Effects of Density and Rest Stops on Movement Rates of Unrestrained Horses during Transport

The goal of this study was to provide estimates of how much loose (unrestrained) horses move during transport. Data were collected from six shipments of slaughter horses that were transported in a 16.2-m, single-deck semi-trailer in June and July of 2004 for 18 to 20 hours as part of an earlier project. Usable video was obtained from five groups of mature horses transported at “low” density (five to seven horses per group averaging 216.5 kg/m²) and three groups of horses transported at “moderate” density (10–11 horses per group averaging 345.5 kg/m²). Three low-density and two moderate-density groups had access to six water bowls inserted through the sides of the compartments during 1-hour rest stops occurring after 8 hours and at the end of transport. Twelve cameras, one mounted in each corner of the three compartments, were used to record behavior. Distance and rate of movement by individual horses during transport and during two 1-hour rest periods were determined by analysis of 206 hours of usable video footage of individual horses. Mean movement rate tended to be higher during travel (4.23 m/hour) than during the 1-hour periods when the truck was stopped (2.75 m/hour), but it did not seem to be influenced by group density. Movement was stimulated by the availability of water during the rest stops. In general, movement was strongly influenced by one or two horses causing disruption of the group, and not by independent actions of members of the group.     

Modulation of nociceptive withdrawal reflexes evoked by single and repeated nociceptive stimuli in conscious dogs by low-dose acepromazine

ObjectivesTo investigate the modulation of the nociceptive withdrawal reflex (NWR) and temporal summation (TS) by low‐dose acepromazine (ACP) in conscious dogs. To assess the short‐ and long‐term stability of the reflex thresholds.Study designRandomized, blinded, placebo‐controlled cross‐over experimental study.AnimalsEight adult male Beagles.MethodsThe NWR was elicited using single transcutaneous electrical stimulation of the ulnar nerve. Repeated stimuli (10 pulses, 5 Hz) were applied to evoke TS. The responses of the deltoideus muscle were recorded and quantified by surface electromyography and the behavioural reactions were scored. Each dog received 0.01 mg kg^?1 ACP or an equal volume saline intravenously (IV) at 1 week intervals. Measurements were performed before (baseline) and 20, 60 and 100 minutes after drug administration. Sedation was scored before drug administration and then at 10 minutes intervals. Data were analyzed with Friedman repeated measures analysis of variance on ranks and Wilcoxon signed rank tests.ResultsAcepromazine resulted in a mild tranquilization becoming obvious at 20 minutes and peaking 30 minutes after injection. Single (I_t) and repeated stimuli (TS_t) threshold intensities, NWR and TS characteristics and behavioural responses were not affected by the ACP at any time point. Both I_t and TS_t were stable over time.Conclusions and clinical relevanceIn dogs, 0.01 mg kg^?1 ACP IV had no modulatory action on the NWR evoked by single or repeated stimuli, suggesting no antinociceptive activity on phasic nociceptive stimuli. The evidence of the stability of the NWR thresholds supports the use of the model as an objective tool to investigate nociception in conscious dogs. A low dose of ACP administered as the sole drug, can be used to facilitate the recordings in anxious subjects without altering the validity of this model.     

Effect of lidocaine on the minimum alveolar concentration of sevoflurane in dogs

Objective  To investigate the effects of a low-dose constant rate infusion (LCRI; 50 μg kg⁻¹ minute⁻¹) and high-dose CRI (HCRI; 200 μg kg⁻¹ minute⁻¹) lidocaine on arterial blood pressure and on the minimum alveolar concentration (MAC) of sevoflurane (Sevo), in dogs.
Study design  Prospective, randomized experimental design.
Animals  Eight healthy adult spayed female dogs, weighing 16.0 ± 2.1 kg.
Methods  Each dog was anesthetized with sevoflurane in oxygen and mechanically ventilated, on three separate occasions 7 days apart. Following a 40-minute equilibration period, a 0.1-mL kg⁻¹ saline loading dose or lidocaine (2 mg kg⁻¹ intravenously) was administered over 3 minutes, followed by saline CRI or lidocaine LCRI or HCRI. The sevoflurane MAC was determined using a tail clamp. Heart rate (HR), blood pressure and plasma concentration of lidocaine were measured. All values are expressed as mean ± SD.
Results  The MAC of Sevo was 2.30 ± 0.19%. The LCRI reduced MAC by 15% to 1.95 ± 0.23% and HCRI by 37% to 1.45 ± 0.21%. Diastolic and mean pressure increased with HCRI. Lidocaine plasma concentration was 0.84 ± 0.18 for LCRI and 1.89 ± 0.37 μg mL⁻¹ for HCRI. Seventy-five percent of HCRI dogs vomited during recovery.
Conclusion and clinical relevance  Lidocaine infusions dose dependently decreased the MAC of Sevo, did not induce clinically significant changes in HR or arterial blood pressure, but vomiting was common during recovery in HCRI.     

外源NO对非洲菊切花保鲜效果及作用机制

以硝普钠(SNP)作为外源NO的供体,分别采用0,10,100,500μmol·L-1浓度的SNP溶液作为非洲菊‘阳光海岸’的瓶插液,观察NO对非洲菊鲜切花的保鲜效果.同时,测定了花瓣超氧化物歧化酶(SOD),过氧化物酶(POD)、过氧化氧酶(CAT)活性的变化以及H2O2、丙二醛(MDA)、可溶性蛋白含量的变化.结果显示,100μmol·L-1浓度处理的非洲菊切花瓶插寿命最长,比对照延长了31.4％;外源NO提高了花瓣SOD,POD,CAT等保护酶的活性,也提高了可溶性蛋白质的含量,而H2O2,MDA含量比对照降低,从而延缓了非洲菊切花花瓣的衰老.     

