46 



Journal of Agricultural Research 



Vol. XV, No. I 



animal carrying horns recessive, and polled Galloway cows may not be disqualified 

 as pure-breds because they happen to produce horned offspring. Therefore, although 

 the behavior of the Galloway cows Nos. 154 and 49, one-half of whose offspring by a 

 PpbuU have been horned, is "not in harmony with what we would expect" if they 

 were pure-bred animals, nevertheless, it does not serve as conclusive evidence that 

 they are not such. But if these two cows were bona fide pure-bred Galloways it is at 

 least plain that we can not rely upon pedigree and registration as assurance that 

 animals, purchased as pure-breds, are homozygous for the polled trait. 



Thus, in the opinion of these authors the occurrence of horns on the 

 heifers were due to their female parents being heterozygous for the 

 homed factor. 



In this same paper data on the segregation of polledness are given. 

 In back crosses of P'pXpp (where P' is the polled and p the horned 

 factor) 7 polled to 9 horned were obtained where the expectation was 

 8 to 8. In P'pxP'p matings 20 polled to 8 horned were obtained 

 where the expectation was 21 to 7. Their conclusion (20, p. 102a) on 

 this evidence would seem substantiated : 



The present results substantiate the allelomorphic nature of the horned and polled 

 condition in cattle. 



The citations seem to prove conclusively that polledness is a simple 

 Mendelian character. Some exceptions to this conclusion in our crosses, 

 the results of which are presented in Table XXVI, gave ground for the 

 belief that other factors influenced the result. 



Table XXVI. — Behavior of the polled character in the parental and first filial generations 



On the above interpretation, the data in Table XXVI offer several 

 interesting anomalies. The first is an animal resulting from a mating 

 of Kayan to the Ayrshire cow Dot Alaska. This mating produced a 

 male. No. 21, with heavy 4-inch solidly attached horns (PI. 6, B). By his 

 previous breeding record, where each mating constituted a back cross, 



