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ABSTRACTCase history: Data were collected from 47 outbreaks of dropped hock syndrome (DHS) that were reported by veterinarians in New Zealand to the Ministry for Primary Industries between October 2012 and August 2017. There were 181 affected dairy cows from 44 farms. Of those with records, all 86 were aged between 2–3 years-old, and 4/94 (4%) were Friesian, 56/94 (60%) were Jersey and 33/94 (35%) were Jersey/Friesian cross. Of the 47 outbreaks, 45 (96%) occurred during winter and 37 (79%) in the South Island.Clinical findings: Of 151 cases with records, hindlimb weakness (117 cows), shortened gait (112 cows) and dropped hocks (106 cows) were most commonly reported, with 110 cases being bilaterally affected. The level of diagnostic work-up and the data recorded by veterinarians for each outbreak were highly variable. Creatine kinase and aspartate aminotransferase activities were reported for 22 cases and were within normal ranges for cows with mild disease but increased in cows with severe disease. Concentrations of Cu in serum and liver were below normal for 13/22 and 9/10 cows, respectively, from six outbreaks. Of 41 cows with records for clinical outcomes, 12 had complete resolution, 18 had partial resolution, and 11 had no resolution.Pathological findings: Post-mortem data were available from 26 cases. Muscle necrosis and haemorrhage of the origin of the gastrocnemius muscle were the key gross findings. In 14 cows with records for muscle histopathology, myodegeneration and recent haemorrhage were observed, and connective tissue pathology was reported to predate muscular pathology in seven cases.Diagnosis: DHS appeared to be a degenerative rather than inflammatory condition primarily affecting the connective tissue of the hind limb, especially at the dense collagen interfaces of the gastrocnemius. Although no evidence of neuropathy was found, this cannot definitively be ruled out as a potential cause.Clinical relevance: A more standardised and systematic approach to investigating cases and recording case data is required to make robust inferences about the aetiology, risk factors, and treatment interventions for DHS. 相似文献
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The capabilities of central office (CO) telephone switches in four southeastern states (Kentucky, Mississippi, North Carolina, and Tennessee) provide detail on spatial variation in telecommunications technologies. A proposed six‐level hierarchy of switch capability was used. Switches with digital capability are concentrated disproportionately in metropolitan areas, largely in response to larger numbers of business establishments. The overall picture in the Southeast is one of tremendous variation—variation across states and variation within the four states being studied. Rural (nonmetro) counties generally, but not always, have both fewer switches overall and fewer switches with digital capability. North Carolina and Tennessee, the two most urban of the four states, also have seen the greatest entry by new telecommunications competitors. These two states have the largest percentages of advanced (digital) switches in both metro and rural counties. At the county level, the number of switches is primarily a function of a county's population but, even more significantly in three states, of the number of business establishments in the county. On the whole, it is residents of metropolitan—not rural—areas who are most likely to be served by newer forms of digital telecommunications. 相似文献
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Neuhauser E. F. Loehr R. C. Milligan D. L. Malecki M. R. 《Biology and Fertility of Soils》1985,1(3):149-152
Summary Development of methods to measure the effect of man's residuals on soil ecosystems is desirable. Earthworms, as one of the largest and most easily obtained components of the soil biota, are suitable for evaluating perturbations to soil ecosystems.The impact of five metals (Cd, Cu, Ni, Pb, and Zn) on the survival of the earthworm Eisenia fetida (Savigny) was evaluated using the contact and artificial soil tests. There was no difference in toxicity between the different metal salts (acetate, chloride, nitrate, and sulfate) of each of the five metals using the contact test. In the contact test, the order of toxicity, from most toxic to least toxic, was Cu > Zn > Ni Cd > Pb. The nitrate salt of the five metals was tested using the artificial soil test and the order of toxicity, from most toxic to least toxic, was Cu Zn Ni > Cd > Pb. Stress on earthworm populations, as shown by weight loss, was shown to increase with increasing concentrations of metal salts.These studies indicate that: (a) earthworms can be a suitable biomonitoring tool to assist in measuring the effect of metals in wastes added to soils and (b) the contact and artificial soil tests can measure the biological impacts.Research Associate, Research Technician, and Research Support Specialist, respectivelyAt the time of this research, Dr. Loehr was a Professor of Agricultural Engineering and of Environmental Engineering, Cornell University. He currently is the H.M. Alharthy Centennial Chair Professor, Civil Engineering Department, University of Texas, Austin, Texas 78712 相似文献
