Diet Effects on Feed Efficiency

Iowa State researchers evaluates diet type effects on feed efficiency during growing and finishing phases.

by Bridget Beran, intern, Angus Media

MANHATTAN, KAN. (June 15, 2016) — Stephanie Hansen, Iowa State University, spoke to producers about the impact of different diet types at the 2016 Beef Improvement Federation Annual Meeting and Symposium hosted in Manhattan, Kan.

Hansen focused on the digestibility of different diet types, as well as the impact of growing phase feed efficiency on finishing phase growth performance and carcass characteristics of beef steers fed different diet types. The researchers evaluated six groups of steers, totaling nearly 1,000 head, during a five-year period.

The calves spent the growing phase at the University of Missouri in dirt lots where they were fed either a corn-based diet or a roughage-base diet. The steers were ranked according to residual feed intake (RFI) and grouped into upper, middle or lower one-third for each dietary type.

After the growth phase, the steers were moved to Iowa State University where they were transitioned to a corn-based or a byproduct-based finishing diet. They were blocked into pens based on their growing phase diet and RFI rank grouping (see graphic).

Hansen said location made little difference on feed efficiency; if an animal was efficient while it was in Missouri, it continued to be efficient once it reached Iowa. In other words, feed efficiency was repeatable from the growing to the finishing phase. She noted that dry-matter intake tending to drive feed efficiency in corn-grown steers, while average daily gain drove feed efficiency in roughage-grown steers.

There was a negative correlation between phases in the steers fed a grain diet during the growing phase and a roughage diet during the finishing phase.

“When cattle are grown on roughage … we are picking up more noise in the data when we shift them to a finishing-type diet,” Hansen explained. “The correlations are a lot weaker if you grew on roughage and finished on corn. I think one of the things we need to keep in mind is that whatever environment we’re testing our cattle on, that really needs to be reflective of whatever we’re selecting for.”

Research showed that more highly efficient calves tended to have bigger ribeyes, though the data on that is not perfect Hansen said. Highly feed efficient calves also tended to have the lowest marbling scores, though that may be reflective of their larger ribeyes.

Feed efficiency was found to be relatively repeatable across the different phases of feeding.

Hansen addressed how producers can relate this to their own work by saying that knowledge of how cattle consume different diets and the effects on their feed efficiency can help with breeding stock selection as well as terminal animal management. It can also help producers to improve their own efficiency and sustainability.

Editor’s Note:This summary was written under contract or by staff of Angus Media. Through an agreement with the Beef Improvement Federation, we are encouraging reprinting of the articles to those who will adhere to the reprint guidelines available on this site. Please review those guidelines or contact Shauna Rose Hermel, editor, at 816-383-5270. PowerPoints are posted with permission of the presenter and may not be reproduced in whole or in part without the express permission of the presenter.

Angus Media's coverage of the event is made possible through collaboration with BIF and sponsorship of LiveAuctions.tv. For questions about this site, or to notify us of broken links, click here. Look for additional coverage in the Angus Journal, the Angus Beef Bulletin, the Angus Journal Daily, the Angus Beef Bulletin EXTRA and Angus TV.