14 PRINCIPLES OF BREEDING 



the same as the sires of the black calves of 1 892 makes the 

 results of this experiment all the more interesting. 



In the case of the colour of the crosses derived from 

 two or more distinct breeds, reversion to some ancestral 

 form plays an important part. Certain colours, as a rule, 

 can be depended upon to produce in the young other and 

 altogether different colours from those of the parents ; for 

 instance, a black Galloway cow and a pure white Shorthorn 

 bull almost constantly throw a very dark roan or a blue-grey. 

 A light roan bull might give the same result as a white ; 

 but a dark roan or red will generally get either black or red 

 calves, which are not so much desired. In the same way, 

 when Ayrshire cows are crossed with a Shorthorn, a light- 

 coloured bull, as compared with a dark one, throws more of 

 the Shorthorn character into the colours of the calves, and 

 these bring the highest prices, as they are usually reared for 

 fattening purposes. All constancy in colour is lost in crosses 

 other than first crosses. The second and later calves by the 

 same bull and cows that produce blue-greys as first calves 

 are sometimes not so uniform in colour. 



CROSSING AND IN-AND-IN BREEDING. 



"The presence of free crossing and the intentional 

 matching of individual animals are the corner-stones of the 

 breeder's art. . . . Free crossing has in all cases played an 

 important part in giving uniformity of character to all the 

 members of the same domestic race and of the same natural 

 species, though largely governed by natural selection and 

 by the direct action of the surrounding conditions. 1 . . . 

 The half-wild cattle in each of the several British parks are 

 nearly uniform in character ; but in the different parks, from 

 not having mingled and crossed during many generations, 

 they differ to a certain small extent." (WARFIELD.) 



The crossing of families not related to each other usually 

 gives increase of vigour and of size to the offspring, though 

 sometimes the distance between the characters of those 

 families is so great that the immediate result is somewhat 

 like a cross between two distinct breeds, and consequently 

 the full benefit is not at first realised, but is deferred to a 



1 This is the first function of crossing ; the second or opposite results 

 are dealt with later. 



