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排序方式: 共有67条查询结果,搜索用时 31 毫秒
1.
Influence of boar and semen parameters on motility and acrosome integrity in liquid boar semen stored for five days 总被引:1,自引:0,他引:1
Ninety ejaculates from a total of 76 AI boars were extended in Beltsville Thawing Solution (BTS). Boar identity, breed, weight of the ejaculate and sperm concentration were registered. Motility and acrosome integrity were assessed after storage at 16-18 degrees C for 6, 30, 54, 78, and 102 h. Storage time had a significant influence on both motility (p < 0.01) and acrosome integrity (p < 0.001). The Least Square Means for percentage of motility showed a small decline from 79.8% after 6 h of storage to 78.4% at 102 h. Motility at 78 and 102 h was significantly different from motility at 6 h (p < 0.05). The percentage of sperm cells with normal acrosomes declined throughout the experiment. The Least Square Means for 6, 30, 54, 78, and 102 h of storage were 93.9%, 90.6%, 88.0%, 84.8%, and 78.2%, respectively. The decrease in acrosome integrity from one storage time to the next was highly significant throughout the trial (p < 0.001). There was a significant influence of boar (p < 0.001) and sperm concentration (p < 0.01) on motility, while acrosome integrity was affected only by boar (p < 0.001). Breed of the boars and weight of the ejaculate did not influence the dependent variables. 相似文献
2.
Radar soundings of the subsurface of Mars 总被引:2,自引:0,他引:2
Picardi G Plaut JJ Biccari D Bombaci O Calabrese D Cartacci M Cicchetti A Clifford SM Edenhofer P Farrell WM Federico C Frigeri A Gurnett DA Hagfors T Heggy E Herique A Huff RL Ivanov AB Johnson WT Jordan RL Kirchner DL Kofman W Leuschen CJ Nielsen E Orosei R Pettinelli E Phillips RJ Plettemeier D Safaeinili A Seu R Stofan ER Vannaroni G Watters TR Zampolini E 《Science (New York, N.Y.)》2005,310(5756):1925-1928
The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick. 相似文献
3.
This is a comparative study of uptake of trimethoprim from 1) fresh water, 2) salt water after 7 days of adaption and 3) salt water without previous adaptation. The rate and extent of absorption were found to vary significantly. The salt water adapted group reached a plasma concentration of approx. 1 µg/ml after 10 h, the unadapted salt water group after 24 to 48 h and the fresh water group did not reach this concentration. The results are discussed in relation to the non-ionic diffusion theory and to the alterations taking place in euryhaline species of fish during adaptation to salt water. 相似文献
4.
Dan Olsen Erling Sehested 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(1):1-11
Optimal use of limited resources as nucleus and testing capacity is important when organizing crossbreeding schemes in pigs. This paper introduces a method of modelling pig crossbreeding schemes consisting of nucleus, multiplier and commercial tiers. As an efficient alternative to the gene flow method (Hill, W.G. 1974. Anim. Prod. 18, 117-139), lag, original genetic level and annual genetic improvement for each line and cross are combined into one single evaluation criterion, the average discounted revenues of the breeding scheme. An optimum allocation of nucleus and testing capacity within breeding schemes, as well as an optimum solution between schemes can be found. As an example, the optimization of a four-way crossbreeding scheme is shown. the optimum allocation of nucleus capacity was 35% and 15% in each dam line and sire line, respectively. The corresponding figures for testing capacity were 23% and 27%. 相似文献
5.
Anki Roxström Erling Strandberg Britt Berglund Ulf Emanuelson Jan Philipsson 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(1):7-14
The main objective of this study was to estimate genetic correlations between fertility and production traits in first, second and third lactations as well as between fertility traits measured in the same way at different ages. The fertility traits studied were: number of inseminations per service period, number of treatments for reproductive disturbances, interval between first and last inseminations, interval between calving and first insemination, and interval between calving and last insemination. Early milk production was measured as the average of the energy-corrected milk yield at the second and third monthly testdays in a lactation. The number of records was approximately 450 000, 350 000, 180 000 and 75 000 in the heifer period, first, second, and third lactations, respectively. A linear, trivariate model that included the effects of herd-year, year, month, age and sire of the cow was applied. To reduce the effect of ongoing selection, 305-days kg protein production in first lactation was included as a variate in all of the analyses. Correlations between the herd-year effects indicated that factors of herd-year level conducive to increased production had a tendency to increase the number of inseminations as well as the number of reproductive treatments, although there was an earlier start and termination of the insemination period. Genetic correlations between fertility traits and production were in the range of 0.2-0.4, all of them unfavourable and higher at later parities. The genetic correlations between fertility traits in the heifer period and the same traits in first lactation were 0.7. Genetic correlations between the first and second lactation varied between 0.7 and 0.9, and between the second and third lactation they were all 0.9 or higher. In conclusion, fertility and production traits need to be selected for simultaneously if fertility is going to be maintained along further genetic improvement on production, and such selection should include fertility results from lactating cows. 相似文献
6.
