Survey of horse transportation in Australia: issues and practices          下载免费PDF全文

B Padalino  SL Raidal  E Hall  P Knight  P Celi  L Jeffcott  G Muscatello 《Australian veterinary journal》2016,94(10):349-357

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Convergence of microclimate in residential landscapes across diverse cities in the United States     

Sharon J. Hall  J. Learned  B. Ruddell  K. L. Larson  J. Cavender-Bares  N. Bettez  P. M. Groffman  J. M. Grove  J. B. Heffernan  S. E. Hobbie  J. L. Morse  C. Neill  K. C. Nelson  J. P. M. O’Neil-Dunne  L. Ogden  D. E. Pataki  W. D. Pearse  C. Polsky  R. Roy Chowdhury  M. K. Steele  T. L. E. Trammell 《Landscape Ecology》2016,31(1):101-117

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Long-term feed intake regulation in sheep is mediated by opioid receptors     

Obese FY  Whitlock BK  Steele BP  Buonomo FC  Sartin JL 《Journal of animal science》2007,85(1):111-117

These experiments were conducted to determine if 1) syndyphalin-33 (SD33), a mu-opioid receptor ligand, affects feed intake; 2) SD33 effects on feed intake are mediated by actions on opioid receptors; and 3) its activity can counteract the reduction in feed intake associated with administration of bacterial endotoxin. In Exp. 1, 5 mixed-breed, castrate male sheep were housed indoors in individual pens. Animals had ad libitum access to water and concentrate feed. Saline (SAL; 0.9% NaCl) or SD33 (0.05 or 0.1 micromol/kg of BW) was injected i.v., and feed intake was determined at 2, 4, 6, 8, 24, and 48 h after the i.v. injections. Both doses of SD33 increased (at least P < 0.01) feed intake at 48 h relative to saline. In Exp. 2, SAL + SAL, SAL + SD33 (0.1 micromol/kg of BW), naloxone (NAL; 1 mg/kg of BW) + SAL, and NAL + SD33 were injected i.v. Food intake was determined as in Exp. 1. The SAL + SD33 treatment increased (P = 0.022) feed intake at 48 h relative to SAL + SAL. The NAL + SAL treatment reduced (at least P < 0.01) feed intake at 4, 6, 8, 24, and 48 h, whereas the combination of NAL and SD33 did not reduce feed intake at 24 (P = 0.969) or 48 h (P = 0.076) relative to the saline-treated sheep. In Exp. 3, sheep received 1 of 4 treatments: SAL + SAL, SAL + 0.1 micromol of SD33/kg of BW, 0.1 microg of lipopolysaccharide (LPS)/kg of BW + SAL, or LPS + SD33, and feed intake was monitored as in Exp. 1. Lipopolysaccharide suppressed cumulative feed intake for 48 h (P < 0.01) relative to saline control, but SD33 failed to reverse the reduction in feed intake during this period. These data indicate that SD33 increases feed intake in sheep after i.v. injection, and its effects are mediated via opioid receptors. However, the LPS-induced suppression in feed intake cannot be overcome by the opioid receptor ligand, SD33.  相似文献   

Effect of cow urine upon denitrification     

A.W. Limmer  K.W. Steele 《Soil biology & biochemistry》1983,15(4):409-412

The influence of urine application upon the zone and rate of denitrification of a pastoral soil was studied using a short term incubation technique. Under the condition of full enzyme induction, no increase in denitrification activity was measured with the addition of cow urine. The zone of maximum denitrification activity was within the top 30 mm and did not shift with increasing C and N substrate at the 60–90 mm depth.  相似文献   

Environmental monitoring using populations of birds and small mammals: Analyses of sampling effort     

Benjamin B. Steele  Robert L. Bayn  C. Val Grant 《Biological conservation》1984,30(2):157-172

Characteristics of bird and small mammal communities can be valuable in monitoring for impacts on specific plots of land. In Utah (USA), significant differences were found among years, habitats and seasons in bird and small mammal abundance, species diversity, and species richness; thus, estimates of these characteristics are consistent and repeatable and can be used for detecting change. Also, bird and small mammal communities are dependent on a wide variety of food resources and habitat characteristics; thus they should reflect a variety of impacts.A comparison is made between two methods of handling bird data from transects: enumeration (individual birds per km) and density (birds per unit area). Correlation between the two was high (r = 0·93). However, density estimates may be necessary to trace an impact to a particular group, guild or species and possibly to its cause.An analysis is made of how much sampling is necessary to make an adequate estimate of the characteristics of bird and small mammal communities. Estimates of bird abundance, species richness and species diversity (from enumeration) may be obtained with three repetitions of 2 km of transect. Three repetitions are also sufficient to estimate abundance of small mammals on 12 by 12 trapping grids. To estimate species richness and species diversity, however, four or more repetitions are needed. Small mammal community characteristics are not well predicted by trapping on transects or small grids except in grids 9 by 9 or larger. These results of sampling effort may only apply to certain habitats but data from bird and small mammal communities should be useful in environmental monitoring at any site.  相似文献   

