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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Carl P. Birkelo


Thirty-three pregnant, nonlactating first-calf Angus x Hereford females were used to determine the relationship between production efficiency (PE) and the metabolizable energy required for maintenance (MEm), fasting heat production (FHP) and the efficiency of using metabolizable energy for maintenance (Km). Production efficiency was defined as the grams of calf weaned/total Mcal ME intake of the female and calf during a 12-month period. Variation was observed among females in PE as well as the energy parameters MEm, FHP and Km However, only a small relationship was found to exist between PE and MEm, FHP and Km (r2 = .04, .04 and .00, respectively). The reason for this is unclear, but it may be due to the relatively high plane of nutrition provided during the PE phase of the study and/or the physiological state in which metabolism measurements were made. Additionally, FHP was closely related to MEm (r2 = .69), suggesting it could be used as an indicator of fed maintenance requirements.

Library of Congress Subject Headings

Beef cattle -- Feed utilization efficiency
Energy metabolism




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