Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/16/2007
Publication Date: 4/30/2007
Citation: Ferrell, C.L., Jenkins, T.G. 2007. Biological type and production efficiency: Where have we been and where are we going. In: Proceedings of the IV World Brangus Congress, April 23-28, 2007, Salto, Uruguay, 2007 CDROM.
Technical Abstract: Early studies showed that about 73% of the total feed costs of the cow were attributable to feed required for maintenance, 20% were required for milk production and 7% was required for pregnancy. Those studies also showed that feed energy required for maintenance could differ by 25% or more among diverse types of cows, and that estimates of maintenance were associated with differences in body size and genetic potential for production. Variation in energy costs of lactation are primarily associated with amount milk produced, and to the influence of milk production potential on maintenance requirements. Differences in energy required for gestation are relatively minor. Differences in maintenance requirement had a large impact on total feed requirement of the cow and have a large effect on overall production efficiency. Findings that maintenance requirements were associated with production potential suggested that animals having genetic potential for high productivity may have less advantage or be at a disadvantage in a more restrictive environment, and suggested the need to synchronize animal genetic resources with production environment. Cows having relatively low maintenance requirements and low production potential were favored in the more restrictive nutritional environments, whereas those having greater production potential were favored in less restrictive environments. Reproductive efficiency and milk were primary contributors to differences in efficiency. Application of currently available technologies offers the potential to improve maintenance and system efficiency through identification of individual animal phenotype and genetic uniqueness, and application of that knowledge through marker assisted management and/or marker assisted selection.