THE PERIOD OF GESTATION IN COWS. 



Since 1889, observations of the period of gestation have been 

 regularly made on all the cows in the University herd. The 

 herd has contained an average of about twenty cows, about two- 

 thirds Holstein and high grade Holstein, and one-third Jersey 

 and high grade Jersey wnth a few native, mixed, and cross bred 

 cattle. Nearly all the animals w^ere bred and raised on the farm 

 from dams so bred and raised. So that the observations were 

 taken from a single herd and its descendants. In all, 194 obser- 

 vations have been made ; of these, 9 terminated in the birth of 

 dead calves prior to 253 days of pregnancy and three more were 

 doubtful so that the 12 have been excluded and the averages con- 

 fined to the 182 births that may be considered normal. The 

 number of days required for gestation in each of these cases, and 

 the sex of the offspring, is shown in Table I. 



TABLE I. 



