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]>oriod of pregnancy may var}' a few days with diffei'ent 

 individuals and under different circumstances. 



Abortion, from an economic standpoint, takes rank 

 among former animals as follows : Cow, Mare, Sheep, 

 Sow. The cow is the most liable while the sow is sel- 

 dom sul>j<'ct to the mishap. 



The viability or whether the fcetus is capable of living 

 is another question. Usually it is dead. A dead foetus 

 may be delivered at any time during pregnancy, but 

 when abortion occurs in the first two-thirds of pregnan- 

 cv the foetus is ahvavs dead. Tn the last third a live 

 f(etns is frequently born. 



The later the stage the more likely is the little ciea- 

 ture to live. Many die immediately, and others are weak- 

 ly and prove to be absolutely worthless, and in rare in- 

 stances one becomes sufficiently vigorous to develop into 

 a valuable animal. 



Some idea of the number of living calves delivered 

 by aborting cows in the last months of pregnancy and 

 their value may be had from the record reported by Nel- 

 , son of the New Jersey Experiment Station. Twelve 

 » cows alwrted. Four births occurred between the 6th and 

 7th months; four between the 7th and 8th mouths; 

 and four between the 8th and 9th months. Three of 

 the twelve were dead : 1 died; were killed and 2 were 

 raised. Thus onl^'^ a small percentage were of sufficient 

 promise to be kept, and it is a question if it ever pays in 

 the long run to raise any of them. 



Abortion may be either non-infectious or infectious. 

 When occurring in the latter form it assumes an enzootic 

 or an epizootic type and it is of greatest importance to 

 recognize this form in order to prevent the spread of the 

 contagion. 



Non-infectious abortion. 



Non-infectious abortion results from some known 

 ' cause or accident, irreg-ular feeding, improper feed, etc., 



3 



