1920.] 



Breeding Dairy Cattle. 



655 



judging" of dairy bulls is gaining ground, particularly among 

 Friesian breeders, but it is so important that it deserves wide- 

 spread publicity. This should lead to a fuller realisation of the 

 very true saying among farmers, that " the bull is half the 

 herd." 



For the purpose of obtaining a progeny record of a bull, it 

 is necessary to have the milk records of the dams as well as those 

 of the daughters, and the breeding value of the bull can be 

 judged by the difference between the average record of the former 

 and of the latter. To illustrate this important point, the progeny 

 records of two bulls used in the herd at the University College 



Farm are shown below : — 



Progeny Records of Bull "A." 



Dams. Daughters. 

 Number of Animals ...... 8 8 



Number of Lactation Periods ... 20 20 



Average Yield per Lactation Period 8518 lb. 8479 lb. 



Loss per Lactation Period ... ... 39 lb. 



Average Lactation Period ... ... 46*4 wks. 44*3 wks. 



Average Dry Period 10*0 wks. 113 wks. 



Average Period between Calvings 56*4 wks. 55*6 wks. 



Gain between Calvings ... ... 0'8 wks. 



Note I. — The dams were a selected group of cows purchased from different 

 places, and they show a remarkably high average yield. 



Note II. — The 20 lactation periods of the daughters comprise more tirst and 

 second periods than the 20 of the dams, and a larger proportion of these 

 periods commenced during the summer months, thus handicapping the 

 daughters. When these two conditions are taken into account, it can 

 confidently be said that the daughters were superior to the dams, showing 

 that Bull "A" possessed exceptional breeding value for milk production. 



Progeny Records of Bull tl 6'." 



• Dams. Daughters. 



Number of Animals 9 12 



Number of Lactation Periods ... 20 25 



Average Yield per Lactation Period 8001 lb. 6468 lb. 



Loss per Lactation Period ... ... 1533 lb. 



Average Lactation Period ... ... 43*3 wks. 38*3 wks. 



Average Dry Period 10*1 wks. 13*6 wks. 



Average Period between Calvings 53 - 4 wks. 51*9 wks. 



Gain between Calvings ... ... 1*5 wks. 



Note I. — The dams include cows purchased for their apparent milking qualities, 

 and several of the daughters of Bull " A." The average yield is notably 

 good. 



Note IT. — The 25 lactation periods of the daughters include 5 more first and 

 second periods than the 20 of the dams, and to a certain extent this 

 handicaps the daughters. The season of calving gave no advantage to 

 either group. The yields show that Bull " C " lacked the breeding value 

 for milk production of Bull " A," but was nevertheless a useful dairy bull. 



The above results show that Bull " A " was capable of siring 

 female progeny which gave an average milk yield of 8,479 lb. 

 in an average lactation period of 44-3 weeks, and which were at 

 least equal to their dams in productive powers. The heifers and 



