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Thesis (M.S.)—University of Nebraska—Lincoln, 1950. Department of Dairy Husbandry.


Copyright 1950, the author. Used by permission.


Practical dairymen have long recognized that high production during a dairy cow’s lactation is dependent on two factors.The first is how high the production goes during the maximum month and the second is the persistency of lactation.Persistency of lactation is an important economic characteristic of the dairy cow.One of the reasons why the dairy cow is usually a higher milk producer than the beef or dual-purpose cow is that she is inherently a more persistent milk producer.To be profitable, a dairy cow must produce large daily amounts of milk over a long period of time; in other words, she must be persistent.

Many phases of the problem of persistency have been examined. However, a lack of critical work exists on the effect of frequency of milking on persistency.This is probably due to a lack of readily available data.Sufficient intra-herd data to make a critical study of the effect of number of times of milking per day on persistency are difficult to find.Since 1896 daily milk weights have been kept on the production of all dairy cows milked in the University of Nebraska herd.Enough records are now at hand to provide data for an intra-herd study of differences in persistency due to different number of times of milking per day.The lack of conclusive work on the problem and the availability of suitable data indicated that a study of this kind would prove profitable.

Advisor:Mogens Plum