Reproduction Management of Herds/Flocks of Exotic Animals: Investigating Breeding Failures in Birds,Reptiles, and Small Mammals     

《Veterinary Clinics of North America: Exotic Animal Practice》2021,24(3):661-695

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水霉属菌(Saprolegnia)分离培养技术研究   总被引：1，自引：0，他引：1  

文冰  郑耘 《植物病理学报》1996,26(3):277-281

 对水霉(Saprolegnia)的分离培养技术进行了探索,筛选出大麻籽、油菜籽、红花籽、苍蝇、蚜虫、小麦粒、玉米片、茶叶、葵花仁9种材料作为诱发水霉菌的诱饵。其中油菜籽能防止腐霉菌(Pythium)污染,是初步纯化菌种、排除杂菌的适宜饵料。同时发现控制温度能使水霉在最短时间内分别产生无性或有性繁殖。在水培条件下,25℃左右适合菌丝及无性器官的发育,有性器官却不能产生,而只有在15~17℃条件下才能使水霉很快进入有性生殖阶段;在加入200mg/L链霉素的CMA培养基上促发有性阶段则需要在25℃左右的温度下进行,方能缩短培养时间。  相似文献   

Impact of postovulatory food deprivation on the ova transport, hormonal profiles and metabolic changes in sows.     

P Razdan  A M Mwanza  H Kindahl  F Hultén  S Einarsson 《Acta veterinaria Scandinavica》2001,42(1):45-55

The effect of food deprivation on ova transport, hormonal profiles and metabolic changes was studied in 20 crossbred multiparous sows during their second oestrus after weaning. To determine the time of ovulation, transrectal ultrasonographic examination was performed. The sows were divided into 2 groups, one control group (C-group), which was fed according to Swedish standards, and one experimental group (E-group). The E-group sows were deprived of food from the first morning meal after ovulation until slaughter. Blood samples were collected every second hour from about 12 h before expected ovulation in the second oestrus after weaning until slaughter and were analysed for progesterone, prostaglandin F2 alpha-metabolite, insulin, glucose, free fatty acids and triglycerides. All sows were slaughtered approximately 48 h after ovulation and the genital tract was recovered. The isthmic part of the oviduct was divided into 3 equally long segments and flushed separately with phosphate buffered saline (PBS). Uterine horns were also flushed with PBS. A significantly greater number of ova were found in the first and second part of the isthmus in the E-group (p = 0.05) while in the C-group most of the ova were found in the third part of the isthmus or the uterus (p = 0.01). The level of prostaglandin F2 alpha-metabolite was significantly higher in the E-group compared with the C-group. The concentration of progesterone increased in both groups after ovulation but there were no significant differences between the groups. The other blood parameters showed that the food-deprived sows were in a catabolic state. The 48 h period of fasting results, directly or indirectly in an delayed ova transport, which may be due to a delayed relaxation in the smooth circular muscle layer of the isthmus.  相似文献   

Leptin对动物繁殖机能的影响及其应用前景   总被引：2，自引：0，他引：2  

张海艳  岳文斌 《畜牧兽医杂志》2003,22(3):14-16

Leptin是由脂肪组织分泌的一种“厌食”激素。自1995年发现以来，就成为最活跃的研究领域。它可通过下丘脑或直接作用于卵巢，对动物青春期的发育、生殖器官的发育以及性激素的分泌都有重要的调节作用。本文综述了Leptin的生物学特性、作用机理及其在繁殖方面的作用，井指出了它在畜牧生产中应用前景。  相似文献   

加工现场微机控制系统抗干扰的研究     

刘少凤  陈友明 《湖南农业大学学报(自然科学版)》1996,23(6)

针对制造业加工现场的环境特点，分析了微机控制系统的干扰来源和途径，介绍了实用的抗干扰措施。实践证明：这些软硬件抗干扰措施的综合运用，使自动化加工中微机控制系统的稳定性得到了较大的提高。  相似文献   

