Effects of oral powder electrolyte administration on packed cell volume,plasma chemistry parameters,and incidence of colic in horses participating in a 6-day 162-km trail ride     

Wade T. Walker  Robert J. Callan  Ashley E. Hill  Kelly B. Tisher 《The Canadian veterinary journal. La revue veterinaire canadienne》2014,55(8):765-771

This study evaluated the effects of administering oral powder electrolytes on packed cell volume (PCV), plasma chemistry parameters, and incidence of colic in horses participating on a 6-day 162-km trail ride in which water was not offered ad libitum. Twenty-three horses received grain with powder electrolytes daily while 19 control horses received grain only. Horses were ridden approximately 32 km a day at a walk or trot. Packed cell volume and plasma chemistry parameters were analyzed daily. Episodes of colic were diagnosed and treated by a veterinarian unaware of treatment group allocation. Blood parameters and incidence of colic were compared between treatment groups. Electrolyte administration did not alter PCV or plasma chemistry parameters compared to controls. The incidence of colic was significantly higher in treated horses (P = 0.05). Oral powder electrolytes did not enhance hydration status or electrolyte homeostasis and may be associated with colic in horses participating on long distance trail rides similar to this model.  相似文献   

Taxonomic and functional macroinvertebrate diversity of high-altitude ponds in the Macun Cirque,Switzerland     

Matthew J. Hill  Paul J. Wood  Kate L. Mathers 《水产资源保护:海洋与淡水生态系统》2021,31(11):3201-3214

1. Global environmental change is threatening freshwater biodiversity with ecological impacts predicted to be particularly severe in high-altitude regions. Despite this, an ecological understanding of high-altitude pond networks remains patchy, with only limited knowledge of the environmental and spatial predictors of taxonomic and functional diversity. Moreover, previous studies of pond ecosystems have focused primarily on taxonomic richness and largely overlooked functional diversity.
2. This study examined the influence of local environmental and spatial factors on taxonomic and functional α and β diversity (including the turnover and nestedness-resultant components) of 17 high-altitude (~2,500 m above sea level) pond macroinvertebrate communities, in the Macun Cirque, Switzerland.
3. Spatial processes (pond connectivity) were important drivers for taxonomic α diversity, while local environmental variables (pond permanence and surface area) were important determinants of functional α diversity. Species turnover was the most important component of β diversity for taxonomic composition, and functional composition demonstrated a nested spatial pattern.
4. Variation in taxonomic and functional composition (and the turnover and nestedness components of β diversity) were determined by local environmental variables despite the limited environmental gradients within the pond network. No significant effects of spatial variables on community composition were recorded for either facet of diversity, indicating that compositional variation was determined at a local scale. Water temperature, depth and pond permanence were consistently the most important measured drivers of diversity.
5. Given the importance of both spatial and environmental variables in structuring taxonomic and functional diversity, landscape-scale conservation and management activities that aim to improve or protect high-altitude freshwater biodiversity should focus on maintaining connectivity among ponds and environmental heterogeneity, particularly pond surface area, water depth, and hydroperiod. Understanding the mechanisms driving taxonomic and functional diversity will be critically important for the management and conservation of macroinvertebrate communities in high-altitude pond networks in the face of climatic warming.

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Estimating the component of soil respiration not dependent on living plant roots: Comparison of the indirect y-intercept regression approach and direct bare plot approach     

Georgia R. Koerber  Paul W. Hill  Gareth Edwards-Jones  David L. Jones 《Soil biology & biochemistry》2010,42(10):1835-1841

Distinguishing between root and non-root derived CO₂ efflux is important when determining rates of soil organic matter turnover, however, in practice they remain difficult to separate. Our aim was to evaluate two methods for determining the component of below-ground respiration not dependent on plant roots (i.e., basal soil respiration; R_b). The first approach estimated R_b indirectly from the y-intercept of linear regressions between below-ground respiration (BGR) and root biomass. The second approach involved direct measurements of soil respiration from bare plots. To compare the contrasting approaches, BGR and crop biomass measurements were collected throughout the year in a range of agricultural systems. We found that both methods were very closely correlated with each other. Values of R_b determined by the intercept approach, however, were slightly higher than those determined by measurement of bare plots. Both approaches showed a seasonal trend with estimates of R_b lowest in winter months at 0.02 t C ha⁻¹ month⁻¹ for the y-intercept approach and 0.11 t C ha⁻¹ month⁻¹ for the bare plots approach, even after the data had been corrected for the influence of soil temperature. Highest rates of R_b occurred from the height to the end of the crop growing season (0.8-1.5 t C ha⁻¹ month⁻¹). The annual CO₂ efflux due to R_b was estimated to be 8.1 t C ha⁻¹ y⁻¹ from the y-intercept approach and 6.8 t C ha⁻¹ y⁻¹ from bare plots. Annual BGR was 12.1 t C ha⁻¹ y⁻¹. We conclude that both methods provide similar estimates of R_b, however, logistically the bare plots approach is much easier to undertake than the y-intercept approach.  相似文献   

