New Yorx AGRIcuLtTuRAL ExpERIMENT STATION. 1935 
Relation of Sex in Thoroughbred Calves. 
The following inquiry was institutéd, not with a purpose to 
elaborate any theory in addition to the many already advanced 
in reference to this interesting and practically important matter, 
but simply to secure, so far as possible, an addition to the many 
facts: which have been already accumulated, leaving them for 
each to explain as might seem to him best. 
A circular was addressed to many breeders of thoroughbred 
stock of the different breeds, requesting only the order of suc- 
cession of sex of the calves born to their different animals, and 
this inquiry was made of such breeders for the reason that only 
such would have preserved the necessary records. 
F A very gratifying response was made and the following tables 
_ have been compiled from the records sent from 68 herds, includ- 
ing 10 breeds, 769 cows and 3,614 calves. 
: These records include herds from many of the States and the 
Canadas. 
It may be safely assumed that as a rule any one keeping such 
records of his herd has maintained his animals in good 
condition. 
It is stated thatat the beginning of the last century there were 
atleast 500 different theories as to the causes which determined 
_ the sex, and certainly the correspondence in this matter develops 
_ the fact that at the present day one or another theory is held by 
_ very many of the breeders at the present day. 
_ The following facts will, in a measure; show the results of 
_ many attempts to carry one or another of these theories into 
practice. 
The following table gives the number of cows of each breed 
4 and the number of calves of each sex in their order from the first 

to the thirteenth. 
a _ Incases where the number of calves is less than that of the 
cows, asfor example, the first calves of the Jerseys, the explanation 
__ is that the record .was lost of certain cows reported as to her first 
m.calt. 
Occasional twin calves will also explain the possible excess of 
_ calves over the number of cows reported. 
