Influence of feeding regime on timing of parturition in beef cattle and the relationship of vaginal temperature to parturition

The timing of parturition was recorded for a total of 56 beef cattle (Japanese Black × Holstein Friesian) on different dietary treatments. The rate of calving during daylight hours in cows night‐fed (18.00 hours) with a roughage diet was significantly higher than that in cows night‐fed with a high concentrate diet (79.2% vs 38.5%, P < 0.05). Subsequently, the vaginal temperature (VT) of these cows was analyzed using a cosinor method. When the feeding schedule was changed from twice daily (08.30 and 15.30 hours) to night feeding, the periodicity, the acrophase and the bathyphase, which were the parameters of the cosine curve, were unstable from the first day of night feeding until after day 6 (P < 0.05). Prior to parturition, the midline‐estimating statistic of rhythm (MESOR) and the amplitude for the cows that were fed a high‐roughage diet at night and that calved at night‐time were lower and larger, respectively, than that for the other treatments (P < 0.01). Based on these results, the time of parturition in most of the beef cows was influenced by feeding time and diet composition. Those cows that calved at night‐time in spite of night feeding had lower vaginal temperatures.     

Impact of High Night‐Time and High Daytime Temperature Stress on Winter Wheat

High temperature is a major environmental factor that limits wheat (Triticum aestivum L.) productivity. Climate models predict greater increases in night‐time temperature than in daytime temperature. The objective of this research was to compare the effects of high daytime and high night‐time temperatures during anthesis on physiological (chlorophyll fluorescence, chlorophyll concentration, leaf level photosynthesis, and membrane damage), biochemical (reactive oxygen species (ROS) concentration and antioxidant capacity in leaves), growth and yield traits of wheat genotypes. Winter wheat genotypes (Ventnor and Karl 92) were grown at optimum temperatures (25/15 °C, maximum/minimum) until the onset of anthesis. Thereafter, plants were exposed to high night‐time (HN, 25/24 °C), high daytime (HD, 35/15 °C), high daytime and night‐time (HDN, 35/24 °C) or optimum temperatures for 7 days. Compared with optimum temperature, HN, HD and HDN increased ROS concentration and membrane damage and decreased antioxidant capacity, photochemical efficiency, leaf level photosynthesis, seed set, grain number and grain yield per spike. Impact of HN and HD was similar on all traits. Greater impact on seed set, grain number and grain yield per spike was observed at HDN compared with HN and HD. These results suggest that HN and HD during anthesis cause damage of a similar magnitude to winter wheat.     

不同昼夜温度对甜瓜幼苗生长的影响

试验研究了6组昼/夜温度处理(30/30、30/25、30/20、30/15、25/15、20/15℃)对甜瓜幼苗形态指标、生长量、叶绿素含量及根系特征的影响。结果表明,在以上6个试验条件下,甜瓜幼苗生长均受到不同程度的影响,25/15℃温度条件下,幼苗未出现徒长状况,并且甜瓜幼苗地下部鲜重最大,比相同夜温处理下的30/15、20/15℃2组分别高出35%、64%;壮苗指数呈现相同的趋势,25/15℃温度处理下壮苗指数和叶绿素含量最高,同样比其他2个处理分别高出43%、35%,幼苗根系活力也最高。对各项指标的分析表明,25/15℃气候条件下较适宜甜瓜幼苗生长发育,利于培养壮苗。     

南宁吴圩国际机场春季鸟类研究

南宁吴圩国际机场及其附近的春季鸟类群落由112种组成，分别隶属于13目38科，其中留鸟58种（51．8％），夏候鸟15种（13．4％），冬候鸟37种（33．0％），旅鸟2种（1．8％）。重要性值分析表明，最重要的种类有3种，即黄腹鹪莺Prinia flaviventris、纯色鹪莺P．inornata和棕扇尾莺Cisticola juncidis。按鸟类的生境分布系数划分，中性分布型有58种，占总种类数的51．8％，构成了该地各生境鸟类群落组成的主体。机场及其附近鸟类日活动规律显示，清晨7：00～8：00以及傍晚17：00～18：00两个时段，鸟类的活动是最明显的，但前者的峰值要高于后者，而中午13：00～14：00时段鸟类的种类和数量都是全天中最少的。     

笼养孟加拉虎雌雄白昼行为的差异

2005年12月～2006年8月,采用瞬时扫描取样法和全事件取样法,对云南野生动物园内5只孟加拉虎行为进行了初步观察。结果表明,在观察期内,笼养孟加拉虎白昼行为时间分配上两性存在一定差异,即雌性的睡眠和卧息多于雄性的睡眠和卧息;雌性的走动和其它行为少于雄性的走动和其它行为。在活动节律上,两性有极大的相似性,只是雌虎在下午的卧息高峰值比雄虎晚约1h。     

