J. Anim. Sci. 2005. 83:486
© 2005 American Society of Animal Science
Glen Pher Lofgreen1
R. Zinn
"I have lived simply, I have laughed frequently, and I have loved deeply. What more can I ask?"
Glen Pher Lofgreen was born September 28, 1919, in St. David, AZ. He was the 10th of 19 children, including six half brothers and two half sisters. Growing up on a small farm, he loved sports, music, homemade ice cream, and cattle. Following high school graduation in 1937, he enrolled in the animal husbandry course at the University of Arizona. After Pearl Harbor was bombed in 1941, he enlisted in the military, but in 1942, he was given a medical discharge when he contracted rheumatic fever. Returning to St. David, Glen worked as a high school janitor and met June McRae. Their marriage in 1945 was blessed with seven children. When he died on October 14, 2004, he left 38 grandchildren, and 21 great-grandchildren. Glen received his B.S. degree in animal husbandry at the University of Arizona in 1944. Shortly after their wedding, Glen and June traveled to Ithaca, NY, for his graduate studies. Mentored by Jack Loosli, Glen investigated nitrogen metabolism and theoretical nitrogen requirements of sheep and cattle, receiving his M.S. and Ph.D. degrees at Cornell University in 1946 and 1948, respectively. Glen started his teaching and research career at Montana State University during the winter of 1948. Quickly realizing a preference for the warmer climes of his youth, he joined the faculty of the University of California, serving on the Davis campus from 1948 to 1968, and subsequently at the University’s Desert Research and Extension Center (in El Centro) until he retired in 1977. Then, Glen joined New Mexico State University, serving for 13 yr as superintendent of the newly inaugurated Clayton Livestock Research Center.
Throughout his career, Glen was a prolific scientist, authoring or co-authoring more than 133 peer-reviewed manuscripts. He made substantial research contributions in the areas of energetics, protein and phosphorus nutrition, forage evaluation (particularly alfalfa), and nutritional management of shipping-stressed calves. Glen will be remembered by science and industry most for his innovative insights that led to development of the California Net Energy System, a system that evolved in an era of considerable confusion about energy requirements. For years, Glen and his colleagues had conducted comparative slaughter trials deriving NE values for feedstuffs using the "barley replacement" technique. In short, energy retention based on carcass-specific gravity was painstakingly measured for cattle fed test diets at two levels of intake above maintenance. The NEp value of the diet was calculated as the additional carcass energy retained divided by the additional feed intake. The NEp values derived by Glen and co-workers were lower than prevalent NE values because, at that time, NE was presented as a single value (maintenance plus gain). It soon became evident that the partial efficiency of ME used for maintenance was greater than the ME used for gain, and that the apparent NE (maintenance plus gain) value of the diet decreased as level of intake increased. It was noted in Lofgreen et al. (1963)
that ". . . confusion which exists concerning the use of NE and its variability may be the result of confusion . . . whether the value quoted is for maintenance alone, production alone or for both maintenance and production." The breakthrough in development of the new system discovered by Glen and his colleagues was that partial efficiency of NE utilization for growth was independent of the level of intake above maintenance (Lofgreen et al., 1963). Based on this idea, it became clear immediately that the partial efficiency of energy used for maintenance and gain were more nearly constant than the combined value was. Hence, the California Net Energy System was born, a system that ascribed two NE values to each feedstuff: one for maintenance and one for gain (Lofgreen, 1963). For both steers and heifers, NE retention was closely related (r2 = 0.94) to gain per unit of metabolic size, and maintenance requirements per unit metabolic size were equal (0.077W0.75) for steers and heifers (Lofgreen and Garrett, 1968). These observations transformed cattle energetics into a practical tool for evaluating and predicting growth that is employed in commercial feedlots around the World.
In addition to his research and teaching, Glen’s diverse professional service included serving as president of the Western section of ASAS and as president of ASAS (1972 to 1973). He also served on the NRC subcommittee on Beef Cattle Nutrition, the NRC subcommittee on Horse Nutrition, the editorial board of the Journal of Animal Science, as director-at-large of ASAS, and on the Board of Directors of CAST. He received the ASAS Feed Manufacturers Association Nutrition Research Award (1963), the Western section of ASAS Distinguished Service Award (1976), and the ASAS Animal Industry Service Award (1985). In his personal life, Glen was a deeply religious and devoted family man, serving for many years as a bishop of the Church of Jesus Christ of Latter-day Saints. Shying from accolades and formal titles, he desired to be thought of as "just a cowboy" and to be addressed simply as "Glen."
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Footnotes
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1 My thanks to Dr. Richard Zinn, University of California, Desert Research and Extension Center, El Centro, for writing this memorial to Dr. Lofgreen. People such as Glen Lofgreen, who make such enormous contributions to science and industry, are rare. Like Dr. Zinn, I am grateful for the privilege of having known and worked with Dr. Lofgreen.—M. L. Galyean, editor-in-chief. 
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Literature Cited
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 Top
 Literature Cited
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Lofgreen, G. P. 1963. Net energy—The new way to reckon rations. West. Livestock J. 41:40.
Lofgreen, G. P., D. L. Bath, and H. T. Strong. 1963. Net energy of successive increments of feed above maintenance for beef cattle. J. Anim. Sci. 22:598–771.[Abstract/Free Full Text]
Lofgreen, G. P., and W. N. Garrett. 1968. A system of expressing net energy requirements and feed values for growing and finishing beef cattle. J. Anim. Sci. 27:793–806.[Abstract/Free Full Text]
