排序方式： 共有35条查询结果，搜索用时 15 毫秒
11.
W. Ullmann C. Fischer K. Pirhofer-Walzl S. Kramer-Schadt N. Blaum 《Landscape Ecology》2018,33(9):1505-1517
Context
Movement is one of the key mechanisms for animals to deal with changes within their habitats. Therefore, resource variability can impact animals’ home range formation, especially in spatially and temporally highly dynamic landscapes, such as farmland. However, the movement response to resource variability might depend on the underlying landscape structure.Objectives
We investigated whether a given landscape structure affects the level of home range size adaptation in response to resource variability. We tested whether increasing resource variability forces herbivorous mammals to increase their home ranges.Methods
In 2014 and 2015 we collared 40 European brown hares (Lepus europaeus) with GPS-tags to record hare movements in two regions in Germany with differing landscape structures. We examined hare home range sizes in relation to resource availability and variability by using the normalized difference vegetation index as a proxy.Results
Hares in simple landscapes showed increasing home range sizes with increasing resource variability, whereas hares in complex landscapes did not enlarge their home range.Conclusions
Animals in complex landscapes have the possibility to include various landscape elements within their home ranges and are more resilient against resource variability. But animals in simple landscapes with few elements experience shortcomings when resource variability becomes high. The increase in home range size, the movement related increase in energy expenditure, and a decrease in hare abundances can have severe implications for conservation of mammals in anthropogenic landscapes. Hence, conservation management could benefit from a better knowledge about fine-scaled effects of resource variability on movement behaviour.12.
Organogenesis and foetal haemodynamics during the normal gestation of healthy black‐rumped agoutis (Dasyprocta prymnolopha,Wagler, 1831) bred in captivity 
下载免费PDF全文
下载免费PDF全文 FCA Sousa GT Pessoa LS Moura JR Araújo RPS Rodrigues MAPS Barbosa AN Diniz AB Souza EG Silva LU Lucena MP Sanches OF Silva‐Filho PC Guerra JM Sousa WC Neves FR Alves 《Reproduction in domestic animals》2017,52(1):60-66
The objective of this study was to define the patterns of organogenesis and foetal haemodynamics during the normal gestation of healthy agoutis (Dasyprocta prymnolopha) kept in captivity. Thirty pregnant agoutis that ranged in size from small to medium and weighed between 2.5 and 3 kg underwent B‐mode and Doppler ultrasonography for the biometric evaluation of the foetal organs. The foetal aortic blood flow proved to be predominantly systolic, and the measured flow velocity was 78.89 ± 2.95 cm/s, with a maximum pressure gradient of 2.12 ± 0.27 mmHg. The liver was characterized by its large volume, occupying the entire cranial aspect of the abdominal cavity, and it was associated cranially with the diaphragm and caudally with the stomach. The flow velocity in the portal vein was estimated to equal 12.17 ± 2.37 cm/s, with a resistivity index of 0.82 ± 0.05. The gallbladder was centrally located and protruded cranially towards the diaphragm. The spleen was visualized as an elongated structure with tapered cranial and caudal extremities, and the foetal kidneys were visualized bilaterally in the retroperitoneal region, with the right kidney positioned slightly more cranially than the left. The morphological characterization and hemodynamic analysis of the foetal organs of black‐rumped agoutis via B‐mode and Doppler ultrasonography allow determination of the vascular network and of reference values for the blood flow required for perfusing the anatomical elements essential for maintaining the viability of foetuses at different gestational ages. 相似文献
13.
