62 



Mendelian Experiment with Cattle 



i*2 4 



Fa .8 

 Fa 14 

 Fa 20 

 Fa 25 



F,l 



F, 7 



1914 



liilo 

 1910 

 1917 

 1918 



Male (cast.) 



Male (cast.) 

 Female 

 Female 

 Female 



Hardseurs Black 

 under hair 



Horned Black 



Horned Black 



Polled Red 



Polled Black 



Fa 5 

 Fa 9 

 Fa 15 

 Fa 21 

 F222 



F, 1 



Fi 8 



1914 

 1915 

 1916 

 1917 

 1918 



Female 

 Male (cast.) 

 Male (cast.) 

 Female 

 Male 



Polled 



Horned 



Horned 



Polled 



Polled 



Black 

 Black 

 Black 

 Black 

 Black 



Fa 10 

 Fa 16 



F, 1 



Fi 9 



1915 

 1916 



Female 

 Female 



Polled 

 Polled 



Black 

 Black 



Note. There is some doubt about the respective dams of Fa 13 and 14 and 19 and 20. 

 It is possible that the dams are reversed in either case or both, i.e. 13 and 19 may be from 

 F] 7 and 14 and 20 from Fj 6. 



In the present experiment the F^ generation females were all " clean 

 polled," i.e. without any trace of horn development. F^ No. 3, a bull calf, 

 was sold for slaughter at three months of age, at which time no horn 

 development had occurred. The bull ^1 No. 1 (PI. XII, fig. 1) developed 

 peculiar short stout horns, which grew at an abnormally slow rate. At 

 18 months they were about 4 ins. long. At 6 years they measured 10 ins. 

 There can be no doubt that this animal, like the other F^ crosses, was 

 heterozygous for the polled character. We should therefore conclude 

 that the polled condition is completely dominant in the female, while 

 in the hybrid male the horn development is inhibited, but at least not 

 always completely suppressed. These results are in accord with those of 

 Gowen (5) who obtained the following in first hybrids between Aberdeen- 

 Angus and various horned breeds. 



Horned 



Hard scurs 



Loose scurs 



Polled 



Male 