Erling Sgnen 《Acta veterinaria Scandinavica》1967,8(1):76
A method is described for the preparation of a suspension of single cells of the intestinal mucosa by the calcium chelators ED TA and EGTA.Preliminary experiments with oxygen consumption and glucose-utilization indicate a considerable metabolic activity of the cell suspension.The difference in glycine uptake in presence and absence of sodium and the effect of phlorizin on the glucose metabolism of the cells indicates the existence of a qualitatively normal membrane function.The application of a similar method for the purpose of obtaining viable in vitro preparations from intestinal tissue of larger animals is suggested. 相似文献
7.
8.
Hanne Christine Bertram Niels Bastian Kristensen Mogens Vestergaard Søren Krogh Jensen Jakob Sehested Niels Christian Nielsen Anders Malmendal 《Livestock Science》2009,120(1-2):127-134
The metabolic profile of calf rumen epithelial tissue was for the first time characterized by 1H NMR spectroscopy of chloroform/methanol extracts. The metabolite profiles comprised a number of amino acids, creatine, taurine, short-chain fatty acids and triglycerides. The effects of two dietary interventions; i) four levels of milk allowance with a concomitant different uptake of starter concentrate, and ii) two diets with varying content of starch and fibre in the concentrate, were elucidated. Partial least square regression analysis revealed that the intensity of NMR signals assigned to leucine, isoleucine and valine (0.90 ppm), propionate (1.06 and 2.18 ppm), lactate (1.32 ppm), butyrate (1.56 ppm), acetate (1.93 ppm), glutamine/glutamate (2.18, 2.35 and 3.75 ppm), creatine (3.04 and 3.94 ppm) and glycine (3.55 ppm) decreased with increasing milk allowance. In addition, the analysis revealed that the main difference between the two diets was the content of propionate in the epithelia tissue extracts. Previous morphological analyses of the same rumen epithelia were not able to detect any significant effects of either milk allowance or dietary starch content. Accordingly, the present study demonstrated that 1H NMR spectroscopy applied on extracts is a useful tool for metabolite profiling of epithelial tissue and for following the development of epithelia tissue in young calves, and that the technique may be more sensitive to dietary effects than morphological studies. 相似文献
9.
Toke Koldborg Jensen Jette Nielsen Erling P. Larsen Jens Clausen 《Journal Of Aquatic Food Product Technology》2013,22(3-4):214-226
Mathematical models for simulating and optimizing aspects of supply chains such as distribution, planning, and optimal handling of raw materials are widely used. However, modeling based on a holistic chain view including several or all supply chain agents is less studied, and food-related aspects such as quality and shelf-life issues enforce additional requirements onto the chains. In this article, we consider the supply chain structure of the fish industry. We discuss and illustrate the potential of using mathematical models to identify quality and value-adding activities. The article provides a first step toward innovative supply chain modeling aimed to identify benefits for all agents along chains in the fish industry. 相似文献
10.
To implement biosecurity measures at farm-level is a motivational challenge to dairy farmers as emerging diseases and their consequences largely are unpredictable. One of the reasons for this challenge is that outcomes are more likely to benefit society than the individual farmer. From the individual farmer's point of view the impacts of zoonotic risk, international trade and welfare concerns appear less obvious than the direct costs at farm-level. Consequently, a social dilemma may arise where collective interests are at odds with private interests. To improve biosecurity at farm-level farmers must be motivated to change behavior in the 'right' direction which could provide selfish farmers with unintended possibilities to exploit the level of biosecurity provided by other dairy farmers' collective actions. Farmers' perception of risk of disease introduction into a dairy herd was explored by means of Q-methodology. Participating farmers owned very large dairy herds and were selected for this study because Danish legislation since 2008 has required that larger farms develop and implement a farm specific biosecurity plan. However, a year from introduction of this requirement, none of the participating farmers had developed a biosecurity plan. Farmers' perception of biosecurity could meaningfully be described by four families of perspectives, labeled: cooperatives; confused; defectors, and introvert. Interestingly, all families of perspectives agreed that sourcing of animals from established dealers represented the highest risk to biosecurity at farm-level. Farmers and policy-makers are faced with important questions about biosecurity at farm-level related to the sanctioning system within the contextual framework of social dilemmas. To solve these challenges we propose the development of a market-mediated system to (1) reduce the risk of free-riders, and (2) provide farmers with incentives to improve biosecurity at farm-level. 相似文献