheep grazing ryegrass (Lolium perenne) containing lolitrem B or ryegrass containing both lolitrem B and ergovaline.

METHODS: Ninety lambs, aged approximately 6 months, were grazed on plots of perennial ryegrass infected with either AR98 endophyte (containing lolitrem B), standard endophyte (containing lolitrem B and ergovaline) or no endophyte, for up to 42 days from 2 February 2010. Ten lambs were grazed on three replicate plots per cultivar. Herbage samples were collected for alkaloid analysis and lambs were scored for ryegrass staggers (scores from 0–5) weekly during the study. Any animal which was scored ≥4 was removed from the study.

RESULTS: Concentrations of lolitrem B did not differ between AR98 and standard endophyte-infected pastures during the study period (p=0.26), and ergovaline was present only in standard endophyte pastures. Ryegrass staggers was observed in sheep grazing both the AR98 and standard endophyte plots, with median scores increasing in the third week of the study. Prior to the end of the 42-day grazing period, 22 and 17 animals were removed from the standard endophyte and AR98 plots, respectively, because their staggers scores were ≥4. The cumulative probability of lambs having scores ≥4 did not differ between animals grazing the two pasture types (p=0.41).

CONCLUSIONS AND CLINICAL RELEVANCE: There was no evidence for ergovaline increasing the severity of ryegrass staggers induced by lolitrem B. In situations where the severity of ryegrass staggers appears to be greater than that predicted on the basis of concentrations of lolitrem B, the presence of other tremorgenic alkaloids should be investigated.     

Orthopedic Infections in Equine Long Bone Fractures and Arthrodeses Treated by Internal Fixation: 192 Cases (1990–2006)

Objective: To determine the rate of postoperative infection (POI) for internal fixation repaired equine long bone fractures and arthrodeses and identify associated risk factors. Study Design: Case series. Animals: Horses (n=192) with fracture repair of the third metacarpal and metatarsal bones, radius, ulna, humerus, tibia, and femur, or arthrodesis with internal fixation. Methods: Medical records (1990–2006) were reviewed for signalment, anatomic location, fracture classification and method of repair, technique and surgical duration, bacterial species isolated, postoperative care, onset of POI, and outcome. Results: Of 192 horses (171 [89%] closed, 21 [11%] open fractures), 157 (82%) were discharged from the hospital. Infection occurred in 53 (28% horses), of which 31 (59%) were discharged. Repairs without POI were 7.25 times more likely to be discharged from the hospital. Closed fractures were 4.23 times more likely to remain uninfected and 4.59 times more likely to be discharged from the hospital compared with open fractures. Closed reduction and internal fixation was associated with a 2.5‐fold reduction in rate of POI and a 5.9 times greater chance for discharge from the hospital compared with open reduction and internal fixation. Females had a strong trend for increased POI when compared with colts and stallion but not geldings. Conclusions: Overall rate of POI was 28%. Fracture classification, method of repair, gender, and surgical duration were significant risk factors.     

Conservative management of 17 horses with nonarticular fractures of the tibial tuberosity

REASONS FOR PERFORMING STUDY: Fractures of the tibial tuberosity (FTT) are caused by direct trauma, and are the second most commonly reported injury in event horses with stifle trauma. Conservative management of horses with FTT has been advocated, but results and prognosis for this method of therapy are unknown. OBJECTIVES: To report and review the findings of a retrospective study of 17 horses admitted to a veterinary teaching hospital from 1986-2001 with nonarticular FTT that received conservative management. METHODS: Subject details, aetiology of the accident, limb affected, degree of lameness at time of admission, size and degree of displacement of the fracture fragment, complications such as comminution of the fracture fragment or damage to soft tissue structures within the affected stifle, and treatment recommendations were obtained from medical records. Owners and trainers were contacted regarding the horse's return to athletic use. The follow-up period consisted of 11-154 months. RESULTS: Two horses were reportedly sound, but unable to return to competition for unrelated reasons. Of the horses that completed the rehabilitation period, 12/15 (80%) returned to athletic use at the same level as before the injury. Three horses were diagnosed with damage to soft tissue supporting structures of the affected stifle and could not return to their former level of competition. CONCLUSIONS: Concurrent soft tissue damage, diagnosed at the time of the initial injury, was statistically significant in precluding horses from returning to athletic careers. All other variables were found to have no effect upon outcome. POTENTIAL CLINICAL RELEVANCE: This retrospective study suggests that the conservative management of nonarticular FTT is a viable treatment modality in managing athletic equine patients presenting with these fractures.     

Surgical treatment of perforating duodenal ulcer in a dog by use of modified choledochoduodenostomy and gastrojejunostomy

Modified choledochoduodenostomy and gastrojejunostomy were used successfully to treat extensive duodenal ulceration and perforation in a dog. Concomitant pyometra, simultaneously managed by ovariohysterectomy, may have predisposed the dog to stress ulceration. Choledochoduodenostomy was performed by transplantation of the entire common bile duct and associated major duodenal papilla to a more distal duodenal location. An indwelling choledochostomy tube was used to stent the anastomotic site, externally divert bile flow, and allow postoperative cholangiography. Early postoperative complications included presumed metronidazole-induced neurotoxicosis, choledochostomy tube obstruction, and pancreatitis, all of which resolved within 2 weeks. The dog was clinically normal and medication (ranitidine and sucralfate) was discontinued 35 months later.