母猪的科学饲养管理

1要选好种母猪种母猪 应当从青年公母猪交配所产的2-4胎春季断奶仔猪中进行选留（后备母猪）,选留这个时期的仔母猪生长快,生育力强。在后备母猪6～8月龄时选繁殖用的种母猪,应当选留生长快、饲料报酬高、四肢开阔、乳头发育均匀良好的母猪。     

Temperature Difference Between the Air and Organs of Rice Plant and Its Relation to Spikelet Fertility

Based on the experiment of measuring panicles and leaves, air temperature, and humidity above the canopy of rice cultivars after heading in 2005 and 2006, we investigated the temperature difference （TD） between the air and organs of rice plant and its relationship with spikelet fertility. The results showed that TDs between the air and organs of rice varied with air temperature, air humidity, and plant type. For similar air humidity, TDs were lower at the air temperature of 28.5℃ than at higher temperature of 35.5℃, whereas for the same air temperature, the TDs decreased as the air humidity increased. TDs were also affected by plant type of the cultivars. Erect panicle cultivars showed higher TDs than those with droopy panicles under similar climatic conditions, and cultivars with panicles above flag leaf （PAFL） had higher TDs than those with panicles below the flag leaf （PBFL）. Cultivars grown in a location with lower air humidity and higher temperature, such as Taoyuan, China, had higher spikelet fertility than those in higher humidity under the similar air temperature during the grain filling stage. This is partially attributed to the larger TDs under the lower humidity. Rowspacing and the ratio of basal-tillering to panicle-spikelet fertilizer showed a significant influence on TD and subsequently on spikelet fertility, suggesting the possibility of increasing spikelet fertility by agronomic management.     

营养物质对绵羊繁殖的影响

营养物质对绵羊正常的生理机能是必需的,一切的营养物质对羊的繁殖总有着直接或间接的影响。在养羊生产上,常见的营养缺乏,如饲料能量的缺乏、蛋白质缺乏、维生素缺乏和矿物质缺乏等症均可引起繁殖障碍。另外,营养过剩也会使绵羊的生育力下降,以致绵羊出现营养性不育。1能量在养羊生产上,碳水化合物是动物日粮