几种豆禾牧草混播初期生长互作效应的研究

选用豆科与禾本科牧草各两种互为混播组合，研究其混播状态下种子萌发及幼苗生长的互作效应，结果表明：当以白三叶、紫花苜蓿为作用牧草，并随期播量增加时，受体牧草高羊茅与紫羊茅种子萌发及幼轩生长受到显著影响，受体牧草紫花苜蓿种子萌发及幼苗生长则对幼苗生长有促进作用。互作效应强度的进一步分析表明，豆科牧草对禾本科牧草的作用一般较强，并在初期生长阶段有较好的表现。这一结果与混播草地豆科牧草所表现的特征相符。因此本研究可从一个侧面为混播草地豆禾组合相容性提供可资借鉴的高效简捷的判定方法。     

Digestibility, intake and mineral utilization of combinations of grasses and legumes by lambs

Defined mixtures of two grass (orchardgrass, perennial ryegrass) and two legume (alfalfa, red clover) hays, harvested in two cuttings in 2 yr, were fed in digestibility, intake and mineral balance trials to wether lambs. Each mixture was fed in ad libitum amounts to six crossbred wether lambs weighing 35 to 45 kg. The effect of increasing proportion of legume in mixtures on dry matter digestibility (DMD), neutral detergent fiber digestibility (DNDF) and digestible dry matter intake (DDMI) differed with species combination. For all combinations, a quadratic regression (P less than .05) for DMD and DNDF indicated a small, negative associative effect for mixtures of grasses and legumes compared with pure species. Dry matter intake (DMI) showed a quadratic increase with level of legume inclusion, indicating a positive associative effect. The observed increase of DMI was approximately 6 to 7% over predicted values with 25 or 50% legume in the mixture. Intake of NDF also showed a quadratic response to level of legume, but lambs tended to eat to a fairly constant intake of 42 to 43 g NDF/kg wt.75. Mineral utilization (apparent absorption, retention) differed (P less than .05) with cutting but not species combination, and generally improved with increasing legume content in the mixture. With the exception of calcium retention (negative quadratic effect), there was little evidence for significant associative effects between grasses and legumes in mineral utilization.     

Effect of cutting frequency on the yield and quality of legumes and grasses under irrigation

Abstract

Four pasture legumes and seven grasses were subjected to a range of cutting frequencies during the 1980/81 season. A wide range of responses emerged, judged by both the dry matter and TDN yield responses of the different species. Whereas two cultivars of white clover and Ruanui ryegrass were most productive with frequent harvesting (every 2 to 4 weeks), kikuyu and Sirocco Phalaris responded well to a long interharvest interval (8 to 10 weeks). A number of pasture types, including lucerne, Currie cocksfoot, K31 fescue and Ariki ryegrass produced well at intermediate harvesting frequencies (6‐weekly) while in yet others (Kenland red clover and Seedmaster Phalaris) yield was not materially different over a wide range of cutting intervals in the range 6 to 10 weeks.     

豆-禾混播草地种间关系研究进展

禾本科与豆科牧草的混播,是人工草地建植的最主要方式之一,而了解其之间的种间互作机理,对于维持混播草地的持续稳定生产具有重要意义。本研究从光照、养分、水分和空间等资源方面展开探讨了禾草和豆科牧草在混播时所采取的不同生存策略,阐述了豆—禾混播草地草种之间的竞争与促进关系,分析了豆科牧草固氮和转氮能力的影响因素及深根系豆科牧草与浅根系禾草的共存机制,提出了可以通过混播建植技术、草地管理措施及草地利用方式避免或减弱混播草地豆禾牧草之间的竞争,以此提高混播草地的生产力并维持混播草地持久力和稳定性。     

Evaluation of the palatability of three nonsteroidal antiinflammatory top-dress formulations in horses

The efficacy of top-dress antiinflammatory drugs ultimately depends on a patient's willingness to consume treated feed. The current study compares the palatability of two phenylbutazone top-dress formulations (Equipalazone Powder, Dechra Pharmaceuticals, and Pro-Dynam, VetXX, Ltd.) and a suxibuzone top-dress formulation (Danilon Equidos, Janssen Animal Health). Results of a three-period, crossover study on 18 healthy horses showed that Pro-Dynam was significantly less palatable, with significantly less consumption of treated feed compared with either Equipalazone Powder or Danilon Equidos. There was no statistically significant difference in terms of consumption of treated feed and palatability scores between Equipalazone Powder and Danilon Equidos.     

Linseed oil supplementation in diet for horses: Effects on palatability and digestibility

Feed palatability and in vivo apparent digestibility of nutrients were compared in horses fed concentrates in which barley was, or not, partially substituted by 8% linseed oil. According to a cross-over design, three geldings and one stallion were fed at near maintenance level hay plus low or high fat diet (50/50). The last days of each 3-months sub-periods, partial faeces collections were performed and concentrate intake rate was measured to estimate the digestibility and the palatability of the diet. The inclusion of linseed oil did not affect the palatability of the diet and increased significantly (P < 0.05) the apparent digestibility of DM (66.5 vs 64.1%), CF (83.7 vs 57.3%) and NDF (53.0 vs 50.7%) but not of CP and ADF.     

