144 Maine Agricultural Experiment Station. 1918. 



The polled character in the offspring of these crosses occurs 

 most frequently in the females. In 7 offspring from matings of 

 horned males with polled females, 3 polled females were pro- 

 duced to 1 polled male. One male and 1 female had scurs 

 and 1 male had heavy horns. In the reciprocal cross of polled 

 male bred with horned female, 1 male was doubtfully recorded 

 as loose scurs under the skin. He died before this could be 

 checked. Of the others 7 females were polled, 3 males had sol- 

 idly attached scurs, 6 had loose scurs and 1 was horned. Cross- 

 bred No. 21 shows this horned condition. 



These data make it probable that sex has some influence on 

 the horned condition. The parallel with the case of sheep is of 

 special interest for castration experiments have established the 

 presence of a secretion by the testis which materially aids the 

 production of horns with this species. On the basis of this the 

 testis in the bull would be expected to secrete a hormone which 

 would allow him to grow horns with one dose of the horned 

 genes where two doses of the horned gene would be required 

 by the female. The parallel is still further emphasized by the 

 variability, both intra and interracially and in the length of time 

 necessary for its action in producing horns, as this work has 

 shown for cattle and as the work of ArkelP has shown for sheep. 

 This may be the explanation of- the results obtained by Lloyd- 

 Jones and Evvard where out of 78 offspring of a Shorthorn bull 

 to Galloway cows they obtained only 6 scurred and two horned 

 animals. Here it is conceivable that in this cross the secretion 

 may be lacking or very small in amount as in some of the Meri- 

 nos that Arkell bred. That is, the concentration or amount of 

 the secretion may be lower in Galloway crosses than it is in Aber- 

 deen-Angus crosses. In all events the secretion in cattle seems 

 intermediate in its action between the reindeer and the sheep 

 since castration of horned breeds does not retard the horn 

 growth although it does tend to make the horn longer and more 

 slender. 



THE INHERITANCE OF BEEF AND DAIRY CONFORMATION. 



The component elements which go to make up conformation 



or type are obviously complex. In the crosses of the two types, 

 dairy and beef, the offspring break up more or less strictly into 



