Alberta. Border disease virus isolated from twin lambs          下载免费PDF全文

Lees VW  Loewen KG  Deregt D  Knudsen R 《The Canadian veterinary journal. La revue veterinaire canadienne》1991,32(8):501

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Veterinary manpower in Canada          下载免费PDF全文

Knudsen R 《The Canadian veterinary journal. La revue veterinaire canadienne》1976,17(4):121

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Organic zinc and copper supplementation on antioxidant protective mechanism and their correlation with sperm functional characteristics in goats          下载免费PDF全文

M Narasimhaiah  A Arunachalam  S Sellappan  VK Mayasula  PR Guvvala  SK Ghosh  V Chandra  J Ghosh  H Kumar 《Reproduction in domestic animals》2018,53(3):644-654

Trace minerals feeding had significant effects on sperm production and fertility with better absorption and proper utilization within the body for optimum reproductive function. Several studies have shown that more influenced trace elements in the diets of animals are copper (Cu) and zinc (Zn). Bucks showing deficiency of this mineral might affect the quality of semen production which in turn would affect the fertility. This experiment was thus designed to test the effects of organic Cu and Zn supplementation on antioxidants enzyme activities and sperm functional attributes in fresh semen of bucks. Forty bucks (n = 40, Aged 5 months) were assigned to ten groups of four animals in each group, supplemented (for a period of 8 months) with different levels of organic Zn: 20 mg (T2), 40 mg (T3) and 60 mg (T4), organic Cu: 12.5 mg (T5), 25 mg (T6), 37.5 mg (T7) and combined organic Zn and Cu: 20 + 12.5 mg (T8), 40 + 25 mg (T9), 60 + 37.5 mg (T10), respectively, per kg dry matter and no additional mineral diet (control; T1). One hundred and sixty semen samples were collected through electro‐ejaculator and analysed for sperm quantity, quality, acrosome intactness and plasma membrane integrity and correlated with the catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase enzyme activities in seminal plasma. The results indicated organic Cu and zinc supplemented bucks produced more sperm cells, had higher sperm concentrations, maintained higher (p < .01) sperm livability, plasma membrane and acrosome integrities, more motility and velocity. The increased antioxidant enzyme activities, reduced oxidative stress and lowered lipid peroxidation were positively correlated (p < .05) with the sperm functional attributes. In conclusion, organic Cu and Zn supplement to male goats showed protective roles against oxidative damage and maintained better fresh semen characteristics.  相似文献   

Ultrastructural changes and antigen localization in tissues from foot-and-mouth disease virus-infected guinea-pigs   总被引：1，自引：0，他引：1  

S H Wool  J Polatnick  R C Knudsen 《Veterinary microbiology》1982,7(5):391-400

Foot-and-mouth disease virus (FMDV)-induced ultrastructural changes in guinea-pig tongue, heelpad, mammary and liver tissues were examined using scanning and transmission electron microscopy. FMDV infection caused cell rounding and the release of virus in membrane limited vesicles in the animal tissues similar to that seen in other work in cell cultures. Microfilaments were present which may be responsible for cell rounding. Immunoperoxidase labeling revealed the attachment of the virus-infection associated (VIA) antigen to the smooth vacuoles of mammary and liver tissues, and to milk fat globules. The electron microscope immunoperoxidase procedure increased the sensitivity of detection sufficiently to allow the visualization of VIA antigen in tissues not previously shown to have the antigen. It is postulated that the release of the smooth vacuoles from the liver cells stimulates the animal's immune response to the VIA antigen.  相似文献   

The fermentative capacity of growing pigs and adult sows fed diets with contrasting type and level of dietary fibre     

Henry Jrgensen  Anja Serena  Mette S. Hedemann  Knud Erik Bach Knudsen 《Livestock Science》2007,109(1-3):111-114

Adult sows have a more developed gastro-intestinal system than young growing pigs resulting in a superior capacity to digest fibrous components. The main objective of this study was to describe the capacity of sows and growing pigs to digest the fibre components in concentrated low dietary fibre (DF) diet and two high DF diets similar in DF but with contrasting DF solubility. Six sows and four growing pigs were fitted with a simple T-cannula at the terminal ileum. Each balance experiment consisted of a 7-day initial period followed by a 3-day collection of faeces and a 2 or 3-day collection of ileal digesta for growing pigs and adult sows, respectively. When feeding diets with high proportions of soluble non-starch polysaccharides (NSP), the difference in fermentation capacity between growing pigs and adult sows was small. The adult sows showed a higher fermentative capacity, evidenced by a higher fermentation and a higher methane production, when high fibre diet with high amount of insoluble fibre was fed.  相似文献   

Divergent, genetically based feeding behaviour of two sympatric Arctic charr, Salvelinus alpinus (L.), morphs   总被引：1，自引：0，他引：1  