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1. Survival of emu spermatozoa during in vitro storage is not affected by increasing the extracellular [K+] to the point where it does not adversely affect spermatozoa function. 2. In three experiments, the effects were studied of [K+] in a diluent in the range 12·5–80?mM/l on emu spermatozoa survival for up to 48?h at 5, 10 or 20°C. 3. At the end of the storage period, spermatozoa viability, motility, fertilising ability and morphology were measured. 4. In Experiment 1, spermatozoa viability and morphology were adversely affected after storage (P?M/l [K+] whereas spermatozoa motility decreased as [K+] increased from 12·5 to 80?mM/l. 5. In Experiment 2, during storage at 5°C, the spermatozoa viability was comparable among any of the diluents (standard or modified) but morphology was better (P? 6. In Experiment 3, after 48?h of storage in a diluent containing 40?mM/l of [K+], the spermatozoa functions were better preserved at 10°C than at 5 or 20°C. 7. It is concluded that a higher than physiological level of potassium can be used in a diluent without detrimental effect on emu spermatozoa survival during 48?h storage and that the best outcome was with storage at 10°C rather than 5 or 20°C. 相似文献
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1. A study was conducted on ～14000 ostrich eggs to estimate genetic parameters for eggshell traits that could benefit the hatchability of ostrich eggs. Traits measured included the number of pores on the eggshell, the average diameter of these pores, the total area of pores on the eggshell, permeability (pore area/shell thickness) and eggshell thickness. 2. Heritability estimates ranged from 0·16 for total pore area to 0·41 for the natural logarithm of pore count. The heritability estimates for water loss on 21 and 35?d (WL21 and WL35) of incubation were high at 0·23 and 0·24, respectively. 3. On a genetic level, pore count was negatively correlated with average pore diameter (?0·73) and shell thickness (?0·28), whereas it was positively correlated with total pore area (0·58), WL21 (0·24) and WL35 (0·34). The direct and maternal genetic correlations of pore count with total pore area (0·58) and permeability (0·59) were high and significant. Permeability was positively correlated to WL21 and WL35, both on the direct and maternal genetic levels. 4. The estimated genetic parameters indicate that it should be possible to select for the various eggshell traits in ostrich eggs, or for permeability and water loss. However, as a trait with an intermediate optimum, direct selection for permeability and other eggshell traits would not be straightforward, and the possible application of these results to improve hatchability of ostrich eggs in the future needs consideration. 相似文献
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Effect of astaxanthin on the quality of boar sperm stored at 17°C,incubated at 37°C or under in vitro conditions 
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下载免费PDF全文 A Basioura CM Boscos I Parrilla G Tsousis IA Tsakmakidis 《Reproduction in domestic animals》2018,53(2):463-471
The aim of the study was to investigate the effect of the antioxidant astaxanthin on boar semen. Twenty ejaculates from 10 boars (two ejaculates/boar) were extended and split in three groups: semen control (SC), solvent control (C; semen with dimethyl sulfoxide, the diluent of astaxanthin) and semen with astaxanthin (A) in concentration 0.5 μmol/L. Sperm quality parameters (motility and kinetics, morphology, viability, functional integrity of sperm plasma membrane by Hypo‐Osmotic Swelling Test [HOST] and DNA integrity) were assessed at 0, 24 and 48 hr of storage at 17°C (experiment I), before (0 hr) and after (1 hr) of sperm thermal resistance assay at 37°C (experiment II) and finally before (0 hr) and after (1 hr) sperm in vitro incubation (38.5°C, 5% CO2, maximum humidity [experiment III]). In experiment I, group A performed overall better than group SC and as a tendency better than group C regarding viability. Total motility, rapid spermatozoa and HOST remained constant across time in group A, whereas they decreased in the remaining groups. In experiment II, regarding motility and viability, group A displayed better results across time than the other two groups. In experiment III, viability and total motility decreased in groups SC and C, while in group A, these parameters were not significantly different between the examination time points. In conclusion, astaxanthin has a beneficial and protective effect on boar semen quality under the investigated conditions. 相似文献
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木材微波加热厚度的确定 总被引：4，自引：0，他引：4
较之传统加热方法，微波加热是一种新型加热技术。在简述木材微波加热的机理上．阐述了影响术材介电特性的因素，指出其中木材古水率和温度是影响木材节电性质的两个最重要的因素．通过理论计算确定微波在木材中的穿透深度．计算表明：随着木材含水率和微波工作频率的增加，微波在木材中的穿透深度减少；当用频率为915MHz和2450MHz的微波加热或干燥具有高含水率的木材时，木材的最大厚度应分别控制在16cm和6cm左右． 相似文献
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R.P. Singh P.K. Rybnik-Trzaskowska U. Farooq I.A. Malecki K.V.H. Sastry G.B. Martin 《British poultry science》2013,54(2):259-264
1. An assessment of the efficiency of the acrosome reaction (AR) provides an important predictor of the fertilizing potential of semen and for diagnosis of the causes of infertility. A standardized protocol was therefore developed for initiation of the acrosome reaction in emu spermatozoa in vitro, and the role of CaCl2 or perivitelline membrane (PVM) proteins in determining the outcome of the reaction was investigated.
2. The acrosome reaction (assessed by FITC-PNA) was successfully induced in live spermatozoa by incubation for 2 min in NaCl-TES medium supplemented with 5 mM CaCl2. The maximum response was 32% live acrosome-reacted spermatozoa (LAR) achieved after 10 min incubation.
3. Compared to the outcome with 5 mM CaCl2 or PVM protein alone, the response was significantly better with a combination of PVM protein and CaCl2.
4. A significant variation in the percentage of LAR spermatozoa among individual males was observed. No treatment affected the percentage of dead acrosome-reacted spermatozoa.
5. The results emphasize the important role played by both PVM proteins and Ca2+ in the in vitro initiation of the acrosome reaction. 相似文献
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