HORSES AND MULES 



341 



Upon investigation, however, all evi- 

 dence for the supposed fertility of mules 

 has proved unsatisfactory. Male mules 

 are amorous and have to be castrated, 

 to prevent them from worrying mares, 

 but no colts have come from such occa- 

 sional breeding. 



Zebroids — Within recent years experi- 

 ments have been carried out in crossing 

 zebra stallions on mares. The resulting 

 hybrid is known as a zebroid. The most 



poses, or for heavy and light draft work, 

 their size and form depending upon that 

 of the mare. Percheron, Clydesdale and 

 Suffolk mares produce draft zebroids, 

 while thoroughbred mares produce ze- 

 broids of considerable speed. Breeding 

 may be done either in the spring or fall, 

 but preferably in moderately warm 

 weather. Eecently, the Bureau of Ani- 

 mal Industry has undertaken some ex- 

 periments in breeding zebroids. 



conspicuous men in this work are Pro- 

 fesssor Ewart and Baron de Parana of 

 Brazil. Zebroids tend to inherit the 

 size and conformation of the mare, be- 

 having like mules in this respect. The 

 stripes of the zebra, however, are not 

 entirely obliterated in the hybrid. 

 Zebroids are active, gentle, docile, good 

 feeders and of remarkable power. They 

 are rather more elegant animals than 

 mules and are claimed to be better 

 workers and of more tractable disposi- 

 tion, They may be bred for saddle pur- 



Fig. 227 FIVE-YEAR-OLD JACK 



(Courtesy Converse Bros.) 



Selection of jack — In raising mules, 

 the selection of the jack is an important 

 matter. We may, therefore, proceed to 

 describe the various breeds of jacks, 

 which may be used for the purpose. In 

 general, the best grades of jacks of ail 

 breeds are used for raising jacks and are 

 called jennet jacks, while the some- 

 what less valuable ones are bred to 

 mares for the production of mules and 

 are called mule jacks. In the following 

 account of jack breeds, Goodpasture's 



