新疆褐牛导入美国瑞士褐牛后代犊牛放牧补饲试验

[目的]研究新疆褐牛导入杂交后代在不同生产方式下的生产性能与适应性.[方法]选择美新褐杂交F1代、F2代犊牛68头,并按品种类型、性别随机分为2组,试验组为放牧补饲生产,对照组为天然放牧生产.[结果]表明:美新褐牛F1代、F2代犊牛试验组与对照组相比日增重显著(P＜0.05),试验组F1代较F2代公牛日增重提高10％,...     

Diameter-Selective Raman Scattering from Vibrational Modes in Carbon Nanotubes

Single wall carbon nanotubes (SWNTs) that are found as close-packed arrays in crystalline ropes have been studied by using Raman scattering techniques with laser excitation wavelengths in the range from 514.5 to 1320 nanometers. Numerous Raman peaks were observed and identified with vibrational modes of armchair symmetry (n, n) SWNTs. The Raman spectra are in good agreement with lattice dynamics calculations based on C-C force constants used to fit the two-dimensional, experimental phonon dispersion of a single graphene sheet. Calculated intensities from a nonresonant, bond polarizability model optimized for sp2 carbon are also in qualitative agreement with the Raman data, although a resonant Raman scattering process is also taking place. This resonance results from the one-dimensional quantum confinement of the electrons in the nanotube.     

美国东部黑核桃不同家系幼树年生长节律研究

通过对引进的3个家系美国东部黑核桃4-5年生幼树的年生长节律及物候分析比较,结果表明:(1)黑核桃春季萌动、抽梢生长较晚,生长期仅为80 d左右,高、径生长集中在5-7月;(2)为使新梢充分木质化,预防2次生长带来的早、晚霜危害,树木停止高生长后,及时有效控水;(3)同一种源不同家系间,高、径生长存在差异,引进种子苗木时,应考虑引进经过区域试验种源的优良家系。     

Pregnancy-associated Glycoprotein Profile during the First Trimester of Pregnancy in Egyptian Buffalo Cows

Pregnancy-associated glycoprotein (PAG) concentrations were measured in buffalo cows starting from day 28 after breeding. Oestrus was synchronized in 10 buffaloes using two injections of 25 mg prostraglandin (PG)F_{2 α} (Lutalyse^®) at a 11-day interval. Blood sampling was conducted nearly twice weekly. Results indicated that plasma PAG concentrations in non-pregnant buffaloes were low (<0.20 ng/ml) during the whole experimental period (day 28 to 103), while in pregnant animals plasma PAG levels increased from day 28 (4.48 ± 0.92 ng/ml) until day 41 (27.27 ± 6.74 ng/ml), remaining high (20.71 ± 9.20 ng/ml) until day 103. Progesterone levels were significantly (p < 0.0001) higher in pregnant (3.51–4.80 ng/ml) than in non-pregnant buffaloes (0.28–1.52 ng/ml). A significant difference (p < 0.0001) in plasma PAG concentrations between pregnant and non-pregnant animals starting at day 28 after breeding suggests that PAG-radioimmunoassay could be suitable for pregnancy diagnosis in buffaloes during this period. In conclusion, PAG test offers the advantages that it requires a single plasma sample for early pregnancy diagnosis as well as the accuracy of the test for the detection of pregnancy as early as day 28.     

