Jeng-Jung Yee

Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Dairy Science


The composition of cow's milk, including both the fat and solids-not-fat (SNF) content, is known to vary over rather broad ranges. Breed and individuality of the cow are the major factors influencing this, but many other factors are known to exert their influence. However, it has generally been observed that compensation or complementing occurs when the milk of cows is mixed together; so that the composition of milk from a herd will tend toward averages or norms. This effect usually is even more marked as the milk from two or more herds is commingled. Payment for milk on the basis of fat content has been the common practice for many decades. When the practice sta1·ted it was a logical approach, as the principal product made from milk was butter. However, milk is currently used for many other purposes besides butter-making, and it has been suggested that the SNF of milk should also be given consideration when the value of milk is established. Very logically the fat and/or solids-not-fat content will affect the yield of manufactured dairy products made from a given supply of milk. The Dairy Science Department at South Dakota State University has received reports of lower than average product yields in several dairy plants in the state, especially during certain times of the year. Lower product yields make for lower economic returns to the processing plants and so management and stockholders become very concerned. Dairy and Food Science Departments in other states of the North Central Region have indicated that dairy plants in those states have had similar experience in that milk composition does not always fit the average reported. If this proves true throughout the country, the reliability of the average values derived by Jacobson (38) which is the basis for computing milk solids-not-fat from the percent fat in milk may no longer be valid. Hence there is a definite need for data on the composition of milk currently being produced in the United States. The purpose of this investigation was to determine in detail the characteristic composition of milk from various parts of South Dakota during the four seasons of the year with special emphasis on the effect of composition on functional properties of milk and the yield of products manufactured from it.

Library of Congress Subject Headings

Milk -- Composition


Includes bibliographical references (pages 87-94)



Number of Pages



South Dakota State University


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Dairy Science Commons