High geomagnetic intensity during the mid-Cretaceous from Thellier analyses of single plagioclase crystals

Recent numerical simulations have yielded the most efficient geodynamo, having the largest dipole intensity when reversal frequency is low. Reliable paleointensity data are limited but heretofore have suggested that reversal frequency and paleointensity are decoupled. We report data from 56 Thellier-Thellier experiments on plagioclase crystals separated from basalts of the Rajmahal Traps (113 to 116 million years old) of India that formed during the Cretaceous Normal Polarity Superchron. These data suggest a time-averaged paleomagnetic dipole moment of 12.5 +/- 1.4 x 10(22) amperes per square meter, three times greater than mean Cenozoic and Early Cretaceous-Late Jurassic dipole moments when geomagnetic reversals were frequent. This result supports a correlation between intervals of low reversal frequency and high geomagnetic field strength.     

Validation of ultrasonography in detecting structural disease of the urogenital tract of the koala,Phascolarctos cinereus

A retrospective review of case records of ultrasonography and necropsy outcomes of 62 koalas was used to investigate the accuracy of ultrasonography in assessing koala urogenital tract structural disease at the Port Macquarie Koala Hospital. The results showed high concordance, supporting ultrasonography as an effective tool for evaluating structural disease of the koala urogenital tract, most commonly seen with chlamydiosis. The study also illustrates the advances benefiting animal welfare that can be made by wildlife carer groups through using a scientific, evidence‐based approach.     

Kinematic Motion Patterns of the Cranial and Caudal Canine Cervical Spine

Objective: To define the kinematic motion patterns of the canine cervical spine, with a particular emphasis on identifying differences between the cranial (C₂–C₄) and caudal (C₅–C₇) segments, and to determine the significance of coupled motions (CM) in the canine cervical spine. Study Design: Cadaveric biomechanical study. Sample Population: Cervical spines of 8 Foxhounds. Methods: Spinal specimens were considered free of pathology based on radiographic, computed tomography, and magnetic resonance imaging examinations. All musculature was removed without damaging ligaments or joint capsules. Spines were mounted in a customized pure‐moment spine testing jig, and data were collected using an optoelectronic motion capture system. Range of motion, neutral zone and CM in flexion/extension, left/right lateral bending and left/right axial rotation were established. Data were analyzed using mixed‐effects maximum likelihood regression models. Results: Total flexion/extension did not change across the 4 levels. There was no difference between flexion and extension, and no CM was identified. Lateral bending was not different across levels, but tended to be greater in the cranial spine. Axial rotation was ～2.6 times greater in the caudal segments. Lateral bending and axial rotation were coupled. Conclusions: Kinematics of the cranial and caudal cervical spine differed markedly with greater mobility in the caudal cervical spine.     

Cholinergic activity of intestinal musclein vitro taken from horses with and without equine grass sickness

Equine grass sickness (EGS) is a pan-dysautonomia of horses that involves central and peripheral neuronal degeneration and ultimately depletion. This is the first reported functional study on the motility of equine intestine taken immediatelypost mortem from horses with EGS. Strips of smooth muscle from the small intestine of healthy and EGS-affected horses were suspended in an organ bath and their motility was measured isometrically. The activity of the cholinergic system was studied. Physostigmine enhanced the motility of all muscle strips. Tissues taken from horses suffering from acute grass sickness (AGS) had the longest latency before a measurable response could be obtained (p<0.05). The ileum appeared to be damaged by EGS to a greater extent than the duodenum. For the duodenal strips the enhanced rate of spontaneous contractions was significant (p<0.05) for both normal tissue and that affected by grass sickness but this was not the case for the ileal strips. Muscarinic receptor sensitivity investigation using bethanecol suggested a hypersensitivity of receptors with AGS material,Abbreviations AGS acute grass sickness - CGS chronic grass sickness - ED₅₀ median effective dose - EGS equine grass sickness - VIP vasoactive intestinal peptide     

Anaesthesia with ketamine/medetomidine in the rabbit: influence of route of administration and the effect of combination with butorphanol

Objective To compare the characteristics of anaesthesia induced with ketamine/medetomidine administered by the subcutaneous and intramuscular routes and to assess the effects of the addition of butorphanol to this combination. Study design Prospective randomised study. Animals Six female New Zealand White rabbits. Methods Rabbits were given one of four combinations of ketamine and medetomidine (K/M) either subcutaneously (SC) or intramuscularly (IM) on four successive occasions with a 7‐day interval between treatments. The dose combinations were; 15/0.25 mg kg^?1 SC; 15/0.25 mg kg^?1 IM; 15/0.5 mg kg^?1 SC, and 15/0.25 mg kg^?1 together with 0.4 mg kg^?1 butorphanol (K/M/B) SC. The effects of anaesthesia on arterial blood gas values and cardiovascular variables were recorded at predetermined time points. Toe and ear pinch reflexes were judged to determine the duration of surgical anaesthesia. Loss of the righting reflex was used to measure the duration of sleep time. Analyses used repeated measures analysis of variance. Results All groups lost the righting reflex and ear pinch response. Three animals in the groups that received K/M alone lost their toe pinch reflex, whereas four lost this reflex when given K/M/B. Time of onset of loss of the righting, toe and ear pinch reflexes did not differ significantly among the groups. The higher dose combination of medetomidine with ketamine and the combination of K/M/B produced a greater duration of loss of the ear pinch response than the lower dose of K/M administered by either route. No significant differences were found among the groups in the duration of loss of the toe pinch reflex. All animals developed a moderate bradycardia (mean heart rate <166 beats minute^?1) and moderate hypoxaemia (mean P_aO₂ < 6.0 kPa). Animals given butorphanol showed the greatest reduction in respiratory rate (31 ± 13 breaths minute^?1, p < 0.05) but this was not reflected in any significant differences in arterial PCO₂, PO₂ or pH among the groups. Conclusions Administration of K/M by the SC route produced equivalent effects in comparison to intramuscular administration. The addition of butorphanol increased the duration of anaesthesia, but produced a slight increase in the degree of respiratory depression. All dose rates resulted in hypoxaemia so oxygen should be administered when these combinations are used in rabbits. Clinical relevance Subcutaneous administration is both technically simpler and may cause less discomfort to the animal than IM injection, and so is preferred. The combination of K/M with butorphanol has relatively minor effects on the depth and duration of anaesthesia, so offers little advantage to the use of K/M alone.