杉木林地套种绿肥筛选初报   总被引：4，自引：1，他引：3  

马祥庆  何智英 《福建林学院学报》1992,12(3):343-346

收集了三十种绿肥,在杉木当年造林地上进行套种试验,根据其生长状况、生物量、覆盖度及对杉木生长的影响,把供试绿肥分成三类,初步筛选出羽扁豆、决明豆、日木草为适宜杉木林地种植的林用绿肥。同时对今后林用绿肥的选择提出了有益的建议。  相似文献   

Reproductive roles predict sexual dimorphism in internal and external morphology of lake whitefish,Coregonus clupeaformis     

S. J. Casselman  A. I. Schulte‐Hostedde 《Ecology of Freshwater Fish》2004,13(3):217-222

Abstract – The different reproductive roles of the sexes can predict the direction and magnitude of sexual dimorphism of external and internal morphology. Males should have enlarged structures that enhance the acquisition of mating opportunities, whereas females are predicted to have enlarged organs that are associated with the production of eggs. We tested these predictions in male and female lake whitefish, a species in which both sexes have similar overall body size and shape. After controlling for body size, male lake whitefish had significantly longer jaws and pectoral and pelvic fins, larger hearts, and more muscle than females. Sexual dimorphism in relative muscle mass may be one of the most fundamental morphological differences between males and females. Females had relatively heavier livers than males. Because the liver is important for the breakdown of fats and vitellogenesis, selection should favour an enlarged liver in females for the processing of energy and the production of large numbers of eggs.  相似文献   

ZIKA种母兔饲粮适宜营养水平的研究   总被引：2，自引：0，他引：2  

唐良美  谢晓红  刘曼丽  兰永化 《中国养兔杂志》1994,(3)

连续三年在相同的繁殖季节，使用齐卡Ｎ系母兔１４８只，分别观察测定了四种不同营养水平组合日粮对不同繁殖状态母兔繁殖能力的影响。结果表明：在延期繁殖（母兔断奶后再配种）条件下，不同能量、蛋白水平对母兔繁殖性能的影响差异不显著（Ｐ＞０。０５），但中能高蛋白（ＤＥ１０．８８兆焦／公斤、ＣＰ１９％）的第３组日粮略胜于其它组合。由此得出，在引延期繁殖的ＺＩＫＡ能繁母兔，适宜的营养水平为：消化能（ＤＥ）１０兆焦／公斤，粗蛋白（ＣＰ）１９％，粗纤维（ＣＦ）１０％。在母兔进行半频密繁殖（母兔产后第１４天开始配种）情况下，高能高蛋白（ＣＤＥ１２．１３兆焦／公斤、ＣＰ１９％）饲粮对提高繁殖性能的效果明显优于高能低蛋（ＤＥ１２．１３兆焦／公斤，ＣＰ１５％）和低能低蛋白（ＤＥ１０．８８兆焦／公斤）和ＣＰ１５％）饲粮（Ｐ＜０．０５），尤其对提高母兔泌乳力效果明显（Ｐ＜０；０１），因此，实行频密（产后立即配种）或半频密繁殖的母兔，适宜营养水平为消化能１２兆焦繁殖的母兔，适宜营养水平为消化能１２兆焦／公斤，粗蛋白１９％，粗纤维９－１２％．  相似文献   

家兔选育性状典型相关分析   总被引：3，自引：0，他引：3  

李岩  孙杰 《黑龙江畜牧兽医》2003,(10):14-16

选择日本大耳白和新西兰两个品种家兔的生长、繁殖、以及体尺3组共17个性状，应用多元统计方法进行了典型相关分析，结果表明；日本大耳白兔的初生重、初生窝重、21日龄重、泌乳力、胸围等5个性状，新西兰兔的产活仔数、初生重、21日龄重、泌乳力、断奶窝重、母兔体重等6个性状为主要性状。  相似文献   

模拟发电机组专用可控硅直流调速系统     

刘觉民  夏永祥 《湖南农业大学学报(自然科学版)》1995,22(3)

本文从分析同步发电机原动系统基本数学模型入手，提出了一种实现同步发电机原动系统仿真的专用可控硅直流调速系统及其实用装置。该控制系统采用有差调节的模拟调速器，水汽管道特性模拟、自平衡特性模拟和集成块模拟触发器，以及过流与超速保护，并可实现有差－无差调节的转换。  相似文献