Sr^S Cattle Problems. 



There is a large venous proportion of blood that does not 

 enter the udder ; but this also temporarily fills artery space ; 

 and it is safe to say that the space filled and occupied by 

 the mammary artery-blood is increased generally as much 

 or more than yield is increased. And when yield is grad- 

 ually increased, during three or four years in heifers, and 

 so on through several generations of their successors, a very 

 evident increase in the size of the hind quarter results from 

 the increased extent of space filled by the increased blood- 

 supply ; and increased ramifications and size of the arteries 

 containing it, previous to its entering the udder. 



In the embryo the circulation commences before the 

 formation of the frame, to convey the frame-forming ma- 

 terial. But in heifers, or young cows, previous to maturity, 

 the increased extent of the artery tubes, and of the fluid 

 and solid substances within them, gradually expand the di- 

 mensions of the frame-work and size in the hind quarters, 

 and at the same time the length, size, and strength of the 

 bony frame and its connections are correspondingly in- 

 creased by nutrition, from the general circulation. 



So special demand at the udder leads to large increase 

 in the contents or substances of the correspondingly in- 

 creased space occupied by the mammary arteries and their 

 contents; thus expanding the general size or dimensions 

 of the hind quarters, and so contributing to establish large 

 yield by forming — in effect — a blood reservoir near the 

 udder. 



It requires constant perseverance, in careful feeding 

 and close milking, continued through several generations 

 of heifer cows, to develop and establish the best forms, 

 found in milking families of good cows ; and it being de- 

 sirable to establish them, it is equally desirable to continue 

 them by descent and inheritance, which is practicable, as 

 experience has demonstrated in establishing such forms in 

 various families of cows. 



