Incidence of ryegrass staggers in white rhinoceros (Ceratotherium simum) at Auckland Zoo

Abstract

Extract

Most perennial ryegrass (Lolium perenne) plants in pastures in New Zealand contain a naturally occurring fungal endophyte, Neotyphodium lolii. Endophyte-infected perennial ryegrass produces alkaloids that vary in concentration during the year. Some alkaloids enhance the persistence and productivity of ryegrass pastures by protecting them against insect attack. However, when other alkaloids are consumed they can reduce animal performance and lead to health problems. The alkaloid lolitrem B, for example, causes the neuromuscular disorder ryegrass staggers (Fletcher et al 1999 Fletcher, LR, Sutherland, BL and Fletcher, CG. 1999. “The impact of endophyte on the health and productivity of sheep grazing ryegrass-based pastures”. In Ryegrass endophyte: an essential New Zealand symbiosis Grassland Research and Practice Series Edited by: Woodfield, DR and Matthew, C. Vol. 7, 11–17.  [Google Scholar]). Clinical symptoms of ryegrass staggers in animals range from slight muscular tremors through to staggering and complete collapse. Severely affected animals create management problems and are prone to accidental death. Outbreaks occur sporadically, particularly in summer and autumn and affect sheep, cattle, deer, horses, llamas (Lama glama) and alpaca (Lama pacos). Lolitrem B appears to be a stable compound, which tends to be concentrated in the leaf sheath at the base of the ryegrass plant and in the seed-heads (di Menna et al 1992 di Menna, ME, Mortimer, PH, Prestidge, RA, Hawkes, AD and Sprosen, JM. 1992. Lolitrem B concentrations, counts of Acremo ni um lolii hyphae, and the incidence of ryegrass staggers in lambs on plots of A. lolii-infected perennial ryegrass. New Zealand Journal of Agricultural Research, 35: 211–217. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]; Keogh et al 1996 Keogh, RG, Tapper, BA and Fletcher, RH. 1996. Distributions of the fungal endophyte Acremonium lolii, and of the alkaloids lolitrem B and peramine, within perennial ryegrass. New Zealand Journal of Agricultural Research, 39: 121–127. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). Hay made from endophyte-infected perennial ryegrass contains large numbers of seed-heads and lolitrem B concentrations can be high, especially if it is made in late summer or autumn and, consequently, animals fed such hay are at risk of developing ryegrass staggers.     

ULTRASONOGRAPHY OF THE NORMAL FELINE PANCREAS AND ASSOCIATED ANATOMIC LANDMARKS: A PROSPECTIVE STUDY OF 20 CATS

The sonographic appearance of the feline pancreas and associated anatomic landmarks including the pancreatic duct, duodenum, duodenal papilla, portal vein, and gastric lymph node were evaluated in 20 healthy, awake cats. The pancreas appeared nearly isoechoic to surrounding mesenteric tissues, isoechoic to slightly hyperechoic to adjacent liver lobes, and hypoechoic to the spleen. The mean thickness measurements for the right pancreatic lobe, body, and left pancreatic lobe were 4.5 mm (range 2.8-5.9), 6.6 mm (range 4.7-9.5), and 5.4 mm (range 3.4-9.0), respectively. The pancreatic duct was consistently visualized in the left pancreatic lobe and had a mean thickness of 0.8 mm (range 0.5-1.3). It could be differentiated from the pancreatic vessel, by its central location, and the duct's lack of Doppler flow signal. The duodenum was used as a landmark to identify the right lobe of the pancreas. The mean duodenal wall thickness measurement was 2.8 mm (range 2.1-3.8) in sagittal section, and 3.0 mm (range 2.2-4.4) in transverse section. The duodenal papilla was identified in 4 of 20 cats. It ranged in size from 2.9 to 5.5 mm in width, and had a maximum height of 4.0 mm in transverse section. The portal vein was used as a consistent anatomic landmark for identification of the left lobe and body of the pancreas. The mean diameter of the portal vein at the level where the pancreatic body joins the left pancreatic lobe was 4.3 mm (range 2.7-5.9) when viewed in sagittal section, and 4.5 mm (range 3.6-6.1) in transverse section. The gastric lymph node was identified cranial and ventromedial to the pyloroduodenal angle in 6 of 20 cats. It had an asymmetrical shape with a larger caudal pole in five of the six cats. The largest dimensions of the gastric lymph node were 10 mm in length, and 6 mm in width for the larger caudal pole, and 5.1 mm in width for the smaller cranial pole.     

