HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tedeschi, L. O. Articles by Kirschten, D. P. Search for Related Content PubMed PubMed Citation Articles by Tedeschi, L. O. Articles by Kirschten, D. P.

Identifying differences in feed efficiency among group-fed cattle

L. O. Tedeschi^*,1, D. G. Fox, M. J. Baker and D. P. Kirschten

^* Department of Animal Science, Texas A&M University, College Station 77843 and and Department of Animal Science, Cornell University, Ithaca, NY 14853

¹ Corresponding author: luis.tedeschi{at}tamu.edu

Identification of efficient animals in the postweaning growth phase for use in selection for improved feed efficiency is important to improve the economic and environmental sustainability of the beef cattle industry. Progeny testing using group-fed animals in commercial feedlots is the most common and practical method used to evaluate postweaning growth on large numbers of animals. We developed the Cornell Value Discovery System (CVDS) to dynamically predict growth rate, accumulated weight, days required to reach target body composition, carcass weight, and composition of individual beef cattle fed in group pens. Observed BW, ADG, BW at 28% empty body fat (EBF), breed type, environmental conditions, and dietary ME concentration are used by the CVDS to predict, for each animal in a pen, the feed DM required for maintenance (FFM), the feed DM required for gain, and the total DM required for maintenance and gain (DMR). The CVDS then computes DMR-to-ADG ratio (DMR:ADG), which is a feed conversion measure, and ADG-to-DMR ratio (ADG:DMR), which is a feed efficiency measure, for each animal. This study used the observed F:G ratio of 362 individually fed steers to evaluate CVDS-predicted indicators of feed efficiency and the Kleiber ratio. A subset of 37 data points was used to evaluate residual feed intake (RFI) as an indicator of feed efficiency. The database included 4 published studies, each with detailed individual animal description, environment, diet, and body composition information. The CVDS-predicted DMR:ADG accounted for 84% of the variation in the actual F:G ratio with a mean bias of 1.94% (P = 0.20). The predicted FFM to actual DMI ratio had a high correlation with actual ADG (R² = 0.76), and indicated a decay-type nonlinear dilution of FFM as ADG increased. The CVDS-predicted ADG:DMR and the Kleiber ratio had a significant (R² = 0.88) logarithmic relationship. In an analysis of a contemporary group within the database, RFI was highly correlated with the F:G ratio (r = 0.71). There was a positive relationship between RFI and EBF. The RFI_M (DMI – DMR) was moderately correlated with DMI and ADG (0.37 and –0.38; respectively), suggesting that selecting for low RFI_M would decrease DMI and increase ADG in this database. We conclude that the CVDS model can be used to identify differences in the F:G and G:F ratios by predicting DMR for individual growing cattle fed in groups.

Key Words: cattle • feed efficiency • growth • modeling • selection

This article has been cited by other articles:

				S. S. Moore, F. D. Mujibi, and E. L. Sherman Molecular basis for residual feed intake in beef cattle J Anim Sci, April 1, 2009; 87(14_suppl): E41 - E47. [Abstract] [Full Text] [PDF]

				M. J. Baker, L. O. Tedeschi, D. G. Fox, W. R. Henning, and D. J. Ketchen Using ultrasound measurements to predict body composition of yearling bulls J Anim Sci, October 1, 2006; 84(10): 2666 - 2672. [Abstract] [Full Text] [PDF]