Toxocara vitulorum in beef calves kept on effluent-irrigated pastures in Zimbabwe     

V S Pandey  F W Hill  D G Hensman  L C Baragwanath 《Veterinary parasitology》1990,35(4):349-355

Faeces from 20 calves aged 13 +/- 5 days were examined for Toxocara vitulorum eggs fortnightly for a period of 20 weeks. The age of calves when eggs were first detected varied from 24 to 110 days (mean 41 +/- 20 days). The mean egg count varied from 257 to 19,821 g-1 of faeces with a highest count of 68,400. The patency period of T. vitulorum lasted from 14 to 112 days (mean 65 +/- 30 days). None of the calves showed clinical signs of illness.  相似文献   

Development and validation of a soil-based geographic information system model of habitat of Fossaria bulimoides, a snail intermediate host of Fasciola hepatica     

Stanley H. Zukowski  John M. Hill  Farrell W. Jones  John B. Malone 《Preventive veterinary medicine》1991,11(3-4):221-227

Soil maps were investigated for their potential to indicate the spatial distribution of habitat of the amphibious snail, Fossaria bulimoides, the intermediate host of Fasciola hepatica in Louisiana. On a 760 ha farm adjacent to the Gulf of Mexico, most snail habitats clustered along interfaces of cheniers (relict beaches with sandy soils) with marsh (heavy, gleyed clays). A few small foci occurred on the cheniers above interfaces. Virtually no habitats occupied marsh away from these interfaces, on this or several other farms previously examined. Habitat and soil map overlays were analyzed in a raster-based geographic information system (GIS) with a 10 m pixel size; a model of habitat was generated as bands 50–90 m wide at chenier-marsh interfaces. The model was extrapolated to a 29 000 ha study area and tested on 12 additional farms not adjacent to the Gulf. On these farms, snail surveys were carried out as transects on three strata: waveface (WF, former beachfront) and backslope (BS) chenier-marsh interfaces, and chenier. The perimeters of all habitats encountered were outlined. The interface of marsh with chenier backslopes occupied 5.25% of the area of the farms, but held 21.69% of snail habitat area. Additionally, chenier soils of the Hackberry-Mermentau complex (HM) occupied 12.32% of farm area, but held 61.39% of habitat. Habitat area was related by regression analysis to the proportion of farm consisting of HM soils (r² = 0.41, P < 0.05).  相似文献   

Monensin controlled-release intraruminal capsule for control of bloat in pastured dairy cows   总被引：1，自引：0，他引：1  

LB LOWE  GJ BALL  VR CARRUTHERS†  RC DOBOS‡  GA LYNCH  PJ MOATE  PR POOLE†  SC VALENTINE 《Australian veterinary journal》1991,68(1):17-20

Monensin, a polyether ionophore antibiotic, is potentially an important agent for bloat relief in dairy cows grazing temperate legume-based pasture. A series of studies was undertaken to determine the effect of monensin, when delivered continuously in the rumen of lactating dairy cows by means of controlled-release capsules (monensin CRC). Such devices release approximately 300 mg/head/day for 100 d. A short-term pilot study made at Ruakura, New Zealand, tested monensin CRC in cows selected for high susceptibility to bloat and grazing lucerne (Medicago sativa) or red clover (Trifolium pratense). Treatment significantly reduced the incidence of bloat, while milk yield and protein yield were increased. There was no effect on fat yield. Following the pilot study, 6 large-scale field experiments involving a total of 368 lactating dairy cows, were made in Australia and New Zealand to confirm the effectiveness of monensin CRC for bloat control and to measure the effect of such treatment on milk production and composition. A severe bloat problem occurred in 2 experiments, mild bloat occurred in 2 others, while no visual signs of bloat were observed in the remaining 2 experiments. Bloat was significantly (P less than 0.05) reduced by monensin CRC treatment when data was pooled over the 4 experiments in which bloat occurred. Daily milk yield was increased in all experiments from a mean of 17.7 in untreated groups to 18.8 kg/head/day (P less than 0.05) in monensin CRC-treated cows. Protein percentage was not affected by treatment, while there was a decrease from 4.29 to 4.10% fat, although total fat yield was not affected.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Rotavirus excretion by village pigs in Papua New Guinea     