The use of analgesics in post‐operative adhesion (POA) research is problematic due to POA‐inhibiting effects of anti‐inflammatory agents and bowel motility‐inhibiting effects of opioids, which may increase adhesion formation. This study was conducted to assess a buprenorphine (BUP) protocol for analgesic efficacy and its effects on POA formation in a rat cecal abrasion model. The protocol was approved by the University of Florida's Institutional Animal Care and Use Committee (IACUC). Forty‐one female Sprague‐Dawley rats were randomized into two groups (n = 20 or 21 group). Body weight, food and water intake were recorded daily from 2 days before until 7 days after surgery. Treatment rats received 0.05 mg kg–1 BUP SQ at anesthesia induction and 0.3 mg kg–1 BUP orally in flavored gelatin 6 hours after surgery. Control rats received saline placebo injection and plain gelatin. All rats underwent laparotomy and controlled cecal abrasion. At 3, 6 and 24 hours post‐operatively rats were individually observed in 10‐minutes periods for pain related behavior incidence: ‘twitch’ (contraction of muscles along dorsum and/or head), ‘back arch’ (cat‐like position with front legs extended and pushing backward), ‘writhe’ (flank contraction), and ‘stagger/fall’ (momentary loss of balance while grooming or ambulating), using the method of Roughan and Flecknell (Pain 2001,90, 65–74). On post‐op day seven rats were euthanized by CO2 inhalation and POA evaluated (0 to 4 scale; ³Grade 2 = clinically significant.) BUP treated rats had lower mean pain scores than control rats at 3 hours (1.6 ± 1.7 versus 20.3 ± 13.5 (mean ± SD); p < 0.001) and 6 hours (2.1 ± 2.7 versus 23.7 ± 12.9; p < 0.001) but not 24 hours (1.5 ± 1.3 versus 4.9 ± 6.6; p = 0.35) post‐operatively. Predominant pain behavior was ‘writhe’ (flank contraction) in contrast to ‘twitch,’‘back arch,’ and ‘stagger/fall’ reported as most common pain indicators in other rat strains. BUP rats had greater mean adhesion incidence (2.4 ± 1.7 versus 1.4 ± 1.8; p < 0.03) and severity (90%³Gr.2 versus 65% of controls; p < 0.05). The BUP protocol appeared to provide effective analgesia for at least 24 hours post‐operatively. Strain of rat may affect pain related behavior. BUP should be used with caution after abdominal surgical procedures having high risk of POA formation. 相似文献
14.
Mayer Martin Ullmann Wiebke Heinrich Rebecca Fischer Christina Blaum Niels Sunde Peter 《Landscape Ecology》2019,34(10):2279-2294
Landscape Ecology - Human land use intensified over the last century and simultaneously, extreme weather events have become more frequent. However, little is known about the interplay between... 相似文献
15.
16.
KC Silva‐Santos GMG Santos C Koetz Júnior F Morotti LS Siloto TN Marcantonio MR Urbano RL Oliveira DCM Lima MM Seneda 《Reproduction in domestic animals》2014,49(2):228-232
Interest in indicus–taurus cattle has been increasing, as these animals are likely to present the best characteristics of Zebu and European bovine breeds. The aim of this study was to compare the embryo production of indicus–taurus donors with high vs low antral follicle counts obtained by ovum pickup/in vitro production (OPU/IVP) and superovulation (SOV)/embryo collection. Braford females at weaning age (3/8 Nelore × 5/8 Hereford, n = 137, 9 ± 1 month old) were subjected to six serial ovarian ultrasonographs and were assigned to two groups according to the number of antral follicles ≥3 mm as follows: G‐High antral follicular count (AFC, n = 20, mean ≥40 follicles) and G‐Low AFC (n = 20, mean ≤10 follicles). When the females (n = 40) reached 24 months of age, they were subjected to both OPU/IVP and SOV/embryo collection. The average number of follicles remained highly stable throughout all of the ultrasound evaluations (range 0.90–0.92). The mean number of COCs recovered (36.90 ± 13.68 vs 5.80 ± 3.40) was higher (p < 0.05) for females with high AFC, resulting in higher (p < 0.05) numbers of total embryos among females with high vs low AFC (6.10 ± 4.51 vs 0.55 ± 0.83). The mean number of embryos per collection was also higher (p < 0.05) for G‐High vs G‐Low (6.95 ± 5.34 vs 1.9 ± 2.13). We conclude that a single ultrasound performed at pre‐pubertal ages to count antral follicles can be used as a predictor of embryo production following IVP and SOV/embryo collection in indicus–taurus females. 相似文献
17.
