留茬高度对人工草地牧草产量及质量的影响   总被引：14，自引：5，他引：9  

瓦庆荣  代志进  卢琪 《草业学报》2000,9(1):65-68

试验对黑麦草／白三叶混播草地在不同留茬高度下的生产特性进行了分析研究,研究结果表明,草地牧草的枯死率与留茬高度呈正比关系,在不同留茬高度下,草地牧草青绿物质的生长速度和产量呈抛物线形式变化;青绿牧草产量占牧草总产量的百分比随留茬高度的上升而下降,而死亡物质的数量占牧草产量的百分比随留茬高度的上升而增加。  相似文献   

Treatment of feline hyperthyroidism using orally administered radioiodine: a study of 40 consecutive cases     

R. MALIK  WA LAMB  DB CHURCH 《Australian veterinary journal》1993,70(6):218-219

SUMMARY Forty cats with hyperthyroidism were treated using 200 to 300 (typically 250) mBq of orally administered ¹³¹I. Thirty-six cases (90%) were successfully treated, as assessed by resolution of clinical signs and reduction In plasma thyroxine concentrations to normal or reduced values after treatment. Although higher doses of ¹³¹I appear to be required when the radioisotope is administered orally rather than Intravenously, a less stressful administration procedure and greater availability of therapy capsules offer useful advantages for treating thyrotoxic cats.  相似文献   

Hyperthermia in Merino wethers affected with humpyback disease     

BHG PEARSE  SKJ PEUCKER  WA HOEY 《Australian veterinary journal》1992,69(4):94-95

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贵州优良草坪草种质资源评价   总被引：1，自引：1，他引：0  

尚以顺  吴佳海  瓦庆荣  赵熙贵  刘贵林  张文 《草业科学》2003,20(1):26-28

通过对1998－2000年引种征集的19个草坪草品种特性试验以及对供试草种的密度、质地、色泽、均一性、抗性等进行测定，分析表明：参试的19个草坪草品种，大多数在独山地区的气候、土壤等自然条件下生长良好，是较理想的草坏草，可供生产上利用。  相似文献   

Pyelonephritis, nephrolithiasis and perinephric abscessation in a dog     

DC LEWIS  DRT ADAMSON  KA JACOBS  WA LAMB 《Australian veterinary journal》1988,65(6):195-196

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Chronological Appearance of Apoptosis in Bovine Embryos Reconstructed by Somatic Cell Nuclear Transfer from Quiescent Granulosa Cells     

JO Gjørret  J Wengle  P Maddox-Hyttel  WA King 《Reproduction in domestic animals》2005,40(3):210-216

Efficiency of cloning has remained low and in spite of attempts to improve this technology, many reconstructed embryos do not implant or are lost during early pregnancy. Chromosomal aberrations, deviant gene expression patterns and abnormal regulation of cell death may be involved in this increased early embryonic loss. Here, we investigate the chronological onset of both apoptotic changes in nuclear morphology and DNA degradation [detected by transferase-mediated dUTP nick-end labelling (TUNEL) reaction] in bovine two-cell- to blastocyst-stage embryos. Such embryos were generated either by reconstruction with nuclear transfer from quiescent granulosa cells or by regular in vitro embryo production. Nuclear condensation was observed from the two-cell stage and TUNEL labelling was observed from the six-cell stage in reconstructed embryos, whereas nuclear condensation was evident from the eight-cell stage and TUNEL labelling from the 13-cell stage in embryos derived in vitro. Furthermore, reconstructed embryos displayed elevated ratios of embryos containing apoptotic nuclei at pre-compaction stages and higher indices of apoptotic nuclei in morula and blastocyst stages when compared with in vitro-produced embryos.  相似文献   

Calf and colostrum management practices on New Zealand dairy farms and their associations with concentrations of total protein in calf serum     

EL Cuttance  WA Mason  RA Laven  KS Denholm  D Yang 《New Zealand veterinary journal》2018,66(3):126-131

AIMS: To gather information on management practices and farmer attitudes to management of cows and calves during the immediate post-partum period on dairy farms in New Zealand, and to assess these practices for associations with concentrations of total protein (TP) in serum of calves 1–8 days-old.

METHOD: Between July and September 2015 blood samples were collected from calves aged between 24 hours and 7 days, from dairy farms (n=105) in nine areas in New Zealand, on three occasions throughout the calving period. Concentrations of TP were determined in all serum samples. At each visit technicians collected 1?L of the pooled colostrum that was intended for feeding to newborn calves that day. These samples were assessed for Brix, coliform and total bacterial counts. After the last sampling visit, the calf rearer or farm manager were asked to complete a questionnaire describing calf and colostrum management practices on the farm. Potential farm-level variables associated with concentrations of TP in serum of sampled calves were identified using univariable and multivariable linear mixed models.

