10 Feb., 1916.] Herd Improvement. 89 



HERD IMPROVEMENT. 



Breeding for Butter Fat. 



Ill/ B . A. Barr, Senior Dairy Supervisor. 



Apart from the value of feed, the principal factor iu breeding for 

 butter fat is selection: — -Ist, When purchasing untested cows, select on 

 dairy type. Dairy type is a term glibly used, yet difficult to define; 

 it exemplifies a type which is the result of the development of the 

 special purpose dairy cow. 2nd. Proving tlie earning capacity of the 

 selected animals and all cows in herd by use of Babcock tester and 

 scales. 3rd. Selection and use of a pure-bred dairy bull, whose im- 

 mediate female ancestors have proved profitable butter-fat producers. 



To the stock-breeder the maxim " like begets like" is delusive, inso- 

 much as no two animals are exactly alike in all unit characters; and 

 even if it were possible tO' breed from animalsi possessing exactly the 

 same external characters as measured by the eye, we have no means of 

 determining beforehand those characters which have passed to the 

 animals from previous generations. Characters which, although not 

 apparent in the parent, may appear in the offspring. The conforma- 

 tion of the bull does not assure the breeder that he will have profitable 

 dairy cows even when used with a breed of good dairy cows. The 

 character of milking capacity is not visible in the bull ; but if his female 

 ancestral line were profitable one may reasonably anticipate this quality 

 to be transmitted to the heifers. In the practice of breeding it is not 

 only necessary for the dam and sire to possess those qualities which are 

 desired in the offspring, but it is equally important that such qualities 

 s.ho ild have been possessed by the immediate ancestors. Although the 

 above maxim is misleading, breeding is not a matter of chance. The 

 germ cells of tha cow and bull contain bodies which determine the trans- 

 mission of hereditary characters. These determiners act as a link 

 between the conjugating male and female blood strains as well as be- 

 tween successive generations. For this reason frequently a calf is born 

 differing greatly from the parents, but showing a marked resemblance 

 to some remote ancestor. 



Tlic system to be practised in breeding dairy cows should lead to 

 an accumulation of those characters which are associated witli milk pro- 

 duction. It is remarkable that no determined effort i& made by dairy 

 farmers to increase the earning of the herd from year to year. Where 

 an effort is made the general practice is to cull by selection on type ; 

 but type docs not cause a cow to be a profitable milker. It is the re- 

 suit of a continuous variation in response to the extraordinary develop- 

 ment of the udder as a secretory organ. Dairy type is the result and 

 not the cause of udder activity. Conscquently"it can be readily under- 

 stood that cows may possess this type and yet be unprofitable. The 

 type may be given by the cow. and tlie liull, being from a line of un- 

 profit-ible milkers, may transmit poor milkiug quality lo his stock. The 

 capacity of a cow to secrete a heavy flow of milk or large amount of 

 butter "fat is not regulated by type. It is inherent, and according to 

 its degree onlv is it proportional to the amount of food coiisununl. If 

 the amount of butter fat were proportional to the amount of food con- 

 sumed, all cows consuming the same amount of food would yield the 



