10 June, 1916.] Contagious Abortion. 323 



quickly warp, twist, and split, and need constant repairs. The careful 

 builder will know his timbers, and build a lasting edifice, and will oil 

 paint, and varnish it. So with the dairy herd — the good manager 

 will know his cows, will use a good bull, one that will improve his herd, 

 not merely get calves, he will rear his females, and by painting the 

 inside with nourishing food build up a business that gives him a hand- 

 some profit. By knowing his animals he can improve them, by avoiding 

 indiscriminately purchasing, he will obviate the danger of introducing 

 disease into his herd. 



Th:s brings us to another cause of depletion, and one which the bad 

 manager is going to keep with us in good or bad seasons — I refer to 

 contagious abortion. This disease has been known to exist for many 

 years. As far back as 1567 attention was drawn to it in England, but 

 it was not until 1876 that it was conclusively proved to be due ta in- 

 fection. It then took twenty years to find and prove which organism 

 was responsible — this was done in 1896, by Bang. The losses that occur 

 as the result of this disease are enormous — not, unfortunately, from the 

 death of the infected animals, for if this occurred it could more easily 

 be controlled ; but by virtue of the fact that every affected animal lives 

 and acts as a centre of distribution, and thus the disease becomes difficult 

 to eradicate. 



It has been estimated that in some parts of England 50 to 60 per 

 cent, of cows are affected, while the' evidence given before a committee 

 appointed by the Board of Agriculture and Fisheries in 1909 to inquire 

 into the disease, goes to show that approximately 25 per cent, of 

 animals in England and Scotland were inficted. Gilruth, some years 

 ago, estimated the loss to the dairy farmer in New Zealand as between 

 ^200,000 and i;300,000 p^r annum. 



How, some may ask, do the losses arise since the cow does not die. 

 The one who asks this question has evidently not experienced the trouble, 

 and should use his utmost endeavours to keep his herd free. The losses 

 may be classified under three headings, viz.: — 



1. Loi-s of calf aborted. This is probably the smallest, yet, in view 

 of our shortage of stock, a very serious one. 



2. Diminislied milk yield due to premature calving. This is a very 

 considerable loss, for it is well known that a cow that slips her calf 

 seldom if ever comes to her full milking capacity in that year. 



3. A combination of the previous two repeated in subsequent years. 

 This is the most serious loss, for the sterility that so often follows, and 

 is shown by the cow jjersistently returning to the bull after she has 

 aborted, means that if she does hold to the bull she comes in ♦^^oo late in 

 the season to make lier maximum profit or remains barren, then for 

 several years the calf is not produced and the cow remains dry 



It is extremely difficult to give an accurate estimate as to wi.U this 

 all amounts to for reasons at once obvious, but let us take some figures 

 in order to see the possibilities. So as not to be classed as too bio; an 

 alarmist, bv taking the English figures,— 25 per cent, affected— let ns 

 suppose that 10 per cent, of the cows in Victoria were to become affected 

 with the disease; on the latest statistics there are 451.088 cows in 



