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Armsby Calorimeter

The Armsby Calorimeter at Penn State was completed in 1902 and was used to perform experiments on the energy metabolism of cattle.
Armsby Calorimeter  - Interior View With Equipment
The respiration calorimeter, with Raymond Swift
seated, during an experiment in 1955.

The Penn State  Armsby Calorimeter was completed in 1902, and in 1907, Henry Armsby became director of the newly-formed Institute of Animal Nutrition. From that time, and until his death in 1921, Armsby and his staff operated the calorimeter continuously, while performing experiments on the energy metabolism of cattle.

He recognized the importance of heat loss as a waste of feed energy, which had gotten little attention in the past, and was determined to gather the data that would enable publication of net energy value of all the feedstuffs used in formulating livestock rations. Net energy is that feed energy remaining after subtracting that lost in feces, urine, combustible gases, and that used in metabolizing the feed itself (heat increment)-in other words-that energy available for animal production.

Dr. E. B. Forbes became director of the Institute after Armsby's death. Forbes, August Fries (who had worked with Armsby from the beginning), and R. W. Swift led a staff of scientists and technicians in the operation of the calorimeter and in the pursuit of Armsby's goal of a feeding standard based upon net energy. However, by the time of Forbes' retirement in 1946, he and Swift concurred that net energy is influenced by so many factors not related to the feed that it cannot be used as a routine expression of the nutritive value of any feed. Swift likened labeling a feed with a net energy value to stating an expected crop yield on the label of a sack of seed or fertilizer. In Pennsylvania Agricultural Experiment Station Bulletin # 615 (1957), he commented on the futility of the "estimated net energy" value included on many feed labels and concluded that accuracy, ease of measuring, and other factors make digestible energy a more practical measure of nutritional value.

Armsby Calorimeter
The calorimeter building of the Institute of Animal
Nutrition, circa 1900.

After Forbes' retirement in 1946, the Institute of Animal Nutrition became the Department of Animal Nutrition with Swift as head. The calorimeter was modified to accommodate four sheep instead of one large ruminant and was used mainly in comparative evaluation of forages until the mid-1950s, when it was converted to study the relationship of proportion of nutrients (fat, protein, etc.) to energy metabolism in humans. These experiments demonstrated the sensitivity of the calorimeter, as the operator could easily detect the burst of heat generated when the volunteer student subject turned over in his sleep or was stimulated by sight of a volunteer coed delivering his meal.

The Dairy Husbandry department was formed in 1905 and in 1954 was renamed the Department of Dairy Science. Almost from the beginning, the department offered two courses of study: dairy manufacturing and dairy production. Both options were available to students until 1975. At that time, the dairy manufacturing faculty joined with selected faculty from animal science, poultry science, horticulture, and home economics/human development to form the new Department of Food Science. In 1976 the dairy production faculty was merged with that of animal science, becoming the Department of Dairy and Animal Science, under the leadership of B. R. Baumgardt.

When Swift retired in 1960, the Department of Animal Nutrition was merged with Animal Husbandry. The calorimeter was converted to a museum in 1969. Under Forbes' and Swift's leadership, the department had served as a training ground for younger scientists, since the six junior faculty members (calorimeter operators) had instructorships allowing time for graduate study, usually leading to a Ph.D. Some of their theses involved use of the large calorimeter. Many of them were studies of dietary balance as related to energy metabolism of albino rats, in total body balance trials, or in measuring heat production indirectly with a miniature calorimeter in which the respiration chamber was a half-gallon Mason jar.

Author: Robert L. Cowan, Professor of Animal Nutrition