18.
19.
LS Barter JE Ilkiw EP Steffey BH Pypendop A Imai JA Bolich 《Veterinary anaesthesia and analgesia》2003,30(2):105-105
Minimum alveolar concentration (MAC) of an inhalant is an indicator of its anesthetic potency. Individuals vary in their sensitivity to anesthetic agents as demonstrated by different individual MAC values. We hypothesized that individual animal sensitivity would be maintained with different inhalant anesthetics. As part of separate studies, six female DSH cats, aged 24 ± 2.5 (mean ± SD) months and weighing 3.5 ± 0.3 kg, were studied similarly on three separate occasions over a 12‐month period to determine the MAC of isoflurane (ISO), sevoflurane (SEVO), and desflurane (DES), respectively. In each study, chamber induction was followed by orotracheal intubation, and anesthesia was maintained via a nonrebreathing circuit. ECG, pulse oximetry, Doppler systolic blood pressure, end‐tidal gases, and esophageal temperature were monitored. End‐tidal gases were hand‐sampled from a catheter whose tip lay level with the distal end of the ET tube. Gases were analyzed by Raman spectrometry and, for each agent, the analyzer was calibrated with at least three gas standards. MAC was determined in triplicate using standard tail‐clamp technique. Data were analyzed by two‐way anova followed by Tukey's test and significant differences were found. Average MACs (%) for ISO, SEVO, and DES were 1.90 ± 0.18, 3.41 ± 0.65, and 10.27 ± 1.06, respectively. Body temperatures, Doppler systolic blood pressure, and SpO2 were recorded at the time of MAC determinations for ISO, SEVO, and DES were 38.3 ± 0.3, 38.6 ± 0.1, 38.3 ± 0.35 °C; 71 ± 8, 75 ± 16, 88 ± 12 mm Hg; 99 ± 1, 99 ± 1, 99 ± 1%, respectively. Both the anesthetic agent and the individual cat had significant effects on MAC (p = 0.0001 and 0.0185, respectively). MAC varied between individuals and cats were consistent in their order of sensitivity to inhalant anesthetics across the three agents. Within this group of cats, the relationship of individual MAC to the group MAC for each of the three inhalant agents was maintained. This suggests that any individual may be consistently more or less sensitive to a variety of inhalant agents. 相似文献
20.
Two non-destructive techniques for estimating herbage mass (dry matter yield) were evaluated during the growing season of 1988, from April to September. Samples were collected from four sites, with ten observations made on twenty-five days at each site, giving a total of 612 sample units. Observations were obtained from each unit, either with a plastic rising-plate meter (335) or with a metal rising-plate meter (227). In addition, measurements with a single-probe capacitance meter (Pasture Probe) were also made on all units. The usefulness of the non-destructive methods for predicting the actual yield was evaluated by calibrating them by means of regression on the yield determined by mowing 1·5-m2 quadrats, weighing, subsampling and drying the grass. The yield measurements were logarithmically transformed to correct for the proportionality of the residual variance with the mowed dry matter yield. Logarithmic transformation of the sensor measurements improved the linearity of the calibration relationships. The combination of one rising-plate meter and the Pasture Probe resulted in a linear and additive model with a larger adjusted R2 than models with just one of these two sensors. The addition of the predictors ‘external moisture’ (e.g. dew), ‘day number after mowing’ and ‘site number’ significantly increased the goodness of fit of many models. In some models addition of the logarithm of the ‘dry matter percentage’ was significant. Other predictors in these models such as “Julian day number” and “grazing” proved not to be significant. The adjusted R2s in the best models for the metal and the plastic discs were 89·7% and 87·3% respectively. The corresponding coefficients of variation were 26·2% and 26·1%. The results show that further research is necessary to refine the techniques or to develop new techniques to estimate the dry matter yield, before the sensors can be usefully integrated into a management system. 相似文献