HEIFERS DURING PREGNANCY AND SUBSEQUENTLY 9I 



food more or less from the system of the pregnant 

 mother yet undeveloped and immature. This means, 

 first, more or less arrested development, and, second, 

 an extra tax upon the energies of the system ; first, to 

 sustain the fetus and, second, to carry it. As a result, 

 the mature cow is of less size and vigor than if breed- 

 ing had been deferred longer. The lessened vigor may 

 not be discernible, but it is reasonable to conclude that 

 it is present. It would seem to be more than question- 

 able, therefore, if the gain resulting from thus attempt- 

 ing to strengthen the milking habit is not more than 

 counterbalanced by the loss in the two directions men- 

 tioned. There is the further loss in the lesser develop- 

 ment of the calf (see page 102) produced by the heifer 

 which comes into milk at 24 months as compared 

 with that of the heifer bred later. Moreover, with the 

 latter, the necessity for deferred production is also les- 

 sened, hence she may be expected to make up largely 

 or entirely for the loss in milk production resulting from 

 the later period at which she comes into milk. Because 

 of the loss in size and stamina referred to, some of the 

 most practical breeders of dairy stock are deferring the 

 period of bringing heifers into milk to 27 months, and, in 

 some instances, to 30 months, according to the strength 

 and development which they possess. 



Heifers reared to produce beef animals are not 

 usually bred so young as those intended for the dairy. 

 With the former, the first calf is commonly reared as 

 well as those produced later. Experience has shown 

 that if heifers of this class are allowed or required to 

 breed at too young an age, sufficient growth in many 

 instances is not obtained from the calf when matured or 

 previously. The breeders of pure-bred cattle have erred 

 probably more than others by breeding heifers at too 

 early an age. The temptation to do so comes from 

 the desire to secure quick increase from high-priced 

 stock. That the average of individual excellence in 