RESULTS: Mean concentration of TP in serum of calves across all farms was 59.8 (95% CI=59.4–60.2) g/L, and was associated with region and herd size in the final multivariable model. Concentrations of TP were lower in calves from farms in Otago (56.2 (95% CI=53.4–58.9) g/L) and Southland (56.9 (95% CI=54.1–59.7) g/L) compared to calves on farms in the Far North (62.6 (95% CI=59.8–65.3) g/L), and were lower in calves from farms with a herd size >600 (58.3 (95% CI=56.7–59.8) g/L) than ≤600 (61.3 (95% CI=60.1–62.5) g/L) cows. After accounting for fixed effects, farm accounted for only 8.4% of the unexplained variation. There was no association between any of the measures of colostrum quality and concentrations of TP in serum (p>0.2).

CONCLUSION AND CLINICAL RELEVANCE: Very few herd-level variables were associated with concentrations of TP in serum. Risk factors that have been shown to be of importance in previous studies outside New Zealand were not identified as important in the current study. It is possible that, in the situation where calves are kept at pasture with their dams for prolonged periods, variables which influence how well a cow can feed its calf in the first 12–24 hours have a larger influence on concentrations of TP in serum than the collection and management of calves once they reach the rearing shed.  相似文献   

Enrichment of Y‐Chromosome‐Bearing Bull Spermatozoa by Swim‐up Through a Column     

A Azizeddin  FA Ashkar  WA King  T Revay 《Reproduction in domestic animals》2014,49(1):e1-e4

With the advancement of assisted reproductive biotechnologies, preselecting the sex of offspring has become an important goal for cattle and other livestock breeding as well as for research. The aim of this study was to investigate the feasibility of producing enriched pools of X‐ or Y‐chromosome‐bearing sperm by vertical swim‐up through a long, narrow column. Sperm recovered from the top portion of the column was predominantly Y‐bearing (60%, p < 0.05), which were capable of fertilizing matured oocytes and produce significantly more male embryos compared with standard swim‐up protocol.  相似文献   

补饲马铃薯藤对山羊生长性能、消化率和胴体特征的影响     

邓培华  王娟  洼桑措  付建 《中国饲料》2021,1(6):107-110

本研究旨在探讨马铃薯藤饲喂水平对山羊生长性能、养分消化率和胴体特征的影响。试验将平均初始体重为（14.42±0.24）kg的40头山羊随机分为4组,每组5个重复,每个重复2头。T1组仅饲喂干草,T2组饲喂干草+100%马铃薯藤,T3组饲喂干草+50%马铃薯藤+50%浓缩料,T4组饲喂100%浓缩料。在为期10周的饲养试验后屠宰,分析胴体特征。结果：T2～T4组山羊的末重、增重、日增重和饲料效率显著高于T1组（P＜0.05）,其中T1组山羊的日增重和增重均表现出负增长。T2～T4组山羊的干物质、有机物、粗蛋白质和代谢能摄入量均显著高于T1组（P＜0.05）,但T2和T3组山羊中性洗涤纤维摄入量显著高于T1和T4组（P＜0.05）。T2、T3和T4组山羊干物质和有机物表观消化率显著高于T1组（P＜0.05）,T4组山羊粗蛋白表观消化率显著高于T1和T2组（P＜0.05）。T2、T3和T4组山羊屠体重、热胴体重、眼肌面积、可食用内脏和不可食用内脏重量均显著高于T1组（P＜0.05）。T3组山羊的屠宰率显著高于其他组（P＜0.05）。结论：在干草为基础的日粮中添加马铃薯藤可以提高山羊采食量、饲料转换率、养分消化率、屠宰率和胴体特征。 [关键词]马铃薯藤|山羊|生长性能|消化率|胴体特征  相似文献   

Enhanced tolerance of photosynthesis to high-light and drought stress in Pseudotsuga menziesii seedlings grown in ultraviolet-B radiation     

Poulson ME  Donahue RA  Konvalinka J  Boeger MR 《Tree physiology》2002,22(12):829-838

We investigated the effects of an ambient dose of ultraviolet-B (UV-B) radiation on chamber-grown Pseudotsuga menziesii var. glauca (Beissn.) Franco (Douglas-fir) seedlings, to determine if the presence of UV-B radiation in the growth light regime induces tolerance to environmental stresses such as high light and drought. Douglas-fir seedlings were grown without UV-B radiation or with 6 kJ m-2 day-1 of biologically effective UV-B, which is ambient for the intermountain regions of Idaho. Non-stressed seedlings grown with UV-B radiation had 35% lower seedling dry mass, 36% higher concentrations of UV-B absorbing compounds per unit leaf area, 30% lower stomatal frequencies, 25% lower light-saturated photochemical efficiencies of Photosystem II and 45% lower light-saturated stomatal conductance than non-stressed seedlings grown without UV-B radiation. After 4 days of high-light stress, seedlings grown with UV-B radiation had 32% higher light-saturated carbon assimilation rates (A(CO2)) than seedlings grown without UV-B radiation. After water was withheld from the seedlings for up to 15 days, seedlings grown with UV-B radiation had 50% higher A(CO2) and 40% higher seedling water potentials than seedlings grown without UV-B radiation. The results support the hypothesis that UV-B radiation can act as an environmental signal to induce tolerance to high-light and drought stress in Douglas-fir seedlings. Possible mechanisms for the enhanced stress tolerance are discussed.  相似文献