Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/31/2001
Publication Date: 7/25/2001
Citation: Ferrell, C.L. 2001. Energy nutrition of ruminants: Keeping books [abstract]. Journal of Animal Science. 79(Suppl. 1):13.
Technical Abstract: Goals of energy metabolism research with ruminants have historically been to 1) develop an accurate means for evaluating feedstuffs and stating animal requirements, and 2) establish the tissue and biochemical origin of heat production or energy expenditures. Techniques employed in nutritional energetics of ruminants have classically been concerned with the partitioning of dietary energy into fecal, urinary, methane, heat, and recovered or product energy. Attributes of feeds that influence the partition of dietary energy has received limited attention recently. Indirect respiration calorimetry and comparative slaughter techniques continue to be important energetics research tools. Techniques utilizing blood flow, thermal dilution and gas analyses to quantify and separate heat generated from the GI tract into aerobic and anaerobic origins has been successfully applied to ruminants. Assessment of tissue energy metabolism from blood flow and substrate flux across the PDV, liver, gravid uterus, fetus, mammary gland, and hind limb have contributed substantially to our understanding of tissue energy expenditures and sources of their variation. Studies at the organ, tissue, cellular, and subcellular levels, including substrate turnover and channeling, ion transport, proton leakage, and uncoupling proteins have increased our understanding of the biochemical processes involved. A major challenge of the future lies in not only establishing the biological and biochemical bases for energy expenditures, but also in determining the genetic and biological bases for differences among animals. It is equally critical that we be able to translate fundamental knowledge gained through these endeavors to functional understanding that can be applied to the whole animal.