Evaluation of cardiorespiratory and biochemical effects of ketamine‐propofol and guaifenesin‐ketamine‐xylazine anesthesia in donkeys (Equus asinus)

ObjectivesTo evaluate the cardiorespiratory and biochemical effects of ketamine-propofol (KP) or guaifenesin-ketamine-xylazine (GKX) anesthesia in donkeys.Study designProspective crossover trial.AnimalsEight healthy, standard donkeys, aged 10 ± 5 years and weighing 153 ± 23 kg.MethodsDonkeys were premedicated with 1.0 mg kg^?1 of xylazine (IV) in both treatments. Eight donkeys were administered ketamine (1.5 mg kg^?1) and propofol (0.5 mg kg^?1) for induction, and anesthesia was maintained by constant rate infusion (CRI) of ketamine (0.05 mg kg^?1 minute^?1) and propofol (0.15 mg kg^?1 minute^?1) in the KP treatment. After 10 days, diazepam (0.05 mg kg^?1) and ketamine (2.2 mg kg^?1) were administered for induction, and anesthesia was maintained by a CRI (2.0 mL kg^?1 hour^?1) of ketamine (2.0 mg mL^?1), xylazine (0.5 mg mL^?1) and guaifenesin (50 mg mL^?1) solution. Quality of anesthesia was assessed along with cardiorespiratory and biochemical measurements.ResultsAnesthetic induction took longer in GKX than in KP. The induction was considered good in 7/8 with KP and in 6/8 in GKX. Anesthetic recovery was classified as good in 7/8 animals in both treatments. Xylazine administration decreased heart rate (HR) in both treatments, but in KP the HR increased and was higher than GKX throughout the anesthetic period. Respiratory rate was higher in GKX than in KP. PaO₂ decreased significantly in both groups during the anesthetic period. Glucose concentrations [GLU] increased and rectal temperature and PCV decreased in both treatments. Arterial lactate [LAC] increased at recovery compared with all time points in KP. [GLU] and calcium were higher in GKX than in KP at recovery.Conclusion and clinical relevanceThese protocols induced significant hypoxemia but no other cardiorespiratory or metabolic changes. These protocols could be used to maintain anesthesia in donkeys, however, they were not tested in animals undergoing surgery.     

Sinoscopic Treatment of Rostral Maxillary and Ventral Conchal Sinusitis in 60 Horses

Objective— To evaluate the use of sinoscopy for detection and treatment of ventral conchal sinus (VCS) and/or rostral maxillary sinus (RMS) disease in horses.
Study Design— Case series
Animals— Horses (n=60) with suspected paranasal sinus disease.
Methods— Horses were evaluated by sinoscopy through a conchofrontal sinus (CFS) portal with ventral conchal bulla (VCB) fenestration. Other endoscopic sinus approaches and adjunctive diagnostic tests; oral examination, computed tomography, radiography, scintigraphy and endoscopic examination of the upper portion of the respiratory tract were used in some horses.
Results— The CFS approach permitted adequate observation of the RMS and VCS in 53 horses (88%). Hemorrhage caused by VCB fenestration prevented examination of the RMS and/or VCS in 12 horses (21%). Observation of lesions was possible in all horses diagnosed with neoplasia, sinus cysts, and progressive ethmoidal hematomas. Endoscopy of the paranasal sinuses was useful diagnostically in 82% of horses with primary sinusitis. Other diagnostic modalities were usually required to confirm a diagnosis of dental sinusitis.
Conclusions— Trephination into the CFS with VCB fenestration is a minimally invasive technique that provides consistent access to the RMS and VCS. It facilitates diagnosis of many sinus disorders and endoscopically guided treatment of many horses with sinus cysts and primary sinusitis, in combination with sinus lavage.
Clinical Relevance— Many diseases affecting the RMS and VCS can be diagnosed and resolved endoscopically using a CFS approach with VCB fenestration, thus avoiding the need for osteoplastic sinus surgery and its associated risks and complications.     

Prevalence of tick-borne encephalitis virus antibodies in dogs from Denmark

Background

Large regions of central and eastern Europe are recognized as areas where tick-borne encephalitis virus (TBEV) is endemic, including countries neighbouring Denmark. It is therefore timely and relevant to determine if TBEV infections occur in Denmark. This study investigates the presence of antibodies against TBEV in a cross-section of the Danish canine population to assess the level of exposure to TBEV and possibly identify TBEV microfoci in Denmark.

Methods

Blood samples were collected from 125 dogs originating from five regions of Denmark between November 2005 and March 2006. Serum was tested by indirect ELISA. All positive and borderline samples were re-evaluated by neutralisation test (NT).

