334 DAIRYING COWS AND THEIR MANAGEMENT 



but this is a rule to which there are exceptions with certain 

 animals and under special conditions. 



Causes of Premature Labour. i. Eating ergotised 

 grass in autumn. 2. Injury, as from horning by other cattle, 

 hunting by dogs, crushing through narrow doorways, shaking 

 and bruising on a railway journey, etc. 3. Walking through 

 a dung heap, or over boggy or soft land, and getting strained. 

 4. Very cold or foul water, or too many frosted turnips, 

 especially if given in the house while the animal is not moving 

 freely about. 5. Superpurgation, either natural or induced by 

 physic. 6. Infection arising from association with newly 

 aborted cows which are contaminated with the organism 

 which produces contagious abortion, or from the use of a 

 bull which had served an aborted cow even six months 

 before. This is the most common, most insidious, and 

 dangerous of all the causes of abortion. A good illustration 

 occurred in 1905 among animals belonging to J. W. Wallace, 

 Ford, Thornhill, N.B. On December 2Oth a Galloway bull 

 that had served an aborted cow on September 2Oth was put 

 to seven Irish Shorthorn heifers. All aborted, the first heifer 

 three months before she was due to calf. Five went till within 

 six weeks and one within three weeks of their proper periods. 

 No other heifer in the lot of twenty herding together aborted, 

 but they were served by a different bull. This fact also 

 indicates that heifers which have become contaminated with 

 the organism do not communicate it to others until after 

 premature labour. That aborted cattle do communicate the 

 tendency to others was illustrated a few years before on a 

 neighbouring farm, Holme of Blaplain, where cows from a 

 contaminated dairy repeatedly broke through a fence, and 

 mingling with the Holme cows gave them the disease. 

 Without preventive treatment abortion declines, and ulti- 

 mately dies out in a dairy, and the more quickly if the newly 

 introduced heifers be grazed apart from the others. A cow 

 rarely aborts more than three times, and her tendency is to 

 carry her calf a little longer each time, and ultimately to bear a 

 calf that lives. It is an undetermined question whether or not 

 a cow which has aborted as the result of an accident is capable 

 of communicating the tendency to other in-calf cows. 



Indications of approaching labour are usually seen for 

 days, or even a week or two, before the crisis comes on. A 



