Risk Factors for the Development of Haemorrhagic Anovulatory Follicles in the Mare

Haemorrhage into the dominant follicle during the reproductive season is a subtle but definitive cause of infertility in the mare population. This condition however can be of high relevance for an individual in which its incidence is abnormally high. Little is known about the nature and factors affecting the incidence of haemorrhagic anovulatory follicles (HAFs) in the mare. The objectives of the study were to define and characterize the ultrasonographic development and incidence of HAFs and to investigate possible risk factors influencing its occurrence. Detailed reproductive and ultrasound records of seven mares studied during their entire reproductive lives (>10 years and 612 oestrous cycles) were analysed retrospectively and computed into a statistical mixed model. Of all animal studied, two mares were found to have an unusually high incidence of HAFs of approximately 25%. Time of season and use of induction treatments (Cloprostenol) were found to influence its incidence. It appears that early‐enhanced stimulatory effect of LH on an ovary with the presence of small and immature follicles might increase the risk of ovulatory failure of those follicles later in the cycle. Mares during the months of highest follicular activity (May to August) and after treatment with hormones to induce oestrus and ovulation are at greater risk to develop HAFs. The potential relevance of this study is two folds: clinical relevance for the practitioner to better understand this condition and so improve reproductive management of mares with abnormally high incidence; and to provide useful insights for researchers willing to further investigate the nature of this phenomenon.     

Herbage measurement in situ by electronics. 3. Calibration, characterization and field application of the earth-plate forage capacitance meter: a prototype

Calibration of an earth-plate forage capacitance meter was conducted on pure stands of Festuca arundinacea Schreb., Medicago sativa L., Cynodon dactylon (L.) Pers. and Trifolium repens L. and a mixture of Trifolium repens and Dactylis glomerata L. Dry weight (DW) prediction equations were developed using the instrument capacitance reading modified by visual estimates of height, stand density and species percentage. In general, meter readings (MR) correlated better with DW than with fresh weight or weight of water and especially when the area harvested exceeded 0·537 m². Correlation between MR and DW improved with increasing top plate area and with decreasing distance between the top plate (suspended sheet of aluminium) and the earth-plate ground. The use of a plastic shield to suppress the forage to a uniform height caused a reduction in the correlation between MR and DW.
The use of MR to predict DW from selected settings, their linear and curvilinear relationships and several auxiliary observations gave results with R ² values ranging from 0·94 to 0·99, depending on species and mixture.     

Evolution of overland flow after a severe forest fire,Point Reyes,California

Forest fires on granitic soils often increase overland flow and erosion. Runoff generation was monitored on a small hillslope plot on Mt. Vision near Point Reyes Peninsula, California, after it had been burned by a wildfire on October 3, 1995. After the fire, the ground surface was covered with up to 2 cm of ash, which overlaid a 5–20 cm thick hydrophobic (water repellent) soil layer. We used nine recording tensiometers to monitor soil-water potentials during infiltration and runoff. Surface-runoff rates were determined by diverting the flow into a collection tank. The subsurface flow through the upper 6 cm of soil was collected and measured in a second tank. The surface runoff was diverted to a tank in order to record its rate. The initial intense rainfall infiltrated into the base of the ash-bed; here, the hydrophobicity limited deeper penetration and led to both subsurface and shallow saturation overland flow. The preferential flow paths through the ash layer contributed to deeper water penetration. As the ash was eroded and consolidated with successive rainstorms, the preferential flow paths clogged, the infiltration capacity reduced, thus preventing the storage of shallow permeable soil; therefore, the runoff generation changed to Hortonian overland flow. Correspondingly, the runoff ratio increased from approximately 0.2 during the early storms to 0.8 during intense rain bursts. These results suggest that runoff mechanisms evolve simultaneously with the eroding soil surface.     

Soil water content on drip irrigated cotton: comparison of measured and simulated values obtained with the Hydrus 2-D model

Crop irrigation with subsurface drip (SDI) is increasing in the semiarid Texas High Plains (THP). Information on drip-tubing positioning, irrigation strategies, and wetted soil area is needed to increase rainwater effectiveness when well capacities are inadequate to meet full irrigation requirements. Time and resources necessary to test SDI strategies for different conditions through field experimentation is too large. However, a mechanistic model such as Hydrus-2D can quantify the effect of different installation geometries and irrigation strategies. Our objective was to experimentally validate the Hydrus-2D in an Amarillo soil in THP so that the model can be used to evaluate different irrigation frequency and timing strategies for SDI cotton. Results showed that Hydrus-2D simulated volumetric soil water content within ±3% of measured values, and simulation bias represented the smaller portion of the simulation error, indicating that the model can be used to evaluate irrigation strategies.     

