DAIRYING 39 



from 7 pounds to I pound with one cow, and in per cent of fat 

 in the milk from about 4.0 to 1.6 with another cow when the grain 

 which they had been accustomed to have during milking was not 

 fed until after milking. This must not be interpreted as showing 

 the advantage of feeding cows during milking, because many cows 

 have not been accustomed to being fed at that time and they give 

 as much milk as can be expected of them ; probably they would 

 not give more if they were fed during milking. It shows a serious 

 loss in milk may be caused by failure to follow a certain routine in 

 feeding to which the cows have become accustomed. 



R. Age of the Cow. 



196. The usefulness of any cow as a milk producer will 

 naturally depend on her individuality and her treatment during 

 the different years of her life, but under the best conditions there 

 is a limit to the number of years she will give milk at a profit. 

 The rate at which the milk production increases and decreases dur- 

 ing the average life of a cow has been studied by a number of in- 

 vestigators. Hills, of Vermont,* reports the following figures 

 from an exhaustive study of the yearly records of 99 cows. 



Age of cow 



years . . 2 3 4 5 6 1 8 910 



Milk, Ibs.. 4172 4797 5061 5394 5493 5549 5613 5678 5642 

 Fat % . . 5.43 5.33 5.34 5.27 5.21 5.33 5.37 5. 25 5.28 

 These are only a few of the many figures given in Hills' study 

 of this question, and he concludes that "the differences one year 

 with another in no case are large, and that heifers practically "strike 

 their gait" so far as the quality (or richness) of the milk is con- 

 cerned in their first lactation period." 



An inspection of the records of 150 cows in Germany gave the 

 following results.** 



Lactation period ist 2nd 3rd 4th 5th 6th Beyond6th 

 Milk, pounds ....5490 6600 7040 7209 7535 7434 6790 

 Fat per cent 3.65 3.68 3.64 3.65 3.61 3.62 3.58 



Another study of records of 2454 cows showed an increase in 

 the annual milk production to the seventh lactation, and after this 



*Vt. Expt. Sta. 1906. 



** Kirchner Milchwirtschaft. 



