132 A MANUAL OF MENDELISM 



for high quahty which are not carried by the latter, 

 and therefore the chances of improving Ayrshire or 

 Red Danish cows' milk by operating within the breeds 

 themselves are much greater than the chances of 

 improving in a similar manner the milk of Dutch cows. 



Milk records have been kept in Denmark for nearly 

 half a century and, using the information so collected, 

 the Danish farmers have been able to raise their cows' 

 yields very substantially. Two sires, Taurus IV, born 

 in 1894, and Lombjerge IV, born in 1897, are regarded 

 as very important, and, in two volumes, " Tyreslagters 

 Indfledelse paa Afkommets Ydelse " — volume i, Lomb- 

 jerge IV and volume ii, Taurus IV — Mr. A. M. Christen- 

 sen has shown in detail how the Red Danish breed has 

 been influenced by these sires and their sons and grand- 

 sons. 



The quantity and quality — where known — of the 

 milk of the dams with which the sires were mated 

 and of the daughters produced are given side by side, 

 and from these it is possible to discover the improve- 

 ments effected. The yield was improved by both lines 

 of sires, more decidedly by the Lombjerge than by the 

 Taurus line ; but the quality, which was practically 

 unaffected by the Lombjerge line, was raised by the 

 Taurus line. The diagram on page 133, which shows 

 the qualities of milk given by the cows with which the 

 Taurus sires were mated and by their daughters, indi- 

 cates the improvement of the daughters upon the dams. 

 The average rise is from 3*56 per cent, in the dams to 

 3*75 in the daughters. 



But an examination of the results in a few individual 

 cases will show the steps by which the rise takes place. 

 The diagrams on pages 131 and 133 suggest that cows fall 