4种牧草不同生长期C、N生态化学计量特征

摘要：在甘肃庆阳（降水量517 mm）和榆中（降水量350 mm）的大田栽培条件下,研究了3种豆科牧草陇东苜蓿（Medicago sativa cv. Longdong）、红豆草（Onobrychis viciaefolia）和箭筈豌豆（Vicia sativa）以及1种禾本科牧草一年生黑麦草（Lolium multiflorum）主要生长期的C、N含量及计量比变化。结果表明,不同生长期牧草有机碳含量差异不大;全氮含量随生长期呈降低趋势或在孕穗（蕾）期较低,叶全氮含量高于茎和根;C/N随生长期呈增加趋势或在孕穗（蕾）期较高,叶C/N低于茎和根,禾本科牧草C/N高于豆科牧草。榆中一年生黑麦草C/N高于庆阳,而豆科则相反。牧草C/N随生长期的变化与不同植物不同阶段C同化和N吸收有关。     

黔南地区4种禾/豆牧草混播组合比较研究

研究了2种禾本科牧草(一年生黑麦草和燕麦)分别与2种豆科牧草(光叶紫花苕和箭筈豌豆)混播组合的生产性能,结果表明,鲜草产量为一年生黑麦草与光叶紫花苕组合的总鲜草产量最高,达281 685.50kg/hm2;分蘖数或分枝数及死亡率、茎叶比和干鲜比,一年生黑麦草与光叶紫花苕组合均优于其他3个组合;4种牧草组合的最优混播比例有待进一步研究。综合分析,一年生黑麦草与光叶紫花苕组合适宜作为黔南地区刈割型牧草地种植利用。     

Preliminary safety and biological efficacy studies of ethyl pyruvate in normal mature horses

Reasons for performing the study: Endotoxaemia causes substantial morbidity and mortality in horses with colic and sepsis. Ethyl pyruvate is a novel anti‐inflammatory medication that improved survival in preclinical models of severe sepsis endotoxaemia and intestinal ischaemia and reperfusion in rodents, swine, sheep and dogs and may be a useful medication in horses. Hypothesis: Ethyl pyruvate has no adverse effects in normal horses and is biologically active based on suppression of proinflammatory gene expression in endotoxin stimulated whole blood, in vitro. Methods: Physical and neurological examinations, behaviour scores, electrocardiograms and clinicopathological tests were performed on 5 normal healthy horses receiving 4 different doses of ethyl pyruvate. Doses included 0, 50, 100 and 150 mg/kg bwt administered in a randomised crossover design with a 2 week washout period between doses. Biological efficacy was assessed by stimulating whole blood with endotoxin from the horses that received ethyl pyruvate prior to and 1 and 6 h after drug infusion. Gene expression for TNFα, IL‐1β and IL‐6 was assessed. Results: There were no effects of drug or dose (0, 50, 100 or 150 mg/kg bwt) on any of the physical or neurological examination, behaviour factors, electrocardiogram or clinical pathological results collected from any of the horses. All parameters measured remained within the normal reference range. There was a significant reduction in TNFα, IL‐1β and IL‐6 gene expression in endotoxin stimulated whole blood from horses 6 h after receiving 150 mg/kg bwt ethyl pyruvate. There were no detectable effects on gene expression of any of the other doses of ethyl pyruvate tested. Conclusion: We were unable to detect any detrimental effects of ethyl pyruvate administration in normal horses. Ethyl pyruvate significantly decreased proinflammatory gene expression in endotoxin stimulated blood 6 h after drug administration. Clinical relevance: Ethyl pyruvate may be a safe, effective medication in endotoxaemic horses.     

13种观赏草引种的生物安全性初探

为了防止观赏草的盲目推广带来生物灾害,该研究针对引入的13个观赏草品种分别从种子、不定根、检疫性病虫害3个方面分析了是否存在生物入侵的风险,并就观赏草生态适应性和在景观应用中的安全性进行了分析。结果表明,试验期间种子无自播现象;距离原始植株0.1～1.0 m半径范围内无蔓发性根发苗现象;未发现检疫性病虫害;水葱（Scirpus validus）和花叶水葱（S.validus ‘Mosaic’）与高抗逆性品种的关联度最高,为0.763 9,蒲苇（Cortaderia selloana）和矮蒲苇（C.selloana ‘Pumila’）稍次之,关联度为0.748 0;13种观赏草在园林景观中造成火灾危害的可能性极低。以上结果证明,所引品种在宁波地区种植存在生物入侵的可能性极低,可以在宁波及周边地区推广应用。     

Occurrence of associative effects between grasses and legumes in binary mixtures on in vitro rumen fermentation characteristics