Chemical composition of Mongolian mare milk

Abstract

This study was carried out to determine the influence of three ecological regions and two milking seasons on daytime milk yield, chemical composition, protein fraction distribution and amino acids (AA) profile of milk samples from Mongolian native breed mares under traditional nomadic pasture conditions. Average daily daytime milk yield was 3975 ml. The milk contained 11.0% total solids, 2.0% fat, 6.6% lactose, 2.2% protein and 0.3% ash on average. Content of true whey protein was 36.8% and of casein 52.4%, respectively. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis demonstrated that the whey fraction contained 37.1% α-lactalbumin, 29.6% β-lactoglobulin, 16.1% immunoglobulins, 8.1% lactoferrin and 4.7% lysozyme. The content of essential AA in the protein fraction was 48.4%. Results show that composition of mare milk can be influenced by regional differences.     

短期昼间亚高温胁迫对番茄光合作用的影响

为了探讨日光温室春末夏初亚高温环境对番茄光合作用的影响,采用人工气候室模拟环境,在番茄第1花序第1花开花当天,以25℃为对照,研究35℃昼间亚高温处理对番茄光合作用日变化的影响。结果表明：在适宜光照度条件下,3 d以下35℃昼间亚高温处理可提高番茄净光合速率,而6 d以上昼间亚高温处理可明显降低番茄的净光合速率;同时适宜温度（对照,25℃）处理的番茄净光合速率日变化未出现“光合午休”现象;而35℃昼间亚高温处理的番茄净光合速率日变化出现轻度“光合午休”现象;昼间亚高温处理可提高番茄叶片气孔导度、降低气孔限制值、增加开放气孔的比率、提高胞间CO2浓度和蒸腾速率。这些结果说明,在适宜光照条件下,番茄遭受昼间亚高温胁迫的初期可通过调节自身一些相关反应来适应环境,避免光合速率的降低,而当胁迫时间达到6 d以上时则会对光合作用产生不良影响,同时番茄“光合午休”现象不仅与光照度有关,而且与温度有关;昼间亚高温对番茄光合速率的影响与气孔无关,是由非气孔因素限制的。     

诱导Badila提早开花的主要气象因子初探

通过连续两年人工诱导结果表明，提早诱导时间、暗期气温高低、光照期间破坏性高温天数是诱导Badfla提早开花的主要原因。     

北太平洋海域白天利用水下灯钓捕大型柔鱼的试验报告

光诱鱿钓捕捞技术就是利用鱿鱼趋光、集群的特性 ,采用钩钓作业的一种渔法。利用水下灯进行钓捕鱿鱼是一种新的捕捞技术。该技术在 80年代中期首先在日本、韩国等国的鱿钓船中得到应用。分布在北太平洋中部海域的大型柔鱼 ( 1～ 2ｋｇ) ,栖息水层白天一般在 30 0～ 40 0ｍ ,使用水下灯进行深水层的诱集柔鱼 ,使白天作业成为可能 ,从而大大延长了作业时间。由于柔鱼具有昼夜垂直移动现象 ,夜间栖息水层为 30～ 40ｃｍ ,因而一般不采用水下灯。我国鱿钓船从 1 997年开始 ,初步得到应用 ,特别是在 1 998年鱿钓渔场探捕调查和生产过程中 ,取得了…     

氯前列醇钠与卡贝缩宫素对荣昌猪和涪陵黑猪母猪分娩时间的影响

氯前列醇钠作为人工合成的前列腺素类似物被广泛的应用于诱导各种母畜的分娩。卡贝缩宫素作为一种具有长效特性的新型催产素类样分子,有望在母猪分娩过程中替代缩宫素起到收缩子宫启动分娩的作用。试验一主要对氯前列醇钠注射部位和剂量进行研究,将母猪随机分为自然分娩组(n=74)、2 mL肌肉注射组(n=52)、2 mL后海穴注射组(n=63)和1 mL后海穴注射组(n=57)。研究结果表明,2 mL后海穴注射组的母猪分娩时间上表现更为集中,产仔持续时间最短(228 min),白天分娩比例最高(90.48%)。说明通过调整母猪注射氯前列醇钠时间、剂量以及部位等因素能够一定程度的缩短母猪产仔时间,提高母猪白天分娩率。试验二主要对卡贝缩宫素(CBT)与氯前列醇钠的联合应用进行研究,试验将母猪随机分为自然分娩组(n=81)、氯前列醇钠注射组(n=70),CBT注射组(n=67),氯前列醇钠+CBT注射组(n=64)。研究结果表明,氯前列醇钠与卡贝缩宫素联合应用能够缩短母猪产仔持续时间(205 min),并且大幅提高母猪在白天工作时间分娩比例(95.31%)。