Results

The prevalence of TBEV serocomplex antibodies was 30% by ELISA and 4.8% by NT (with 100%-neutralising capacity). The island of Bornholm was the only area in Denmark with NT positive samples.

Conclusions

The island of Bornholm is an area with a high risk of encountering TBEV microfoci. The presence of TBEV serocomplex antibodies in many sentinel animals from other parts of Denmark points toward existence of other TBEV microfoci. Discrepancies found between ELISA and NT results stress the importance of careful evaluation of serological tests, when interpreting results.     

Elevated temperature (heat stress) in vitro reduces androstenedione and estradiol and increases progesterone secretion by follicular cells from bovine dominant follicles

Dairy cattle are susceptible to heat stress-induced reductions in fertility; however, direct effects of hyperthermia on specific reproductive functions are difficult to determine in vivo. The objective of this experiment was to examine the effect of elevated temperature in vitro on follicular steroidogenesis, to gain insight into specific follicular responses associated with heat stress. Dominant follicles were obtained from Holstein heifers on day 6 post-estrus (luteal phase; n = 4) or day 8, 36 h after an injection with 25 mg PGF(2alpha) to induce regression of the corpus luteum (follicular phase; n = 4). Pieces of follicle wall were isolated from dominant follicles and cultured for 96 h with 0, 2 or 100 ng/ml LH or FSH at 37, 39 or 41 degrees C. Concentrations of androstenedione, estradiol and progesterone were determined in culture media collected every 24h. During the last 48 h of culture, basal secretion of androstenedione and estradiol by pieces of follicle wall was lower at 41 degrees C than at 37 or 39 degrees C (P < 0.05). In contrast, cumulative secretion of progesterone by pieces of follicle wall in medium alone was higher at 41 degrees C than at 37 or 39 degrees C (P < 0.05). Pieces of follicle wall responded to treatment with both low (2 ng/ml) and high (100 ng/ml) doses of gonadotropins at all temperatures. However, gonadotropin-induced secretion of androstenedione and estradiol was generally lower, whereas gonadotropin-induced secretion of progesterone was higher at 41 degrees C and sometimes at 39 than at 37 degrees C. The changes in basal steroidogenesis and in responses to gonadotropins suggest that follicular cells begin to luteinize at elevated temperatures in vitro. Premature luteinization of follicular cells in vivo has been associated with reduced fertility in cattle with persistent follicles, suggesting that the premature differentiation of follicular cells observed in the current study may be responsible, in part, for the reduced fertility of dairy cattle under heat-stressed conditions.     

Climate Change During the Last Deglaciation in Antarctica

Greenland ice core records provide clear evidence of rapid changes in climate in a variety of climate indicators. In this work, rapid climate change events in the Northern and Southern hemispheres are compared on the basis of an examination of changes in atmospheric circulation developed from two ice cores. High-resolution glaciochemical series, covering the period 10,000 to 16,000 years ago, from a central Greenland ice core and a new site in east Antarctica display similar variability. These findings suggest that rapid climate change events occur more frequently in Antarctica than previously demonstrated.     

Estimation of the marbling development pattern in Japanese Black cattle by using serial ultrasound measurement data

The objective of this study was to develop mathematical equations for describing the change in marbling in Japanese Black steers using longitudinal measurements. Serial ultrasound measurements were taken at 14, 16, 20, and 26 months of age and analyzed using an image analysis software. The longitudinal marbling measurements from the ultrasound images and carcasses were fitted into a nonlinear logistic curve. Data used for the analysis consisted of 749 steers that converged in nonlinear curve fitting and showed reasonable estimated parameters of the logistic curves. The average predicted mature beef marbling score (BMS) and maturation rate were 6.26 and 0.353, respectively, and the average maturity levels at 24 months of age were 83.9%. The heritability estimates for the predicted maturity traits were moderate, indicating that these traits may have potential for genetic improvement. There was a negative relationship between the expected progeny differences between carcass BMS and maturity traits, suggesting that genetic improvement by carcass BMS may lead to the selection of bulls with late maturity for marbling. The results indicate that ultrasound and model building for marbling can be useful tools to correctly select candidate bulls with high marbling in the early fattening period.     

Neural mechanisms for the coordination of duet singing in wrens

Plain-tailed wrens (Pheugopedius euophrys) cooperate to produce a duet song in which males and females rapidly alternate singing syllables. We examined how sensory information from each wren is used to coordinate singing between individuals for the production of this cooperative behavior. Previous findings in nonduetting songbird species suggest that premotor circuits should encode each bird's own contribution to the duet. In contrast, we find that both male and female wrens encode the combined cooperative output of the pair of birds. Further, behavior and neurophysiology show that both sexes coordinate the timing of their singing based on feedback from the partner and suggest that females may lead the duet.