When animals are fed a grass and legume mixture, digestive interactions can occur in the rumen between the substrates contained in the different plants, and the response of the animal to the combination of forages can differ from the balanced median values of their components considered individually. Our objective was to assess the associative effects between temperate forages in 8 grass-legume binary combinations on in vitro rumen fermentation characteristics to highlight synergies or antagonisms in terms of nutritional and environmental impacts. Two grasses (cocksfoot, CF; ryegrass, RG) and 4 legume species (alfalfa, A; white clover, WC; red clover, RC; sainfoin, SAN) were incubated alone and in grass-legume mixture (1:1, wt/wt) in batches containing buffered rumen fluid during 3.5 and 24 h. For each substrate and each incubation time, parameters describing the degradation of the energetic and nitrogenous compounds and their partition into fermentation end products were measured. Data were subjected to ANOVA using a mixed procedure to test quadratic contrasts. At 3.5 h of incubation, many quadratic effects were observed. The presence of A, WC, or RC in mixtures quadratically increased the NH(3)-N production (up to +28% when compared with the calculated value, P < 0.001), whereas the presence of condensed tannin (CT) activity in SAN considerably decreased it (up to -67%, quadratic effect, P < 0.001) and the N disappearance. To a lesser extent, the presence of SAN reduced the proportion of methane in the gas produced (up to 7%, quadratic effect, P = 0.018). Generally, the degradation of OM and NDF was not stimulated by mixing grass and legume, except for SAN. However, the presence of SAN severely impaired the NDF digestion at the early phase of fermentation. At 24 h of incubation, few associative effects were observed in comparison with those observed at 3.5 h of incubation, but the effect of CT of SAN on N metabolism was still clearly present. This study shows that, among the grass-legume mixtures tested in vitro, only the presence of SAN can interact with the grasses to reduce the degradation of proteins and the production of methane but with a transitory negative effect on fiber digestion.     

多效唑对高羊茅叶片糖酶活性的影响

高羊茅草坪草施用多效唑后，叶片的垂直生长受抑，叶片光合同化物向根系运输增强，叶片和根系中淀粉及可溶性糖含量升高。数据表明：叶片中淀粉含量与淀粉酶活性呈正相关（r=0.88)。，另外，叶片中酸性转化酶活性增加，但中性转化酶活性降低，且叶片中可溶性碳水化合物含量一直维持在较高水平，说明酸性转化酶在多效唑对草坪草叶片垂直生长的调节中起重要作用。草坪草生长动态的变化与多效唑改变碳水化合物代谢酶活性有关。可溶性糖的积累有利于增强草坪草抗逆性，促进新器官的发生。     

Pharmacokinetic studies on tobramycin in horses

The objective of the study was to evaluate the pharmacokinetics of tobramycin in plasma and urine in the horse (n = 7) after intravenous administration of a dose of 4 mg/kg b.w. Plasma tobramycin concentrations were assayed microbiologically and by means of HPLC analyses. Pharmacokinetic parameters, calculated on the basis of concentrations determined with the microbiological assay were not statistically different from those obtained when data from HPLC analysis were used, but the microbiological assay was more sensitive in the detection of low plasma and urine values. The values of the total body clearance (Cl(B)) were 101.4 +/- 30.1 and 130.0 +/- 49.9 mL/kg/h, respectively. The overall extraction ratio was 2.9%. The determined capacity of elimination of tobramycin in horses was similar to those for other aminoglycosides. Within 24 h after treatment, 57.6 +/- 12.2% of injected antibiotic was excreted in the urine.     

Clinical and therapeutic studies on mange in horses

At Kafr El-Sheikh province, Egypt, out of 117 examined drafting horses, mites were detected in 20 (17.09%) horses. The recovered mites were 14 Chorioptes, four Psoroptes and two Sarcoptes whereas mites were not detected in four cases clinically showed typical mange lesions. Interestingly, neither the age nor the sex of the examined horses had a clear influence on the prevalence of the infection. Clinical signs observed in mange infested horses were in the form of irregular skin lesions, severe itching and sometimes biting of affected skin areas and decrease feed consumption. The skin lesions mainly start as erythematous area followed by developing of papules and crust formation. Skin scratches as a result of traumatized lesions usually occurred. Hair was lost on the affected parts developing irregular alopecic areas. Distribution of the lesions was varied according to the type of mite. Chorioptic mite was detected in para-anal fold, distal portion of legs and tail lesions, Psoroptic mite was detected in withers, mane, shoulder and flank lesions whereas Sarcoptic mite was isolated mainly from lesions on the head and neck. Complete clinical and parasitological cure for mite infestation were obtained within 2 weeks in both moxidectin and ivermectin treated groups with 100% recovery rate. Our results indicated that moxidectin oral gel is effective and good alternative for the treatment of chorioptic mange in horse to avoid drug resistance that may develop as a result of the intensive use of ivermectin alone for long periods.