11 
The following excerpt from the Fuehnen herdbook 
illustrates the relations very well; the cows 1, 4, 5, 11, 12, 
15, 35, and 45 gave 183, 139, 158, 184, 126, 115, 109 and 187 
Ibs. of butter less in the year when they were sterile than in 
the preceding normal year. 
The higher milk production which generally sets in in 
the year following the temporary sterility is not sufficient 
to compensate the loss. For example the cow “Thyra” of 
Bellinge gave in her sterile years only 144 lbs. of butter, 
while giving in the two preceding years 320 and 370 Ibs., 
and in the two following normal years 442 and 409 Ibs. 
Granted that this may be an extreme example, there are still 
the many corroborating reports of the farmers, that they 
are experiencing a loss of 2000 lbs. of butter or more, in the 
yearly production due to temporary sterility. Of course 
single or few cases are of no signifiance, especially not in the 
big herds; but if many herds and many cows in each herd are 
affected, it is a serious matter. 
Another result of sterility is the difficulty of procuring 
the necessary offspring; a selection of the best calves for 
breeding purposes is then, of course, out of question, since 
one has to breed every heifer calf. Therefore in herds with 
a high breeding standard, sterile animals, even if only tempo- 
rarily sterile, are a serious handicap. 
The number of sterile animals in our country can be 
rather accurately ascertained through the books of the 
Breeders’ Societies. It is shown there that about 11% of 
the registered cows have either aborted or been sterile during 
the year. That number is nearly constant from year to year, 
a good indication of its correctness. 
Eleven per cent does not appear to be such a high per- 
centage, but one has to bear in mind that many of the herds 
included in the records were entirely free from either abor- 
tion or sterility. 