A. Klemetsen  R. Knudsen  R. Primicerio  P.-A. Amundsen 《Ecology of Freshwater Fish》2006,15(3):350-355

Abstract –  Arctic charr, Salvelinus alpinus (L.), is one of the several northern fishes that show resource polymorphisms in postglacial lakes. Two reproductively isolated morphs of Arctic charr coexist in distinct ecological niches in the subarctic lake Fjellfrøsvatn, North Norway. Offspring of the two morphs (termed littoral charr and profundal charr) were reared separately but under identical conditions. Their feeding behaviour was compared experimentally using different kinds of live prey. The fishes had no experience with natural prey before the experiments. The littoral morph were more effective in eating live plankton ( Daphnia ) and littoral benthos ( Gammarus ), and had a higher attack rate against pleuston (surface prey, Gerris ) compared with the profundal morph. The two morphs behaved in accordance with expectations from their in situ niche utilisation towards the three prey types. This indicates a case of incipient ecological speciation where divergence in resource utilisation in contrasting niches has evolved adaptations in feeding behaviour by natural selection.  相似文献   

Allelic losses and gains during translocations of a high conservation value fish,Coregonus lavaretus     

Kim Præbel  Colin W. Bean  Jennifer A. Dodd  Elizabeth C. Etheridge  Andrew R.D. Gowans  Rune Knudsen  Alexander A. Lyle  Peter S. Maitland  Ian J. Winfield  Colin E. Adams 《水产资源保护:海洋与淡水生态系统》2021,31(9):2575-2585

1. The use of translocations to establish new or ‘refuge’ populations for species with high conservation value is controversial but widely used in conservation management. One of the risks of this approach is that an establishing population does not adequately capture the genetic diversity of the donor gene pool. This effect, rarely examined, is tested here.
2. In this study the genetic consequences of two conservation translocations after five generations (16 years) of the European whitefish, Coregonus lavaretus, were quantified. Both translocations were made using almost the same genetic groups and thus represent a partly replicated natural study.
3. Analysis of 12 informative microsatellites showed that expected heterozygosity, the mean number of alleles per locus and allelic richness did not differ between donor and translocated populations. There was also no loss of heterozygosity in the translocated populations, nor deviations from Hardy–Weinberg equilibrium expectations, nor signs of linkage disequilibrium.
4. All populations were genetically differentiated but pairwise F_ST values were low, indicating that the magnitude of divergence was small.
5. There was no evidence of inbreeding but there were significant differences in private allelic richness between donor and translocated populations. Of 50 alleles found in the donor population, 16% of the rarer alleles were lost in one translocated population and 8% in the other.
6. Allele loss without a reduction in heterozygosity strongly points to stochastic drift effects having occurred following translocation. The evidence indicates that alleles that were not detected in the donor population have arisen de novo in the translocated populations.
7. It is concluded that conservation translocations comprising even a modest number of propagules can successfully capture a high proportion of genetic variation of the host population, and that reduced genetic variation in the translocated population may be mitigated by the emergence of new variation over short time periods.

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Components of Response in Barley Anther Culture   总被引：2，自引：0，他引：2  

S. Knudsen    I. K. Due  S. B. Andersen 《Plant Breeding》1989,103(3):241-246

Anther culture response with 17 widely-grown varieties and one model variety of barley was studied with one replication from field-grown donor plants and one replication from a growth-chamber. Plants were regenerated from all 18 varieties and green plants were obtained from 16 of them. On average, 1.6 green plants were obtained per 100 cultured anthers from all the material. Estimated variance components for the formation of embryos/callus from the anthers were dominated by the effects of the genotypes and interactions between plant material and environments which together accounted for 60.1 and 17.0 % of the total variation respectively, while environments were nonsignificant for this character. Plant regeneration from embryos/callus were not significantly influenced by either genotype or environments. Components of variance for green plant formation were dominated by the effects of the genotypes, accounting for 73.2 % of the total variation, and a smaller effect from environments accounting for 11.2% of the total variation. Main effects from genotypes on the percentage of green regenerants divided 7 varieties into two distinct groups, indicating that major genetic factors were involved. The genetic basis for green plant regeneration seems different from that governing embryo formation. The results are discussed with respect to the possible prediction of anther culture response for new barley hybrids, as a means for directing the use of barley anther culture towards material that responds well.  相似文献   

Field assessment of partial resistance to powdery mildew in spring barley     

J. Chr. Nørgaard Knudsen  H. H. Dalsgaard  J. Helms 《Euphytica》1986,35(1):233-243

Summary Partial resistance to powdery mildew in spring barley was evaluated in three plot types: large isolation plots, in 1.4 m² plots in chessboard design with guard plots of spring wheat and in single rows. Percentage leaf area covered by powdery mildew was scored four to six times during the season and partial resistance was characterized by the area under the disease progress curve. Varietal differences were revealed in al three plot designs, differences between the most resistant and susceptible genotypes being of a factor five. Differences between varieties decreased with decreasing plot size. The relationship between single scores of amount of powdery mildew on the upper four leaves and the area under the disease progress curve was high in all plot designs during the first two to three weeks after heading, allowing selection for the trait by one or two scorings. Differential ranking of varieties between different plot designs was observed, and is assumed to be due to increasing plot interference with reduced plot size and reduced distance between plots. A reliable selection for partial resistance could be made in large isolation plots and in 1.4 m² plots, but hardly in single rows.  相似文献   

Use of dietary supplements in Denmark is associated with health and former smoking     

Knudsen VK  Rasmussen LB  Haraldsdóttir J  Ovesen L  Bülow I  Knudsen N  Jørgensen T  Laurberg P  Perrild H 《Public health nutrition》2002,5(3):463-468

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