Journal of Agricultural Research 



Vol. XV. No. 1 



following pages. The conclusions drawn from them are the author's, 

 and he is alone responsible for them. 



FOUNDATION HERD 



The stock available for the crosses consisted of the following breeds 

 in the relative proportions shown in Table I : Holstein-Friesian, Guern- 

 sey, Jersey, Ayrshire, and Aberdeen- Angus. 



Table I. — Breeds available as foundation stock for the crossbred herd 



Breed. 



Holstein-Friesian 



Holstein-Friesian grades. 



Guernsey • • • • 



Jerseys 



Maine State Jerseys 



Maine State grades 



Ayrshire 



Angus 



Total, all breeds. 



Male. 



Female. 



3 

 37 

 i6 



lO 



6 



I 



86 



It will be noted that there were a number of grades carrying in,uch 

 Holstein-Friesian blood. These were not used, since to carry convincing 

 proof the ultimate results must be based on experiments with stock 

 bred for some generations for the characters which were to be studied: 

 milk, butter fat, and beef; otherwise the results might be explained by 

 the heterogenous mixture of factors contained in the grades. The 

 stock, together with the breeds which were finally used in the foundation 

 crosses, is shown in Table II. They are all animals of good breeding and 

 come from lines productive in milk, butter fat, or beef production, as the 

 case may be. 



It seems well at this, point to consider the qualities of this foundation 

 herd in respect to its inbreeding and possibilities of increased vigor due 

 to heterosis of the crossbred progeny. Studies of the known inbreeding 

 of this foundation herd have been made. The choice of a definite numeri- 

 cal measure of this inbreeding is necessary to any adequate study. 

 Several such figures have been given to the students of inbreeding through 

 studies of this laboratory (27-38). It is thought wise to use only one of 

 these measures — namely, the coefficient of inbreeding — as this measures 

 the total amount of inbreeding which has taken place in the pedigree of 

 a given animal. Table III gives this amount of inbreeding in the suc- 

 cessive generations, up to the fourth, known to have taken place in the 

 pedigree of the animals used in this foundation herd. It will be noted 

 that these inbreeding coefficients are, in general, low, compared with 

 those of the animals already studied in this laboratory. This indicates 

 that inbreeding would have little efifect in increasing the vigor or pro- 

 duction by the animals of the crossbred herd. 



