A study of amylolytic streptococci from the rumen of the sheep

Ruminants comprise a large class of mammals distributed over the greater part of the earth's surface. The digestive system of these animals has been adapted for the digestion of grass and other cellulosic materials which form the natural diet of the group as a whole. Since this diet is both bulky and indigestible it is to be expected that the ratio of the capacity of the digestive system to body weight is higher in ruminants than it is for example in carnivorous animals. For this purpose the lower part of the oesophagus in the ruminant forms a large sac or rumen. The ingested food passes into the rumen and is mixed with the dense rumen microbial population. It is in the rumen that the digestion of cellulose by rumen bacteria takes place. The relationship between the rumen microflora and the host is thought to be symbiotic and since a large percentage of the world's human population is dependent directly or indirectly upon ruminants for food the economic importance of this symbiotic relationship cannot be over emphasised. Especially asp but for these animals much of the yearly crop of grass and other cellulosic material would not be converted into protein but broken down by soil bacteria and so be lost to man.In most parts of the world the continuous growth of plants is not possible, due to the sequence of the seasons or to the alternation of wet and dry periods. Thus, at intervals, herbivores must live on vegetation which has completed its growth cycle and has become dry, woody and resistant to digestion. The digestive system of the ruminant can utilise such material and as a result these animals are not seriously affected by drought and other inclement weather conditions. This may account for the success of the group in the modern world. In addition it is this ability to utilise cellulose efficiently that has led to the domestication and breeding of the ruminant