Surgical correction of rectovaginal fistula in mares and subsequent fertility     

SL Jalim  AO McKinnon 《Australian veterinary journal》2010,88(6):211-214

Objective To evaluate the fertility of mares bred at various intervals relative to surgical management of rectovaginal fistula (RVF). Materials and Methods Surgical repair of RVF was performed in 28 mares at variable times relative to foaling (30 days to 24 months) and also relative to rebreeding (same cycle or delayed). Postoperative fertility was then evaluated. Results Two mares were already pregnant at the time of surgery and 20 of 23 mares (87%) that were bred immediately prior to or following surgery conceived from their first service. When mares were bred in the same cycle as surgery, the next cycle following surgery or in the following breeding season after surgery the pregnancy rate was 5/5, 5/6 and 10/12, respectively, and the foaling rates were 4/5, 4/6 and 7/12. The two mares already pregnant at the time of surgery foaled successfully. Conclusions Excellent fertility can be achieved following surgical repair of RVF and our results suggest that delaying breeding until the following breeding season is not necessary. In addition, breeding in the same cycle as the surgical repair is a previously unreported technique that should be considered to maintain normal fertility and a yearly foaling interval.  相似文献   

A reduced organic carbon component in martian basalts     

Steele A  McCubbin FM  Fries M  Kater L  Boctor NZ  Fogel ML  Conrad PG  Glamoclija M  Spencer M  Morrow AL  Hammond MR  Zare RN  Vicenzi EP  Siljeström S  Bowden R  Herd CD  Mysen BO  Shirey SB  Amundsen HE  Treiman AH  Bullock ES  Jull AJ 《Science (New York, N.Y.)》2012,337(6091):212-215

The source and nature of carbon on Mars have been a subject of intense speculation. We report the results of confocal Raman imaging spectroscopy on 11 martian meteorites, spanning about 4.2 billion years of martian history. Ten of the meteorites contain abiotic macromolecular carbon (MMC) phases detected in association with small oxide grains included within high-temperature minerals. Polycyclic aromatic hydrocarbons were detected along with MMC phases in Dar al Gani 476. The association of organic carbon within magmatic minerals indicates that martian magmas favored precipitation of reduced carbon species during crystallization. The ubiquitous distribution of abiotic organic carbon in martian igneous rocks is important for understanding the martian carbon cycle and has implications for future missions to detect possible past martian life.  相似文献   

Susceptibility to scrapie and disease phenotype in sheep: cross-PRNP genotype experimental transmissions with natural sources     

González L  Jeffrey M  Dagleish MP  Goldmann W  Sisó S  Eaton SL  Martin S  Finlayson J  Stewart P  Steele P  Pang Y  Hamilton S  Reid HW  Chianini F 《Veterinary research》2012,43(1):55

It has long been established that the sheep Prnp genotype influences the susceptibility to scrapie, and some studies suggest that it can also determine several aspects of the disease phenotype. Other studies, however, indicate that the source of infection may also play a role in such phenotype. To address this question an experiment was set up in which either of two different natural scrapie sources, AAS from AA₁₃₆ Suffolk and VVC from VV₁₃₆ Cheviot sheep, were inoculated into AA₁₃₆, VA₁₃₆ and VV₁₃₆ sheep recipients (n = 52). The immunohistochemical (IHC) profile of disease-associated PrP (PrP^d) accumulation in the brain of recipient sheep was highly consistent upon codon 136 homologous and semi-homologous transmission, but could be either similar to or different from those of the inoculum donors. In contrast, the IHC profiles were highly variable upon heterologous transmission (VVC to AA₁₃₆ and AAS to VV₁₃₆). Furthermore, sheep of the same Prnp genotype could exhibit different survival times and PrP^d profiles depending on the source of infection, and a correlation was observed between IHC and Western blot profiles. It was found that additional polymorphisms at codons 112 or 141 of AA₁₃₆ recipients resulted in a delayed appearance of clinical disease or even in protection from infection. The results of this study strongly suggest that the scrapie phenotype in sheep results from a complex interaction between source, donor and recipient factors, and that the Prnp genotype of the recipient sheep does not explain the variability observed upon codon 136 heterologous transmissions, arguing for other genetic factors to be involved.  相似文献   

