为农业信息服务的图书馆

文中论述了农业的现状及存在的原因，分析了图书馆为改变农业现状提供文献信息服务的优势，提出了图书馆文献信息为农业用户服务的具体方法和措施。     

Factors that alter rumen microbial ecology

Ruminant animals and ruminal microorganisms have a symbiotic relationship that facilitates fiber digestion, but domestic ruminants in developed countries are often fed an abundance of grain and little fiber. When ruminants are fed fiber-deficient rations, physiological mechanisms of homeostasis are disrupted, ruminal pH declines, microbial ecology is altered, and the animal becomes more susceptible to metabolic disorders and, in some cases, infectious disease. Some disorders can be counteracted by feed additives (for example, antibiotics and buffers), but these additives can alter the composition of the ruminal ecosystem even further.