During the spring of 1889, while engaged in analyzing the milk of the college herd, I was impressed anew with the very great need, long felt by farmers, dairymen and breeders, of a speedy, easily worked, inexpensive and reasonably accurate method for testing the quality of milk— a method capable of being executed by anyone at home, in the dairy or in the farmer’ s kitchen, and which would enable the milk producer or the breeder to determine, at trifling expense, the yield of butter fat (or milk fat) from the individual cows of his herd.
That great differences often prevail among the cows of a herd, as regards the butter making quality of milk produced, is well known ; likewise that breed is not a guaranty of quality— the difference between two cows of the same breed being frequently as great as between the averages for different breeds, even for those of very unlike average quality.
So it is regarding the actual, or possible, butter product for the year, of herd or animal— it depends upon individual peculiarities or tendencies, which vary widely within the same as well as among different breeds.
Patrick, G. E.
"The “Iowa station milk test." A new dairy test for determining the amount of butter fat in milk,"
Bulletin: Vol. 1
, Article 2.
Available at: https://lib.dr.iastate.edu/bulletin/vol1/iss8/2