Some ewes at six years of age lose their teeth ("broken mouths"), 

 and should then be sold. "Ewes average a larger percentage of in- 

 crease in lambs after they reach full maturity at three years of age, 

 and until after they are six years old, when the rate of increase di- 

 minishes/' 27 



Age in a sheep may be readily estimated, since the permanent 

 set of teeth gradually replaces the temporary (milk) teeth. A sheep 

 is a lamb until the first pair of incisors replaces the central pair of 

 temporary incisors (sheep have no incisors on the upper jaw), at 

 about twelve months of age. The second pair of permanent incisors 

 replace their corresponding temporary teeth at the end of two years, 

 the third pair are replaced at the end of three years, and the fourth 

 pair at the end of four years, when a sheep is said to be fully matured. 



Cross-Breeding 



Many of our present day mutton breeds were founded by crossing 

 two or more breeds, resulting, after years of careful selection, in 

 established breeds. Cross-breeding may be used for the production 

 of market lambs, but the breeding stock should be bred pure. Com- 

 bining the grazing and early breeding character of the Merino with 

 some mutton breed makes an excellent market lamb. There is, how- 

 ever, sufficient variation in type within breeds to give a great range 

 for the selection of characters that are necessary to meet market re- 

 quirements of mutton and wool. 



Inbreeding. 



By inbreeding is meant the mating of closely related animals. 

 Promiscuous inbreeding leads to low constitution, loss of vigor, non- 

 breeding character and decrease in weight and size. This method 

 of breeding intensifies all characters, both good and bad. Only in 

 the hands of the experienced breeder, who is thoroughly familiar with 

 the ancestry of his animals and a good judge of sheep, should in- 

 breeding be practiced. 



Care, Feed and Management of Ram. 



Since the ram usually represents more than fifty per cent, of 

 the influence of heredity on each crop of lambs, his care, feed and 

 management must be duly considered. He should not be allow< 

 to run with the breeding flock. Keep him separate with a young rai 

 or wether for association. During all seasons of the year he should 



- 7 Wisconsin Bulletin No. 95. 



22 