D. ALPERS  RC SANDERS†  DJ HAMPSON ‡ 《Australian veterinary journal》1991,68(2):65-67

Cohort studies were conducted on 29 pigs from 3 villages in the Highlands of Papua New Guinea. Animals ranged in age from 9 d to 5 m old. Three hundred and twenty nine faecal samples were collected from individual pigs followed over 3 to 6 w periods, and were examined for group A rotavirus antigen by ELISA, and rotaviral genomic RNA by polyacrylamide gel electrophoresis (PAGE). Electron microscopy was also conducted on selected samples. Group A rotavirus was detected in the faeces of 16 pigs with infected individuals coming from all villages. Non-group A rotavirus resembling group C was found in faeces from pigs from 2 villages. All of the group A rotaviruses examined had the same electrophoretype and this was distinct from that of the common type infecting humans in the area at the time of the study. None of the group A positive samples reacted with monoclonal antisera specific for human group A rotaviruses of serotypes 1, 2, 3, 4, or 8. The non-group A rotaviruses also all had identical electrophoretypes. In contrast to previous findings in intensive piggeries, rotavirus infection did not occur in all young pigs and was not limited to young animals under 2 m of age. Infected pigs varied in age from 12 days to 20 weeks of age. This pattern of infection was attributed to the non-intensive husbandry situations in the villages, with less opportunity for transmission to occur than in intensive piggeries.  相似文献   

Spironucleus muris in laboratory mice     

A. WHITEHOUSE  MP FRANCE  SE POPE  JE LLOYD  RC RATCLIFFE 《Australian veterinary journal》1993,70(5):193-193

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Vaccination of cows with rough Escherichia coli mutants fails to protect against experimental intramammary bacterial challenge     

A. W. Hill 《Veterinary research communications》1991,15(1):7-16

Vaccination of cows with rough Escherichia coli mutants fails to protect against experimental intramammary bacterial challenge. Vaccine A, a heat-killed Re mutant of strain K12, (UB 1574), was administered as a single parenteral and local dose to 5 cows with 3 control animals and Vaccine B, a heat-killed mutant of O111:B4 (J5) was administered as three parenteral doses into 5 cows with 5 control animals. Following intramammary challenge with a smooth wild-type strain (P4), an acute, severe clinical mastitis developed in all 14 quarters (9 vaccine A and 5 vaccine B) of the vaccinated animals which was indistinguishable from that in the 11 quarters of the control animals. Following vaccine B there was an elevation in serum IgG1 and IgG2 antibody to the common core antigen of endotoxin which, in contrast to the control animals, showed a further increase after intramammary infection.  相似文献   

Tomato Production and Soil Salt Distribution under Line-Source Trickle Irrigation1     

A. M. Abu-Awwad  R. W. Hill 《Journal of Agronomy and Crop Science》1991,167(3):188-195

Yield of red cherry tomatoes and soil salt distribution as affected by different amounts and salinities of irrigation water was studied in a field plot experiment during the summer of 1988 at Utah State University. Four different amounts of fresh water and two amounts of saline water were imposed with line source trickle irrigation on a sandy loam soil in lysimeters. Tomato yield and seasonal evapotranspiration increased in a linear fashion with increasing irrigation water. Tomato yields with fresh water (EC = 0.33 dS/m) were significantly higher than with saline (EC = 4.0 dS/m) water. There were no significant differences in seasonal evapotranspiration between the two salinity levels with two levels of deficit irrigation. Soil water depletion and availability decreased as the soil water salinity increased. Soil water salinities increased with both vertical and horizontal distance from trickle lines and reached a maximum at the bottom of the wetted area and between trickle lines.  相似文献