不同温度对甜菜种子吸胀过程中线粒体CCO和MDH活性的影响

吸胀温度显著地影响甜菜种子的萌发速率。吸胀温度为３０℃和２０℃时,５０％萌发所需要的时间分别为３６ｈ和５６ｈ;在７℃中吸胀１２０ｈ,仍未见萌发。在种子吸胀过程中,粗线粒体蛋白的含量,细胞色素Ｃ氧化酶和苹果酸脱氢酶的活性增加,且它们在３０℃和２０℃中的活性较高,在７℃下较低。     

Transmission of virulent footrot between sheep and goats

OBJECTIVE: To determine the infectivity of ovine and caprine strains of Dichelobacter nodosus for both sheep and goats. DESIGN: Pen experiments in which 20 sheep and 19 goats were challenged directly with the two strains, and transmission experiments on pasture, using donors infected by experimental challenge. RESULTS: Sheep and goat strains of D nodosus infected both animal species in experimental challenges. Animals so infected transmitted footrot to both sheep and goats on pasture plots. A significantly smaller proportion of goats than sheep was infected when challenged with either strain. The interval between exposure and development of footrot in goats was longer than in sheep when recipient animals were exposed to infected donors on pasture. The disease was less invasive in goats than in sheep. CONCLUSIONS: With the strains of D nodosus used there was no evidence of host specificity. Direct transmission of footrot can occur between sheep and goats in the same environment. There is a need to include goats in ovine footrot eradication programs and vice versa.     

Seroepidemiology of undifferentiated fever in feedlot calves in western Canada.

The relationships between 4 bacterial and 3 viral antibody titers and morbidity (undifferentiated fever (UF)) and mortality were investigated in recently weaned beef calves. Blood samples from 100 animals that required treatment for UF (Cases) and 100 healthy control animals (Controls) were obtained: upon arrival at the feedlot (Arrival), at the time of selection as a Case or Control (Selection), and at approximately 33 d of the feeding period (Convalescent). Seroconversion to Pasteurella haemolytica antileukotoxin was associated with an increased risk of UF (OR = 2.83); however, seroconversion to bovine herpesvirus-1 G-IV glycoprotein was associated with a decreased risk of UF (OR = 0.43). Higher Arrival bovine viral diarrhea virus antibody titer was associated with a decreased risk of UF (OR = 0.83). Increases in Mycoplasma alkalescens antibody titer after Arrival were associated with an increased risk of UF (OR = 1.10). Higher Arrival Haemophilus somnus antibody titer and increases in Haemophilus somnus antibody titer after Arrival were both associated with a decreased risk of UF (OR = 0.76 and OR = 0.78). The odds of overall mortality (OR = 5.09) and hemophilosis mortality (OR = 11.31) in Cases were significantly (P < 0.05) higher than in the Controls. Higher Arrival bovine herpesvirus-1 antibody titer was associated with an increased risk of mortality (OR = 1.30). Protective immunity to Pasteurella haemolytica antileukotoxin, Haemophilus somnus, bovine herpesvirus-1 G-IV glycoprotein, bovine viral diarrhea virus, and Mycoplasma spp. may be necessary to reduce the occurrence of UF. Animals with UF are at an increased risk of overall and hemophilosis mortality.     

The Solar Acoustic Spectrum and Eigenmode Parameters

The Global Oscillation Network Group (GONG) project estimates the frequencies, amplitudes, and linewidths of more than 250,000 acoustic resonances of the sun from data sets lasting 36 days. The frequency resolution of a single data set is 0.321 microhertz. For frequencies averaged over the azimuthal order m, the median formal error is 0.044 microhertz, and the associated median fractional error is 1.6 x 10(-5). For a 3-year data set, the fractional error is expected to be 3 x 10(-6). The GONG m-averaged frequency measurements differ from other helioseismic data sets by 0.03 to 0.08 microhertz. The differences arise from a combination of systematic errors, random errors, and possible changes in solar structure.     

Aetiology of an ulcerative disease in goldfish, Carassius auratus (L.): experimental induction of the disease

Abstract. Infection experiments were conducted to determine the primary aetiology of an ulcerative disease in goldish, Carassius auratus (L.). Goldfish were exposed to atypical Aeromonas salmonicida and A. hydrophila , previousl y isolated from cutaneous ulcers, and to 04 5 μm filtrates of cutaneous ulcers and kidneys from diseased fish. Fish were exposed to each preparation by intraperitoneal, intramuscular or subcutaneous injection and by a method in which a small patch of scales was removed from each side of the fish and the inoculums applied. Most of the fish injected with A. salmonicida died without developing coetaneous ulcers; however, ulcers were induced in five of the ten fish exposed by the scale removal technique. Exposure to ultra filtrates or A. hydrophila did not result in consistent ulcer formation o r death. Additional experiments showed that a 30-min exposure of goldfish, without prior treatment, to water containing 3 × 10⁵ colony forming units (cfu/ml) of A. salnumicida was sufficient to produce cutaneous lesions in nine often fish exposed. Multiple lesions were produced in most fish and A. salmonicida was consistently recovered. Fish exposed by similar waterborne challenge s to 6·2 × 10⁶ cfu/ml of A. hydrophila or to 7·2 × 10⁶ cfu/ml of another lesion isolate identified as a member of the A. hydrophila complex produced no lesions, eve n when scales were removed. The studies demonstrate that atypical A. salmonicida can initiate cutaneous lesion s characteristic of ulcerative disease, while A. hydrophila and an A. hydrophila complex organism cannot.