Oct. 7,1918 Crosses between Dairy and Beef Breeds of Cattle 53 



alone appears as such a dominant. The white spots on the face (star, 

 star snip, and blaze), neck, shoulders, rump, flanks, and legs are, in gen- 

 eral, suppressed in their offspring when such animals are mated to solid 

 color. 



(3) As has been suggested, but as has never been tested before, the 

 pigmented muzzle is dominant to the one not so pigmented. 



(4) Agreeing with the previous work of this laboratory it is shown 

 that a pigmented tongue is dominant to a nonpigmented one. 



(5) A black switch appears to cause the suppression of the other 

 switch colors in the offspring. Because of this suppression and because 

 all of the matings had at least one animal with a black switch as parent, 

 it was impossible to study the behavior of the other colors. There v/as 

 one case of segregation of a deep red-orange switch from a back cross of a 

 black animal carrying an orange coat and white switch, genetically. 

 This case showed the segregation of the factor for orange switch from 

 that for both white and black. 



(6) The character of polledness has been studied. Two-horned ani- 

 mals resulting from crosses of polled X horned appeared. On the basis 

 of the other results these could have not resulted from a heterozygous 

 polled condition. One of these cases had the horns tight on the head 

 and the other loose. These cases then form exceptions to the previously 

 accepted hypothesis of simple dominance for the polled character and 

 require a subsidiary hypothesis. The hypothesis suggested is that the 

 testes have some action on the presence or absence of horns. Partial 

 proof to this hypothesis is given by the fact that of the polled animals 

 10 were females, 2 males, i doubtfully polled. Of those with scurs i 

 female and 7 males had loose scurs ; of those with tight scurs all (3) were 

 males; of those with horns all (2) were males. This would seem like a 

 clear case where the male has some influence. The explanation of this 

 difference appears to be due to a hormone secreted by the germ cells. 

 Should this prove true, this forms an interesting parallel between cattle 

 and sheep, in which the sex glands are known to produce such changes. 



(7) The qualities of beef production are shown to be divisible into 

 four general regions of the body: head, fore quarters, barrel, and hind 

 quarters. The type of head and heavy, deep fleshed fore quarters are 

 transmitted to the offspring when either parent is of Aberdeen-Angus 

 breed. The body and hind quarters appear intermediate, but resemble 

 most the dairy parents. 



(8) Data are given on the milk and fat production of some of the 

 crossbreds. The results indicate that milk and fat production behave 

 separately. High milk production is dominant to low, but high fat per- 

 centage is recessive to a low fat percentage in the milk. 



