Gowen: Transmission of Milk Yield 
difference between the milk yield of 
the daughter and the dam,—that is 
these differences do not always blend 
gradually, in fact as a rule they pro- 
gress by wide steps. Further it is at- 
tempted to show that the sires in the 
red Dannish breed appear to be differ- 
entiated into those whose daughters 
are all low producers; those whose 
daughters may be low producers, me- 
dium producers, and high producers; 
and thirdly those whose daughters are 
all high producers. The data to sup- 
port these conclusions are admittedly 
fragmentary and open to several criti- 
cisms. It is however held to show that 
milk yield is transmitted in mendelian 
fashion with the heterozygote inter- 
mediate between the pure forms. 
The manner of grouping the data 
and its correction for age, etc., would 
seem to more or less force this con- 
clusion. It does therefore offer no 
further critical information to differ- 
entiate between the transmission of 
milk yield by factors showing partial 
dominance as was apparently the case 
in our experiment and any other hy- 
pothesis. 
Two practical experiments carried 
on by breeders in England are of par- 
ticular interest as their crosses parallel 
some of those in these experiments. 
The object of the experiments was to 
cross the Jersey with the Aberdeen- 
Angus and to fix in the resulting off- 
spring the hardiness of the Angus with 
the milk yield of the Jersey. The 
original crosses were made Aberdeen- 
Angus bull to Jersey cows. Although 
records were kept, no figures are cited 
in the paper® on this herd. The quali- 
tative statement is, however, made 
that the F, cows show a high yield of 
® Parlour, W. Jersey-Angus Cattle. 
Kuhlman, A. H. Jersey-Angus Cattle. 
7Stevens, H. D.E. Jersey-Angus Cattle. 
pris2. 
8 Kildee, H. H. and McCandlish, A. C. 
Increasing Dairy Production. Bul. 165. 
VI. 
Fat. Maine Agricultural Experiment Station. 
Gowen, John W. 1919. 
Maine Agricultural Experiment Station. 
1916. 
Iowa Agricultural Experiment Station, pp. 383-402. 
® Pearl, Raymond, Gowen, John W., and Miner, John Rice. 
Transmitting Qualities of Jersey Sires for Milk Yield, Butter-Fat Percentage and Butter- 
Annual Report for 1919, pp. 89-205. 
Report of Progress on Animal Husbandry Investigations in 1919. 
Annual Report for 1919, pp. 249-284. 
315 
milk, ranking almost as high as their 
Jersey dams. 
In another section of England a 
similar cross was made by another 
breeder with the same objects in view. 
This breeder, Mr. Stevens,’ makes a 
similar statement in regard to the milk 
yield of the F,; cows. 
Kildee and McCandlish,’ record a 
similar experiment which incidentally 
furnishes some data on the transmission 
of milk yield. They crossed scrub 
cattle whose milk yield averaged be- 
tween 3300 and 3900 pounds to Hol- 
stein-Friesian sires. The resulting F, 
offspring averaged 5561.6 pounds of 
milk. Crosses to Guernsey and to 
Jersey bulls did not increase the F, 
average production over that of the 
scrubs, although one daughter of a 
Guernsey sire did nearly double her 
milk yield over that of her dam. No 
age correction was applied to these 
records. The length of lactation was 
also not strictly comparable between 
animals. Several bulls of each breed 
were used. Despite these handicaps 
the results indicate that there was a 
partial dominance for milk yield ex- 
pressed in the F, offspring of the Hol- 
stein-Friesian sires. The case of the 
single exceptional offspring of one of the 
Guernsey sires can likewise be explained 
on this basis for it has been shown that 
within a breed wide differences be- 
tween sires in their ability to transmit 
milk yield may occur.’ Such differ- 
ences of course argue for differences 
in the factors for transmitting milk 
yield within the breeds similar to those 
illustrated in the experiments previ- 
ously described. 
Another extensive experiment was 
begun for similar practical objects by 
In Live Stock Jour. (London) 77 (1913) No. 2025, p. 85. 
In Jour. Heredity 5 (1915) No. 2, pp. 68-72. 
In Live Stock Jour. (London) 77 (1913) No. 2025, 
Influence of Environment and Breeding in 
1919. Studies in Milk Secretion. 
