18 PRINCIPLES OF BREEDING 



female progeny ; and the Yorkshire coaching horse is the 

 result of crossing the old Cleveland Bay with the thoroughbred. 



Darwin, quoting Spooner, says : " Nature opposes no 

 barrier to successful admixture ; in the course of time, by the 

 aid of selection and careful weeding, it is practicable to estab- 

 lish a new breed. After six or seven generations the hoped- 

 for result will in most cases be obtained ; but even then an 

 occasional reversion or failure to keep true may be expected." 

 The recently formed Romney-Lincoln sheep of New Zealand 

 is an example. 



Certain distinct breeds of sheep are not sexually attracted 

 to each other. This is most observable when a ram is put 

 to a mixed flock of ewes, half of which belong to another 

 breed than his own. He attends first to those of his own 

 kind, and either wholly or, more frequently, partially neglects 

 the others. In certain instances the difference of the habits 

 of mountain and lowland sheep run in one flock does to some 

 extent account for the difference of results, but not so when 

 the animals mingle freely in confined areas. 



Crosses between two distinct breeds mated the proper 

 way make the best fattening animals. The sire should be of 

 the more improved breed as regards early maturity qualities, 

 unless both are equally good ; for example, the Shorthorn 

 bull breeds well with cows of milking breeds, or of slow 

 maturing sorts, as Kerry, Dexter, Ayrshire, West Highland, 

 or Galloway. Crossing in any other way is usually un- 

 successful. Of late years, since the Polled Angus breed has 

 been so much improved, farmers cross Shorthorn cows suc- 

 cessfully with Angus bulls (p. 169). 



In farm stock it has been fallaciously but very generally 

 believed that the male contributes specially to the external 

 shape, the female more to the vital and internal organs, in 

 spite of the fact that a calf has often a very strong likeness 

 to its mother in expression and in form. 



With a thoroughbred horse on a mare of another breed, 

 the resulting offspring has generally a symmetrical appear- 

 ance. A cross bred the other way is often strong and 

 useful, but plain, usually about the hind quarters and head. 



Sheep come under the same rule as cattle. Rams of any 

 of the improved varieties of Leicesters or Downs may be 

 used with advantage, under certain conditions, to put to 