Subtidal macrozoobenthic assemblages along the River Minho estuarine gradient (north‐west Iberian Peninsula)

• 1. The community composition and spatial distribution of the macrobenthic fauna in relation to abiotic factors was investigated at 20 sites along the River Minho estuarine gradient, in the north‐west Iberian Peninsula.
• 2. A total of 68 taxa were identified and the non‐indigenous invasive species Corbicula fluminea dominated both numerically (43.1%) and by biomass (97.7%).
• 3. Multivariate analysis identified spatial differences in structure and composition of assemblages and suggests a continuum between five distinct assemblages along the length of the estuary. This situation fits the two‐ecocline model in which an ecocline from the sea to mid‐estuary overlaps with an ecocline from freshwater to mid‐estuary.
• 4. Each assemblage was found in a particular physico‐chemical environment and had a specific composition. The distribution and diversity patterns were linked to salinity. However, inside each assemblage the sediment characteristics (granulometry and organic matter content) played an important role.
• 5. The highest abundances, biomasses and total species numbers were recorded from upstream freshwater tidal areas, indicating the importance of these habitats within estuarine ecosystems.

Copyright © 2007 John Wiley & Sons, Ltd.     

MAGNETIC RESONANCE IMAGING OF ARTICULAR PROCESS JOINT GEOMETRY AND INTERVERTEBRAL DISK DEGENERATION IN THE CAUDAL LUMBAR SPINE (L5–S1) OF DOGS WITH CLINICAL SIGNS OF CAUDA EQUINA COMPRESSION

The geometry of the lumbosacral region has been suspected to play a role in the development of degenerative lumbosacral stenosis in the dog. In this study, 50 dogs (21 German Shepherd dogs and 29 dogs of other breeds) with clinical signs of cauda equina compression were studied by magnetic resonance (MR) imaging. The orientation of the articular process joints in the L5-S1 region and the angle difference between two adjacent motion segments were calculated. Intervertebral disc degeneration of the same region was identified and classified in four stages. A positive association between MR-imaging stage and articular process joint angle difference in the transverse plane was found in the two groups of animals. German Shepherd dogs and dogs of other breeds had different geometry of the lumbosacral region with different articular process joint angles in the transverse plane and statistically different stages of disc degeneration.     

Continuous infusion of ketamine in hypovolemic dogs anesthetized with desflurane

Objective: To evaluate the cardiorespiratory effects of continuous infusion of ketamine in hypovolemic dogs anesthetized with desflurane. Design: A prospective experimental study. Animals: Twelve mixed breed dogs allocated into 2 groups: saline (n=6) and ketamine (n=6). Interventions: After obtaining baseline measurements (time [T] 0) in awake dogs, hypovolemia was induced by the removal of 40 mL of blood/kg over 30 minutes. Anesthesia was induced and maintained with desflurane (1.5 minimal alveolar concentration) and 30 minutes later (T75) a continuous intravenous (IV) infusion of saline or ketamine (100 μg/kg/min) was initiated. Cardiorespiratory evaluations were obtained 15 minutes after hemorrhage (T45), 30 minutes after desflurane anesthesia, and immediately before initiating the infusion (T75), and 5 (T80), 15 (T90), 30 (T105) and 45 (T120) minutes after beginning the infusion. Measurements and main results: Hypovolemia (T45) reduced the arterial blood pressures (systolic arterial pressure, diastolic arterial pressure [DAP] and mean arterial pressure [MAP]), cardiac (CI) and systolic (SI) indexes, and mean pulmonary arterial pressure (PAP) in both groups. After 30 minutes of desflurane anesthesia (T75), an additional decrease of MAP in both groups was observed, heart rate was higher than T0 at T75, T80, T90 and T105 in saline‐treated dogs only, and the CI was higher in the ketamine group than in the saline group at T75. Five minutes after starting the infusion (T80), respiratory rate (RR) was lower and the end‐tidal CO₂ (ETCO₂) was higher compared with values at T45 in ketamine‐treated dogs. Mean values of ETCO₂ were higher in ketamine than in saline dogs between T75 and T120. The systemic vascular resistance index (SVRI) was decreased between T80 and T120 in ketamine when compared with T45. Conclusions: Continuous IV infusion of ketamine in hypovolemic dogs anesthetized with desflurane induced an increase in ETCO₂, but other cardiorespiratory alterations did not differ from those observed when the same concentration of desflurane was used as the sole anesthetic agent. However, this study did not evaluate the effectiveness of ketamine infusion in reducing desflurane dose requirements in hypovolemic dogs or the cardiorespiratory effects of ketamine–desflurane balanced anesthesia.     

First Report of an Outbreak of African Horsesickness Virus Serotype 2 in the Northern Hemisphere

A case of a rapidly fatal disease in polo horses caused by African horsesickness (AHS) virus serotype 2 is described. The pattern of polo tournaments, environmental/management conditions (moist and warm), as well as probable importation strategies with no regard for import control and quarantine, favored introduction and spread of the virus. The outbreak, which involved a large number of horses, was characterized by severe respiratory distress, fever, supraorbital edema, and death. This is the first time a widespread epidemic of AHS has been reported in Nigeria and this is the first report of AHSV serotype 2 in the northern hemisphere. In addition, we amplified the complete genome of the virus using RNA extracted from clotted blood. This report indicates that AHS is expanding its geographical territory northwards and assuming a new microbial ecology.