SEASONAL VARIATION IN HEPATIC MICROSOMAL OXIDATIVE METABOLISM IN VITRO AND SUSCEPTIBILITY TO CARBON TETRACHLORIDE IN A FLOCK OF SHEEP     

A. A. Seawright  BVSc.Ph.D.  D. P. Steele  Dip.Ind.Chem. R. E. Menrath  B.Sc. 《Australian veterinary journal》1972,48(9):488-494

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Hyperkalemic periodic paralysis, plasma lactate and exercise tolerance     

Deborah S. Steele BSc  Jonathan M. Naylor BVSc  PhD 《Journal of Equine Veterinary Science》1996,16(8):327-333

The purpose of this, trial was to determine the effect of hyperkalemic periodic paralysis (HYPP) on exercise tolerance in Quarter Horses. Five HYPP affected and five nonaffected horses were matched for age, size, gender and reproductive status. HYPP status was diagnosed by DNA analysis and potassium chloride challenge testing. Plasma lactate concentration and heart rate were used as indicators of work intensity. Serum potassium concentrations were also monitored. Two exercise experiments were conducted, the first being forty-five minutes of slow, aerobic exercise (hacking) and the other being moderate, partially anaerobic exercise (galloping). Post-exercise the horses were cooled out by randomly assigning them to either forty minutes, of standing still or forty minutes of walking. Heart rates of HYPP affected and unaffected horses were not significantly different during exercise or recovery. Plasma lactate concentrations changed slightly following slow exercise and were significantly higher for HYPP affected horses (P=0.01).At the end of exercise, values were 1.4±0.2 mmol/L and 1.0±0.1 mmol/L for HYPP affected and unaffected horses, respectively. Following moderate exercise, plasma lactate concentrations were much greater, and the difference (P<0.001) between affected and unaffected horses was more marked: immediately following exercise concentrations were 10.6±1.8 and 6.2±1.0 mmol/L in affected and unaffected horses, respectively. The higher post-exercise plasma lactate concentrations in affected horses indicates increased anaerobic muscle metabolism. Serum potassium concentrations rose following exercise and significantly higher values were seen in horses that were walked rather than stood still post-exercise.Hyperkalemic periodic paralysis (HYPP) is a dominant autosomal genetic defect occurring in American Quarter Horses and related breeds. ^1–5 The condition is widely geographically distributed and has been estimated to affect 0.4% of all Quarter Horses.⁶ Signs include sporadic attacks of muscle fasciculation, muscle spasm, sweating and weakness. Oral administration of potassium chloride produces a more severe hyperkalemia in HYPP affected horses and induces clinical attacks.¹ Electromyography reveals widespread continuous, spontaneous, muscle contraction.² Some people believe that HYPP affected horses are suitable for riding⁷; others have expressed doubts about the safety of this practice and the exercise tolerance of affected horses. HYPP affected horses have an unstable muscle membrane potential causing random muscle fiber contractions,^2,8 which could antagonize purposeful movement. This, in combination with increases in extracellular potassium concentration occurring during exercise,^9–11 may cause affected horses to stumble or collapse while being ridden, posing a danger to both horse and rider. In HYPP affected people, potassium concentration rises approximately one to two hours after exercise during which time HYPP attacks can occur.^9,10 For these reasons, the exercise tolerance of HYPP affected horses and the effects of exercise on spontaneous HYPP attacks deserves investigation.We standardized the exercise test and chose heart rate and plasma lactate concentrations as indicatoors, of exercise tolerance and energy metabolism.¹² Heart rate is the major determinant of oxygen delivery to muscle and the rate rises with exercise intensity until it reaches a plateau at high velocities.^13,14 Several lines of investigation indicate that plasma lactate concentrations reflect muscle work. Lactate release from resting muscle is minimal but large amounts are released during strenuous exercise.^15–17 Lactate release increases with increasing muscle work.^16,18 During exercise, muscle oxygen consumption increases until eventually a plateau is reached after which no further increase in oxygen consumption in response to increased work loads is possible.¹⁸ At this point the mitochondrial electron chain transport system is operating at its maximal possible rate, energy production can only be supplemented by the use of inefficient anerobic glycolytic metabolism and the muscle starts to release lactate. If the concentrations of plasma lactate are high, the muscles are depending on anaerobic metabolism and are working closer to exhaustion^16,18–21The objectives of this experiment were twofold. One was to determine if HYPP adversely affects exercise performance. The second was to study the effects of cooling out, by either standing still or walking, on serum potassium and plasma lactate concentrations.  相似文献