Gowen: Transmission of Milk Yield 303 
CROSSBRED NO. 1 
This crossbred is from the Jersey and Holstein-Friesian parents shown on the opposite page. It 
will be noted that the shape of the nose and body of the crossbred resemble the Holstein-Friesian 
parent, while the size of body and udder resemble the Jersey parent. In the top graph of Fig. 14, 
compare the records of milk production of the offspring with that of her parents as explained in 
the text on page 301. (Fig. 7.) 
tial milk production of the Jersey sire 
is given as adot and dash line (——-—). 
The milk production of the crossbred 
clearly follows that for the sire’s expec- 
tation. The milk production of the 
Holstein-Friesian dam follows a course 
much higher than does that of the 
crossbred daughter. The daughter may 
therefore be said to have only the in- 
heritance of the low milk producing 
breed. In view of what follows in 
these curves this result is somewhat 
surprising. The result cannot, how- 
ever, be a mistake, because the cross- 
bred daughter’s milk production is 
based on four lactations; the milk pro- 
duction of the Holstein-Friesian dam 
is based on 11 lactations, and poten- 
tial milk production of the sire is based 
on four daughters having two lacta- 
tions each. These facts make it seem 
probable that the milk production for 
the matings are somatically as repre- 
sented in the top drawingof Figure 14. 
The photographs of the animals com- 
prising this mating are shown in Figs. 
5: (OvanGise 
EIGHT MONTHS LACTATION PERIOD 
The duration of milk production for 
most cows of the leading dairy breeds 
depends largely on the will of the herds- 
man as to when the lactation will close. 
Such being the case it is desirable to 
have for the whole lactation a time inter- 
val over which to compare the milk 
yield of one cow with that of another. 
For convenience this time interval has 
been chosen as eight months. Such a 
duration of time will allow the inclusion 
of the records of the Aberdeen Angus 
cows and their crossbreds where one of 
the main causes of their low milk yield 