Challenges in research on rhizomatous clonal plants北大核心CSCD

根茎克隆植物是克隆植物的一个类型,地下系统的特殊性赋予其独特的繁殖和生长方式,也赋予其对环境的特有适应能力。但是,受研究手段限制,人们对根茎克隆植物在表型可塑性、克隆整合、觅食行为和克隆分工等方面与其他类型克隆植物有何异同,这些行为对预防植物入侵、应对气候变化、进行退化生态系统恢复有何特殊意义尚不很清晰。鉴于此,通过梳理和总结前人工作,提出了根茎克隆植物研究面临的挑战。根茎克隆植物下一步研究重点应体现在下述方面:1)可塑性性状的选择与测定方法;2)环境因子对克隆整合的影响机制;3)综合植物特征和环境特征的觅食模型。     

The Impact of Reproductive Technologies on Stallion Mitochondrial Function

The traditional assessment of stallion sperm comprises evaluation of sperm motility and membrane integrity and identification of abnormal morphology of the spermatozoa. More recently, the progressive introduction of flow cytometry is increasing the number of tests available. However, compared with other sperm structures and functions, the evaluation of mitochondria has received less attention in stallion andrology. Recent research indicates that sperm mitochondria are key structures in sperm function suffering major changes during biotechnological procedures such as cryopreservation. In this paper, mitochondrial structure and function will be reviewed in the stallion, when possible specific stallion studies will be discussed, and general findings on mammalian mitochondrial function will be argued when relevant. Especial emphasis will be put on their role as source of reactive oxygen species and in their role regulating sperm lifespan, a possible target to investigate with the aim to improve the quality of frozen–thawed stallion sperm. Later on, the impact of current sperm technologies, principally cryopreservation, on mitochondrial function will be discussed pointing out novel areas of research interest with high potential to improve current sperm technologies.     

不同放牧环境下绵羊牧食行为的比较研究

为了研究同品种绵羊在不同放牧环境下的牧食行为差异,在典型草原区沙质草地和高平原草地两种放牧环境下,对四品种双杂交杂种绵羊的牧食行为进行了观察.结果表明:不同放牧环境下绵羊的采食时间和游走时间占放牧时间的80%左右,放牧环境对采食行为有显著的影响.绵羊在沙质草地采食和游走时间占总放牧时间的66.54%和15.63%,在高平原草地为77.49%和7.79%.不同放牧环境下卧息、站立等时间存在显著差异.     

2种植物生长调节剂对四季玫瑰嫩枝生根作用的研究

在四季玫瑰嫩枝扦插育苗试验中,用ABT1^#生根粉和吲哚丁酸(IBA)不同浓度溶液处理。结果表明：植物生长调节剂ABT11^#和IBA对四季玫瑰扦插生根都有很大的促进作用,生根率比对照可提高20％～60％,在设计的几种处理中生根率效果最好的为IBA200mg／L、300mg／L、100mg／L,生根率分别为91．0％、90％、88．2％;其次为ABT11^#生根粉200mg／L,生根率为88．3％。植物生长调节剂不同浓度处理对插穗生根的质量均有显著的影响。     

五种荒漠灌木密度与水热气候因子的关联分析

以1994—2000年内蒙古阿拉善锡林高勒地区荒漠灌木的定位观测资料为基础,利用灰色关联分析方法,分6个时段分析了5种荒漠灌木种群密度与日平均气温、日平均最高气温、日平均最低气温、降水量和0—20cm、20—80cm地温6个水热气候因子的关联性。结果表明,白刺与上年旺盛生长季降水量,霸王与上年生长季降水量有较大关联性,其它3个灌木种则与当年生长季降水量的关联性最大。当年全年日平均气温、日平均最低气温与刺叶柄棘豆和红砂,当年全年0—20cm地温、日平均最低气温与短脚锦鸡儿,当年全年日平均最低气温和当年生长季0—20cm地温与霸王,以及当年生长季日平均气温和0—20cm地温与白刺的种群密度具有较高的关联度。多数荒漠灌木种群密度与降水量的关联性大于热量因子（霸王除外）,但由于生长、发育低温阈值偏高,日平均最低气温可能是荒漠灌木种群波动的基础性气候因子。此外,霸王作为荒漠灌木的优势种,对荒漠高温、少雨的干旱气候有着极强的适应性,这些研究结果对深人开展荒漠灌木种群生态与气候关系研究具有一定参考意义。