不同精粗比全混合颗粒饲粮对母羊营养物质表观消化率、氮代谢和能量代谢的影响

本试验研究了不同精粗比全混合颗粒饲粮对母羊营养物质表观消化率、氮代谢和能量代谢的影响,以确定母羊饲粮适宜精粗比[或中性洗涤纤维(NDF)水平]。试验采用单因素完全随机区组设计,将30只体况良好、8月龄、体重相近的杂交母羊(萨福克羊×阿勒泰羊)随机分为6个处理,每个处理5只羊,分别饲喂6种不同精粗比(85∶15、70∶30、55∶45、40∶60、25∶75、10∶90)的全混合颗粒饲粮。预试期10 d,消化代谢试验18 d,呼吸测热试验2 d。结果表明:1)全混合颗粒饲粮精粗比对母羊干物质(DM)、有机物(OM)和NDF表观消化率均产生了极显著影响(P<0.01),DM和OM表观消化率随精粗比的上升而升高,精粗比为55∶45的饲粮NDF表观消化率最高,与精粗比为85∶15和70∶30的饲粮差异不显著(P>0.05)。2)消化氮随着精粗比的上升而升高,过高或过低精粗比均不利于氮的沉积,精粗比为55∶45时,母羊对氮的利用效率最高。3)消化能、代谢能、总能消化率和总能代谢率均随着精粗比的上升而出现极显著的升高(P<0.01)。在本试验条件下,母羊对精粗比为70∶30和55∶45(NDF水平分别为37.78%和45.80%)的全混合颗粒饲粮消化吸收较好。     

Bluetongue virus infection in sheep: haematological changes and detection by polymerase chain reaction

SUMMARY Eight sheep vaccinated with 10⁶ pfu of attenuated Australian bluetongue virus serotype 23 (BTV-free sheep were challenged with virulent BTV 23. There was little subsequent variation in the mean clinical score, or in the mean lymphocyte and platelet concentrations in the peripheral blood of the eight vaccinated sheep. There was a marked thrombocytopenia and lymphopenia in the naive sheep as the mean lymphocyte and platelet concentrations fell to a minimum at days 8 and 11 after inoculation, respectively. Similar changes were observed in three other naive sheep inoculated with field isolates of BTV 1, 9 or 23. BTV was detected by nested polymerase chain reaction in whole blood of these sheep between days 6 and 28, in mononuclear leukocytes between days 3 and 14, and in platelets between days 6 and 21.     

肉牛早期断奶试验研究

[目的]旨在研究早期断奶技术对不同品种肉用犊牛生长发育的影响,[方法]本试验在草原牧区应用犊牛代乳料产品开展了不同品种犊牛的早期断奶工作,[结果]表明:安杂牛、新褐杂牛、荷斯坦牛三组间日增重差异不显著(P>0.05),安杂组增重成本8.25元/kg,新褐杂增重成本组9.27元/kg,荷斯坦组增重成本9.62元/kg,但...     

Presence and diversity of mixed avian Plasmodium spp. infections in introduced birds whose distribution overlapped with threatened New Zealand endemic birds

ABSTRACT

Aims: To determine the presence of infection and co-infection of Plasmodium lineages in introduced birds at translocation sites for the North Island saddleback (Philesturnus rufusater), to investigate their role as Plasmodium spp. reservoirs.

Methods: Blood samples were collected from introduced bird species, with a special focus on blackbirds (Turdus merula) and song thrushes (Turdus philomelos), at six locations in the North Island of New Zealand that were the origin, or translocation sites, for North Island saddleback. Where available, blood smears were examined, and blood samples were tested using nested PCR with subsequent sequence analysis, for the presence of Plasmodium spp.

Results: Of the 55 samples tested using PCR analysis, 39 (71%) were positive for Plasmodium spp., and 28/40 (62%) blood smears were positive for Plasmodium spp. Overall, 31 blood samples were from blackbirds with 28/31 (90%) samples positive for Plasmodium spp. Six distinct avian Plasmodium lineages were identified, including three cosmopolitan lineages; Plasmodium vaughani SYAT05 was detected in 16 samples, Plasmodium matutinum Linn1 in 10 samples and Plasmodium elongatum GRW6 in eight samples. Mixed infections with more than one lineage were detected in 12 samples. Samples from two Australian magpies (Gymnorhina tibicen) were positive for Plasmodium. sp. lineage MYNA02, previously not identified in New Zealand.

Conclusions and clinical relevance: This is the first report from New Zealand in which specific Plasmodium spp. mixed infections have been found in introduced birds. Co-infections with several cosmopolitan Plasmodium lineages were identified, as well as the first report in New Zealand of an exotic avian Plasmodium sp. lineage, in Australian magpies. Whilst the role of introduced birds in maintaining and spreading pathogenic avian malaria in New Zealand is unclear, there is a potential infection risk to native birds, especially where distributions overlap.