INHERITANCE IN CROSSES OF DAIRY 
AND BEEF BREEDS OF CATTLE 
III. Transmission of Butter-Fat Percentage to the First Generation! 
Joun W. GOWEN 
Agricultural Experiment Station, Orono, Maine 
HE inheritance of milk yield in the 
first generation crosses of dairy and 
beef breeds of cattle was treated 
in the second paper of this series.2 The 
inheritance of butterfat percentage for 
the same crosses will be analyzed here. 
Butter-fat percentage has been 
shown to have a considerable variation 
with age in the Ayrshire breed, some 
relation to age in the Jersey and Guern- 
sey breeds and no significant relation 
to age in the Holstein-Friesian breed. 
These relations necessitate the appli- 
cation of age correction factors to the 
Jersey, Guernsey and Ayrshire records 
for butter-fat percentage to make these 
records comparable. Without any pre- 
vious knowledge as to how age will 
effect the butter-fat percentage of the 
crosses between these breeds, it has 
been thought advisable to correct the 
crossbred records with the same set of 
correction factors which were used for 
the Jersey and Guernsey. When a 
butter-fat percentage record is men- 
tioned in any subsequent section of 
this paper it is to be understood that 
it is an age corrected record. 
HOW THE RECORDS ARE OBTAINED 
The butter-fat percentage record for 
any given crossbred cow or her dam is 
obtained by taking the mean butter- 
fat percentage of the different lacta- 
tions during the cow’s life at the same 
corresponding month of lactation. The 
butter-fat percentage of the sires, Tau- 
rus Creamelle Hengerveld and Lake- 
land’s Poet, are the mean of the butter- 
fat percentage of their daughters other 
than crossbred daughters. The record 
of Kayan, where no pure bred daugh- 
ters are available, is obtained by aver- 
aging the records of the Aberdeen- 
Angus cows in the herd. The record 
for Delva’s University DeKol is the rec- 
ord of Taurus Creamelle Hengerveld. 
The records of the last two sires are 
subject to the same criticisms cited in 
the second paper of the series. 
The details of the number of lacta- 
tions which make up the record of the 
given cow are given in the second paper 
of this series and need not be repeated 
here. 
BUTTER-FAT PERCENTAGES 
The first graph in Figure 24 shows the 
monthly butter-fat percentage of Cross- 
bred No. 1, her pure bred Holstein- 
Friesian dam, Pauline Posch and the 
potential record of her Jersey sire, 
Lakeland’s Poet. Photographs show- 
ing Crossbred No. 1 and her parents 
are shown in the previous paper of this 
series. The solid line (———————) 
represents the crossbred’s butter-fat 
percentage, the dotted line(.-.-.-.---- ) 
the butter-fat percentage of her dam 
and the dot and dash line (:—:—-—- ) 
the potential butter-fat percentage of 
her sire. The butter-fat percentage 
of this crossbred is clearly intermediate 
between that of her high butter-fat test 
sire and her low butter-fat percentage 
dam. The eight months’ butter-fat per- 
centage for Crossbred No. 1 was 3.899. 
The butter-fat percentage for her Hol- 
stein-Friesian dam was 2.758 and for 
her Jersey sire was 4.705. The cross- 
bred cow was consequently 0.806 per 
cent less than her Jersey parent and 
1.141 per cent more than her low test- 
ing Holstein-Friesian parent. The 
‘Papers from the Biological Laboratory of the Maine Agricultural Experiment Station, 
No. 136. 
? Gowen, John W., 1920. Inheritance in Crosses of Dairy and Beef Breeds of Cattle. II. On 
the Transmission of Milk Yield to the First Generation. JoURNAL oF HEREDITY, Vol. XI (1920), 
No. 7, pp. 300-316. 
365 
