252 FEEDS AND FEEDING, ABRIDGED 



of the breed associations has reached a standard set by the association. 

 Entry in these registers increases the money value, not onl}^ of the 

 given cow, but also of her relatives, for progressive breeders in buy- 

 ing animals now rely more and more on records of production and 

 less upon show-ring successes. 



Records of great cows. — Thru skilled breeding combined with 

 expert feeding, truly marvelous records of dairy production have 

 been secured. The world's records have been steadily raised during 

 recent years until now Duchess Skylark Ormsby, a 5-year-old, pure- 

 bred Holstein, has produced 1,205.09 lbs. of butter fat in a single year, 

 and Tilly Alcartra, another Holstein, holds the record for milk pro- 

 duction, with 30,451.4 lbs. of milk to her credit in one year when a 

 5-year-old. These records, thought impossible a few years ago, show 

 how far the breeding and feeding of dairy cows has advanced. 



II. Factors Influencing the Composition and Yield of Milk 



Composition of milk. — The milk of different breeds of cows and 

 even of individual cows of the same breed varies quite widely in com- 

 position. While the fat content may range from less than 3 per ct. 

 to 7 per ct. or over, there is much less range in the other constituents. 

 The milk sugar commonly ranges from 4 to 5 per ct., the casein from 

 2 to 3 per ct., the albumin from 0.4 to 0.9 per ct., and the mineral 

 matter from 0.6 to 0.9 per ct. 



The average composition of milk from the different breeds is shown 

 in the following table: ^ 



Composition of milk of different hreeds 



Breed Total solids Fat 



Per et. Per ct. 



Jersey 14.70 5.35 



Guernsey ' 14.71 5.16 



Devon 14.50 4.60 



Shorthorn 13.38 4.05 



Brown Swiss 13.27 4.24 



Ayrshire 12.61 3.06 



Holstein-Friesian 11.85 3.42 



The Jerseys and Guernseys give the richest, and Ayrshires and 

 Holstein-Friesians the poorest, milk. However, the breeds which 

 give the richest milk usually yield a smaller quantity, so that the 

 total amount of fat and total solids is nearly the same for all dairy 

 breeds. Not only does the composition of milk depend on the breed 

 but it is also influenced by the several factors discussed in the fol- 

 lowing paragraphs. 



5 Chiefly from Wing, Milk and Its Products, p. 33. 



