366 
Crossbred No. 1 is consequently nearer 
the high test parent than the low test 
parent. It is perhaps fair in this connec- 
tion to say that the butter-fat percent- 
age of Pauline Posch is low even for the 
Holstein-Friesian breed, the mean for 
the breed being nearly .5 per cent 
higher than her average. 
Crossbred No. 2 has her butter-fat 
percentage shown in the second graph 
in Figure 24. She is the result of a 
cross of the Holstein-Friesian sire, 
Delva’s University De Kol, to the 
Guernsey cow, Canada’s Creusa. The 
photograph of Crossbred No. 2 is 
shown in Fig. 18. The characteristics 
of the Holstein-Friesian parent are seen 
in the rump, the size of body and the 
profile of the nose. 
The butter-fat percentage of this 
crossbred clearly resembles that of her 
low testing Holstein-Friesian parent. 
The average butter-fat percentage of 
Crossbred No. 2 for the eight months’ 
period was 3.241. The average but- 
ter-fat percentage for her Guernsey 
dam, Canada’s Creusa, was 3.961,° 
and for the potential butter-fat test of 
her Holstein-Friesian sire, Delva’s Uni- 
versity DeKol was 3.399. The butter- 
fat percentage of the crossbred cow is 
consequently slightly less than that for 
either parent. The difference from her 
Guernsey parent is 0.720 per cent and 
from her Holstein-Friesian parent 0.158 
per cent. Crossbred No. 2 resembles 
the low butter-fat percentage 4.5 times 
as closely as she does the high butter- 
fat percentage. 
The third graph in Figure 24 repre- 
sents the butter-fat percentage of the 
Crossbred No. 11 and that of her pure 
bred Jersey sire, Lakeland’s Poet, and 
her pure bred Holstein-Friesian dam, 
Delva Johanna DeKol. 
Photographs of the animals used in 
this mating are shown in Figs. 19, 20 and 
21. The dark underline and fair Jer- 
sey conformation of Lakeland’s Poet are 
clearly seen. Delva Johanna DeKol 
shows the typical conformation of her 
body and udder. Crossbred No. 11 
has an appearance of size in the fore 
The Journal of Heredity 
quarters and a lack of these qualities 
in the hind quarters which is due largely 
to the position in which she is stand- 
ing. 
While the butter-fat percentage of 
Crossbred No. 11 is intermediate be- 
tween that of her high testing and her 
low testing parents throughout the en- 
tire lactation, it is equally clear that 
the butter-fat percentage of the cross 
is much nearer that of her low testing 
parent than it is to that of the high 
testing parent. The mean butter-fat 
percentage of Crossbred No. 11 for the 
eight months’ period is 3.403, that for the 
Holstein-Friesian dam 3.224, the po- 
tential butter-fat percentage for the 
Jersey sire is 4.705. The difference 
between the low testing dam and the 
crossbred cow is consequently 0.179. 
The difference between the crossbred 
and her high testing sire is 1.302, or 
Crossbred No. 11 resembles the butter- 
fat percentage of the low testing parent 
7.3 times as closely as she does the 
butter-fat percentage of the high test- 
ing parent. 
The butter-fat percentage of Cross- 
bred No. 12 and her Guernsey dam, 
College Gem, together with the poten- 
tial butter-fat percentage of her Hol- 
stein-Friesian sire is shown in the 
fourth graph of Figure. 24. Photo- 
graphs of the animals composing this 
mating are shown in the previous paper 
of this series. The butter-fat percent- 
age of College Gem, the mother to this 
crossbred cow, and that of Creusa’s 
Lady, the dam of Crossbred No. 29, is 
considerably higher than that of other 
animals used in these crosses. A study 
of the butter-fat percentage of the 
breed to which these cows belong and 
also of the Jersey breed makes it appear 
quite possible that there are at least two 
levels of butter-fat percentage, speak- 
ing from the inheritance viewpoint, 
within these breeds. Should such prove 
to be the case the results of the crosses 
including these relatively high butter- 
fat testers might produce a different 
result than those including the lower 
testing cows. 
* The butter-fat percentage for Canada’s Creusa is clearly very low for a Guernsey cow. In 
the advanced registry of this breed the average year test is 4.9 per cent of butter-fat. 
