Aug. 2, 1920.] Agricultural Gazette ofN,S.W. 575 



small paddocks, where a fair number of cows are confined, of breaking 

 up the clods" and heaps of dung for the purpose of fully exposing it all to 

 the sunlight. Both measures must very sensibly reduce the risk of infection. 



In a previous article the possible spread of anthrax through the fa3ces of 

 dogs and other animals was referred to, but except in very rare cases nothing 

 can be done to prevent this. Swine fever is largely spread through the 

 agency of the faeces and urine, the latter especially containing the infective 

 virus — hence the necessity of good drainage, preferably into a cultivation 

 paddock and not in the direction of other pigsties. The organism of 

 tetanus is present in the dung of herbivorous animals to such an extent 

 as to render almost every dirty stable, cow-shed, and sheep yard a possible 

 source of infection. White scour in calves has been ascribed on good 

 grounds to infection through the umbilicus by the fseces of already infected 

 animals. 



The danger arising from the flies bred in manure and dung heaps is one 

 more particularly applicable to human beings, but since the infection of 

 milk by flies is quite within the range of probability the necessity of 

 removing all accumulations of dung to a reasonable distance from milk 

 rooms must be mentioned. The irritation to which animals are subjected by 

 flies is not without its influence on their condition. Recent research has 

 shown that certain parasites of horses and cattle, notably the worm producing 

 worm nodules in cattle and that producing tumour-like growths in the 

 stomachs of horses, are fly-borne. The extreme probability that ophthalmia, 

 as seen in stock in this country may be carried from animal to animal by 

 flies of one sort or another, renders it all the more requisite that excreta, 

 should be dealt with in such a way as to reduce the breeding of those pests 

 as much as possible. 



Grazing : The Danger of Overstocking. 



All that needs to be said in respect to grazing might be put into three words : 

 Overstocking is dangerous. It may be laid down as a rule to which there is 

 practically no exception that the increase in the risk from disease occasioned 

 by overstocking is out of all proportion to the increase in the number of 

 stock added to those already on a given area. This increase in risk involves 

 three types of disease — infectious, parasitic, and dietetic. The chances of 

 infectious disease spreading is of course obviously greater where animals 

 come into more dii-ect contact with one another, and the longer such contact 

 is continued the greater the risk. Since in most instances of parasitic 

 infestation the eggs or embryos of the parasites are passed out of the animal 

 with the fteces, it is equally obvious that the more stock arc crowded 

 together the more they will tend to become re-infected with the parasites. 



Dietetic diseases are in most instances only to be expected when over- 

 stocking is continued for a long period ; such diseases are sometimes so 

 delayed in their appearance, and the exhaustion of the soil by overstocking 

 is also so gradual that it is difficult at first sight to connect the two, but the 

 connection undoubtedly exists. This refers to overstocking of a whole 



